solar system- these are 8 planets and more than 63 of their satellites, which are being discovered more and more often, several dozen comets and a large number of asteroids. All cosmic bodies move along their clear directed trajectories around the Sun, which is 1000 times heavier than all the bodies in the solar system combined. The center of the solar system is the Sun - a star around which planets revolve in orbits. They do not emit heat and do not glow, but only reflect the light of the sun. There are currently 8 officially recognized planets in the solar system. Briefly, in order of distance from the sun, we list them all. And now some definitions.
Planet- this is a celestial body that must satisfy four conditions:
1. the body must revolve around a star (for example, around the Sun);
2. the body must have sufficient gravity to have a spherical or close to it shape;
3. the body should not have other large bodies near its orbit;
4. the body should not be a star
Planet satellites. The solar system also includes the Moon and the natural satellites of other planets, which all of them have, except for Mercury and Venus. More than 60 satellites are known. Most of the satellites of the outer planets were discovered when they received photographs taken by robotic spacecraft. Jupiter's smallest moon, Leda, is only 10 km across.
is a star, without which life on Earth could not exist. It gives us energy and warmth. According to the classification of stars, the Sun is a yellow dwarf. The age is about 5 billion years. It has a diameter at the equator equal to 1,392,000 km, 109 times larger than the earth. The rotation period at the equator is 25.4 days and 34 days at the poles. The mass of the Sun is 2x10 to the 27th power of tons, approximately 332950 times the mass of the Earth. The temperature inside the core is about 15 million degrees Celsius. The surface temperature is about 5500 degrees Celsius. According to the chemical composition, the Sun consists of 75% hydrogen, and of the other 25% of the elements, most of all helium. Now let's figure out in order how many planets revolve around the sun, in the solar system and the characteristics of the planets.
The four inner planets (nearest to the Sun) - Mercury, Venus, Earth and Mars - have a solid surface. They are smaller than four giant planets. Mercury moves faster than other planets, being burned by the sun's rays during the day and freezing at night.
Period of revolution around the Sun: 87.97 days. Diameter at the equator: 4878 km.
Rotation period (turn around the axis): 58 days.
Surface temperature: 350 during the day and -170 at night.
Atmosphere: very rarefied, helium.
How many satellites: 0.
The main satellites of the planet: 0.
More like the Earth in size and brightness. Observation of it is difficult because of the clouds enveloping it. The surface is a hot rocky desert. 
Period of revolution around the Sun: 224.7 days.
Diameter at the equator: 12104 km.
Rotation period (turn around the axis): 243 days.
Surface temperature: 480 degrees (average).
Atmosphere: dense, mostly carbon dioxide.
How many satellites: 0.
The main satellites of the planet: 0.
Apparently, the Earth was formed from a gas and dust cloud, like other planets. Particles of gas and dust, colliding, gradually "raised" the planet. The temperature on the surface reached 5000 degrees Celsius. Then the Earth cooled down and became covered with a hard stone crust. But the temperature in the depths is still quite high - 4500 degrees. Rocks in the bowels are molten and pour out to the surface during volcanic eruptions. Only on earth there is water. That's why life exists here. It is located relatively close to the Sun to receive the necessary heat and light, but far enough away so as not to burn out.
Period of revolution around the Sun: 365.3 days. Diameter at the equator: 12756 km.
The period of rotation of the planet (rotation around the axis): 23 hours 56 minutes.
Surface temperature: 22 degrees (average).
Atmosphere: mostly nitrogen and oxygen.
Number of satellites: 1.
The main satellites of the planet: the Moon.
Due to the similarity with the Earth, it was believed that life exists here. But the spacecraft that landed on the surface of Mars found no signs of life. This is the fourth planet in order. 
Period of revolution around the Sun: 687 days.
Diameter of the planet at the equator: 6794 km.
Rotation period (rotation around the axis): 24 hours 37 minutes.
Surface temperature: -23 degrees (average).
Atmosphere of the planet: rarefied, mostly carbon dioxide.
How many satellites: 2.
Main moons in order: Phobos, Deimos.
Jupiter, Saturn, Uranus and Neptune are made up of hydrogen and other gases. Jupiter is more than 10 times larger than Earth in diameter, 300 times in mass and 1300 times in volume. It is more than twice as massive as all the planets in the solar system combined. How much planet Jupiter does it take to become a star? It is necessary to increase its mass by 75 times!
The period of revolution around the Sun: 11 years 314 days. Diameter of the planet at the equator: 143884 km.
Rotation period (turn around the axis): 9 hours 55 minutes.
Surface temperature of the planet: -150 degrees (average).
Number of satellites: 16 (+ rings).
The main satellites of the planets in order: Io, Europa, Ganymede, Callisto.
This is the number 2 largest of the planets in the solar system. Saturn draws attention to itself thanks to a system of rings formed from ice, rocks and dust that orbit the planet. There are three main rings with an outer diameter of 270,000 km, but their thickness is about 30 meters. 
The period of revolution around the Sun: 29 years 168 days.
Diameter of the planet at the equator: 120536 km.
Rotation period (turn around the axis): 10 hours 14 minutes.
Surface temperature: -180 degrees (average).
Atmosphere: mostly hydrogen and helium.
Number of satellites: 18 (+ rings).
Main satellites: Titan.
Unique planet in the solar system. Its peculiarity is that it revolves around the Sun not like everyone else, but "lying on its side." Uranus also has rings, although they are harder to see. In 1986, Voyager 2 flew 64,000 km and had six hours of photography, which it successfully completed.
Orbital period: 84 years 4 days. Diameter at the equator: 51118 km.
The period of rotation of the planet (rotation around the axis): 17 hours 14 minutes.
Surface temperature: -214 degrees (average).
Atmosphere: mostly hydrogen and helium.
How many satellites: 15 (+ rings).
Main satellites: Titania, Oberon.
At the moment, Neptune is considered the last planet in the solar system. Its discovery took place by the method of mathematical calculations, and then they saw it through a telescope. In 1989, Voyager 2 flew by. He took amazing photographs of the blue surface of Neptune and its largest moon, Triton. 
The period of revolution around the Sun: 164 years 292 days.
Diameter at the equator: 50538 km.
Rotation period (turn around the axis): 16 hours 7 minutes.
Surface temperature: -220 degrees (average).
Atmosphere: mostly hydrogen and helium.
Number of satellites: 8.
Main moons: Triton.
On August 24, 2006, Pluto lost planetary status. The International Astronomical Union has decided which celestial body should be considered a planet. Pluto does not meet the requirements of the new formulation and loses its "planetary status", at the same time, Pluto passes into a new quality and becomes the prototype of a separate class of dwarf planets.
How did the planets appear? Approximately 5-6 billion years ago, one of the gas and dust clouds of our large Galaxy (the Milky Way), which has the shape of a disk, began to shrink towards the center, gradually forming the current Sun. Further, according to one of the theories, under the influence of powerful forces of attraction, a large number of dust and gas particles rotating around the Sun began to stick together into balls - forming future planets. According to another theory, the gas and dust cloud immediately broke up into separate clusters of particles, which compressed and condensed, forming the current planets. Now 8 planets revolve around the sun constantly.
Here on Earth, we tend to take time for granted, never thinking that the step in which we measure it is rather relative.
For example, how we measure our days and years is the actual result of our planet's distance from the Sun, the time it takes to orbit it, and rotate around its own axis. The same is true for other planets in our solar system. While we earthlings calculate a day in 24 hours from dawn to dusk, the length of one day on another planet is significantly different. In some cases, it is very short, while in others, it can last more than a year.
Day on Mercury:
Mercury is the closest planet to our Sun, ranging from 46,001,200 km at perihelion (the closest distance to the Sun) to 69,816,900 km at aphelion (farthest). Mercury rotates on its axis in 58.646 Earth days, which means that a day on Mercury takes about 58 Earth days from dawn to dusk.
However, it takes Mercury only 87,969 Earth days to go around the Sun once (in other words, the orbital period). This means that a year on Mercury is equivalent to approximately 88 Earth days, which in turn means that one year on Mercury lasts 1.5 Mercury days. Moreover, the northern polar regions of Mercury are constantly in shadow.
This is due to its 0.034° axial tilt (Earth's is 23.4° by comparison), meaning that Mercury does not experience extreme seasonal changes where days and nights can last for months, depending on the season. It is always dark at the poles of Mercury.
Day on Venus:
Also known as Earth's twin, Venus is the second closest planet to our Sun, ranging from 107,477,000 km at perihelion to 108,939,000 km at aphelion. Unfortunately, Venus is also the slowest planet, this fact is obvious when you look at its poles. Whereas the planets in the solar system experienced flattening at the poles due to rotational speed, Venus did not survive it.
Venus rotates at only 6.5 km/h (compared to Earth's rational speed of 1670 km/h), which results in a sidereal rotation period of 243.025 days. Technically, this is minus 243.025 days, since Venus's rotation is retrograde (i.e. rotation in the opposite direction of its orbital path around the Sun).
Nevertheless, Venus still rotates around its axis in 243 Earth days, that is, a lot of days pass between its sunrise and sunset. This may seem strange until you know that one Venusian year is 224.071 Earth days long. Yes, Venus takes 224 days to complete its orbital period, but more than 243 days to go from dawn to dusk.
So one day of Venus is a little more than a Venusian year! It is good that Venus has other similarities with the Earth, but this is clearly not a daily cycle!
Day on Earth:
When we think of a day on Earth, we tend to think it's just 24 hours. In truth, the sidereal period of the Earth's rotation is 23 hours 56 minutes and 4.1 seconds. So one day on Earth is equivalent to 0.997 Earth days. Oddly enough, again, people prefer simplicity when it comes to time management, so we round up.
At the same time, there are differences in the length of one day on the planet depending on the season. Due to the tilt of the earth's axis, the amount of sunlight received in some hemispheres will vary. The most striking cases occur at the poles, where day and night can last for several days and even months, depending on the season.
At the North and South Poles in winter, one night can last up to six months, known as "Polar Night". In summer, the so-called “polar day” will begin at the poles, where the sun does not set for 24 hours. It's actually not as easy as one would like to imagine.
Day on Mars:
In many ways, Mars can also be called Earth's twin. Add seasonal fluctuations and water (albeit in frozen form) to the polar ice cap, and a day on Mars is pretty close to Earth. Mars makes one revolution on its axis in 24 hours. 
37 minutes and 22 seconds. This means that one day on Mars is equivalent to 1.025957 Earth days.
The seasonal cycles on Mars are more similar to ours than on any other planet, due to its 25.19° axial tilt. As a result, Martian days experience similar changes with the Sun rising early and setting late in the summer and vice versa in the winter.
However, seasonal changes last twice as long on Mars because the Red Planet is at a greater distance from the Sun. This results in a Martian year being twice as long as an Earth year, 686.971 Earth days or 668.5991 Martian days or Sol.
Day on Jupiter:
Given the fact that it is the largest planet in the solar system, one would expect a day on Jupiter to be long. But as it turns out, officially a day on Jupiter lasts only 9 hours 55 minutes and 30 seconds, which is less than a third of the length of an Earth day. This is due to the fact that the gas giant has a very high rotational speed of approximately 45,300 km / h. Such a high rotation speed is also one of the reasons why the planet has such violent storms.
Note the use of the word formal. Since Jupiter is not a solid body, its upper atmosphere moves at a different speed than at its equator. Basically, the rotation of Jupiter's polar atmosphere is 5 minutes faster than that of the equatorial atmosphere. Because of this, astronomers use three frames of reference.
System I is used at latitudes from 10°N to 10°S, where its rotation period is 9 hours 50 minutes and 30 seconds. System II applies at all latitudes north and south of them, where the rotation period is 9 hours 55 minutes and 40.6 seconds. System III corresponds to the rotation of the planet's magnetosphere, and this period is used by the IAU and IAG to determine Jupiter's official rotation (i.e. 9 hours 44 minutes and 30 seconds)
So, if you could theoretically stand on the clouds of a gas giant, you would see the Sun rise less than once every 10 hours at any latitude of Jupiter. And in one year on Jupiter, the Sun rises about 10,476 times.
Day on Saturn:
The situation of Saturn is very similar to Jupiter. Despite its large size, the planet has an estimated rotational speed of 35,500 km/h. One sidereal rotation of Saturn takes approximately 10 hours and 33 minutes, making one day on Saturn less than half an Earth day.
The orbital period of Saturn's rotation is equivalent to 10,759.22 Earth days (or 29.45 Earth years), and a year lasts approximately 24,491 Saturn days. However, like Jupiter, Saturn's atmosphere rotates at different rates depending on latitude, requiring astronomers to use three different frames of reference.
System I covers the equatorial zones of the South Equatorial Pole and the North Equatorial Belt, and has a period of 10 hours and 14 minutes. System II covers all other latitudes of Saturn except for the north and south poles, with a rotation period of 10 hours 38 minutes and 25.4 seconds. System III uses radio emission to measure Saturn's internal rotation rate, which resulted in a rotation period of 10 hours 39 minutes 22.4 seconds.
Using these various systems, scientists have obtained various data from Saturn over the years. For example, data acquired during the 1980s by the Voyager 1 and 2 missions indicated that a day on Saturn is 10 hours 45 minutes and 45 seconds (± 36 seconds).
In 2007 this was revised by researchers at the UCLA Department of Earth, Planetary and Space Sciences, resulting in the current estimate of 10 hours and 33 minutes. Much like Jupiter, the problem with accurate measurements is that different parts rotate at different speeds.
Day on Uranus:
As we approached Uranus, the question of how long a day lasts became more difficult. On the one hand, the planet has a sidereal rotation period of 17 hours 14 minutes and 24 seconds, which is equivalent to 0.71833 Earth days. Thus, we can say that a day on Uranus lasts almost as long as a day on Earth. This would be true were it not for the extreme axial tilt of this gas-ice giant.
With an axial tilt of 97.77°, Uranus essentially orbits the Sun on its side. This means that its north or south faces directly towards the Sun at different times of the orbital period. When it is summer at one pole, the sun will shine there continuously for 42 years. When the same pole is turned away from the Sun (that is, it is winter on Uranus), there will be darkness for 42 years.
Therefore, we can say that one day on Uranus from sunrise to sunset lasts as much as 84 years! In other words, one day on Uranus lasts as long as one year.
Also, as with other gas/ice giants, Uranus rotates faster at certain latitudes. Therefore, while the rotation of the planet at the equator, approximately 60° south latitude, is 17 hours and 14.5 minutes, the visible features of the atmosphere move much faster, making a full revolution in just 14 hours.
Day on Neptune:
Finally, we have Neptune. Here, too, the measurement of one day is somewhat more complicated. For example, Neptune's sidereal rotation period is approximately 16 hours 6 minutes and 36 seconds (equivalent to 0.6713 Earth days). But due to its gas/ice origin, the planet's poles rotate faster than the equator.
Taking into account that the speed of rotation of the planet's magnetic field is 16.1 hours, the equatorial zone rotates approximately 18 hours. Meanwhile, the polar regions rotate for 12 hours. This differential rotation is brighter than any other planet in the solar system, resulting in strong latitudinal wind shear.
In addition, the planet's 28.32° axial tilt results in seasonal fluctuations similar to those on Earth and Mars. Neptune's long orbital period means the season lasts for 40 Earth years. But because its axial tilt is comparable to Earth's, the variation in its day length over its long year is not as extreme.
As you can see from this summary of the various planets in our solar system, the length of the day depends entirely on our frame of reference. In addition to that, the seasonal cycle varies, depending on the planet in question, and from where on the planet measurements are taken.
I have always been inspired and amazed by a system that spans the entire cosmos. In particular, my interest fell on our native and beloved planet. The earth is constantly in a state of rotation around the sun, like a top on a table. But, unlike a top, the angular velocity of the Earth does not depend on the force, because it is constant. But how long does it take for our planet to complete one revolution around a large hot ball?
How long does it take the earth to revolve around the sun
Before answering this question, you should find out:
- The exact trajectory of the Earth's movement.
- The relationship between the rotation of the planet and the seasons.
- Influence of the tilt between the planet and the vertical.
So, our planet is constantly spinning around its axis. But, in addition, it simultaneously rotates around one of the largest and closest stars. The path followed by the Earth during rotation is not a circle, because it is slightly elongated. It follows from this that in twelve months the Earth is at a slightly closer distance, and also at a more distant one exactly twice. (the first case is more attractive to me). Of course, you thought that because of this, the seasons change. But, unfortunately, this is not the case. The main culprit of this phenomenon is the same angle between the center of the Earth and the vertical. The fact is that during the movement of the Earth this “defect” remains.
Change of seasons
Imagine that our planet flies past the Sun, the northern part of which is face to face with a star. The sun responds to this side with its warmth and light. Now there are carefree summer holidays. And the edge intended for the south is practically hidden from the Sun. It is now cold and in the New Year mood. But the path of our planet is still going on. And now everything is different. South and north change places. The bear, who was in a once warm climate, is forced to carefully prepare for hibernation.
Only one slope allows our planet to approach the Sun at the same distance. This is the time of golden autumn and blooming spring. Accordingly, this phenomenon is followed by another important consequence, namely, a fourfold change in the seasons.
Time on Earth is taken for granted. People do not think that the interval by which time is measured is relative. For example, the measurement of days and years is based on physical factors: the distance from the planet to the Sun is taken into account. One year is equal to the time for which the planet goes around the Sun, and one day is the time for a complete rotation around its axis. By the same principle, time is calculated on other celestial bodies of the solar system. Many people are interested in how long a day lasts on Mars, Venus and other planets?
On our planet, a day lasts 24 hours. It takes this many hours for the Earth to rotate on its axis. The length of the day on Mars and other planets is different: somewhere it is short, and somewhere very long.
Definition of time
To find out how long a day lasts on Mars, you can use solar or sidereal days. The last measurement option is the period during which the planet makes one rotation around its axis. A day measures the time it takes for the stars to be in the same position in the sky from which the countdown began. Earth's star path is 23 hours and almost 57 minutes.
A solar day is a unit of time it takes for a planet to rotate on its axis relative to sunlight. The principle of measuring with this system is the same as when measuring the day of a sidereal day, only the Sun is used as a guide. Sidereal and solar days can be different.
And how long does a day last on Mars according to the star and solar system? A sidereal day on the red planet is 24 and a half hours. A solar day lasts a little longer - 24 hours and 40 minutes. A day on Mars is 2.7% longer than a day on Earth.
When sending vehicles to explore Mars, the time on it is taken into account. The devices have a special built-in clock, diverging from the earth by 2.7%. Knowing how long a day lasts on Mars allows scientists to create special rovers that are synchronized with the Martian day. The use of special clocks is important for science, as rovers are solar-powered. As an experiment, a clock was developed for Mars that takes into account the solar day, but they could not be applied.
The zero meridian on Mars is the one that passes through the crater called Airy. However, there are no time zones on the red planet like there are on Earth.
martian time
Knowing how many hours there are in a day on Mars, you can calculate how long the year is. The seasonal cycle is similar to Earth's: Mars has the same inclination as the Earth (25.19°) with respect to its own orbital plane. From the Sun to the red planet, the distance fluctuates in different periods from 206 to 249 million kilometers.
Temperature readings are different from ours:
- average temperature -46 °С;
- during the period of removal from the Sun, the temperature is about -143 ° С;
- in summer - -35 ° С.
Water on Mars
An interesting discovery was made by scientists in 2008. The rover discovered water ice at the poles of the planet. Prior to this discovery, it was believed that only carbonic ices existed on the surface. Even later, it turned out that precipitation in the form of snow falls on the red planet, and carbon dioxide snow falls near the south pole.
Throughout the year, storms are observed on Mars, spreading over hundreds of thousands of kilometers. They make it difficult to track what is happening on the surface.
A year on Mars
Around the Sun, the red planet makes a circle in 686 Earth days, moving at a speed of 24 thousand kilometers per second. A whole system of designation of Martian years has been developed.
When studying the question of how long a day on Mars lasts in hours, mankind has made many sensational discoveries. They show that the red planet is close to Earth.
Length of a year on Mercury
Mercury is the planet closest to the Sun. It rotates around its axis in 58 Earth days, that is, one day on Mercury is 58 Earth days. And to fly around the Sun, the planet needs only 88 Earth days. This amazing discovery shows that on this planet a year lasts almost three Earth months, and while our planet flies one circle around the Sun, Mercury makes more than four revolutions. And how long does a day last on Mars and other planets when compared with Mercury time? It's amazing, but in just one and a half Martian days, a whole year passes on Mercury.
Time on Venus
Unusual is the time on Venus. One day on this planet lasts 243 Earth days, and a year on this planet lasts 224 Earth days. It seems strange, but such is the mysterious Venus.
Time on Jupiter
Jupiter is the largest planet in our solar system. Based on its size, many people think that the day on it lasts a long time, but this is not so. Its duration is 9 hours 55 minutes - less than half the length of our earthly day. The gas giant rotates rapidly around its axis. By the way, because of him, constant hurricanes and severe storms rage on the planet.
Time on Saturn
A day on Saturn lasts about the same as on Jupiter, and is 10 hours 33 minutes. But a year lasts approximately 29,345 Earth years.
Time on Uranus
Uranus is an unusual planet, and it is not so easy to determine how long a day of light will last on it. A sidereal day on the planet lasts 17 hours and 14 minutes. However, the giant has a strong axial tilt, which is why it rotates around the Sun almost on its side. Because of this, at one pole, summer will last 42 Earth years, while at the other pole it will be night at that time. When the planet rotates, the other pole will be illuminated for 42 years. Scientists have come to the conclusion that a day on the planet lasts 84 Earth years: one Uranian year lasts almost one Uranian day.
Time on other planets
Dealing with the question of how long a day and a year last on Mars and other planets, scientists have found unique exoplanets where a year lasts only 8.5 Earth hours. This planet is called Kepler 78b. Another planet KOI 1843.03 was also discovered, with a shorter period of rotation around its sun - only 4.25 Earth hours. Every day a person would become three years older if he lived not on Earth, but on one of these planets. If people could adjust to the planetary year, it would be best to go to Pluto. On this dwarf, a year is 248.59 Earth years.
