the planet Mars

General information about the planet Mars. Red Planet

Mars is the fourth largest terrestrial planet from the Sun. In the literature, it is often called the red planet because of the unusual color of the surface, associated with a significant distribution of iron oxide.

The planet Mars is home to the highest volcanoes in the solar system, the largest canyon, the Mariner, and the giant, flat Borealis basin in the northern hemisphere. Some areas of the planet are very similar to such areas on Earth as: the icy deserts of Antarctica and Greenland, the sandy deserts of North Africa with dunes and sandy remnants.

Until recently, the planet was considered the main contender for the role of the second cosmic body on which life could be detected. And the reasons to think so are not without common sense: air temperature comfortable for living organisms (primarily bacteria), the presence of water, including in a liquid state (although today there is thousands of times more water on Mars in the form of ice), the presence of an atmosphere and weak magnetic field. Therefore, it is not surprising that more than 20 spacecraft have visited Mars, which, it would seem, have studied it up and down. But, the planet still has a lot of mysteries. Here are just a few of them:

1) First, the most discussed and replicated in printed sources, is there life on Mars? Today, with almost complete certainty, we can say that at least there was life on the planet Mars. After all, the climate on the planet hundreds of millions of years ago was completely different than it is now. The temperature was more comfortable, the atmosphere was denser and more extended, the planet had a developed river network, there were lakes, seas and oceans. In addition, some minerals were found, the creation of which apparently did not take place without the participation of microorganisms.

2) The presence of water on Mars. Prediction of climatic conditions on Mars under which the appearance of liquid water is possible. An estimate of the total amount of water on the planet.

3) Martian meteorites. More precisely, their origin, time of origin and traces of bacteria found on the surface.

4) Satellites of Mars. question of their education. Drawing up a model for the further evolution of their lives.

All the riddles of the red planet are gradually being solved, and it is possible that soon Mars will present to the earthlings many more interesting discoveries. And about those discoveries that have already been made, you will learn from the following subsections.

Observation of the planet Mars from Earth

It got its name in honor of the Roman god of war for the blood-red bright color, especially distinct during the great confrontations that occur every 15-17 years. At this time, Mars is as close as possible to the Earth and looks like the brightest star in the night sky (-2.7 magnitude). The angular diameter of Mars during great oppositions is 25", while during aphelions it is 14".

The rest of the time, Mars is also visible to the naked eye, although for observation it is a difficult object and it is better to use any, even amateur, telescope for this purpose. The planet looks like a small star with a characteristic color, second only to the Sun, Moon, Venus and Jupiter in brightness.

When observing Mars from the Earth, one can notice that over time, the area of ​​the planet’s disk illuminated by the Sun changes: from a narrow crescent to an almost perfect circle, i.e. there is a change of the Martian phases (by analogy with the phases of the moon). Unlike the Mercury and Venusian phases, the illumination of the disk of Mars is never complete, which is typical for all outer planets (located beyond the Earth's orbit towards the boundaries of the solar system). The maximum illumination of the Martian disk corresponds to the illumination of the Moon's disk 3 days before the full moon.

With a sufficiently strong telescope on the disk of Mars, you can distinguish individual details of its surface, which can be classified as follows:

1. Bright areas, or "continents", occupying 2/3 of the disk. They are uniform light fields of orange-reddish color.

fig.2 North polar cap of Mars. Image from the Mars Global Surveyor spacecraft. Credit: NASA/JPL/MSSS

2. Polar caps - white spots that form around the poles in autumn and disappear in early summer. These are the most noticeable details. They appear as sharp increases in brightness in the ultraviolet (0.37 microns), but are not visible at all in the near infrared region (1.38 microns; here the planet still shines by reflection, and not by thermal radiation). This means that in this case we see not snow or ice on the surface, but clouds (made of fine crystals) floating in the atmosphere. The size of the crystals is so small that at a wavelength of about 1 micron they no longer scatter light. It is possible that these are crystals of ordinary H 2 O ice. At such temperatures, carbon dioxide can also condense.

A significant part of the visible polar cap is solid sediment on the surface, and this sediment is formed by frozen carbon dioxide, under which ordinary water ice lies. In the polar caps (mainly in the completely non-disappearing southern one) contains more CO 2 and H 2 O than in the atmosphere. The following very interesting suggestion has been made. Due to the precession of the polar axis of Mars, once every 50,000 years, it turns out that both polar caps disappear completely and then the pressure in the atmosphere rises, the content of H 2 O increases, and liquid appears. water.

In winter, the polar cap grows in the northern hemisphere, and almost disappears in the southern hemisphere: it is summer there. Six months later, the hemispheres change places.

However, the southern cap in winter grows up to 50 ° in latitude, and the northern one - only up to a third. In summer, the northern polar cap disappears entirely, and a small remnant of the southern polar cap remains. Why are the roles so unequally distributed? This is due to the elongation of Mars' orbit. In the southern hemisphere of the planet, winters are colder and summers are warmer. In the summer of the southern hemisphere, Mars is at the point of perihelion, and in winter - at the point of aphelion.

From the inequality of the polar caps in the winter season, scientists concluded that in the winter of the southern hemisphere, more carbon dioxide is bound in the polar cap, and the pressure in the Martian atmosphere drops. In spring, the southern cap melts, the northern one begins to grow, but leaves more carbon dioxide in the atmosphere, and its pressure increases. With the movement of Mars in orbit, the pressure of its atmosphere changes greatly.

During the melting of both the northern and southern polar caps, "warming waves" spread from the poles. It has been suggested that these waves are associated with the spread of vegetation on the surface of Mars, but more recent data have forced us to abandon this hypothesis. Through the blue filters, the polar caps stand out very contrastingly.

fig.3 Hubble Space Telescope image dated March 10, 1997, which clearly shows the continents and seas. Credit: NASA/JPL

3. Dark areas of gray-green color (or "sea"), occupy 1/3 of the disk of Mars. There are especially many seas in the southern hemisphere of Mars, in the northern hemisphere there are only two seas: the Big Syrt and the Acidalian Plain.

The seas are visible against the background of light areas in the form of spots, different in size and shape, and themselves consist of alternating dark spots and stripes associated with uneven terrain. Isolated dark areas of small size are called "lakes" or "oases". Going into the "continents", the seas form "bays".

The ratio of the brightness of the "continents" and "seas" is maximum in the red and infrared regions (up to 50% for the darkest "seas"), in yellow and green rays it is less, in the blue on the disk of Mars the "seas" do not differ at all. Both those and other details of the relief have a reddish color.

The dark regions, along with the polar caps, are involved in a cycle of periodic seasonal changes. In winter they have the least contrast. In spring, a dark fringe forms along the boundary of the polar cap, and the contrast of the dark areas around the cap increases. Darkening spreads gradually towards the equator, capturing more and more new areas.

Many details that do not differ in this hemisphere in winter become clearly visible in summer. The darkening wave is propagating at a speed of about 30 km per day. In some areas, changes are repeated regularly from year to year, in others they occur differently every spring. In addition to recurring seasonal changes, the irreversible disappearance and appearance of dark details (secular changes) has been repeatedly observed.

Light areas do not participate in the seasonal cycle, but may experience irreversible secular changes.

Initially, astronomers had 2 hypotheses about seasonal changes on the planet Mars. The first of them connected the waves of darkening with vegetation: in spring, plants enter the active phase of their development, due to an increase in temperature and humidity. The second associated darkening with a change in color with an increase in temperature or humidity of the mineral material.

At present, the explanation of seasonality in the location of dark areas sounds like this: most dark areas are hilly areas with numerous craters, heaps of stones and other irregularities that contribute to the formation and development of dust storms and tornadoes, which, carrying huge masses of dust, then "lay off" it at irregularities, thereby creating a contrast between areas of the surface devoid of dust and covered with it. Seasonal changes are thus a consequence of the impact of dust storms, the frequency of which increases significantly in summer.

4. Clouds - temporary details localized in the atmosphere. Sometimes they cover a significant part of the disk, preventing the observation of dark regions. There are two types of clouds: yellow clouds, reputedly dust clouds (there are cases when yellow clouds cover the entire disk for whole months; such phenomena are called "dust storms"); white clouds, most likely consisting of ice crystals, like terrestrial cirruses.

History of exploration of the planet Mars

The planet Mars has been known to people for a very long time. It was known to the inhabitants of Ancient Greece, Babylon and India. Moreover, among all these peoples, the planet was named after the local god of war or was associated with wars and destruction. The reason for this attitude of people to a harmless planet was its blood-red bright color when observed from Earth. So among the ancient Greeks, Mars at the time of Pythagoras was first called Phaethon ("shining, radiant"), and then at the time of Aristotle - Piroeis - the star of the Greek god of war Ares (Ἄρεως ἀστἡρ). In Babylonian astronomy, the planet was called Nergal, after the god of the underworld, war and death. In Hindu religious texts, Mars is known as the war deity Mangala (मंगल) and also as Angaraka and Bhauma in Sanskrit. The ancient Egyptians gave the planet the name of the god of heaven and royalty, Horus. The Chinese and Koreans called it 火星 or fire star. In ancient China, the appearance of Mars in the sky was a sign of "grief, war and murder."

The name Mars, familiar to modern man, was given to the planet by the ancient Romans, in honor of the god of war, identified with the Greek god Ares. Initially, Mars in Greek mythology was the god of fertility. In honor of Mars, as the god of fertility, the first month of the Roman year was named, in which the rite of expulsion of winter was performed. Today this month is known to us as March (lat. Mārtius mēnsis "Mars month").

The symbols of the god Mars were a spear and a shield. Subsequently, these attributes were stylized, combined, and today they have become the astrological symbol of the planet Mars, the alchemical symbol of iron, and the male symbol in biology.

Ancient astronomers conducted observations of the planet, recorded the course of its annual movement across the sky, i.e. made simple astronomical observations. In particular, Chinese astronomers knew the sidereal and synodic periods of Mars. But for a more complete study of the planet, more advanced optical instruments were required, which became telescopes.

The first person to see the planet Mars through a telescope was the Italian scientist Galileo Galilei. It happened in 1609.

In 1638, while viewing Mars through a telescope, the Italian astronomer Francesco Fontana made the first drawing of the planet, in which he depicted a black spot in the center of the sphere and discovered the phases of the planet.

In 1659, the dark spot was discovered by the Dutchman Christian Huygens, who, observing the movement of the spot on the planet's disk, established the period of Mars' revolution around its axis - about 24 hours. Today, scientists believe that Huygens observed the Great Sirte mountain plateau.

A year later, the Italian Jean Dominique Cassini refined Huygens' calculations regarding the period of the planet's revolution. The results of his calculations were close to the real ones - 24 hours 40 minutes.

In 1672, Christian Huygens discovered a white spot at the south pole of Mars.

Fig. 4 Telescope of William Herschel. Source: Leisure Hour. 1867

After 32 years, the French astronomer Jacques Philippe Maraldi at the Paris observatory found that the white spot in the southern hemisphere is slightly shifted relative to the south pole of the planet. And in 1719, he also made the assumption that the white spot is a polar ice cap.

Between 1777 and 1783 Mars observations were made by astronomer William Herschel. As a result, the astronomer found that: the planet's axis of rotation is inclined at an angle of 28 ° 42 "to the plane of the orbit and the seasons can change on Mars, the planet's diameter is almost 2 times smaller than the Earth's diameter, the planet's atmosphere is very rarefied, there are " two remarkable bright spots, the northern polar cap, as well as the southern one, is slightly offset relative to the pole, i.e. eccentric to him, the rotation period of Mars is 24 hours 39 minutes 21.67 seconds. As a result of a series of observations of Mars in 1781 and 1784, Herschel discovered the variability of the southern polar cap of the planet: in 1781 it was very large, in 1984 much smaller, which made it possible to conclude that the main substance of the caps is water ice.

During the observations of Mars, William Herschel made sketches of the planet, which show such details of the Martian surface as the Hourglass Sea (Great Sirte Plateau), the Sabaean Gulf and the Gulf of Meridian.

In the 19th century, observations of Mars and other space objects through telescopes became widespread: research was carried out not only by professional astronomers, but also by amateur astronomers.

So in 1809, French amateur astronomer Honore Floger was able to see dust storms on the surface of the planet, writing that "an ocher-colored veil covered the surface." In 1813, he discovered a decrease in the polar cap in the spring, concluding that the surface of Mars was heated more strongly than the surface of the Earth.

In 1830, two German astronomers Wilhelm Beer and Johann Heinrich von Medler, based on observations of Mars with a refractor telescope, compiled the first map of the planet's surface and proposed a coordinate grid that is used to this day. In addition, astronomers in 1840, with an accuracy of 1 second, measured the period of rotation of the planet around its axis, improving their own result obtained in 1837 by 12 seconds.

After 28 years, the Italian astronomer and priest Angelo Secchi took up the study of Mars. While working at the Vatican Observatory, Secchi discovered some blue features in the planet's atmosphere, which he called the "Blue Scorpio", which were most likely clouds. Some time later, similar formations were observed, along the way making sketches, also by the English astronomer J. Norman Lockyer.

In 1862, when compiling a map of Mars, the Dutch astronomer Frederick Kaiser specified the period of rotation of the planet around its axis. The value he received differed from the actual value by 0.02 seconds.

At the same time, the German astronomer Johann Zollner begins a series of observations of Mars with a personally built spectroscope and calculates the planet's albedo equal to 0.27. At the end of the 19th century, using the Zollner spectroscope, German astronomers Gustav Müller and Paul Kempf found slight variations in the change in reflectivity of Mars, which they interpreted as the presence of a smooth surface on the planet without large elevation changes.

A year after the observations of Mars by Kaiser and Zollner, Secchi creates color drawings of the planet. To designate individual elements of the surface, he uses the names of famous travelers. In 1869, he also discovered channels - linear objects associated with ravines on the surface of Mars.

2 years before the discovery of the Secchi channels, the English astronomer Richard A. Proctor, based on the drawings of his fellow countryman William R. Dawes, compiled in 1864, creates the most detailed map of the planet of his time, on which, for the first time, he uses the names of astronomers to indicate dark and light details of the surface who made a great contribution to the study of the red planet. The zero meridian chosen by Proctor on the compiled map is still used today.

In the same year, the French astronomer Pierre Jules Cesar Janssen, together with the English astronomer William Huggins, made the first attempt to study the composition of the Martian atmosphere using a spectroscope. As a result of their joint research, it was found that the optical spectrum of the planet Mars practically coincides with the spectrum of the Moon, and there is no water vapor in the planet's atmosphere. Later, their findings were confirmed by the German astronomer Hermann Vogel and the English astronomer Edward Maunder.

In 1873, the French astronomer Camille Flammarion put forward the hypothesis of the existence of "herbs and plants" on the planet to explain the reddish color of Mars. The astronomer also writes numerous writings in which he makes extensive use of Proctor's nomenclature of names.

After a short four-year break in the study of the red planet, 1877 came, one of the richest in discoveries in the history of the study of Mars.

This year, Giovanni Schiaparelli Virginio, who is the director of the Brera Observatory in Milan, is creating a new nomenclature for individual details on the surface of Mars, based on the names of mythical characters and geographic terrestrial names. In particular, they were asked to call the light areas continents, and the dark ones - seas, by analogy with the lunar nomenclature. A year later, on the basis of the developed nomenclature, Schiaparelli gives the first names to individual details of the surface and appear on the map of the planet: the seas of Aphrodite, Eritrean, Adriatic, Cimmerian; lakes of the Sun, Lunar and Phoenix, etc.

In September 1877, while Mars was at the point of perhelion, Schiaparelli found strange linear stripes on the surface, which he called "Canali". Due to a misunderstanding, a significant number of people saw in the discovery evidence of the existence of intelligent life on the planet, tk. in English, the word is translated as channels and implies their artificial origin. So the American astronomer Percival Lovell saw in the canals some semblance of Martian irrigation systems, with the help of which the Martians transport water from the polar caps to the arid equatorial regions of the vegetation strip, and the writer Herbert Wells wrote his famous novel "The War of the Worlds" in which the evil Martians invade the Earth.

In 1903, the hypothesis of the man-made origin of the canal network, as well as the existence of the canals themselves, was refuted, because. even the most powerful telescopes of the time found no trace of their existence.

The year 1877 is famous for the discovery of two satellites of Mars: Phobos and Deimos. They were discovered by the American astronomer Asaph Hall, using the 660 mm telescope of the US Naval Observatory. The astronomer observes the first satellite on August 11 as a faint object not far from the planet, and a week later he reports this discovery to the general public.

On August 30, The New York Times reported on the discovery of the third satellite of Mars, which was allegedly discovered by the Americans Henry Draper and Edward Singleton Holden. But the sensation turned out to be false.

The names of the Martian satellites were proposed by Henry Madan, a scientific instructor at Eton College in England, after the horses that carried the chariot of the Roman god Mars: Phobos - fear and Deimos - horror.

In the same year, the English astronomer David Gill, taking advantage of the favorable position of Mars in the sky (the planet was in opposition to the Earth), estimates the daily parallax of Mars and, based on these measurements, estimates the distance from the Earth to the Sun with high accuracy.

In 1879, the American astronomer Carl Augustus the Younger made precise measurements of the planet's diameter.

At the same time, Canadian and American astronomer Simon Newcomb published highly accurate tables for determining the daily position of celestial objects, which are still used today.

In 1887-91. Schiaparelli publishes several very detailed maps of Mars using the nomenclature proposed in 1877.

In 1890, the American astronomer Edward Emerson Barnard, while observing Mars, notes craters on its surface, but does not report the discovery to the public.

In 1892, Camille Flammarion published a work on the planet Mars, which collected descriptions of all its observations since 1600.

In 1894, the American astronomer Percival Lowell began the first observations of the red planet. According to the results of observations in the period from 1895 to 1908. scientists published a series of three books that provided information known at that time about the planet and the possibility of the existence of extraterrestrial life. In particular, they are told that the light areas are deserts, and the dark areas are vegetation. The melting of ice in the spring leads to the formation of numerous water streams, which, flowing towards the equator, contribute to the awakening and rapid growth of Martian plants (the so-called warming waves).

At the same time, another American astronomer, William Campbell, discovers the similarity of the spectra of Mars and the Moon, which went against the conventional theory of a similar terrestrial Martian atmosphere. As a result, Campbell concludes that the planet is not suitable for "life as we know it."

In 1895, the Russian astronomer German Ottovich Struve, based on a study of the satellites of Mars, was able to determine that the equatorial diameter of the planet is 1/190 greater than the polar one. In 1911, the astronomer refined the resulting value to 1/192. After 33 years, Struve's result was confirmed by the American meteorologist Edgar Woolard.

In 1903, in order to search for channels on Mars, the American astronomer Carl O. Lampland from the Lowell Observatory began to photograph the planet. After two years of observations, photographs were published and sent to the Harvard Observatory, in which, according to the astronomer, Martian channels are visible. On May 28, the New York Times publishes a report announcing the first photograph of the Martian canals. However, the resolving power of telescopes of that time, as well as the absence of photographs in newspapers, led many scientists to doubt the reliability of the observations. Literally in the same year, an experiment was set up by the English astronomer Edward Maunder, the results of which showed that the channels on the surface of Mars are most likely an optical illusion. The essence of the experiment was as follows: the subjects from a sufficiently large distance were shown a disk with a random set of spots, instead of which many of them saw “channels”. Experiments were also carried out with the observation of a thin wire against the background of a disk from different distances.

In 1907, the English scientist Alfred Russel Wallace published the work “Is Mars inhabited?”, In which he points out the impossibility of the existence of highly organized life on the planet due to low temperature and low atmospheric pressure, which prevents the existence of water in liquid form. In his work, Wallace also provides information that the planet's polar caps are formed not by water, but by dry ice, which also significantly reduces the chances of finding water in the Martian atmosphere.

In 1909, the absence of channels on the surface was reported by the American astronomer George Ellery Hale.

At the same time, the French astronomer Eugène M. Antoniadi publishes detailed maps of Mars based on observations during the opposition of the planet. Antoniadi's map confirmed the assumption that "the geometric network of channels is an optical illusion." In 1930, Antoniadi published the book The Planet Mars, in which he summarized all the information about the planet's topography known at that time, thus creating the most detailed map of the Martian surface that remained so before the flights of spacecraft.

In 1912, the Swedish chemist Arrhenius Svante suggests that the peculiarities of the changes in the albedo of Mars are caused by chemical reactions occurring in connection with the melting of the polar caps, but are in no way connected with the life cycles of Martian plants.

In 1920, Edison Pettit and Seth Nicholson at the Mount Wilson Observatory (USA) study the temperature of various regions of the planet. As a result of the measurements, it turned out that temperatures on Mars range from +15°C at noon at the equator to -85°C in the early morning at the poles.

In 1922, Estonian astronomer Ernest Julius Epik was able to calculate the density of meteorite craters on the surface of Mars, many years before the practical implementation of this task by spacecraft.

In 1925, the American astrophysicist Donald Menzel, based on a study of photographs of the red planet taken at different wavelengths of light, estimated the pressure of the Martian atmosphere to be 66 millibars.

The following year, American astronomer Walter Sidney Adams makes spectroscopic measurements of the Martian atmosphere. It turns out that the atmosphere of the planet is extremely dry, and the percentage of oxygen does not exceed 1%. However, the scientist does not exclude that even in such difficult conditions primitive species of living beings can exist.

In 1927, American scientists William Koblenz and Carl Otto Lampland took up the study of the temperature of the Martian atmosphere. It turned out that the temperature on the planet experiences significant daily fluctuations, reaching hundreds of degrees, but the temperature of the clouds is almost constant at -30°C. The results obtained indicated a small thickness of the Martian atmosphere.

In 1929, the French astronomer Bernard Lyot, using a polarimeter, set the surface pressure of the Martian atmosphere to be less than or equal to 24 mbar, and from this calculated the thickness of the entire atmosphere, which turned out to be 15 times thinner than Earth's.

In 1947, Dutch-American astronomer Gerard Kuiper discovered carbon dioxide in the atmosphere of Mars. However, due to an error in the calculations, the scientist incorrectly estimated the pressure of the Martian atmosphere and made the erroneous conclusion that the planet's ice caps cannot consist of frozen carbon dioxide. For two decades, water vapor and carbon dioxide were the only known gases that made up the Martian atmosphere, and both gases were not considered to be its main components.

On August 20, 1956, a global dust storm began on Mars, which many astronomers could observe. By mid-September, the storm had engulfed the entire planet.

In 1963, the American astronomer Hiron Spinrad, together with his collaborators, carried out spectroscopic measurements of the atmosphere of Mars, which confirmed its extreme dryness.

In 1964, the American scientist Lewis Kaplan, based on Spinrad's analysis, determined the pressure of carbon dioxide in the Martian atmosphere to be 4 mbar.

By the 60-70s of the XX century, astronomers already knew how the planet Mars revolves around the Sun and around its axis, they knew its mass, diameter and average density. The foundations of areography were laid and detailed maps of the planet were drawn up. But as before, astronomers did not know anything about the surface of Mars (except for the large details that were mentioned above), they did not know the exact composition of its rocks and the composition of the atmosphere. That is why numerous hypotheses appeared, which in their own way interpreted the unresolved Martian issues, of which there were more and more every year.

Fig.6 Spacecraft "Mars-1". Credit: NSSDC

These hypotheses could be confirmed or refuted only by launching a spacecraft to Mars, which was done in early November 1962 by the Soviet Union. Initially, the plans for the Mars-1 mission included: collecting data on cosmic radiation, studying micrometeorites, the magnetic field of Mars, the Martian atmosphere, the radiation situation around the planet, and searching for organic compounds. However, due to depressurization and subsequent gas leakage from one of the cylinders intended for the attitude control system engines, communication with it was interrupted even before the spacecraft approached Mars. It happened on March 21, 1963 at a distance of 106,760,000 km from the Earth.

During stable operation with the device, 61 radio communication sessions were conducted at intervals, first of 2, and then of 5 days. Data were collected on the distribution of meteorite matter from the Taurid stream (at altitudes of 6-40 thousand km) and similar data at a distance of 20-40 million km, cosmic radiation, the magnetic field of the Earth and interplanetary space were studied (the magnetic field of interplanetary space had a strength of 3 -4 scales with peaks in 6-9 scales).

On June 19, 1963, the launched Mars-1 (Sputnik-23) passed at a distance of 197 thousand kilometers from the red planet, after which it entered the heliocentric orbit.

Fig.7 Marsnik 1. Credit: NSSDC

It should be noted that the apparatus "Mars-1" was the fourth in a row, designed to study the planet Mars. In 1958-60. in the USSR, a series of spacecraft 1M was designed. The series included 2 devices: "Mars 1960A" (Marsnik 1) and "Mars 1960B" (Marsnik 2). The name Marsnik was assigned to them in the United States by combining the English words "Mars" and "sputnik".

AMS were designed to study the atmosphere, ionosphere, magnetosphere of Mars, interplanetary space between the orbits of the planet and the Earth. It was supposed to photograph the red planet. For these purposes, a magnetometer, a radiometer, a cosmic ray counter, a micrometeorite detector and other devices were installed on board the vehicles, which were identical to each other. The photo and television camera was installed inside the protective module and allowed taking pictures through special windows after turning on the light sensor.

Unfortunately, the 1M program failed: both devices burned up in the earth's atmosphere after a few minutes of flight. "Mars 1960A" burned down after giving the command to self-destruct at 324 seconds of flight. Four days later, on October 14, 1961, Mars 1960B burns up in the atmosphere. In both cases, the accident was caused by the shutdown of the engines of the third stage of the rocket, caused, in the case of Mars 1960A, by the failure of the control system, and in the case of Mars 1960B, by leakage of liquid oxygen and subsequent freezing of the fuel.

After the 1M program in the USSR, work began on the creation of spacecraft of the 2MB series. 6 devices were built: 3 were intended for the study of Venus, 3 - for the study of Mars. Among the latter was the first successfully launched Mars-1. The remaining vehicles intended for the study of Mars: Sputnik-22 and Sputnik-24, as a result of accidents in near-Earth orbit, did not complete their mission.

Mars 1 was the first spacecraft to fly past Mars. The very first device that received photographs of the Martian surface was the American Mariner-4, launched almost two years later - on November 28, 1964 using the Atlas rocket. The main task of the apparatus was a thorough study of Mars. Less important: the study of interstellar space and the accumulation of experience in interplanetary flights for subsequent spacecraft.

On July 15, 1965, the spacecraft passed at a distance of 10,000 kilometers from the planet's surface, taking several dozen images that covered about 1% of the Martian surface area. Based on the images, scientists concluded that the surfaces of Mars and the Moon are similar, which was later refuted by the results of the research of the planet by Mariner 6 and Mariner 7. Also, using the equipment installed on the device, data were obtained on the density and composition of the atmosphere, the results of which showed that the atmosphere of Mars consists mainly of carbon dioxide and is a hundred times inferior in density to the earth, ranging from 4.1 to 7.0 Mb. No magnetic field has been found around the red planet.

After visiting Mars, Mariner 4 continued to work in near-solar orbit, transmitting solar wind data to Earth using a solar plasma detector, an ionization chamber, and a Geiger-Muller counter. On December 21, 1967, communication with the apparatus ceased.

The Mariner 4 spacecraft was the second in a series of NASA's Mariner spacecraft designed to explore Mars. The first apparatus - "Mariner-3", launched on November 5, 1964, did not fulfill its mission. The failures began on Earth, when during the launch the fairing of the launch vehicle was not dropped. As a result, Mariner-3's solar panels did not turn around and the device failed. It is currently in solar orbit.

The Mariner 3 mission was successfully completed by the identical Mariner 4.

At the same time, the flight of the Zond 2 spacecraft, launched on November 30, 1964 and designed to test the operation of systems in outer space and scientific research, ended unsuccessfully in the Soviet Union. On December 8-18 of the same year, the ship's engines were tested and everything seemed to go according to plan. But at the beginning of May 1965, communication with the device was interrupted, and on August 6 it passed at a minimum speed at a distance of 1500 km from the surface of the planet.

Following the "Mariner-4", in 1969, the NASA spacecraft "Mariner-6" and "Mariner-7" flew to Mars with a difference of one month. Mariner 6 was launched on February 25 from Launch Pad 36B at Cape Kennedy. On March 27, Mariner 7 followed him to study the red planet.

On July 29 of the same year, at Mariner-6, 50 hours before the closest approach to the planet, all scientific instruments were turned on, and after another 2 hours, photography of Mars began. Within 41 hours, 50 images were obtained, including one fractional. On July 31 at 5:30 a.m., the stage of studying the planet at close range began (minimum - 3431 km). During the operation of the apparatus at this stage of the mission, 26 images were taken, which disproved the similarity of the Martian surface with the moon. Over the next few days, data on the composition of the Martian atmosphere, temperature and pressure measurements were transmitted to Earth using the instruments installed on board. Then the device went on a heliocentric orbit, photographing stars along the way, conducting ultraviolet scanning of the Milky Way and studying the possibility of functioning of the engineering systems located on board.

Mariner 7 approached Mars on August 5, approaching the planet at 5:49 a.m. at a minimum distance of 3,430 km. During the stay near Mars, 33 high-resolution images were taken. Then "Mariner-7" studies of "Mariner-6" were repeated, i.e. photographing stars and studying different regions of our galaxy using UV scanning.

In total, during the operation of the vehicles near Mars, they obtained about 200 images: 76 by Mariner-6 and 126 by Mariner-7. In addition, 1177 images were obtained, representing 1/7 of the full image with resolutions both less and more than the full image. They covered 20% of the surface of Mars. Data were obtained on the composition of the Martian atmosphere, its pressure, which, in principle, coincided with the results obtained by Mariner-4. Studies of the polar cap at the south pole of the planet found out its composition from frozen carbon dioxide.

In the same 1969, with a week difference, the Soviet Union launched the spacecraft of the M-69 series "Mars-1969A" and "Mars-1969B". As a result of launch vehicle accidents, both ships were not able to go beyond the Earth: "Mars-1969A" as a result of failure of the main engine at 438.66 seconds, exploded and fell in the Altai mountains, "Mars-1969B" as a result of failure, first one, and then 5 other booster rockets, exploded already at 41 seconds after launch, reaching a height of 3 kilometers.

The scientific equipment of each of the devices consisted of 3 television cameras, a radiometer, a water vapor detector and several spectrometers for studying the solar wind, hydrogen and helium ions. The cameras could broadcast color television, as well as take photographs with a size of 1024 by 1024 pixels and a maximum resolution of up to 200 meters. The number of pictures stored on one camera could be 160.

It can be seen that the quality of the scientific equipment supplied to each of the vehicles was very high, and if it were not for the unfortunate accidents at the very start, high-quality video and photographic images of the Martian surface and new information about the planet’s atmosphere would have been transmitted to Earth.

fig.10 "Mars-2". Credit: NSSDC

In May 1971, 5 spacecraft were launched at once: Mariner-8, Kosmos-419, Mars-2, Mars-3 and Mariner-9. The first 2 devices suffered accidents at the start: Mariner-8 fell into the Atlantic Ocean 560 kilometers north of Puerto Rico after a launch vehicle accident, Kosmos-419 was successfully launched into low orbit, but due to an ignition timer error that included the upper stage, after 2 days the device left the orbit and burned up in the earth's atmosphere. The rest of the devices successfully flew to Mars and made numerous pictures of the surface.

The first to launch from Earth were the Soviet AMS Mars-2 and Mars-3. It happened on May 19 and 28, 1971. The flight to the planet Mars took the stations six months, during which more than 300 radio sessions were conducted with them. At a distance of 20 million km. Earth's magnetic plume was discovered from the Earth. As the vehicles moved further away from the Sun, a decrease in the electron concentration began to be recorded.

On November 27, 1971, the descent vehicle was undocked from the Mars-2 orbital compartment. As a result of a software error in the system, incorrect data on the calculated trajectory of movement were transmitted to the descent compartment just before the compartment, as a result of which the compartment entered the atmosphere at a greater angle than planned. Despite the fact that after 15 minutes the solid-propellant propulsion system worked, straightening the descent module, it was not possible to save the situation and the device crashed.

Unlike the Mars-2 descent vehicle, on December 2, 1971, the Mars-3 descent vehicle landed safely on the surface of the planet, from where it recorded the panorama of the Martian surface for 14.5 seconds. Then the signal disappeared. The same situation was repeated with the second telephotometer installed on board. After careful study of two unfortunate incidents, a hypothesis was put forward about the reason for the shutdown of the broadcast - a corona discharge in the transmitter antennas.

The Soviet stations "Mars-2" and "Mars-3" themselves were soon transferred into orbit around the planet, becoming its first artificial satellites of Mars. The satellites, using an infrared radiometer, measured the temperature of the surface layer and, simultaneously, the temperature of the soil at a depth of several tens of centimeters with a radio telescope; the brightness at different wavelengths, atmospheric pressure and heights by the intensity of CO 2 bands, the content of H 2 O in the atmosphere, the magnetic field, the composition and temperature of the upper atmosphere, the electron concentration in the ionosphere, and the behavior of interplanetary matter in the vicinity of Mars were measured.

It turned out that the temperature of the northern polar cap of Mars is below -110 ° C, while at the equator the temperature during the day can rise up to 13 degrees above zero; the surface pressure of the Martian atmosphere is from 5.5 to 6 Mb; the content of water vapor in the atmosphere is 5000 times lower than on Earth. The ionosphere was detected at altitudes of 80-110 km. 60 detailed images of the planet were transferred to Earth, which later made it possible to create relief maps, detect atmospheric glow at altitudes of 200 kilometers and reveal its layered structure.

In total, the stations worked in orbit for 8 months, during which Mars-2 made 362 revolutions around the planet, and Mars-3 - 20. On August 22, 1972, the mission of the vehicles was completed.

fig.11 "Mariner-9". Credit: NASA/JPL

The American apparatus "Mariner-9" was launched on May 30, 1971 and, like the Soviet "Mars", was transferred into orbit on November 14 of the same year, becoming the first artificial satellite of the red planet.

The height of the periapsis of the Mariner-9 orbit was initially 1398 km above the surface of the planet, the orbital period was 12 hours 34 minutes. Two days later, the periapsis was down 11 km and the orbital period was less than 12 hours. On December 30, after correcting the parameters of the spacecraft's orbit, the height of the periapsis rose to 1650 km, and the orbital time decreased and became 11 hours 59 minutes 28 seconds, i.e. became synchronized with the 64-meter DSN antenna in Goldstone (California, USA) to transmit data obtained during the study of the planet Mars.

Immediately after entering the Martian orbit, observations of the planet were postponed due to a dust storm raging over a large area. The storm began on September 22, 1971, even before the ship approached Mars, and soon covered the entire planet. In November-December, the storm calmed down and Mariner 9 began to carry out its work.

The main goals of the device were: compiling a global map of the Martian surface, studying the atmosphere, searching for volcanic foci, measuring gravity. And all these goals were achieved. So, to map Mars, 7329 photographs were obtained with a resolution of up to 100 meters per pixel, which covered 80% of the planet's surface. It is thanks to these images that scientists were able to see the greatest volcanoes in the solar system, the grandiose canyon system, later named after the spaceship, numerous valleys resembling the channels of earthly rivers, to examine in detail the polar caps of the planet and the moons of Mars. Studies of meteorite craters were carried out, the results of which established the existence of water ice in the near-surface layer and the participation in the formation of the shape of craters by water and wind erosion. Mariner-9 also recorded such phenomena that are familiar to an earthly observer, such as weather fronts and fog, which have a similar origin to earthly counterparts.

On October 27, 1972, after turning off the engines of the vehicle, the Mariner 9 mission was completed. The device was left in orbit for at least 50 years, after which it will burn up in the Martian atmosphere.

Fig. 12 Mars-4 orbital station. Credit: NSSDC

In 1973, for the first time, 4 Mars stations simultaneously flew along an interplanetary route.

The first to go to Mars was the AMS "Mars-4" - on July 21, 1973, whose tasks included: providing communication with the landing modules "Mars-6" and "Mars-7"; photographic survey of the planet's surface, which allows obtaining images with a resolution of up to 100 meters, incl. panoramic; search for hydrogen in the upper atmosphere of Mars; measurement of the planet's magnetic field. With the help of four photometers installed on board, it was planned to determine the content of carbon dioxide, water and ozone. On the way to the end point of its route, Mars-4 had to collect data on the distribution and intensity of solar wind streams and study solar radio emission.

On February 10, 1974, the device approached Mars, but due to an error on the on-board computer, the braking systems did not work, as a result of which Mars-4 flew past the planet at a distance of 2200 km. Having managed to take just one photograph and detect the nighttime ionosphere of Mars, Mars-4 completely failed its mission. Now the device revolves around the sun

Four days after the launch of Mars-4 from the Baikonur cosmodrome, the Mars-5 apparatus, similar in design and pursued goals, was launched. Unlike its predecessor, this device was successfully launched into orbit on February 12, 1974, but almost immediately a depressurization of the instrument compartment in the orbital block, which was responsible for the operation of service systems and scientific equipment, was discovered. Calculations showed that in this state, "Mars-5" will be able to work for no more than 3 weeks. In practice, the device worked for 16 days - until February 28, 1974. During this time, "Mars-5" made 22 revolutions around the planet in an elliptical orbit with the following parameters: periapsis height 1755 km, apocenter height 32555 km, full revolution 24 hours 53 minutes, orbit inclination to the plane of the Martian equator 35.5 °.

During its operation in orbit, the device took 108 photographs of the planet (instead of the planned 960), of which only 43 images were of normal quality: 15 of them were taken by the short-focus Vega-3MSA, 28 by the long-focus Zufar-2CA. Surface temperature measurements were also taken, as a result of which it turned out that the maximum temperature in the afternoon at the equator is 272K, and at night it drops to 200K. The Martian pressure measured by previous spacecraft has been refined. The new value is 6.7 mbar.

With the help of photometers, the presence of water vapor and ozone in the atmosphere of Mars was detected, the measured concentration of which turned out to be thousands of times lower than in the Earth's atmosphere. The temperature of the exosphere was measured, which turned out to be 295-355 K.

"Mars-5" confirmed the data of the "Mars-2" and "Mars-3" devices about the existence of a weak magnetic field near the planet, the strength of which is only 0.0003 of the earth's. He also improved the results of Mars-4 by measuring the electron density of the ionosphere - 4600 per cm3.

Fig. 13 Station "Mars-6". Credit: NSSDC

In addition to the vehicles designed to study the planet Mars from orbit, the four Mars vehicles included 2 stations that carried landing modules on board, designed to study various parameters of the red planet directly from its surface. The first of a bunch of such devices was launched "Mars-6" - August 5, 1973.

The carrier module of Mars-6 arrived at the planet on March 12, 1974. At a distance of 48 thousand km from the surface of Mars, the descent vehicle was separated from the carrier module, which entered the Martian atmosphere at a speed of 5.6 km/s at 09:55:53. After 2 minutes 39 seconds, the parachute opened and the descent vehicle began to transmit information about the temperature, density, pressure and composition of the Martian atmosphere using the accelerometer, mass spectrometer, sensors for measuring density, pressure, temperature, wind strength and direction installed on board. Based on the measurements, data were obtained on the structure of the troposphere of Mars, and a decrease in the ambient air temperature in the direction from the stratosphere to the surface was established. It was also suggested that there was a high content of argon in the atmosphere, which was subsequently refuted by later studies. Most of the data received was never read due to a computer error.

At 9 hours 11 minutes 5 seconds, at the moment the brake engines were activated, communication with the descent module was interrupted.

The carrier module "Mars-6" flew past the planet at a distance of 1600 km, also not fully completing its tasks, including: searching for hydrogen in the atmosphere, measuring the magnetic field strength, studying the features of the interaction of the solar wind with Mars.

The second of the bunch was launched "Mars-7". It happened on August 16, 1973. After 7 months - on March 9, 1974, the device approached Mars, but due to a system error, the separation of the descent module occurred 4 hours ahead of schedule and the module flew past the planet. The carrier module conducted a number of studies of cosmic radiation and micrometeorites on the way to the planet.

In general, only two of the four Mars vehicles completed their mission: Mars-6 landed on the surface in the southern hemisphere, and during the descent in the atmosphere for the first time made direct measurements of its composition, temperature and pressure, and Mars-5 ”was an artificial satellite of the planet for two weeks. "Mars-4" and "Mars-7" conducted research on the planet and interplanetary space on flyby trajectories, and both did not complete their program in full.

Fig. 14 Automatic station "Viking-1". Credit: NSSDC

Fig. 15 Viking-1 landing block. Credit: NSSDC

In 1975, two American automatic orbital landing stations Viking-1 and Viking-2 were launched from Cape Canaveral (Florida, USA), the landing blocks of which reached Mars in 1976 and for the first time transmitted a photo-television image of its surface. The Viking 1 lander made a soft landing on the Chris Plain on July 20, and the Viking 2 landed on the Utopia Plain a month and a half later, on September 3.

With the help of equipment installed on the descent modules of the Vikings - mass spectrometers, infrared spectrometers and radiometers, the following were carried out: direct measurements of the chemical composition of the atmosphere, which showed that it consists of 95% CO 2 ; registration of water vapor in the atmosphere and temperature measurements, which showed its significant fluctuations during the day.

At the landing sites, unique experiments were carried out in order to detect signs of life in the Martian soil. A special device captured a soil sample and placed it in one of the containers containing a supply of water or nutrients. Since any living organisms change their habitat, the instruments had to record this. Although some changes in the environment in a tightly closed container were observed, the presence of a strong oxidizing agent in the soil could lead to the same results. This is why scientists have not been able to confidently attribute these changes to bacteria.

In total, the Viking-1 landing block (since January 1982 renamed in memory of the head of the team for photographing the surface of Mars into the Thomas Match Memorial Station) worked on the surface of the planet for 6 years and 116 days - until November 11, 1982. The Viking-2 block completed its work much earlier - on April 11, 1980 ...

After the separation of the landing blocks, the stations were launched into orbits of artificial satellites of the planet Mars. As a result of their work, detailed photographs of the surface of Mars and its satellites were made (Viking-1 photographed Phobos, Viking-2 photographed Deimos), as well as detailed maps of the planet's surface, geological, thermal and other special maps. As a result of the analysis of the obtained maps, a difference was revealed in the structure of the Martian hemispheres: if the northern one is characterized by extensive lava plains, then the southern one is characterized by volcanic plateaus and highlands.

The Viking-1 orbital module worked until August 7, 1980, having completed more than 1400 revolutions around the planet. The Viking-2 orbital module worked in orbit until July 25, 1978, having completed 706 revolutions. The Viking mission is still the most successful and informative.

Fig. 17 The Soviet device "Phobos-1". Credit: NSSDC

In 1988, 13 years after the flights of the Vikings, the Soviet Phobos-1 and Phobos-2 headed for Mars, whose task was to explore Mars and its satellite Phobos. But, as a result of an incorrect command from the Earth, one of the devices, Phobos-1, lost its orientation a month after the launch. Communication with him could not be restored.

Another device - "Phobos-2" still managed to reach the target, and in January 1989 he entered the orbit of an artificial satellite of Mars. Remote methods have been used to obtain data on temperature changes on the planet's surface and new information about the properties of the rocks that make up the Martian satellite Phobos. 38 images with a resolution of up to 40 m were transmitted to Earth, and the surface temperature of Phobos was measured, which is 30°C at the hottest points. In addition to studying Phobos, the device studied the characteristics of the magnetic field of the red planet itself and its interaction with the solar wind. Based on these studies, in particular, measurements of the oxygen ion fluxes leaving the planet, the rate of erosion of the Martian atmosphere under the influence of solar plasma flows was estimated.

On March 27, 1989, due to a failure in the control system, communication with the vehicle was lost and the main mission, which consisted in delivering two descent modules to the surface of the satellite of Mars, could not be completed.

Following the Soviet research ships, the American Mars-Observer, launched on September 25, 1992, failed. Communication with it was lost on August 22, 1993, a few days before the orbit of the artificial satellite of Mars. A post-accident investigation revealed that the accident was caused by pipeline damage resulting from the mixing and subsequent reaction of nitrogen tetroxide and monomethylhydrazine in the titanium piping of the pressurization system during helium pressurization of the fuel tanks. As a result, electrical circuits were broken in the device.

It was also not possible to put the Russian Mars-96 station on a flight path to Mars, which collapsed five hours after launch due to the failure of the fourth stage of the launch vehicle. As a result, the station entered the upper layers of the earth's atmosphere and burned down.

The Mars 96 mission was the most ambitious at the time. On board the station were two small landing stations designed to study the surface of the planet, in particular photographing, measuring temperature, pressure and humidity of the atmosphere, studying the radiation situation, and two penetrators, with the help of which it was supposed to study the Martian soil in many ways: its physical properties, mechanical characteristics , elemental composition, etc.

Fig. 18 Mars Pathfinder lander. Credit: NASA/JPL

The streak of failures ended in July 1997, when the Mars Pathfinder delivered the first robotic rover to the planet, which successfully probed the surface chemistry and meteorological conditions on Mars.

Fig. 19 Mars rover Sojourner. Credit: NSSDC

The launch of the Delta-2 launch vehicle, with which the Mars Pathfinder went into space, was carried out on December 4, 1996 from Cape Canaveral. 7 months later, on July 4, 1997, the apparatus entered the Martian atmosphere at a speed of about 7.5 km / s without making a single revolution in orbit. From overheating during braking in the atmosphere, the device was protected by a special heat-insulating protection.

Shortly after entering the Martian atmosphere, the spacecraft's velocity dropped to 400 m/s. After 160 seconds, a 12.5-meter parachute was deployed, reducing the speed to 70 m / s. 10 seconds before landing at an altitude of 1.6 km 4 inflated airbags turned the device into a giant, about 5 meters in diameter, inflatable ball. After another 4 seconds, at a height of 98 meters above the surface, 3 rocket engines fired, slowing the fall speed to less than 20 m / s. Upon impact with the surface of Mars, the ball bounced 40 meters, continuing to bounce another 15 times, until it finally stopped a kilometer from the original descent site.

After landing, the airbags descended, and after another 87 minutes, 3 solar panels of the lander opened. The main task of the Mars Pathfinder lander was to provide communication with the Sojourner rover and transfer images and data made using the rover to Earth. In addition, the module was equipped with a camera with two optical inputs for obtaining stereo images, sensors for measuring wind speed and direction, atmospheric pressure, temperature, as well as a data storage system with a capacity of 62.5 thousand KB. After landing, Mars Pathfinder was renamed the Carl Sagan Memorial Station, an American astronomer and science popularizer.

The Sojourner rover did not leave the lander until July 5, due to a failure of the long-range communication network on the lander and communication problems between the module and the rover. And on July 6, Sojourner began his program to study the chemical composition and physical parameters of Martian rocks. In total, during the operation, the rover conducted 15 chemical analyzes of rocks and soil.

fig.20 Panorama of Mars taken by the Mars Pathfinder lander. Credit: NASA/JPL

The Mars Pathfinder mission ended on September 27, 1997. During this time, the lander and the rover collected over 270 MB of information, including 16.5 thousand images from the lander and 550 images from the rover, conducted a study of the environment, on the basis of which it was possible to establish that in the distant past the climate on the planet Mars was warm and humid.

Fig. 21 NASA Mars Global Surveyor Station. Credit: NASA/JPL-Caltech

A month before the launch of the Mars Pathfinder, the BIS (unmanned research station) Mars Global Surveyor was launched from Cape Canaveral, which reached the red planet 300 days after the launch - on September 11, 1997. After approaching Mars, the device carried out orbital maneuvers for 4 months to enter a circular polar orbit. However, maneuvering attempts were thwarted by problems with one of the solar panels. A new stage of entering the orbit continued until April 1998, as a result of which it was possible to put the device into orbit with a periapsis height of 171 km. After another 5 months, maneuvers in near-Martian orbit continued and, finally, in February 1998, the Mars Global Surveyor was launched into a circular polar orbit with a height of 378 km.

In March of the same year, the device began filming the surface of the planet, on the basis of which the March map was subsequently compiled, as well as studying the Martian magnetic field, atmosphere and weather conditions. The main Mars Global Surveyor mission lasted exactly one Martian year, or 687 Earth days. But, due to the fact that the apparatus remained operational even after the expiration of this period, it was decided to extend the mission until April 2002, and after that for an indefinite time, as a result of which the Mars Global Surveyor transmitted information from orbit until November 5, 2006 of the year. According to scientists, the orbital module is still rotating in orbit, but due to the incorrect position of one of the solar panels, the signal from the device is too weak and is not recorded on Earth.

The Mars Global Surveyor is one of the most successful Martian missions to date. The device is the first to shoot spacecraft in orbit of another planet. The Mars Odyssey and Mars Express images were taken in April 2005. A year earlier, the Mars Global Surveyor photographed the Spirit rover on the surface of Mars.

Fig. 22 Japanese station "Nozomi". Copyright: 1998 ISAS. Create by Yasushi YOSHIDA

On July 4, 1998, the Japanese AMS Nozomi set off for the planet Mars. The tasks of the station included: studying the upper layers of the Martian atmosphere and its interaction with the solar wind, building the structure of the magnetic field of Mars, measuring the structure, composition and dynamics of the ionosphere, as well as photographing the surface. Ambitious plans that were not destined to come true. The fact is that a very difficult path was chosen to launch the device into orbit around Mars: first, Nozomi had to fly around the Moon twice, then return to Earth again to receive an accelerating impulse, and only then start moving towards the planet. The problems began already on December 20, when, during acceleration near the Earth, the station entered a near-solar orbit. Japanese scientists managed to bring the station to a new trajectory, but on April 21, 2002, during a solar flare, the power distribution system was disabled. Despite the difficulties, Nozomi managed to carry out 2 gravitational maneuvers in the vicinity of the Earth and will finally go to Mars. But due to difficulties in the power distribution system, the hydrazine rocket fuel in the remote control tanks froze and on December 9, 2003, the device passed a thousand kilometers above the surface of Mars, without completing its mission. Today, Nozomi orbits in a heliocentric orbit with a period of about 2 years.

In late 1998 (December 11), the first of two NASA Mars Surveyor 98 spacecraft called the Mars Climate Orbiter set off from Cape Canaveral to Mars. The device was intended to study from the orbit of the planet the atmosphere of Mars, weather conditions, changes on the surface as a result of wind activity, and to collect evidence of climate change on Mars in the past. The Mars Climate Orbiter was supposed to be used to relay signals from the second apparatus of the Mars Polar Lander program and other future NASA vehicles and descent vehicles of international missions.

Fig. 23 Mars Climate Orbiter. Credit: NASA/JPL

On September 23, 1999, the device approached Mars, but it failed to enter the planned orbit: at 9 hours 37 minutes, when the Mars Climate Orbiter lost contact with it. According to the findings of the commission to investigate the causes of the incident, incorrect commands from the Earth led to the loss of the device, which led to its launch into a much lower orbit than planned (an orbit with a height of 57 km instead of the prescribed 150). As a result, the Mars Climate Orbiter burned up in the lower layers of the Martian atmosphere.

Mars Polar Lander - the second of the vehicles of the Mars Surveyor 98 program went to the planet on January 3, 1999. After 11 months of flight, the device approached Mars without any problems. At 7:45 AM ET (-5 hours off UTC), a half-hour final engine overhaul began. 7 hours later, Mars Polar Lander made the last contact before descending to the surface of the planet. What happened to him next is unknown.

Mars Polar Lander was intended to: study the climate near the south polar cap of Mars, analyze ice and its ability to replenish the Martian atmosphere with water and carbon dioxide, study soil samples for the presence of ice, photograph seasonal changes on the planet. In addition, the device carried 2 Deep Space 2 penetrators, named after the polar explorers Amundsen and Scott. The penetrators were unguided probes, which, before entering the atmosphere, are separated from the main apparatus and, deepening at speed into the ground, transmit data on its composition. Deep Space 2 penetrators were also designed to search for water ice, measure atmospheric pressure and temperature.

Fig. 25 The Mars Odyssey orbiter. Credit: NASA/JPL-Caltech

On April 7, 2001, a Delta-2 launch vehicle carrying NASA's Mars Odyssey orbiter was launched from Cape Canaveral. The device was intended to study the climatic features of Mars, analyze the planet's surface from orbit, the surrounding radiation situation and its danger for subsequent manned missions. Also, within 5 years it was planned to use Mars Odyssey as a repeater for transmitting information from future ground modules.

After 7 months - on October 24, "Mars Odyssey" arrived in near-Martian orbit. Over the next few months, until January 11, 2002, using a series of aerodynamic maneuvers, the device was launched into an orbit with a periapsis height of 201 km, which, as a result of adjustments, was raised to a constant 400 km on January 30 and became polar. Initially, the mission of the device after entering the final orbit was supposed to last 917 days - until July 2004, but then it was extended for another Martian year, until September 2006. Today, Mars Odyssey is used to transmit information from the Spirit and Opportunity rovers that landed on the planet in late 2004.

During the work of the apparatus, data were collected indicating the presence of large reserves of water under the surface of Mars. In some places, the proportion of water ice in the total composition of the rock reached 70%.

In addition, using the THEMIS instrument, surveys of the surface of Mars were carried out in the visible and infrared parts of the spectrum, on the basis of which the most accurate map of the planet's surface with a resolution of 100 meters was built to date.

Fig. 26 The Mars-Express orbiter and the Beagle-2 lander. Credit: Illustration by Medialab, ESA 2001

2 years after the launch of Mars Odyssey from the Baikonur Cosmodrome (Kazakhstan), the European Space Agency launched the Mars Express vehicle carrying the Beagle-2 landing module on board. Launched on June 2, 2003.

Mars Express was designed to photograph the surface of Mars using the HRSC high-resolution camera, to compile global mineralogical and geological maps using the OMEGA spectroscope, to study the composition and structure of the Martian atmosphere, and the interaction of the atmosphere with surface rocks and the interplanetary medium. The main tasks of the landing module were: the study of geological and climatic features at the landing site, surface layers, as well as the search for possible traces of life.

Mars Express arrived in December 2003. On December 19, six days before entering orbit, the Beagle-2 landing module disconnected from the main apparatus, which, after 6 days (intended to search for a possible landing site), was supposed to enter the Martian atmosphere and soon land on the surface of the planet. However, at the appointed time, "Beagle-2" did not get in touch. February 6, 2004 Beagle 2 was declared lost. According to scientists, the landing of the module occurred in the normal mode and it was practically not damaged, which was clearly visible in the pictures taken from the Mars Global Surveyor orbiter in 2005. Failure to communicate due to failure of communication equipment.

Mars-Express Orbital Module On December 25, 2003, the ball was launched into an elliptical orbit with the following parameters: periapsis altitude 250 km, apoapsis altitude 150,000 km, inclination angle 25 degrees. At the end of January of the following year, the device was transferred to a polar orbit, the height of which can change to maintain stable operation of the solar panels. The initial operating time of Mars Express in orbit was to be 1 Martian year, but subsequently the operating time was extended 3 times and today, in addition to performing its main tasks, the device is used as a transmitter of information from the Spirit and Opportunity rovers, and earlier from the landing the Phoenix module, to Earth.

So far, Mars Express has sent a massive amount of data back to Earth. In particular, it was found that, unlike the northern polar cap, the proportion of water ice in the southern polar cap is lower, but at the same time, the total volume of water in the polar caps of Mars is approximately equal. Water ice lies under a layer of frozen carbon dioxide several meters thick.

A small amount of methane has been found in the atmosphere of Mars, the content of which may indicate either ongoing tectonic activity on the planet, or, more interestingly, the vital activity of microorganisms. The latter assumption seems unlikely to scientists.

With the help of ASPERA sensors of neutral and charged particles, the presence of nitrogen monoxide and aerosols was detected in the atmosphere, present at altitudes up to 100 km.

They also compiled: a detailed diagram of the structure of the Martian atmosphere up to altitudes of 150 km, a diagram of the temperature profile of the atmosphere up to altitudes of 50-55 km, a map of the distribution of water vapor and ozone in the atmosphere of the planet. The images of the surface of Mars obtained by Mars Express were subsequently processed and based on them three-dimensional landscape models were compiled.

Fig.27 General view of the Mars Exploration Rover. Credit: NSSDC

In the same year as Mars Express, two NASA rovers, Spirit and Opportunity, launched as part of the Mars Exploration Rover project, set off for the red planet.

Both rovers were identical to each other. They had 6 wheels, each of which was driven by a separate engine. The two front and two rear wheels of the rover were used to turn the apparatus, and therefore each had its own turning mechanism based on servo drives, which did not depend on the mechanisms that ensured the movement of the entire apparatus. The middle pair of wheels of such a mechanism was deprived.

The maximum calculated speed of the rover was 5 cm / s, but in practice it did not exceed 1 centimeter. The rover was capable of climbing obstacles with inclination angles up to 45°, while being programmed to avoid exceeding an inclination angle of more than 30°.

The rover was protected from overheating by airgel, gold foil, thermostats and heaters. From low temperatures - radioisotope (main) and electric (auxiliary) heaters. Solar panels with a power of up to 140 watts served as the energy source. Energy is stored in 2 batteries.

Communication with the Earth and spacecraft was maintained using 3 antennas. An on-board computer was used to process information, having the following characteristics: a 20 MHz processor, 128 MB RAM, and 256 MB flash memory.

The study of the planet was carried out using panoramic cameras installed at a height of 1.4 meters from the base of the wheels of the rover, the APXS X-ray spectroscope, the Mössbauer spectrometer, the microscope and the RAT drill. .

The main goals of the Mars Exploration Rover program were to study the geological features, the history of the formation of the modern relief of the planet, the climate of Mars, and on the basis of all these data, search for an answer to the main question "whether there was life on Mars.

The first of the two rovers to explore Mars was "Spirit" (spirit translated from English), launched by the Delta-2 launch vehicle on June 10, 2003 from the launch pad at Cape Canaveral. After 7 months of interplanetary flight - January 4, 2004 "Spirit" landed on the planet in the Gusev crater. And 3 hours after landing, the rover began to transmit the first images to Earth. The last communication session with the device took place on March 22, 2010. As scientists believe, communication problems are caused by a small amount of electricity generated by solar panels needed to communicate with the Earth. At the moment, the problems have not been fixed and the rover, due to the low temperature inside the case, is possibly badly damaged.

pic.28 Adirondack stone. Credit: Mars Exploration Rover Mission, JPL, NASA

During its work on the surface of the planet, the rover collected data on the chemical composition and structure of six stones: Adirondack, Mimi, Mazatzal-a, Pot of Gold-a, a stone with a high content of magnesium sulfate and Gong-gong. The Gusev and Bonneville craters, Columbia Hills and Husband Hill have been studied. The existence of significant liquid water reserves on Mars has been confirmed in the past, based on the discovery of chemical elements such as sulfur and magnesium, as well as hematite, specific to a humid climate. A large number of high-quality images have been obtained, in which you can see the desert Martian landscapes, clouds in the planet's atmosphere and dust whirlwinds called dust devils. The total length of the distance traveled on the surface of Mars by "Spirit" was 7730.50 meters.

A month after Spirit, on July 7, 2003, the second rover of the program, Opportunity (opportunity), set off for Mars from Cape Canaveral. The rover landed on the surface of the planet on January 25 of the following year. Opportunity is currently in full working order and has traveled 26,658.64 meters (as of January 11, 2011).

Like the Spirit rover, Opportunity was engaged in the study of stones (mainly of cosmic origin, i.e. meteorites) in the region of the Meridian plateau. During the work, the rover found 6 meteorites (the last one in September last year). in addition to searching for and studying stones, the rover conducted extensive studies of Martian surface rocks, features of the planet's surface, and photographed landscapes. Based on the collected data, Opportunity, like Spirit, managed to collect enough data about the existence of once extensive reservoirs on Mars.

fig.29 MRO. Credit: NSSDC

In 2005, NASA's Mars Reconnaissance Satellite, or MRO, set off for Mars. The launch of the Atlas V launch vehicle, which sent the MRO into space, took place on August 12, 2005 from the launch site at Cape Canaveral.

The mission of the "Martian reconnaissance satellite" was designed for a period of one Martian year and was intended to: study the modern climate of Mars, its seasonal and annual changes, search for traces left by water and the water itself, search for areas of interest for future ground missions. Using the HiRISE high-resolution camera, it was planned to take pictures of the surface with a resolution never seen before. With the help of the CTX panchromatic context camera, it was planned to survey the surface of the planet. Using the MARCI camera, it was planned to monitor clouds and dust storms.

fig.30 Athabasca Valles channel. Credit: NASA/JPL/University of Arizona

On March 10, 2006, MRO approached the red planet and began a series of aerodynamic maneuvers to enter the design orbit. The maneuvers in orbit lasted until November, after which the device was launched into a close to circular orbit, with the periapsis at the South Pole and the apocenter over the North Pole, where it remains to this day. Since November 2008, the device has been used as a transmitter of information for rovers operating on the surface of the red planet.

During its work in orbit, MRO has collected data on the distribution and volume of water ice on the surface of Mars. It turned out that the total volume of water ice enclosed in the northern polar cap of the planet is 821 thousand km 3. The CRISM spectrometer also detected water ice in the ejecta of rock surrounding young craters. After some time, the ice from the emissions evaporates, bypassing the liquid state (as a result of the low pressure of the Martian atmosphere). When studying the plains of Hellas, traces characteristic of the activity of glaciers were found, which may indicate a wider distribution of underground ice than previously thought.

With the help of the HiRISE camera, numerous traces of the activity of the flowing water were discovered: river valleys (in the area of ​​​​the Antoniadi crater), river sediments, lake-like landforms. The presence of extensive water-covered areas in the past is also indicated by the widespread distribution of chlorides on Mars, as well as other minerals, the formation of which requires liquid water.

On numerous images of the apparatus, one can also see landslides on the slopes, dunes on the surface of Mars and their movement, spacecraft operating on the planet: Phoenix and Opportunity.

Fig. 31 Landing module "Phoenix". Credit: NASA/JPL

The last spacecraft to visit the red planet to date is the Phoenix lander, launched on August 4, 2007 as part of NASA's Mars Scout program, which also includes the MAVEN orbiter, which is scheduled to launch in late 2013. .

Phoenix arrived on Mars on May 25, 2008, 10 months after launch. The landing of the module was carried out at a point with the following coordinates: 68° north latitude and 125° east longitude, in an area rich in underground water ice reserves. The landing site was chosen specifically in accordance with the missions of the apparatus: studying the climate and weather of the polar regions of Mars, determining the composition of the lower layers of the atmosphere, describing geomorphological features and the history of the formation of the northern plains of the planet, collecting information about the physical properties of near-surface rock layers and searching for water, water ice , as well as a description of the aquatic geological history. With the help of all the data collected during the mission, it was planned to identify conditions favorable for the life of microorganisms.

The mission of the landing module "Phoenix" was designed for a short period: only 5 months, due to the low probability of the normal functioning of the apparatus after the end of the Martian winter. And as it turned out, the calculations were correct. The last session with the landing module took place on November 2, 2008, and on November 10, the successful completion of the mission was announced, the results of which were: detection of water ice under a thin layer of Martian rock, obtaining a chemical analysis of the soil, which revealed traces of salts of perchloric acid, magnesium, sodium , potassium and chlorine, the determination of the pH of the soil, the values ​​of which showed the similarity of the Martian surface rocks with the terrestrial weakly alkaline soils.

On November 25, 2011, NASA launched a new generation rover Curiousity (Mars Science Laboratory) to Mars, which will be larger and more expensive than its predecessors. The rover successfully landed on the surface of the planet near the crater and has even managed to transmit several black-and-white images of Mars. Its main purpose is to search for water and traces of bacterial activity.

In 2011, a mission to jointly study Mars and its satellite Phobos was jointly carried out by Russia and China, launching the Phobos-Grunt and Inho-1 spacecraft from the Baikonur Cosmodrome in November. Unfortunately, as a result of a launch vehicle accident, the Phobos-Grunt apparatus fell into the Pacific Ocean.

In 2013, the launch of the second apparatus of the NASA space program "Mars Scout" - "MAVEN" is scheduled.

Several launches of space programs are scheduled for 2016: the joint Russian-Finnish program MetNet, which involves the delivery of eight stations to the red planet using the Mars-Net spacecraft, which during one Martian year will be able to collect data on seasonal climate changes ; the joint program of NASA and ESA "ExoMars", within the framework of which it is planned to send several orbital and landing modules to Mars; NASA's Martian Astrobiological Field Laboratory program, which is planned to find traces of life.

In 2018, the ExoMars rovers will go to Mars.

After 2020, NASA and ESA plan to deploy a whole group of landers on the surface of the red planet. One of the main goals of the Mars Sample Return Mission is the collection and subsequent delivery of Martian soil samples to Earth.

And of course, several countries at once are preparing for a manned flight to the planet Mars.

Orbital motion and rotation of the planet Mars

fig.32 Distance from the terrestrial planets to the Sun. Credit: Lunar and Planetary Institute

The planet Mars moves around the Sun in an elliptical orbit with an eccentricity of 0.0934. The plane of the orbit is inclined to the plane of the ecliptic at a small angle (1°51").

The average distance from the Sun is 227.99 million km. (1.524 AU). At the point of perihelion, the distance is minimal - 207 million km, at the point of aphelion - maximum - 249 million km. Due to this difference, the amount of energy coming from the Sun varies by 20-30%, having a huge impact on the planet's climate. So the difference between the average temperatures on the planet at the time of passage of the points of aphelion and perihelion is 30°C.

The distance between Mars and Earth varies over a wider range: from 56 to 400 million km. The smallest distance is observed during opposition periods, while all oppositions, when the distance between two planets is less than 60 million km, are called great oppositions. Happen last time in 15-17 years.

The average orbital speed is 24.13 km/sec. Thus, the Martian year lasts 687 Earth days.

The axis of rotation of Mars is inclined to the plane of the ecliptic at an angle of 24.5%. This circumstance leads to a change of seasons on Mars, as on Earth.

The difference is observed only in the duration of these seasons on different planets and different Martian hemispheres. For example, summer in the northern hemisphere of Mars lasts 178 days (Martian), winter - 155, spring - 193 and autumn - 143. Accordingly, in the southern hemisphere, winter is longer - 178 days, and summer is short - 155 days. What is it connected with? And this is due to the large eccentricity of the Martian orbit (0.09), which is an ellipse, in contrast to the Earth's orbit - almost a circle ...

The period of rotation around the axis of Mars is 24 hours 37 minutes 22.58 seconds, i.e. a little more than the period of the earth's rotation.

The internal structure of the planet Mars

The chemical composition of Mars is typical of the terrestrial planets, although, of course, there are specific differences. Early redistribution of matter under the influence of gravity also took place here, as evidenced by the preserved traces of primary magmatic activity.

fig.33 Internal structure of Mars. Credit: NASA

Apparently, having a relatively low temperature (about 1300 K) and low density, the metallic core of Mars is rich in iron and sulfur and large in size. Its radius is about 1500 km, and its mass is about one tenth of the entire mass of the planet. The core is in a molten state. This is indicated by a weak magnetic field around the planet, 800 times inferior in strength to the earth's.

The formation of the core, according to modern theoretical estimates, lasted about a billion years and coincided with the period of early volcanism. Another period of the same duration was occupied by partial melting of mantle silicates, accompanied by intense volcanic and tectonic phenomena.

This period also ended about 3 billion years ago, and although global tectonic processes continued for at least another billion years (in particular, huge volcanoes arose), the gradual cooling of the planet has already begun, which continues to this day. At present, Mars, like Mercury, is a geologically calm planet. There are no active volcanoes and no marsquakes.

The mantle of Mars is enriched in iron sulfide, appreciable amounts of which were also found in the studied surface rocks, while the content of metallic iron is noticeably less than on other planets of the Earth group. The iron content in the Martian mantle is 2 times higher than the iron content in the Earth's mantle. There is also a significant content of such elements as potassium and phosphorus.

The thickness of the lithosphere of Mars is several hundred km, of which only 25-70 km falls on the Martian crust, which has a high content of sulfur and chlorine. In addition to these elements, the crust of Mars contains: silicon, oxygen, iron, magnesium, aluminum, calcium and potassium, which are part of the igneous rocks that cover vast areas of the planet's surface.

The surface of the planet Mars has a reddish color due to the presence of iron oxides and resembles the moon, but only at first glance. In fact, the Martian terrain is very diverse: vast plains and mountain ranges, huge volcanoes and bottomless canyons stretching for thousands of kilometers. Many landforms of the planet are very ancient and were formed at the earliest stages of the evolution of Mars, during times of active volcanism and frequent marsquakes. Currently, there are no active volcanoes on the red planet, but 2 vast ancient volcanic regions are known: Elysium and Tharsis. The formation of these volcanic regions occurred at least a billion years ago, in the era when the formation of the inner Martian layers ended: the core, mantle and crust.

Surface of the planet Mars

The main parameters of the solid body of Mars were established on the basis of observations from the Earth and later corrected according to spacecraft data. It turned out that the radius of Mars in the plane of the equator is 3396 km and is almost 20 km higher than the polar radius of the planet (3376.4 km). Thus, the average radius of Mars is 3386 km, two times smaller than the average Earth. The surface area of ​​Mars, based on calculations, turned out to be 145 million km 2.

fig.34 Comparison of the planets of the solar system. Credit: website

Knowing the radius of Mars, its surface area and internal composition, the mass of the planet was calculated - 6.42 10 23 kg (ie 0.108 Earth mass) and its average density - 3.93 g/cm 3 . The average density of the planet Mars indicates the wide distribution of silicates with a density of 2700 to 4500 kg per cubic meter.

The surface of Mars is very heterogeneous: there are mountains and plains, volcanic and meteorite craters, ancient river valleys and vast basins once occupied by seas in the past. There are many traces of violent tectonic activity on the planet: grinding, canyons, ridges.

The mountains on Mars are concentrated within several regions, the largest of which is the volcanic highlands of Tarsis (Tharsis), which lies near the equator. Its area is about 30 million km 2 (occupies up to 20% of the area of ​​the entire planet), the largest diameter is 4000 km. The average heights within the highlands are 7-10 km, but individual volcanic cones rise to a much greater height. These are Mount Arsia, Mount Peacock and Mount Askrian.

The first of them is a huge volcano with a base diameter of 435 km and a height of 19 km. The Arsia volcano has the largest caldera among all the volcanoes in the solar system, with a length of 110 km. Peacock Mountain lies to the north of Arsia. Its height is 14 km above the average level of the Martian surface. The northernmost of the 3 peaks is Mount Askriyskaya, which is the third highest volcano and mountain of Mars: 18 km above the surface of the planet. The diameter of the base of the volcano is 460 km. The caldera of the volcano was formed as a result of several strong volcanic explosions and is quite deep.

All 3 volcanoes of the Tarsis Highlands are also known as the Tharsis Mountains, stretching from the northeast to the southwest.

Fig. 35 Mount Olympus taken by the Viking-1 station. Credit: NASA

To the northwest of the highlands in the Tharsis Basin is the fourth of the greatest Martian volcanoes - Mount Olympus. It was not for nothing that Olympus was named after the mountain of the same name in Greece, on which, according to myths, the gods led by Zeus lived, because it is the highest mountain in the solar system, the highest point of which lies at an altitude of 27 km in relation to the base and 25 km in relation to to the average level of the Martian surface. The diameter of the base of the volcano is 540 km, the average slope of the slopes is from 2° to 5°. Due to its gigantic size and slight steepness of the slopes, the volcano cannot be fully seen from the surface of Mars. The top of the volcano is crowned by a huge caldera measuring 85 by 60 km and 3 km deep, thanks to the presence of as many as six overlapping craters. Along the edges of the volcano, giant cliffs up to 7 km high were found, which, as it were, limit it from the surrounding area, covered with a network of small mountain ranges - the Halo of Olympus.

Another volcano of the province of Tharsis (includes the highlands and depression of the same name) is the unique shield volcano Alba, which lies to the north of the Tharsis Mountains. The Alba volcano is significantly inferior to Mount Olympus in height - only 6.8 km above the surface, but the diameter of its base of 2000 km is more than 3 times the diameter of the base of the highest volcano in the solar system. The slopes of the volcano contain hundreds of thin channels, over a hundred kilometers long and up to 300 meters wide, formed by very liquid lava. Near the top of the volcano there is a double caldera with traces of at least 5 eruptions.

The second volcanic region of the planet Mars is the Elysium Highlands, which lies several thousand kilometers from the province of Tharsis. The upland has dimensions of 2400 by 1700 km and an average height above the surface of 5 km. Within Elysium, 3 major volcanoes are known: Patera Albor, Dome of Hekate and Mount Elysium. The first of them - Albor, is a low volcanic dome with a base diameter of about 155 km, crowned with a caldera measuring 35 by 30 km. The volcanic cone of Hekate is located 850 km north of Albor. The dimensions of the cone are: the average diameter of the base is 170 km, the height is 6 km above the Martian surface. The summit caldera measures 11.3 by 9.1 km. Approximately in the middle between Albor and Hekates is the largest volcano of Elysium - Mount Elysium. The diameter of the base of this volcano exceeds five thousand kilometers, the height above the surrounding terrain is 9 km, and above the average level of the Martian surface is 14 km. The volcano is topped by a caldera with a diameter of 14.1 km.

Most of the volcanoes on Mars, especially the largest ones, resemble the shield volcanoes of the Hawaiian Islands on Earth. In both groups of volcanoes, the nature of the eruptions is effusive, characterized by a calm, prolonged outpouring of liquid basalt lavas from the caldera. True, the size of Martian volcanoes is ten times greater than the size of the largest Hawaiian ones. This circumstance is apparently related to the fact that the magma chambers that feed the Martian volcanoes remain motionless relative to the surface for hundreds of millions of years, because on Mars, unlike the Earth, no lithospheric plates have been found, the movement of which in areas of modern terrestrial volcanism leads to a gradual weakening and then and the complete cessation of volcanic activity of old volcanic cones and the formation of new ones. As a result, heated deep rocks, whose density decreases with increasing temperatures, rise upwards, as if raising the surface of the planet. Surface rocks with a lower temperature sink down, forming extended faults. In addition, it is possible that the outpouring of lavas on Mars took place for a much longer time and was very intense. The formation of volcanoes ended several hundred million years ago.

Fig. 36 Patera Apollinaris. Credit: Malin Space Science Systems, MGS, JPL, NASA

Along with the effusive nature of volcanic eruptions on Mars, there are volcanoes on the planet of another type - explosive. A similar nature of the eruption is observed in the oldest surviving volcanoes on the red planet - Patera Tirrenia and Patera Hadriaka, lying on the northeastern edge of the vast Hellas basin in the southern hemisphere of the planet. The height of the volcanoes above the surface level is small (about 2 km), the slopes are strongly eroded and dotted with numerous wide channels, as well as craters. This feature speaks, firstly, of the antiquity of volcanic cones (it is believed that they are at least 3.5 billion years old), and secondly, of the composition of volcanoes by pyroclastic layers of ash. There is a large channel on the southeastern outskirts of the Hadriaka volcano, through which the main masses of lava erupted during eruptions.

Explosive eruptions were also characteristic of another Martian volcano - Apollinaris, lying southeast of the Elysium Highlands. The diameter of the base of the volcano is 296 km, and the highest height above the surface is only 5 km. The top of the volcano is crowned with a flat caldera - Patera Apollinaris. Explosive eruptions are indicated by incised valleys and landslides on the slopes of the volcano, which are explosive in origin and have a high content of volcanic ash. At the later stages of the development of Apollinaris, eruptions began to be effusive.

It must be said that the word "patera" on Mars denotes all low, heavily destroyed mountain domes, the tops of which are crowned by irregular volcanic calderas with torn, uneven edges. In particular, the largest Martian volcano in terms of area, Alba, until 2007, was officially called Alba Patera. Today, this name is used only for its central depression.

Pateras are located in many places on the planet, but there are especially many of them within the volcanic highlands. In particular, within the limits of the Tharsis highlands, 6 pateras are located at once: in the northeast, these are the volcanic domes of Keravsky and Ourana, as well as the pateria of Uranus; in its western part - Paters Byblis and Ulysses; and the dome of Tharsis in the east. On the highlands of Elysium and in its vicinity, the pater is smaller: Apollinaris, Albor and Orcus. The latter is a vast plain elongated in the north-north-east - south-south-west direction. The bottom of the patera is located half a kilometer below the level of the surrounding terrain and is limited by an outer rim up to 1800 meters high. The rim is crossed by numerous grabens and faults, which have a west-east direction and are evidence of active tectonic movements. Orcus is now thought to be an ancient impact crater, created by a very low-angle impact with the planet, a large part of which is filled with volcanic deposits.

The formation of numerous faults, canyons and grabens on the surface of the planet is also associated with tectonic activity on Mars.

pic.37 Labyrinth of the Night. A picture of the Mars Reconnaissance Orbiter. Credit: NASA/JPL-Caltech/University of Arizona

In particular, to the southeast of Peacock Mountain lies a whole labyrinth of canyons crossed in different directions, collectively known as the Labyrinth of Night. The canyons run between numerous blocks of homogeneous ancient material. In the upper part, the blocks are badly destroyed and covered with numerous cracks. The rock that makes up the upper part of the blocks is of obvious volcanic origin and was formed over 2 periods of time: the older peaks are distinguished by a highly cratered surface and more durable constituent material, while the younger ones have a smoother surface with a significantly smaller number of meteorite craters and are composed of volcanic material associated with volcanic eruptions in the Tharsis Highlands. The surface between the blocks is also heterogeneous: in some places it is smooth, and in other places it is uneven and rough. It is believed that the smooth surface is formed like terrestrial river sediments, i.e. flowing water or liquid carbon dioxide. Possibly smooth surface areas are formed as a result of wind drifts. The rough surface was formed as a result of the destruction of the walls of the canyons by the action of the wind.

In the east, the Labyrinth of Night merges with the canyons of Io and Tethon, located parallel to each other. Teton Canyon lies to the north, Io - to the south. At the southern wall of Io, the Gerion Mountains stretch, and narrow short valleys stretch from the wall itself to the south (similar valleys stretching to the north are also found from the northern wall). The bottom of the Io canyon is filled with clastic material of its walls, does not contain craters and any traces of erosion. The floor of Teton Canyon is smooth and likely shaped by wind action. The space between the canyons consists of a young plateau composed of volcanic material.

To the east lies a group of 3 canyons: Melas, which is a continuation of Io, Kandor, a continuation of Titon, and Ophir, an oval inside the Kandor canyon. All 3 canyons are interconnected. The bottom of the Melas Canyon is covered with volcanic material and the products of the destruction of the side walls, processed by the wind. At the junction of Melas and Kandor lying to the north, the surface is covered with numerous furrows left by the movement of liquid or ice. There are also traces of wind erosion. It should be noted that the deepest point on Mars is located in the central part of Melas, lying 11 km below the surface of the volcanic plateaus surrounding the canyon.

The next large canyon of Mars is Koprat, a continuation of the Melas canyon. On the slopes of the canyon, distinct layered deposits are found, either of sedimentary or volcanic origin. According to some scientists, the canyon is one of the most suitable places on Mars to search for traces of the vital activity of organisms. In the eastern part, the bottom of the canyon has traces of wind action.

In the east, the Koprat canyon passes into the Eos canyon, from which 2 branches depart: the Capri canyon in the south and the Ganges canyon in the north. In the western part, the Eos Canyon consists of broken material of volcanic origin, later subjected to wind action. In the eastern part, at the bottom of the canyon, numerous stripes and grooves are traced, apparently formed by the flowing liquid. The bottom of the Capri Canyon, which is elongated from the southwest to the northeast, is composed of alluvial deposits formed as a result of the destruction of the walls of the canyon. Exactly the same bottom and the Ganges Canyon.

Stretching first to the east, and then turning to the northeast, the Eos canyon passes into the Chrys plain, passing the so-called. chaos - areas with a chaotic relief: first, the chaos of Eos, located in the southern part of the canyon of the same name, then the chaos of Radiance and the chaos of Hyodraoth.

All the canyons discussed above are part of a huge system - the Mariner Valley. The length of the valley is over 4500 km, the width in the central part is several hundred kilometers. The Mariner Valley is the largest canyon within the solar system.

Fig. 38 Mariner Valley. A photograph of the Mars Odyssey orbiter. Credit: NASA/JPL-Caltech

The formation of the Mariner Valley is caused by tectonic movements, probably associated with the formation of the Tarsis Highlands. In many places of the canyon (especially in its eastern half), numerous grooves, rounded hills, formed from crushed rocks, were also found.

fig.39 Martian channels Tiu (left) and Ares (right). Credit: NASA/JPL-Caltech/ASU

And at the confluence of the canyon with the Chrys plain and on the plain itself, entire channels were discovered, most likely formed by turbulent water flows. Some of the canals, such as the Ares, are so huge that it would take millions of cubic meters of water to form them. It is believed that the formation of channels occurred in geologically short periods of time as a result of floods, when huge masses of water broke through glacial dams. The area in eastern Washington state was formed in a similar way, where catastrophic floods repeatedly occurred when a glacial dam burst with meltwater from Lake Missoula.

Channels are a specific feature of the Martian surface; they do not exist on other planets in the solar system. The channels are formed by flowing water and resemble river valleys with characteristic sediments and structure. The age of the channels is estimated at 4 billion years, but some of the channels, for example, the already mentioned Ares, formed much later. The age of the channels can be determined by their appearance: the ancient channels look like thin winding channels with numerous tributaries (a good example is the Nirgal channel), young ones are large, wide with rare tributaries (an example is the Tiu channel). Those. ancient channels were formed at a time when the climate on Mars was warmer and more humid, and numerous rivers flowed on the surface of the planet, traces of which we are now observing. The young channels were formed as a result of short floods as a result of outpourings of groundwater, when Mars was already a cold, waterless desert...

If we look at the map of Mars, we can see that the surface level in the northern hemisphere of the planet is 3-4 km lower than in the southern one, which affects the nature of the terrain in different hemispheres: in the northern one, there are extensive relatively young volcanic plains, while in the southern, large areas are occupied by ancient plateaus covered with a significant number of meteorite craters. The Martian crust also has different thicknesses: from 32 to 58 km. This anomaly is known as the great cortical dichotomy. What is the reason for such an anomaly in the distribution of matter on the surface of Mars is not completely known, but 2 theories have already been put forward: exogenous and endogenous. The first of them considers the fall of a large asteroid on the surface of Mars as the cause of the anomaly. The second connects the uneven distribution of matter with mantle processes, as a result of which the ancient tectonic plates moved in the direction from north to south. But in any case, the age of the Martian crust in both hemispheres is the same and equals billions of years, which makes it difficult to make a final conclusion about the causes of the anomaly.

A significant part of the northern hemisphere is occupied by the Great Northern Plain, in the south turning into smaller and more elevated ones (in the direction from west to east, starting from the zero meridian): the Utopia Plain is a meteorite crater buried under the layers of rocks, in the south bordering on an ancient impact crater - the plain of Isis and the plain of Elysium, the plains of Arcadia and Amazonia (from north to south), the Acidalian plain, in the south turning into the plain of Chrys. In many places, the plains are crossed by mountains, which are relatively low, extended mountain ranges.

The plains are covered with ancient igneous rocks, in some places even whole petrified rivers are visible. A number of scientists believe that volcanic activity and the associated greenhouse effect could lead to the short-term appearance of liquid water as a result of the melting of underground water ice, and as a result, the development of life. Traces of river sediments are widespread on the northern plains, along with traces of wind erosion: numerous sand dunes, ridges and furrows.

The boundary between the northern plains and the southern mountainous hemispheres is sharply delineated by mesas up to 2-3 km high. The border passes along a large circle inclined at 30 ° to the equator and forms a slope towards the north.

There are only two plains in the southern hemisphere: Hellas and Argir, which are of meteorite origin.

The first of them is a vast basin, 1800 km in diameter, formed as a result of a huge meteorite falling onto the planet. The basin is surrounded by a wide, heavily destroyed ring of mountain ranges caused by the uplift of blocks of the Martian crust. Within the Hellas plain is the lowest point of Mars in relation to the average surface level, lying 8 km below the average level.

The plain of Argir is noticeably smaller than Hellas - 800 km in diameter and is surrounded by a wide belt of mountains. The Harit Mountains in the southern part of the plain are often referred to as ice mountains due to the deposits of dry ice on their slopes in winter. In some places of the mountains, traces of the movement of valley glaciers and the existence of ice sheets are visible.

fig.40 A group of craters in the northwest of the land of Arabia. Credit: NASA/JPL/Malin Space Science Systems

Basically, in the southern hemisphere of Mars, vast volcanic plateaus prevail, with an uneven surface dotted with meteorite craters, which indicates its antiquity and invariability for hundreds of millions of years. The meteorite craters that dot the southern plateau are shallower and smoother than those on the surface of the Moon, but deeper than those on Venus. Also, there are much fewer small craters on Mars. On Mars, there are relatively few, which is associated with strong wind and water erosion that occurred on the planet in the past.

Martian craters are very diverse: they are large craters with a flat bottom and a central peak (or peaks), bowl-shaped craters with a shaft, and elevated craters not subjected to wind erosion. The last 2 types are unique and are not found anywhere else in the solar system.

The density of meteorite craters on the surface of Mars varies greatly in different areas, on the basis of which the scientists concluded that the most cratered areas are older, the less cratered are younger and, based on the available data on the degree of cratering, divided the geological history of the planet into separate periods (eras ). The most ancient era is Noahic, named for the mountainous region in the southern hemisphere east of the Argyre basin. The age of the surface areas attributed to this era is from 4.6 to 3.8 billion years. The areas are densely covered with craters of various sizes, slightly eroded. The next era is Hesperian, named after the plateau of the same name, which lies to the northeast of the Hellas plain. Surface areas attributed to this era are characterized by a smaller number of meteorite craters, most of which are covered with igneous rocks, due to ongoing intense volcanism. The last geological era is the Amazonian, named for the plains in the northern hemisphere. There are much fewer meteorite craters on the surfaces of this period, but volcanic activity continued. The formation of vast smooth volcanic plains is associated with the activity of the latter. The Amazonian era began 3.55 billion years ago and continues to this day.

In conclusion of the story about the surface of Mars, we will give brief cartographic information about how the coordinates were drawn on the map of Mars and on what basis geographical names are given to the details of the relief on it.

fig.41 Map of Mars. Compiled from images from the Mars Global Surveyor. Credit: MGS MOC, NASA/JPL/MSSS

At the moment, the most detailed map of Mars is based on the results of measurements by the Mars Global Surveyor station. The small crater Airy-0, which lies on the land of Arabia in the northern hemisphere, is taken as the reference point for longitudes on Mars. This crater was used in 1830-32 by German astronomers W. Beer and D. Madler to determine the period of rotation of the planet around its axis. Later, the Italian astronomer J.V. Schiaparelli, with the same crater, marked the beginning of the report when compiling a map of the planet. The crater got its name when photographing the Martian surface with the Mariner-9 apparatus. Objects on the map are marked according to the following principle:

Large Martian craters are named after scientists who have made a significant contribution to the study of Mars: the craters Galileo, Herschel and Huygens. Smaller craters are given the names of settlements on Earth: craters Baikonur, Wooster and Kansk. Craters larger than 50 km are called basins.

Large valleys are given the names of the planet Mars in different languages: Hrat (in Armenian) and Maadim (in Hebrew). The only exception is the largest canyon system on the planet - the Mariner Valley.

Valleys that are smaller in length are called the names of earthly rivers: Athabasca, Vistula.

Large landforms are often given the names of different countries or places on Earth. For example, the province of Tharsis is named after the designation of Iran on old maps, the Hellas depression - after the name of Greece in the old days, the Sea of ​​Acidalia - by analogy with the Atsidalian spring, where Aphrodite bathed with the graces

Heavily cratered areas of the surface were called lands: the Land of Prometheus, the Land of Noah and others.

Many names on the modern map were proposed by J.V. Schiaparelli.

Atmosphere of the planet Mars

Above the cold desert - the Martian surface, a rarefied atmosphere was found, consisting mainly of carbon dioxide (about 95%) and small additions of nitrogen (about 3%), argon (about 1.5%) and oxygen (0.15%). The concentration of water vapor is low, and it varies significantly depending on the season. In addition to H 2 O, some other small components were found in the atmosphere of Mars - CO (~ 0.01%), traces of ozone O 3 and methane.

The average pressure of the Martian atmosphere is small and amounts to 6-7 mbar, which is 160 times less than the average pressure of the Earth's atmosphere at sea level. Depending on the height above the average level of the Martian surface, the pressure varies significantly: from 9-12 mbar in the giant Hellas depression to 0.1 mbar at the top of Mount Olympus. The pressure of the atmosphere also changes depending on the seasons of the year, reaching its minimum in winter, when part of the carbon dioxide freezes, turning into dry ice, which makes up a significant part of the composition of the planet's polar caps. In summer, the ice melts and a significant amount of carbon dioxide enters the atmosphere again, thereby increasing its average pressure, sometimes by 25%.

The atmosphere of Mars, despite its insignificant power and low pressure, allows the development of the greenhouse effect, clouds and strong winds. True, the greenhouse effect contributes too modestly to the increase in surface air temperature, raising it by only 5°K.

fig.42 Clouds over the surface of Mars. Based on pictures of the Phoenix module. Credit: NASA/JPL-Caltech/University Arizona/Texas A&M University

Clouds on Mars are made up of ice crystals and form at altitudes less than 20 km above the surface. In the polar regions of Mars, clouds often consist of dry ice, in the equatorial regions, perhaps, of water droplets. Precipitation from clouds falls exclusively in the form of snow.

Significant cloud accumulations are observed near large positive landforms, for example, volcanoes, which is associated with the rise of a warm air mass along the slopes and its further cooling. Extensive cloud systems (the so-called polar haze) are constantly present around the polar caps of the planet. In the same regions, cyclonic formations very similar to terrestrial ones were found - huge eddies with a diameter of 200 to 500 km. Their lifetime is less than a week. Cyclones form on the planet Mars in the warm season at the boundaries of the summer position of the polar front.

The position of the clouds is not constant. They are carried by the wind, during the day they rise high above the surface and lose a significant part of their water component, but at night they sink and turn into something resembling a thick fog.

At altitudes of 110-130 km above the surface of the planet there is a layer of charged particles - the Martian ionosphere. The layer consists of free electrons formed under the influence of solar wind particles on molecules of rarefied atmospheric gas. The electron density within the ionosphere is not uniform: regions with a high density, coinciding with the most magnetized areas, and regions with a low density, above the rest of the territories, have been found.

The atmosphere of Mars is secondary, associated with volcanic eruptions and similar to the atmosphere of ancient Earth. Otherwise, the Martian atmosphere in its composition would be similar to the atmospheres of the giant planets: Jupiter and Saturn, which are dominated by light gases hydrogen and helium.

Several million years ago, the axis of rotation of Mars was inclined to the plane of the ecliptic at a greater angle than today, which led to significant temperature differences between the seasons. An intensive water cycle was observed, and the thickness of the atmosphere was more than 3 times higher than its current level. Rivers flowed on the surface, and lakes formed in the depressions. There is evidence of the existence of a huge ocean in the northern hemisphere of the planet.

Water on Mars

The existence of water on the planet Mars is one of the main questions in the study of this planet. After all, water, as you know, is one of the necessary conditions for the development and existence of life. And there is water on Mars, and it apparently exists in 3 states of aggregation: in the form of vapor in the atmosphere (in a very small amount), in the form of ice around the poles and at a shallow depth below the surface, and in liquid form during the thawing of ice . The last state of aggregation of water has not yet been recorded by spacecraft, only traces of its existence have been recorded.

For the first time, signs of the presence of water on Mars were discovered by the Mariner-9 spacecraft, which discovered a giant quarry system with traces of water erosion, fogs and clouds.

In the process of studying the surface of the planet with the Viking series, branched systems, very similar to terrestrial river networks, were discovered, which were obviously affected by flowing water in the past. Soil analysis has only strengthened the astronomers' assumption that the surface of Mars was once covered in a fairly significant layer of liquid water over vast areas. This was indicated by magnesium sulfate, calcite, magnetite, and other minerals widely distributed on the planet, which are formed on our planet in the aquatic environment. "Viking-2" recorded snowfall, which had lain for several months.

On July 4, 1997, the Mars Pathfinder spacecraft landed on the surface of Mars, from which the Sojourner rover descended on July 5, which worked on the surface for several months and discovered stones similar to earth pebbles, processed by water flows, as well as oddities in the position of some volcanic fragments. The existence of clouds and fogs in the atmosphere of the planet was confirmed.

On September 11 of the same year, the Mars Global Surveyor flew up to Mars. For 9 years, the station conducted observations and photographed the surface of the planet. Numerous channels were discovered, including subsurface ones left by water flows, and the latter appeared during the period when the station was already observing. This discovery allows us to believe that water on Mars in liquid form exists at any time, but not in any place. As a rule, such channels were found on the slopes of craters.

Fig. 43 Northern fault. Canyon in the north polar cap of Mars. Credit: NASA/JPL-Caltech/ASU

Mars Odyssey, which arrived at the planet on October 24, 2001, using the HEND high-energy neutron detector installed on board, was able to detect huge reserves of water ice under the surface of Mars at a shallow depth, which was announced in July 2003 at a conference in California. In the regions around the Martian poles, starting from 55° parallels, 1 kg of soil contains 0.5 kg of water ice. When approaching the equator of the planet, the ice content decreases and does not exceed 10% of the total rock volume. The water appears to be in a bound state with sulfates and clays. At greater depths, the existence of pure ice is also possible. According to some estimates, the total amount of water contained in the form of ice in the surface layers of Mars can cover the entire planet with a layer of up to 1.5 km.

Two years later, the Mars Express spacecraft arrived at Mars. With the help of the equipment installed on board, water ice was discovered as part of the southern polar cap of the planet, maps of the distribution of water vapor and ozone in the atmosphere were compiled. It turned out that the bulk of the water ice on the southern cap is under a layer of frozen carbon dioxide several meters thick.

In 2004, the presence of water in the samples of the Martian soil was shown by the Spirit and Opportunity rovers. In February of the following 2005, Spirit discovers a stone with a high content of magnesium sulfate, which may indicate the effect of water on the stone. And the Opportunity rover, which is still working on Mars, found traces of minerals dissolved in water, which at the present stage are enclosed in igneous rocks.

In 2006, the automatic interplanetary station "MRO" took up the study of the red planet. With the help of the HiRISE high-resolution camera installed at the station, numerous images of the planet were taken, showing that in the distant past there were seas, lakes and numerous rivers on Mars.

Fig. 44 A section of the surface of Mars taken by the Phoenix module. Credit: NASA/JPL-Caltech/University of Arizona

In 2008, the Phoenix lander confirmed the presence of ice in the surface layers of the northern region of Mars. The thickness of the ice layer at the landing site of the module was at least several meters. When samples were heated in the TEGA module, water vapor was obtained at a temperature of 0°C.

Taking into account all the currently known information about the presence of water on Mars, we can summarize the following:

1) The bulk of water in the form of ice is concentrated in the polar regions of the planet - the polar caps lying on the Northern and Southern plateaus. The polar caps were discovered long before the flights of spacecraft - in 1704 by the French astronomer Jacques Philippe Maraldi. It has now been established that water ice lies under a crust of frozen carbon dioxide (the so-called dry ice) and partially directly on the surface of the planet. Part of the ice is contained in the upper soil horizon in a bound state at a shallow depth.

The total volume of water ice contained in the northern polar cap of the planet is 1 million km3. In the southern cap, the water content is several times higher.

In 2005, the Mars Express spacecraft in the northern hemisphere discovered the so-called. "ice lake" - an ancient crater filled with frozen water. In the same year, in the southern hemisphere, the same apparatus within the Elysium Highlands found a whole frozen sea, similar in size and depth to the North Sea on Earth. The surface of the sea is a huge field, consisting of separate heterogeneous ice floes up to 30 km in diameter, which, as it were, float on the surface of the water. The sea was formed apparently from 2 to 10 million years ago.

2) In the past, there were numerous seas, lakes and rivers on Mars, traces of which are widely represented on the modern surface of the planet. In the northern hemisphere, the waters of the vast Borealis ocean, up to 5 km deep, apparently splashed.

At present, liquid water cannot exist on the surface of Mars: too little pressure allows water to pass from a solid to a gaseous state, bypassing the liquid state, at very low ambient temperatures. But, liquid water can flow under the ice, and can also form internal lakes in it, similar to those found in Antarctica.

Physical conditions on Mars

The temperature on the planet Mars varies widely and usually stays below zero degrees. This is due to the low power of the atmosphere, low pressure on the surface and low thermal inertia of the upper soil horizon of the planet. In addition, Mars is located farther from the Sun than the Earth and therefore receives 43% less energy.

fig.45 Spring in the northern hemisphere of Mars. 3 sandstorms are clearly visible. Credit: NASA/JPL/Malin Space Science Systems

The temperature in the lower atmospheric layer of Mars is subject to seasonal fluctuations, almost like on Earth, with one difference: the duration of all seasons here is much longer. So in the northern hemisphere, summer lasts 178 Martian days, winter - 155 days, transitional seasons spring and autumn - 193 and 143 days, respectively. In the southern hemisphere, spring and summer are shorter, while winters and autumns are longer. The different duration of the seasons in different hemispheres is associated with a large eccentricity of the Martian orbit and different speeds of movement along this orbit in different parts. During the summer in the northern hemisphere, Mars passes the aphelion point - the most distant from the equator, but the speed of the planet in orbit at this time is minimal - 22 km / s. During the summer in the southern hemisphere, the planet is closest to the Sun, passing the point of perihelion, but the speed of orbital motion increases to 26.5 km / s. For this reason, summers in the northern hemisphere are long and cool, while winters are short and warm. In the southern hemisphere of Mars, on the contrary, summers are short and hot, and winters are long and cold.

The maximum temperatures on Mars are observed in the region of the Sun's plateau near the equator, where in summer they fluctuate between +22°C during the day and -53°C at night, and in winter they can drop to -100°C. At the poles of Mars, the temperature is lower during the year and usually does not rise above 0°C. The absolute maximum air temperature recorded on Mars is +30°C, the minimum is -139°C.

The temperature of the soil on Mars, unlike the air temperature, changes little during the year and even at the equator it stays below zero. Only in summer, in the warmest areas, the ground temperature rises to 0°C. That is why some scientists propose to call the underground layers of Martian ice permafrost.

In the summer, grandiose dust storms often occur in the southern hemisphere of Mars, sometimes covering the entire planet and lasting several months. In other seasons, the strength and area of ​​distribution of storms is much less.

The mechanism of formation of storms is associated with the rise of warm air above the overheated surface in areas adjacent to the polar caps. As a result, huge amounts of dust rise into the air, which in turn leads to even greater heating of the atmosphere and further cooling of the surface. A large temperature difference leads to strong winds that contribute to the spread of storms for thousands of kilometers. Over time, the wind speed subsides and the dust from the air settles.

Less large-scale atmospheric phenomena on Mars are mini tornadoes - dust devils. On Earth, such formations are observed in desert regions or over separate highly heated areas of the terrain and, as a rule, are small in size. On Mars, their height reaches a kilometer height, and vortices appear in series.

In addition to storms and dust devils, constant winds similar to the terrestrial trade winds are noted on Mars, blowing from the hottest equatorial regions of both hemispheres towards the poles. Along the way, the winds are deflected by the Coriolis force: to the southwest in the northern hemisphere and to the northwest in the southern hemisphere. At mid-latitudes, the air cools and returns to the equator. This movement of the atmosphere is called the Hadley cell.

The magnetic field of the planet Mars. The magnetosphere of the planet Mars

A weak magnetic field has been registered on Mars, the magnetic induction of which is only 0.5 μT. The magnetic field of Mars is quite extensive, but not global: at different points on the planet, its strength can vary by more than 2 times. It has the appearance of narrow bands elongated from west to east, in some places of which the field strength suddenly rises sharply and almost equals the strength of the Earth's magnetic field. The width of the bands is about 1000 km.

The low strength of the planet's magnetic field is explained by the weak mobility of its core, as a result of which the mechanism of the magnetic dynamo does not manifest itself in full force.

The magnetic field of the planet Mars is stronger in the southern hemisphere and is apparently the remnants of a pre-existing global field that disappeared simultaneously with the extreme deceleration of the core about 4 billion years ago. Until now, among scientists there is no single point of view on the account of the event that caused the planet's core to stop. There are only 2 theories. According to the first of them, the reason for stopping the nucleus is the collision of Mars with some large space object. A similar collision took place in the northern hemisphere of the planet, and it is this collision that explains the anomalous distribution of matter in different hemispheres of Mars. According to the second theory, developed by a group of scientists from the universities of Lethbridge and York, the asteroid was, on the contrary, the cause of the magnetic field. As a result of the tidal effect of an asteroid captured by the gravitational field of Mars, for some 10 thousand years, strong convective flows arose in the core of the planet, sufficient to generate a magnetic field. For several million (or hundreds of million) years, the tidal effect of the asteroid maintained the planet's magnetic field until the cosmic body entered the Roche limit and collapsed. The magnetic field gradually weakened...

Moons of Mars

Fig. 47 Mars satellite Phobos. Credit: HiRISE, MRO, LPL (U. Arizona), NASA

Fig. 46 Mars satellite Deimos. Credit: NASA/JPL-Caltech/University of Arizona

Two moons orbit Mars: Phobos (Fear) and Deimos (Horror). The moons of Mars were discovered in 1877 by American astronomer Asaph Hall.

Both satellites of Mars are small in size, have an irregular shape and always face it with the same side. Phobos is 22.2 km in diameter. The diameter of Deimos is even smaller: only 12.4 km.

It is believed that the satellites are asteroids captured by the gravitational field of the planet, which arrived from other parts of the solar system.

Phobos moves in its orbit at a speed three times greater than the speed of circulation of Mars itself, and in one Martian day it manages to make 3 complete revolutions around the planet and travel another 78 °. The observer sees the satellite rising in the west, and setting in the east.

Deimos is a slow satellite. Its period of revolution is greater than the period of rotation of Mars, although not by much. The time between two adjacent moments of the upper culmination of the satellite is 130 hours. Deimos rises in the east, sets in the west.

The gravitational fields of satellites are so weak that they have no atmosphere. But they are covered with a grid of meteorite craters, the largest of which is the Stickney crater on Phobos, reaching a diameter of 10 km.

Actually, this is one of the first questions that most beginner astronomy lovers have.

Some people think that through a telescope you can see the American flag, planets the size of a soccer ball, colored nebulae, as in photographs from Hubble, etc. If you also think so, then I will immediately disappoint you - the flag is not visible, pea-sized planets, galaxies and nebulae are gray colorless spots. The fact is that a telescope is not just a tube for entertainment and getting “happiness in the brain”. This is a fairly complex optical device, with the correct and thoughtful use of which you will get a lot of pleasant emotions and impressions from viewing space objects.

One of the most important parameters of a telescope is the diameter of the objective (lens or mirror). As a rule, beginners buy inexpensive telescopes with a diameter of 70 to 130 mm - so to speak, to get to know the sky. Of course, the larger the diameter of the telescope lens, the brighter the image will be at the same magnification. For example, if we compare telescopes with a diameter of 100 and 200 mm, then at the same magnification (100x), the brightness of the image will differ by 4 times. The difference is especially noticeable when observing faint objects - galaxies, nebulae, star clusters. Nevertheless, it is not uncommon for beginners to immediately purchase a large telescope (250-300 mm), then marvel at its weight and size. Remember: the best telescope is the one that is used most often!

So what can you see with a telescope? First, the moon. Our space companion is of great interest for both beginners and advanced amateurs. Even a small telescope with a diameter of 60-70 mm will show lunar craters and seas. At a magnification of more than 100x, the moon will not fit into the field of view of the eyepiece at all, that is, only a piece will be visible. As the phases change, the appearance of the lunar landscapes will also change. If you look through a telescope at a young or old moon (narrow crescent), you can see the so-called ash light - a faint glow of the dark side of the moon, caused by the reflection of earth's light from the lunar surface.

You can also see all the planets in the solar system with a telescope. Mercury in small telescopes will look just like a star, and in telescopes with a diameter of 100 mm or more, you can see the phase of the planet - a tiny sickle. Alas, Mercury can only be caught at a certain time - the planet is not far from the Sun, which makes it difficult to observe

Venus - also known as the morning evening star - is the brightest object in the sky (after the sun and moon). The brightness of Venus is so high that it can be seen with the naked eye during the day (you just need to know where to look). Even with small telescopes, you can see the phase of the planet - it changes from a tiny circle to a large crescent, similar to the moon. By the way, sometimes people, when looking at Venus through a telescope for the first time, think that they are being shown the moon???? Venus has a dense opaque atmosphere, so you won't be able to see any details - just a white crescent.

Earth. Oddly enough, the telescope can also be used for terrestrial observations. Quite often, people buy a telescope both as a space peeper and a spyglass. Not all types of telescopes are suitable for ground-based observations, namely lens and mirror-lens ones - they can provide a direct image, while in Newton's system mirror telescopes the image is inverted.

Mars. yes, yes, the one that is visible every year on August 27 as two moons ???? And people from year to year are being led to this stupid joke, slamming questions of familiar astronomers???? Well, Mars, even in fairly large telescopes, is visible only as a small circle, and even then only during oppositions (once every 2 years). However, in 80-90 mm telescopes it is quite possible to see the darkening on the planet's disk and the polar cap.

Jupiter - perhaps it was from this planet that the era of telescopic observations began. Looking through a simple homemade telescope at Jupiter, Galileo Galilei discovered 4 satellites (Io, Europa, Ganymede and Callisto). In the future, this played a huge role in the development of the heliocentric system of the world. In small telescopes, you can also see several bands on the disk of Jupiter - these are cloud belts. The famous Great Red Spot is quite accessible for observation in telescopes with a diameter of 80-90 mm. Sometimes satellites pass in front of the planet's disk, casting their shadows on it. It can also be seen with a telescope.

Saturn is one of the most beautiful planets, every time the sight of which simply takes my breath away, although I have seen it more than one hundred times. The presence of the ring can already be seen in a small 50-60 mm telescope, but it is best to observe this planet in telescopes with a diameter of 150-200 mm, in which you can easily see the black gap between the rings (Cassini gap), cloud belts and several satellites.

Uranus and Neptune - planets circling far from the rest of the planets, small telescopes look only in the form of stars. Larger telescopes will show tiny bluish-greenish disks without any detail.

Galaxies. These star islands can be found not only through a telescope, but also through binoculars. It is to find, not to consider. In a telescope, they look like small colorless specks. Starting with a diameter of 90-100 mm, bright galaxies can be seen form. The exception is the Andromeda Nebula, its shape can be easily seen even with binoculars. Of course, there can be no talk of any spiral arms up to a diameter of 200-250 mm, and even then they are noticeable only in a few galaxies.

Nebulae. They are clouds of interstellar gas and/or dust illuminated by other stars or stellar remnants. Like galaxies, in a small telescope they are visible as faint spots, but in larger telescopes (from 100-150 mm) you can see the shape and structure of most bright nebulae. One of the brightest nebulae - M42 in the constellation of Orion - can be seen even with the naked eye, and the telescope will show a complex gas structure similar to clouds of smoke. Some compact, bright nebulae can be seen in color, such as NGC 6210 the Turtle Nebula, which can be seen as a small bluish disk.

I warn you right away - observing the Sun without special protective equipment is very dangerous! Only with a special aperture filter, which must be securely attached to the front of the telescope. No toning films, smoked windows and floppy disks! Take care of your eyes! If all precautions are observed - even in a tiny 50-60 mm telescope you can see sunspots - dark formations on the sun's disk. These are the places from which the magnetic lines come out. Our Sun rotates with a period of about 25 days, so by observing sunspots every day, you can see the rotation of the Sun.

Brief information
The fourth planet from the Sun, named after Mars, the god of war. Mars is 1.5 times farther from the Sun than Earth. Mars makes one revolution around the Sun in 687 Earth days. The average annual temperature of the planet is -60°С, and the maximum temperature does not exceed several degrees above zero. Mars has two natural satellites - Phobos and Deimos.

When to observe Mars?
The best time to observe Mars is its opposition, when the planet is at its minimum distance from the Earth. The oppositions of Mars are repeated at intervals of 2 years and 50 days. These days, the apparent angular size of the planet is 13"-14", and the magnitude is about -1.3. The next oppositions of Mars will take place on March 4, 2012 and April 9, 2014.

However, the real holiday for the observer comes once every 15-17 years, during the so-called great confrontation, when the apparent size of the planet reaches 25”. Unfortunately, the next great opposition of Mars will have to wait long enough, as it will only happen in 2018.

Comparative size of Mars at great opposition, opposition and smallest apparent size (conjunction with the Sun).

Mars has a more elongated orbit than Earth. As you can see in the figure below, great oppositions occur when Mars passes its perihelion, and the most unfavorable from the point of view of observations - when the planet is near aphelion.

Change of seasons on Mars
Like Earth, Mars experiences a change of seasons, and thanks to the tilt of the equator to orbit similar to our planet, seasons on Mars change in much the same way as on Earth.

As on Earth, on Mars, when summer in the northern hemisphere sets in, winter comes in the southern, and vice versa. Summers in the northern hemisphere are long and cold, while winters are short and warm. In the southern hemisphere, the opposite is true: summers are short and warm, and winters are long and frosty. Summer in the southern hemisphere coincides with the passage of the planet through perihelion, and in the northern hemisphere - through aphelion.

Necessary equipment
Under favorable conditions, the tiny disk of Mars can be seen already in a 60-mm telescope, but there is no need to talk about any details on the surface of the planet when observed through such an instrument. Perhaps the minimum telescope that is needed to observe Mars can be considered a 150-mm reflector or 100-mm refractor, and the most optimal in terms of price, weight, size and capabilities is a 250-300 mm Newton system reflector.

Large amateur telescopes (from 350 mm) are strongly affected by atmospheric flows and have a considerable thermal stabilization time, therefore, as a rule, they are not recommended for planetary observations. However, these giants should not be discounted either. In the rare moments when it is possible to capture a calm atmosphere, a well-cooled telescope is able to show an amazing amount of detail on the surface of the Red Planet. Plus, large telescopes more clearly show the shades of colors on the surface of the planet.

It is highly desirable that your telescope be equipped with a stable clockwork mount capable of keeping the planet in the eyepiece's field of view for a long time.

When observing Mars, it is difficult to overestimate the importance of using color filters, which help to see surface features in more detail, as well as to see atmospheric phenomena that might go unnoticed without a filter.

If you are serious about observing Mars, then your collection should include the following color filters:

Red- noticeably improves the contrast between dark areas (seas) and light areas (land). Best of all, the effect of the filter is noticeable with a calm atmosphere and low magnification.

Yellow and orange are one of the most useful if not the most useful filters for observing Mars. Emphasize the red areas of the planet and highlight fine details in them. They work well in dark areas, and also make the image more stable.

Green- used for observations of dark zones around the polar caps, it well highlights dust storms that have a yellow tint. Also, the filter will be useful when highlighting white areas on a red surface.

Blue- emphasizes areas of the surface that have a purple tint. Very useful for detecting water clouds in the upper atmosphere.

Violet- highlights clouds and fogs formed during the melting of the polar caps.

Mars observations
What can be seen on Mars with a telescope
Mars is a very interesting, but at the same time difficult to observe planet. As a rule, most of the time it is a small "pea" without any obvious details on the surface. Of course, a novice observer, having directed his small telescope to Mars, remains disappointed, as he fails to see the legendary polar caps and continents.

Things are somewhat better during oppositions (especially great ones), when a good 100-mm refractor allows you to follow the melting of the polar caps, as well as make out the dark outlines of the continents on the surface of the planet. At 150 millimeters, gray-green areas on the disk of Mars become visible, which astronomers mistook for vegetation in the last century. Now we know that these are just rocks and dust, reflecting light in such a bizarre way.

But still, it is worth remembering that observations of Mars are really interesting only in medium and large amateur telescopes, which, under favorable conditions, allow you to see all the main details of the planet's surface, as well as observe amazing changes in its appearance caused by changes in seasons and weather.

General tips for observing Mars
As a rule, the recommended period for observing Mars begins 40 days before the opposition and ends 40 days after. This recommendation is not without merit. It is on these days that the angular size of the planet is maximum. However, owners of telescopes with a lens of 250 mm and above can quite successfully begin observations 3–4 months before the opposition and another 3–4 months after it ends. Thus, the total duration of the observation of the planet will be more than 6 months. During this period, one can follow very curious changes - the melting of the polar caps and meteorological phenomena.

Distinguishing the details on the disk of the planet is greatly helped by the systematic sketching of its view through the telescope. This is due to a more detailed and thoughtful examination of the planet, since the implementation of the sketch implies the most accurate transmission of what is visible in the eyepiece. But even schematic sketches are useful. They also stimulate the observer and help later, already in comfortable home conditions, to identify what he saw.

Once you start observing Mars regularly, you will realize that the details of its surface are barely perceptible, and therefore it is especially important to focus the telescope very accurately. With Mars, this seemingly simple task becomes a real challenge. Remember a simple rule - it is best to focus the telescope on the polar cap as the most contrasting object.

Don't expect to see Mars in all its details immediately. Starting observations, relax, breathe evenly. Give your eyes a few minutes to recognize what you see. The first thing that catches your eye is the polar cap. It is quite easy to guess, as it contrasts with the surrounding background - blue and white on a relatively uniform orange disk. After a while, the seas will begin to emerge, like dull grey-green spots. Try not to miss sightings and look at Mars at every opportunity. With experience, you will discover many wonders on the surface of the Red Planet.

A specially prepared map of Mars will help to recognize all the main formations available to amateur telescopes.

Mars rotates 45 degrees in longitude in 3 hours. South is at the top on the map.

Note that it takes Mars 37 minutes longer than Earth to make a full rotation on its axis. Therefore, if you look at the planet again at the same time a day later, then the surface features you saw yesterday will appear 37 minutes later than the day before. Daily observations of Mars at a fixed time make it possible to follow the full axial rotation of the planet for 5–6 weeks.

What to see on Mars
polar caps
The most visible features of the Martian surface are the polar caps. Their observation is within the power of every amateur astronomer.

Along with the change of seasons, changes also occur in the appearance of the polar caps. So, with the onset of the spring-summer period, the cap melts in the corresponding hemisphere. Its borders are slowly receding towards the pole. The task of the observer is to follow this process.

south polar cap quite large and visible in modest amateur telescopes during oppositions, when Mars is at perihelion. During the warm season, the southern cap significantly changes its shape and size. During the Martian spring, you can see how the hat splits in two. This is caused by slower snowmelt at the top of the Mitchell Mountains.
Cracks and clearings can often be seen near the southern border of the cap.

Drawings by the English astronomer Patrick Moore show the seasonal decrease in the northern polar cap of Mars. Left to right, top to bottom: November 19, 1960, December 25, 1960, January 11, 1961, February 6, 1961

north polar cap does not undergo such sharp seasonal changes as the southern one. Even during the summer, it does not disappear completely. It is impossible to predict the behavior of the northern cap in advance, and this makes its observations intriguing.
As autumn approaches, fog often appears in the northern hemisphere, which originates over the polar region. Interestingly, with the appearance of fog, the northern cap often stops its melting for a while and begins to increase in size. The sudden appearance of fog is also observed in late spring.

Martian seas and seasonal changes
Changes in appearance associated with the change of seasons on Mars undergo not only the polar caps, but also dark areas of the surface, which are traditionally called the seas. As a rule, changes are manifested in the darkening of surface areas. The initial phase of this phenomenon occurs in the middle of the Martian spring, and it lasts almost until the complete disappearance of the polar cap. The darkening extends from the polar region to the equator and is more noticeable during the periods of those oppositions that fall on the passage of the planet's perihelion.

Gray-green seas not only darken during the spring-summer period, but also increase or decrease in size, and also change their shape. Of course, in order to capture such changes, you must have a good knowledge of the Martian topography.

The following areas of Mars are most subject to seasonal changes: Pandora's Strait (Pandorae Fretum), Sirte Major (Syrtis Major), Sun Lake (Solis Lacus), Pearly Bay (Margaritifer Sinus).

atmospheric phenomena
The appearance of blue-white and white clouds, as well as white fogs, is presumably associated with seasonal changes on Mars. They appear in the Martian spring and disappear in the autumn. Probably, the melting of the polar caps has a direct influence on the formation of clouds.

To distinguish clouds and fog from other surface features, you need to have an excellent understanding of the cartography of Mars. Therefore, this kind of observation is recommended to be carried out with solid experience in contemplating the Red Planet and knowledge of its appearance. Clouds can be fixed by changing the outlines of the seas (when clouds pass over them) and as bright spots over the continents.

A significant help in highlighting clouds and fogs can be provided by color filters that emphasize their shape and increase contrast. To highlight clouds, it is recommended to have the following filters: No. 58 (green), No. 80A, No. 38 and No. 38A (blue).

Clouds and fogs can stay above the Martian surface for several hours and even a whole day.

Yellow clouds and dust storms- another type of atmospheric phenomena, the observation of which is possible with the help of amateur telescopes. As a rule, yellow clouds and dust storms appear on Mars during the passage of perihelion, when the summer solstice occurs in the southern hemisphere.

Dust storm (hover over image) on Mars. Drawing by Jeremy Perez.

Their appearance is caused by the heating of the surface of Mars by the sun's rays, which leads to the formation of strong winds in its atmosphere. Yellow clouds and dust storms can start suddenly and spread quickly. There are frequent cases when dust storms spread throughout the hemisphere and hide the outlines of continents and seas under them.
It is recommended to use yellow and orange filters to isolate dust clouds.

Observation of Phobos and Deimos
Few astronomers can boast that they have visually observed the satellites of Mars. Unlike Jupiter's four brightest moons, Phobos and Deimos are subtle ghosts. However, using simple tricks, you can try to consider the satellites of Mars in modest amateur telescopes.

First, observations Phobos and Deimos should be carried out in periods close to the opposition of Mars, and especially the great one. This is logical: the closer Mars is to Earth, the closer its satellites are, which means they are brighter and easier to see. On such days, Phobos and Deimos are about 11th and 12th magnitude, respectively. It is believed that objects with such brightness can be easily seen in a 4-5-inch telescope. However, not all so simple. The bright light of the planet prevents you from seeing two small "stars". In addition, the brighter Phobos is harder to see because its orbit is closer to Mars than Deimos.

An experienced observer of galaxies and binary stars knows that it is much easier to see a dim object located near a bright star if you move the bright clutter out of the field of view. The same should be done when searching for Phobos and Deimos.

To do this, use an eyepiece with a narrow field of view. An orthoscopic eyepiece is best suited for this purpose. Then determine in advance the time when the satellites will be at the maximum distance from the planet (in east or west elongation). Such information can be obtained using programs such as Guide 9.0 and SkyTools 3.

At the right time, point the telescope at Mars and carefully move it out of view so that its bright light does not interfere with the observation of the satellite of interest to us. After you manage to make out Phobos and/or Deimos, try to bring the planet back into view. It is possible that now you will be able to see the planet and its satellites without additional tricks.

The fact that you can see the American flag through a telescope is a common myth. The flag is such a small object that it is not visible even with a very powerful telescope. But Mars and the rings of Saturn can be seen through a telescope. Is it possible to see other planets of the solar system, as well as galaxies and nebulae, through a telescope?

If the telescope is powerful enough, it will show you all the planets in the solar system, even Neptune, the last planet in our system. What's more, you'll see the moons of Jupiter, snow caps on Mars, and details of Saturn's rings.

In addition to planets, asteroids, comets, hundreds of star clusters and nebulae can be seen through a telescope. For example, the Orion Nebula and the Andromeda Nebula.

Pictured is the Andromeda Nebula.

But the most interesting object to observe is, of course, the Moon. With a powerful telescope, you can see its surface in detail - craters, mountains, hills are visible as if you yourself are walking on the moon. How detailed the image will be depends on the diameter of the telescope objective. The larger it is, the more detailed the picture will be.

For example, telescopes with a 115 mm lens, such as the Levenhuk Strike 115 PLUS, allow you to see the details of the lunar relief up to 5 km in diameter.

Telescopes of the same design, but with a 130-150 mm lens, such as the Levenhuk Strike 135 PLUS, will show details of the lunar surface with a diameter of 3-4 km.

Thus, the lunar rover, the traces of its landing, as well as the traces of Neil Armstrong are not visible through the telescope due to their too small size. What observers take to be footprints are actually terrain features (mountains or lunar seas).

The magnifying power of the telescope also matters. Machines with powerful magnification give such a large image that you will not even see the boundaries of the moon - it will seem that you are standing on it. For example, Levenhuk Strike 135 PLUS gives a magnification of 372 times – as if there are only about 1000 km between the Earth and the Moon.

Speaking about what can be seen through a telescope, it is important to take into account the features of a particular model. The ability of a telescope depends on a combination of several parameters: lens size, magnification, focal length. For telescopes "for beginners" and "for experienced" they are different. Of course, even the simplest telescope will be interesting for a novice astronomer, but only a more advanced model will allow you to dive into the depths of space and see the maximum.

Yes, about the UFO. Beginners see unidentified objects quite often. But experienced astronomers say that they have not yet seen aliens - but in space, even without them, there is a lot of unsolved.

Try watching the night sky through a telescope - it will surprise you!

"When will Mars get close to Earth?" - this question at the end of summer has been worrying the minds of many people for more than ten years in a row. Since August 2003, all those who are not indifferent to the night sky and sensations begin to wait for the appearance of the Red with the Moon overhead, or even more. And every year they are visited by disappointment. Mars, however, is not to blame: its actual size exceeds the lunar parameters, but, fortunately, it simply cannot approach us at such a distance as to look like a night star. Let's try to figure out why this happens. And for this you will have to consider the issue from a scientific point of view, understand where such shocking information came from, and then answer the question: “when will Mars approach the Earth?”

Wandering across the sky

Let's start from afar. The movement of the planets of the solar system is subject to certain laws. Movement along orbits and rotation around the axis is accompanied by a slow displacement of the latter and a slight “rocking” of the cosmic body. In order to understand this process, one can imagine a spinning wheel. For an earthly observer, all these phenomena look somewhat different than in the vastness of space. The planets move across the sky, sometimes ahead of, sometimes catching up with the Sun. Within a year or several years, their size and brightness may change.

Forward and reverse movement

All planets are usually divided into external, or upper, and internal, or lower. The first are located behind the second - closer to our house to the Sun (Mercury and Venus). The outer planets include Mars, Jupiter, Saturn, Uranus, Neptune. Their movement has certain characteristics for the earthly observer. So, it changes at a certain moment from direct to backward. When, for example, Mars is visible in the sky in the west some time after sunset, it moves in the same direction as the Sun. This is called forward movement. The luminary has a greater speed than Mars, so sooner or later it catches up with the Red Planet. The phenomenon is called "conjunction with the Sun". The luminary is between the planet and the Earth. Now Mars will be visible in the east. For an earthly observer, its direct motion will slow down, then the planet will stop and "run" in the opposite direction. There will be a backward movement.

Confrontation

Moving in the opposite direction, the planet describes an arc from east to west. Approximately in the middle of it is an important point. Her name is resistance. It corresponds to the location of the Earth clearly between the Sun and, for example, the same Mars. The planet opposes the sun. It is important that at such a moment the distance from the Earth to it is greatly reduced. With a certain periodicity, the so-called great confrontations occur. They are characterized by the maximum possible decrease in the distance separating two cosmic bodies. It was on such a day in 2003 that Mars approached Earth. Photos depicting two moons in the sky were also timed to coincide with it, but reality was not displayed.

How it was

The so-called Martian hoax began in 2003 with emails. They said: on August 27, the Red Planet will come so close to the Earth that it will look like a second moon. Related photos flooded the Internet. The day when Mars will approach the Earth at such a record small distance was eagerly awaited by many. However, soon after the appearance of the first such messages, the information contained in them was refuted by scientists.

small mistake

E-mails transmitted, as it turned out, either a translation error, or a misunderstanding of the official message about a real astronomical event. On August 27, 2003, the distance between Earth and Mars should have been the smallest in the last few thousand years. On the day of the great confrontation, the Red Planet through a telescope with a magnification of 75 times could be seen the same as with the naked eye. The message also said that Mars will become 75 times larger and will look like a night star on a full moon.

Scientists, commenting on this information, pay attention to the fact that the diameter of the Red Planet is twice that of a similar satellite parameter. He overtakes the moon and in mass. At the same time, the distance between Earth and Mars varies from 55 to 400 million km, depending on their relative position. On the one hand, at such a distance, the Red Planet can only equal or slightly exceed Sirius in brightness in the sky. On the other hand, if Mars approaches us at such a distance as to resemble the size of the Moon, its gravity will cause serious disasters on Earth, that is, it is unlikely that any of the people will be able to admire it.

Movement of Mars and Earth

It should be noted that the confrontation between our and the Red planet happens once every two years. The Earth at this moment is between Mars and the Sun, the distance between the two neighbors is reduced. Great Confrontations are rarer events. Their frequency is 15-17 years. If the orbit of Mars and the Earth were an exact circle, and the trajectories of the planets would lie in the same plane, then the same time would always pass between oppositions, and the degree of convergence would be constant. However, it is not. The Earth is close to a circle, but the orbit of Mars is elongated, and they are located at a slight angle to each other. As a result, during opposition, both planets are each time at a new point, and the distance between them changes.

Maximum Approach

If Mars and Earth converge at the moment when the Red Planet is located near its aphelion, then the distance between them is about 100 million km. This usually happens during the winter in the Northern Hemisphere. If the opposition occurs at the time of the passage of perihelion by Mars, the distance is much less. Great are those rapprochements when the planets are separated by less than 60 million km. One of them happened on August 27, 2003. The distance between the planets was then reduced to 55,758,006 km. According to scientists, such a rapprochement has not occurred for several thousand years. In 1640, 1766, 1845 and 1924 there were great confrontations, only slightly, but still inferior to what happened in 2003.

In the future, an equally close passage of the two planets is expected in 2287 and 2366. and several more times before the end of the millennium. These days, like August 27, 2003, Mars will be visible to the naked eye: a small reddish dot in the east after sunset.

Science value

Since the invention of the telescope, the oppositions of Earth and Mars have been used to study the Red Planet. It was on such a day in 1877 that the astronomer Asaph Hall discovered two satellites, which they later named Phobos and Deimos. Giovanni Schiaparelli, during the opposition, considered dark spots on Mars, which he designated as seas and bays. And although it is known for sure that the Red Planet cannot boast of liquid water, the terminology of the scientist is still used.

Now, for the study of Mars, oppositions are less valuable, since most of the information comes from interplanetary stations and vehicles that have reached the surface of the Red Planet (rovers). However, they are important for the implementation of other projects.

Flight to Mars

Today there are several projects of manned flights to the Red Planet. Naturally, for such purposes it is best to use the time of maximum approach of the two planets. In this case, the cost of the flight and its time are reduced.

The great confrontation of 2003 did not go unnoticed by scientists. On this day, several interplanetary stations were sent to Mars. For 2018, when the two cosmic bodies again come very close to each other, the United States is planning a test flight of a rocket, which in 2030 will have to deliver astronauts to Mars. The calculation of such expeditions is not an easy task. For a successful flight, it is necessary to take into account a lot of factors, including the time of maximum approach of the planets and the speed of their removal from each other.

One of the projects is the flight of astronauts without their return in order to explore the Red Planet and create conditions for the life of other "Martians" on it. This is what NASA plans to implement in the 30s of this century. Thus, one of the days when Mars approaches the Earth at a minimum distance, may become the date of the realization of one of the most daring fantasies of writers of the last century: the start of human colonization of neighboring planets. And our neighbor will be the first cosmic body after the Moon that people have visited.