This article will focus on the history of the discovery of the law of universal gravitation. Here we will get acquainted with biographical information from the life of the scientist who discovered this physical dogma, consider its main provisions, the relationship with quantum gravity, the course of development and much more.
Genius
Sir Isaac Newton is a scientist originally from England. At one time, he devoted a lot of attention and effort to such sciences as physics and mathematics, and also brought a lot of new things to mechanics and astronomy. He is rightfully considered one of the first founders of physics in its classical model. He is the author of the fundamental work “Mathematical Principles of Natural Philosophy,” where he presented information about the three laws of mechanics and the law of universal gravitation. Isaac Newton laid the foundations of classical mechanics with these works. He also developed an integral type, light theory. He also made major contributions to physical optics and developed many other theories in physics and mathematics.
Law
The law of universal gravitation and the history of its discovery go back to the distant past. Its classical form is a law that describes gravitational-type interactions that do not go beyond the framework of mechanics.
Its essence was that the indicator of the force F of gravitational thrust arising between 2 bodies or points of matter m1 and m2, separated from each other by a certain distance r, maintains proportionality in relation to both indicators of mass and is inversely proportional to the square of the distance between the bodies:
F = G, where the symbol G denotes the gravitational constant equal to 6.67408(31).10 -11 m 3 /kgf 2.
Newton's gravity
Before considering the history of the discovery of the law of universal gravitation, let us familiarize ourselves in more detail with its general characteristics.
In the theory created by Newton, all bodies with large mass should generate a special field around themselves that attracts other objects to itself. It's called a gravitational field, and it has potential.
A body with spherical symmetry forms a field outside itself, similar to that created by a material point of the same mass located at the center of the body.
The direction of the trajectory of such a point in the gravitational field created by a body with a much larger mass obeys. Objects of the universe, such as, for example, a planet or a comet, also obey it, moving along an ellipse or hyperbola. The distortion that other massive bodies create is taken into account using the provisions of perturbation theory.
Analyzing accuracy
After Newton discovered the law of universal gravitation, it had to be tested and proven many times. For this purpose, a series of calculations and observations were made. Having come to agreement with its provisions and based on the accuracy of its indicator, the experimental form of evaluation serves as a clear confirmation of general relativity. Measuring the quadrupole interactions of a body that rotates, but its antennas remain stationary, shows us that the process of increasing δ depends on the potential r -(1+δ), at a distance of several meters and is in the limit (2.1±6.2) .10 -3 . A number of other practical confirmations allowed this law to establish itself and take a single form, without modifications. In 2007, this dogma was rechecked at a distance of less than a centimeter (55 microns-9.59 mm). Taking into account the errors of the experiment, scientists examined the distance range and found no obvious deviations in this law.
Observation of the Moon's orbit in relation to the Earth also confirmed its validity.
Euclidean space
Newton's classical theory of gravity is associated with Euclidean space. The actual equality with a fairly high accuracy (10 -9) of the indicators of the distance measure in the denominator of the equality discussed above shows us the Euclidean basis of the space of Newtonian mechanics, with a three-dimensional physical form. At such a point of matter, the area of the spherical surface has exact proportionality with respect to the square of its radius.
Data from history
Let us consider a brief history of the discovery of the law of universal gravitation.
Ideas were put forward by other scientists who lived before Newton. Epicurus, Kepler, Descartes, Roberval, Gassendi, Huygens and others thought about it. Kepler hypothesized that the force of gravity is inversely proportional to the distance from the Sun and extends only in the ecliptic planes; according to Descartes, it was a consequence of the activity of vortices in the thickness of the ether. There were a number of guesses that reflected the correct guesses about the dependence on distance.
A letter from Newton to Halley contained information that the predecessors of Sir Isaac himself were Hooke, Wren and Buyot Ismael. However, before him, no one had been able to clearly, using mathematical methods, connect the law of gravity and planetary motion.
The history of the discovery of the law of universal gravitation is closely connected with the work “Mathematical Principles of Natural Philosophy” (1687). In this work, Newton was able to derive the law in question thanks to Kepler's empirical law, which was already known by that time. He shows us that:
- the form of movement of any visible planet indicates the presence of a central force;
- the force of attraction of the central type forms elliptical or hyperbolic orbits.
About Newton's theory
An examination of the brief history of the discovery of the law of universal gravitation can also point us to a number of differences that distinguished it from previous hypotheses. Newton not only published the proposed formula for the phenomenon under consideration, but also proposed a mathematical model in its entirety:
- position on the law of gravity;
- provision on the law of motion;
- systematics of methods of mathematical research.
This triad could fairly accurately study even the most complex movements of celestial objects, thus creating the basis for celestial mechanics. Until Einstein began his work, this model did not require a fundamental set of corrections. Only the mathematical apparatus had to be significantly improved.
Object for discussion
The discovered and proven law throughout the eighteenth century became a well-known subject of active debate and scrupulous verification. However, the century ended with general agreement with his postulates and statements. Using the calculations of the law, it was possible to accurately determine the paths of movement of bodies in the heavens. Direct verification was carried out in 1798. He did this using a torsion type balance with great sensitivity. In the history of the discovery of the universal law of gravity, it is necessary to give a special place to the interpretations introduced by Poisson. He developed the concept of gravitational potential and the Poisson equation, with which it was possible to calculate this potential. This type of model made it possible to study the gravitational field in the presence of an arbitrary distribution of matter.
Newton's theory had many difficulties. The main one could be considered the inexplicability of long-range action. It was impossible to accurately answer the question of how gravitational forces are sent through vacuum space at infinite speed.
"Evolution" of the law
Over the next two hundred years, and even more, many physicists attempted to propose various ways to improve Newton's theory. These efforts ended in triumph in 1915, namely the creation of the General Theory of Relativity, which was created by Einstein. He was able to overcome the whole range of difficulties. In accordance with the correspondence principle, Newton's theory turned out to be an approximation to the beginning of work on the theory in a more general form, which can be applied under certain conditions:
- The potential of gravitational nature cannot be too large in the systems under study. The solar system is an example of compliance with all the rules for the movement of celestial bodies. The relativistic phenomenon finds itself in a noticeable manifestation of the perihelion shift.
- The speed of movement in this group of systems is insignificant in comparison with the speed of light.
Proof that in a weak stationary gravitational field, general relativity calculations take the form of Newtonian ones is the presence of a scalar gravitational potential in a stationary field with weakly expressed force characteristics, which is capable of satisfying the conditions of the Poisson equation.
Quantum scale
However, in history, neither the scientific discovery of the law of universal gravitation, nor the General Theory of Relativity could serve as the final gravitational theory, since both do not satisfactorily describe gravitational-type processes on the quantum scale. An attempt to create a quantum gravitational theory is one of the most important tasks of modern physics.
From the point of view of quantum gravity, interaction between objects is created through the exchange of virtual gravitons. In accordance with the uncertainty principle, the energy potential of virtual gravitons is inversely proportional to the period of time in which it existed, from the point of emission by one object to the moment in time at which it was absorbed by another point.
In view of this, it turns out that on a small distance scale the interaction of bodies entails the exchange of virtual-type gravitons. Thanks to these considerations, it is possible to conclude a statement about Newton’s law of potential and its dependence in accordance with the inverse proportionality index with respect to distance. The analogy between Coulomb's and Newton's laws is explained by the fact that the weight of gravitons is zero. The weight of photons has the same meaning.
Misconception
In the school curriculum, the answer to the question from history, how Newton discovered the law of universal gravitation, is the story of a falling apple fruit. According to this legend, it fell on the scientist’s head. However, this is a widespread misconception, and in reality everything was possible without such a case of possible head injury. Newton himself sometimes confirmed this myth, but in reality the law was not a spontaneous discovery and did not come in a fit of momentary insight. As was written above, it was developed over a long time and was first presented in the works on the “Mathematical Principles”, which were released to the public in 1687.
We all studied the law of universal gravitation in school. But what do we really know about gravity beyond what our school teachers put into our heads? Let's update our knowledge...
Fact one
Everyone knows the famous parable about the apple that fell on Newton's head. But the fact is that Newton did not discover the law of universal gravitation, since this law is simply not present in his book “Mathematical Principles of Natural Philosophy.” There is no formula or formulation in this work, as anyone can see for themselves. Moreover, the first mention of the gravitational constant appears only in the 19th century and, accordingly, the formula could not have appeared earlier. By the way, the coefficient G, which reduces the result of calculations by 600 billion times, has no physical meaning and was introduced to hide contradictions.
Fact two
It is believed that Cavendish was the first to demonstrate gravitational attraction in laboratory ingots, using a torsion balance - a horizontal beam with weights at the ends suspended on a thin string. The rocker could turn on a thin wire. According to the official version, Cavendish brought a pair of 158 kg blanks from opposite sides to the rocker weights and the rocker rotated at a small angle. However, the experimental methodology was incorrect and the results were falsified, which has been convincingly proven. Cavendish spent a long time reworking and adjusting the installation so that the results would fit the average density of the earth expressed by Newton. The methodology of the experiment itself involved moving the blanks several times, and the reason for the rotation of the rocker arm was microvibrations from the movement of the blanks, which were transmitted to the suspension.
This is confirmed by the fact that such a simple installation of the 18th century for educational purposes should have been installed, if not in every school, then at least in the physics departments of universities, in order to show students in practice the result of the law of universal gravitation. However, the Cavendish installation is not used in educational programs, and both schoolchildren and students take the word that two blanks attract each other.
Fact three
If we substitute reference data on the earth, moon and sun into the formula of the law of universal gravitation, then at the moment when the Moon flies between the Earth and the Sun, for example, at the moment of a solar eclipse, the force of attraction between the Sun and the Moon is more than 2 times higher than between Earth and Moon!
According to the formula, the Moon would have to leave the earth's orbit and begin to revolve around the sun.
Gravity constant – 6.6725×10 −11 m³/(kg s²).
The mass of the Moon is 7.3477 × 10 22 kg.
The mass of the Sun is 1.9891×10 30 kg.
The mass of the Earth is 5.9737 × 10 24 kg.
Distance between the Earth and the Moon = 380,000,000 m.
Distance between the Moon and the Sun = 149,000,000,000 m.
Earth And Moon:
6.6725×10 -11 x 7.3477×10 22 x 5.9737×10 24 / 380000000 2 = 2.028×10 20 H
Moon And Sun:
6.6725 × 10 -11 x 7.3477 10 22 x 1.9891 10 30 / 149000000000 2 = 4.39×10 20 H
2.028×10 20 H
The force of attraction between the Earth and the MoonThe force of attraction between the Moon and the Sun
These calculations can be criticized by the fact that the reference density of this celestial body is most likely not determined correctly.
Indeed, experimental evidence suggests that the Moon is not a solid body, but a thin-walled shell. The authoritative journal Science describes the results of the work of seismic sensors after the third stage of the rocket that accelerated the Apollo 13 spacecraft hit the lunar surface: “the seismic ringing was detected for more than four hours. On Earth, if a missile struck at an equivalent distance, the signal would last only a few minutes.”
Seismic vibrations that decay so slowly are typical of a hollow resonator, not a solid body.
But the Moon, among other things, does not show its attractive properties in relation to the Earth - the Earth-Moon pair moves not around the common center of mass, as it would be according to the law of universal gravitation, and the ellipsoidal orbit of the Earth contrary to this law doesn't become zigzag.
Moreover, the parameters of the orbit of the Moon itself do not remain constant; the orbit, in scientific terminology, “evolves”, and does this contrary to the law of universal gravitation.
Fact four
How can this be, some will object, because even schoolchildren know about ocean tides on Earth, which occur due to the attraction of water to the Sun and Moon.
According to the theory, the Moon's gravity forms a tidal ellipsoid in the ocean, with two tidal humps that move across the Earth's surface due to daily rotation.
However, practice shows the absurdity of these theories. After all, according to them, a tidal hump 1 meter high should move through the Drake Passage from the Pacific Ocean to the Atlantic in 6 hours. Since water is incompressible, the mass of water would raise the level to a height of about 10 meters, which does not happen in practice. In practice, tidal phenomena occur autonomously in areas of 1000-2000 km.
Laplace was also amazed by the paradox: why in the seaports of France full water comes sequentially, although according to the concept of a tidal ellipsoid it should come there simultaneously.
Fact five
The principle of gravity measurements is simple - gravimeters measure the vertical components, and the deflection of the plumb line shows the horizontal components.
The first attempt to test the theory of mass gravity was made by the British in the mid-18th century on the shores of the Indian Ocean, where, on one side, there is the world’s highest rock ridge of the Himalayas, and on the other, an ocean bowl filled with much less massive water. But, alas, the plumb line does not deviate towards the Himalayas! Moreover, ultra-sensitive instruments - gravimeters - do not detect a difference in the gravity of a test body at the same height, both above massive mountains and over less dense seas of kilometer depth.
To save the established theory, scientists came up with a support for it: they say the reason for this is “isostasy” - denser rocks are located under the seas, and loose rocks are located under the mountains, and their density is exactly the same as to adjust everything to the desired value.
It was also experimentally established that gravimeters in deep mines show that the force of gravity does not decrease with depth. It continues to grow, depending only on the square of the distance to the center of the earth.
Fact six
According to the formula of the law of universal gravitation, two masses, m1 and m2, the sizes of which can be neglected in comparison with the distances between them, are supposedly attracted to each other by a force directly proportional to the product of these masses and inversely proportional to the square of the distance between them. However, in fact, not a single proof is known that matter has a gravitational attractive effect. Practice shows that gravity is not generated by matter or masses; it is independent of them and massive bodies only obey gravity.
The independence of gravity from matter is confirmed by the fact that, with rare exceptions, small bodies of the solar system have no gravitational attractive ability completely. With the exception of the Moon, more than six dozen planetary satellites show no signs of their own gravity. This has been proven by both indirect and direct measurements; for example, since 2004, the Cassini probe in the vicinity of Saturn has been flying close to its satellites from time to time, but no changes in the speed of the probe have been recorded. With the help of the same Casseni, a geyser was discovered on Enceladus, the sixth largest moon of Saturn.
What physical processes must occur on a cosmic piece of ice for jets of steam to fly into space?
For the same reason, Titan, Saturn's largest moon, has a gas tail as a result of atmospheric outflow.
No satellites predicted by theory have been found on asteroids, despite their huge number. And in all the reports about double or paired asteroids that supposedly revolve around a common center of mass, there was no evidence of the rotation of these pairs. The companions happened to be nearby, moving in quasi-synchronous orbits around the sun.
Attempts to place artificial satellites into asteroid orbit ended in failure. Examples include the NEAR probe, which was sent to the Eros asteroid by the Americans, or the HAYABUSA probe, which the Japanese sent to the Itokawa asteroid.
Fact seven
At one time, Lagrange, trying to solve the three-body problem, obtained a stable solution for a particular case. He showed that the third body can move in the orbit of the second, all the time being in one of two points, one of which is 60° ahead of the second body, and the second is the same amount behind.
However, two groups of companion asteroids found behind and in front of Saturn's orbit, which astronomers joyfully called the Trojans, moved out of the predicted areas, and the confirmation of the law of universal gravitation turned into a puncture.
Fact eight
According to modern concepts, the speed of light is finite, as a result we see distant objects not where they are located at the moment, but at the point from which the ray of light we saw started. But at what speed does gravity spread? Having analyzed the data accumulated by that time, Laplace established that “gravity” propagates faster than light by at least seven orders of magnitude! Modern measurements of receiving pulsar pulses have pushed the speed of propagation of gravity even further - at least 10 orders of magnitude faster than the speed of light. Thus, experimental research contradicts the general theory of relativity, which official science still relies on, despite its complete failure.
Fact nine
There are natural anomalies of gravity, which also do not find any clear explanation from official science. Here are some examples:
Fact ten
There is a large number of alternative studies with impressive results in the field of antigravity, which fundamentally refute the theoretical calculations of official science.
Some researchers analyze the vibrational nature of antigravity. This effect is clearly demonstrated in modern experiments, where droplets hang in the air due to acoustic levitation. Here we see how, with the help of a sound of a certain frequency, it is possible to confidently hold drops of liquid in the air...
But the effect, at first glance, is explained by the gyroscope principle, but even such a simple experiment mostly contradicts gravity in its modern understanding.
Viktor Stepanovich died under rather strange circumstances and his work was partially lost, but some part of the anti-gravity platform prototype has been preserved and can be seen in the Grebennikov Museum in Novosibirsk.
Another practical application of antigravity can be observed in the city of Homestead in Florida, where there is a strange structure of coral monolithic blocks, which is popularly nicknamed. It was built by a native of Latvia, Edward Lidskalnin, in the first half of the 20th century. This man of thin build did not have any tools, he did not even have a car or any equipment at all.
It was not used at all by electricity, also due to its absence, and yet somehow it went down to the ocean, where it cut out multi-ton stone blocks and somehow delivered them to its site. laying out with perfect precision.
After Ed's death, scientists began to carefully study his creation. For the sake of the experiment, a powerful bulldozer was brought in and an attempt was made to move one of the 30-ton blocks of the coral castle. The bulldozer roared and skidded, but did not move the huge stone.
A strange device was found inside the castle, which scientists called a direct current generator. It was a massive structure with many metal parts. 240 permanent strip magnets were built into the outside of the device. But how Edward Leedskalnin actually made multi-ton blocks move still remains a mystery.
The research of John Searle is known, in whose hands unusual generators came to life, rotated and generated energy; discs with a diameter of half a meter to 10 meters rose into the air and made controlled flights from London to Cornwall and back.
The professor’s experiments were repeated in Russia, the USA and Taiwan. In Russia, for example, in 1999, a patent application for “devices for generating mechanical energy” was registered under No. 99122275/09. Vladimir Vitalievich Roshchin and Sergei Mikhailovich Godin, in fact, reproduced SEG (Searl Effect Generator) and conducted a series of studies with it. The result was a statement: you can get 7 kW of electricity without costs; the rotating generator lost weight up to 40%.
The equipment from Searle's first laboratory was taken to an unknown location while he was in prison. The installation of Godin and Roshchin simply disappeared; all publications about her, with the exception of the application for an invention, disappeared.
The Hutchison Effect, named after the Canadian engineer-inventor, is also known. The effect manifests itself in the levitation of heavy objects, the alloy of dissimilar materials (for example, metal + wood), and the anomalous heating of metals in the absence of burning substances near them. Here is a video of these effects:
Whatever gravity actually is, it should be recognized that official science is completely unable to clearly explain the nature of this phenomenon.
Yaroslav Yargin
Based on materials:
The inhabitants of planet Earth take gravity as a matter of course. It is known that Isaac Newton developed the theory of universal gravitation because an apple fell on his head from a tree. But in reality, Earth's gravity is much more than a fruit falling from a tree. Our review contains several interesting facts about this power.
1. Toilet physics
On Earth, people want to relieve themselves as soon as their bladder is 1/3 full of its maximum capacity. This happens due to the effect of gravity on each of us. That is why astronauts on the ISS do not feel the need to urinate until their bladder is full.
2. Simple colonization
Gravity is a very important issue when colonizing other worlds. In theory, people can live on planets whose gravity differs from Earth's by no more than three times. Otherwise, the blood supply to the brain will be disrupted.
3. Mountain height
In theory, gravity determines the maximum height of the hills that form on the planet. So for the Earth (again in theory), mountains cannot exceed a height of 15 kilometers.
4. Lunar physics
During the historic Apollo mission, astronauts who landed on the surface of the Moon tested Galileo's theory of free fall acceleration. It turned out that objects on the moon, regardless of their mass, fall faster than on Earth. The reason for this is the lack of air and, as a result, resistance.
5. Failed Star
Many scientists consider Jupiter a failed star. The planet has a strong enough gravitational field to gain the mass the star needs, but it does not have a strong enough field to begin transforming into another star.
6. Teleportation
If you take and remove the Sol somewhere in one instant, then the solar system will continue to experience the effect of its gravitational field for some time. For the Earth, in theory, this “happiness” would last about 8 minutes, after which the celestial bodies would begin to lose their orbits.
7. Mountains on the stars
If our Sun ever turns into a neutron star, then according to scientists' calculations, its gravity will be so powerful that the height of the largest mountain on its surface could not exceed 5 millimeters.
8. The mournful singing of the stars
The action of the gravitational field of celestial bodies after their disappearance is not at all a dry theory. Our Solar System and our home planet are constantly experiencing the gravitational field of other stars. Considering the speed of the field's propagation in space, many of these stars ceased to exist a very, very long time ago.
9. Candles in space
If you light a candle in the absence of a gravitational field, then its fire will be round. Moreover, the color of the flame will be blue.
10. Soda kills
Drinking carbonated drinks in a gravity-free environment is definitely not a good idea. Why? This is because the absence of gravity completely changes the principle of distribution of gases in the human body. At best, this can provoke an attack of severe vomiting. This is why astronauts on the ISS don’t drink soda.
All those who are interested in science will be interested in learning about.
We get a basic understanding of gravity at school. There we are usually told that there is such an amazing force that holds everyone on Earth, and only thanks to it we do not fly into outer space and do not walk upside down. This is where the fun practically ends, because at school we are told only the most basic and simple things. In reality, there is a lot of debate about universal gravity, scientists propose new theories and ideas, and there are many more nuances than you can imagine. In this collection you will find several very interesting facts and theories about gravitational influence, which either were not included in the school curriculum, or they became known not so long ago.
10. Gravity is a theory, not a proven law.
There is a myth that gravity is a law. If you try to do online research on this topic, any search engine will offer you many links about Newton's Law of Universal Gravitation. However, in the scientific community, laws and theories are completely different concepts. A scientific law is an irrefutable fact based on confirmed data that clearly explains the essence of occurring phenomena. A theory, in turn, is a kind of idea with the help of which researchers try to explain certain phenomena.
If we describe gravitational interaction in scientific terms, it immediately becomes completely clear to a relatively literate person why universal gravity is considered in a theoretical plane, and not as a law. Since scientists still do not have the ability to study the gravitational forces of every planet, satellite, star, asteroid and atom in the Universe, we have no right to recognize universal gravity as a law.
The robotic Voyager 1 probe traveled 21 billion kilometers, but even at such a far distance from Earth, it barely left our planetary system. The flight lasted 40 years and 4 months, and during all this time the researchers did not receive much data to transfer thoughts about gravity from the theoretical field into the category of laws. Our Universe is too big, and we still know too little...
9. There are many gaps in the theory about gravity
We have already established that universal gravity is just a theoretical concept. Moreover, it turns out that this theory still has many gaps that clearly indicate its relative inferiority. Many inconsistencies have been noted not just within our solar system, but even here on Earth.
For example, according to the theory of universal gravity on the Moon, the gravitational force of the Sun should be felt much stronger than the gravity of the Earth. It turns out that the Moon should revolve around the Sun, and not around our planet. But we know that the Moon is our satellite, and for this, sometimes it’s enough just to raise your eyes to the night sky.
At school we were told about Isaac Newton, who had a fateful apple fall on his head, inspiring him with the idea of the theory of universal gravitation. Even Newton himself admitted that his theory had certain shortcomings. At one time, it was Newton who became the author of a new mathematical concept - fluxions (derivatives), which helped him in the formation of that very theory of gravitation. Fluxions may not sound so familiar to you, but in the end they have become firmly entrenched in the world of exact sciences.
Today, in mathematical analysis, the method of differential calculus is often used, based precisely on the ideas of Newton and his colleague Leibniz. However, this section of mathematics is also rather incomplete and not without its flaws.
8. Gravitational waves
Albert Einstein's general theory of relativity was proposed in 1915. Around the same time, the hypothesis of gravitational waves appeared. Until 1974, the existence of these waves remained purely theoretical.
Gravitational waves can be compared to ripples on the canvas of the space-time continuum, which appear as a result of large-scale events in the Universe. Such events could be a collision of black holes, changes in the rotation speed of a neutron star, or a supernova explosion. When something like this happens, gravitational waves spread across the space-time continuum, like ripples in water from a stone falling into it. These waves travel through the Universe at the speed of light. We don't see catastrophic events very often, so it takes us many years to detect gravitational waves. That's why it took scientists more than 60 years to prove their existence.
For almost 40 years, scientists have been studying the first evidence of gravitational waves. As it turns out, these ripples arise during the merger of a binary system of very dense and heavy gravitationally bound stars revolving around a common center of mass. Over time, the components of the binary star come closer together and their speed gradually decreases, as predicted by Einstein in his theory. The magnitude of gravitational waves is so small that in 2017 they were even awarded the Nobel Prize in Physics for their experimental detection.
7. Black holes and gravity
Black holes are one of the biggest mysteries in the Universe. They appear during the gravitational collapse of a fairly large star, which becomes a supernova. When a supernova explodes, a significant mass of stellar material is ejected into outer space. What is happening can provoke the formation of a space-time region in space in which the gravitational field becomes so strong that even light quanta are not able to leave this place (this black hole). It is not gravity itself that forms black holes, but it still plays a key role in observing and studying these regions.
It is the gravity of black holes that helps scientists detect them in the Universe. Because gravitational pull can be incredibly powerful, researchers can sometimes notice its effects on other stars or on the gases surrounding these regions. When a black hole sucks in gases, a so-called accretion disk is formed, in which matter is accelerated to such high speeds that it begins to produce intense radiation when heated. This glow can also be detected in the X-ray range. It was thanks to the accretion phenomenon that we were able to prove the existence of black holes (using special telescopes). It turns out that if it weren’t for gravity, we wouldn’t even know about the existence of black holes.
6. Theory about black matter and black energy
Approximately 68% of the Universe consists of dark energy, and 27% is reserved for dark matter. In theory. Despite the fact that in our world dark matter and dark energy have been allocated so much space, we know very little about them.
We presumably know that dark energy has a number of properties. For example, guided by Einstein's theory of gravity, scientists have suggested that dark energy is constantly expanding. By the way, scientists initially believed that Einstein’s theory would help them prove that over time, gravitational influence slows down the expansion of the Universe. However, in 1998, data obtained by the Hubble Space Telescope gave reason to believe that the Universe is expanding only at an increasing speed. At the same time, scientists came to the conclusion that the theory of gravity is not able to explain the fundamental phenomena occurring in our Universe. This is how the hypothesis about the existence of dark energy and dark matter appeared, designed to justify the acceleration of the expansion of the Universe.
5. Gravitons
At school we are told that gravity is a force. But it could also be something more... It is possible that gravity in the future will be considered as a manifestation of a particle called graviton.
Hypothetically, gravitons are massless elementary particles that emit a gravitational field. To date, physicists have not yet proven the existence of these particles, but they already have many theories about why these gravitons must certainly exist. One of these theories states that gravity is the only force (of the 4 fundamental forces of nature or interactions) that has not yet been associated with a single elementary particle or any structural unit.
Gravitons may exist, but recognizing them is incredibly difficult. Physicists suggest that gravitational waves consist of just these elusive particles. To detect gravitational waves, the researchers conducted many experiments, in one of which they used mirrors and lasers. An interferometric detector can help detect mirror displacements over even the most microscopic distances, but unfortunately it cannot detect changes associated with particles as tiny as gravitons. In theory, for such an experiment, scientists would need mirrors so heavy that if they collapsed, black holes could appear.
In general, it does not seem possible to detect or prove the existence of gravitons in the near future. For now, physicists are observing the Universe and hope that it is there that they will find answers to their questions and will be able to detect manifestations of gravitons somewhere outside of ground-based laboratories.
4. Theory of wormholes
Wormholes, wormholes or wormholes are another great mystery of the Universe. It would be cool to go into some kind of space tunnel and travel at the speed of light to get to another galaxy in the shortest possible time. These fantasies have been used more than once in science fiction thrillers. If there really are wormholes in the Universe, such jumps may be quite possible. At the moment, scientists have no evidence of the existence of wormholes, but some physicists believe that these hypothetical tunnels can be created by manipulating gravity.
Einstein's general theory of relativity allows for the possibility of mind-bending wormholes. Taking into account the work of the legendary scientist, another physicist, Ludwig Flamm, tried to describe how the force of gravity could distort time space in such a way that a new tunnel would form, a bridge between one region of the fabric of physical reality and another. Of course, there are other theories.
3. Planets also have a gravitational influence on the Sun
We already know that the gravitational field of the Sun affects all objects in our planetary system, and that is why they all revolve around our single star. By the same principle, the Earth is connected with the Moon, and that is why the Moon revolves around our home planet.
However, each planet and any other celestial body with sufficient mass in our solar system also has its own gravitational fields, which affect the Sun, other planets and all other space objects. The magnitude of the gravitational force exerted depends on the mass of the object and the distance between the celestial bodies.
In our solar system, it is thanks to gravitational interaction that all objects rotate in their given orbits. The strongest gravitational attraction, of course, is from the Sun. By and large, all celestial bodies with sufficient mass have their own gravitational field and influence other objects with significant mass, even if they are located at a distance of several light years.
2. Microgravity
We have all seen more than once photographs of astronauts soaring through orbital stations or even going outside the spacecraft in special protective suits. You are probably accustomed to thinking that these scientists usually tumble in space without feeling any gravity, because there is none there. And you would be very wrong if so. There is gravity in space too. It is customary to call it microgravity, because it is almost imperceptible. It is thanks to microgravity that astronauts feel light as feathers and so freely float in space. If there were no gravity at all, the planets simply would not revolve around the Sun, and the Moon would have left Earth’s orbit long ago.
The further an object is from the center of gravity, the weaker the force of gravity. It is microgravity that operates on the ISS, because all objects there are much further from the Earth’s gravitational field than even you are right here now. Gravity weakens at other levels as well. For example, let's take one individual atom. This is such a tiny particle of matter that it also experiences a fairly modest gravitational force. As atoms combine into groups, this force, of course, increases.
1. Time travel
The idea of time travel has fascinated humanity for quite some time. Many theories, including the theory of gravity, give hope that such travel will actually one day become possible. According to one concept, gravity forms a certain bend in the space-time continuum, which forces all objects in the Universe to move along a curved trajectory. As a result, objects in space move slightly faster compared to objects on Earth. More precisely, here’s an example: the clocks on space satellites are 38 microseconds (0.000038 seconds) ahead of your home alarm clocks every day.
Since gravity causes objects to move faster in space than on Earth, astronauts can actually be considered time travelers as well. However, this journey is so insignificant that upon returning home neither the astronauts themselves nor their loved ones notice any fundamental difference. But this does not negate one very interesting question - is it possible to use gravitational influence for time travel, as shown in science fiction films?
Gravity
Today's physics lesson will be devoted to the study of a topic that introduces us to the concept of force. Well, now let's try to understand in more detail what gravity is, and what is simply the concept of force?
For any inhabitant of planet Earth, gravity plays a huge role.
Gravity is the force with which all bodies are attracted to the Earth.
If, for example, we take two objects of the same shape, but different in size, then we will see that both bodies will be attracted to the Earth, but the difference between them is that the force with which they will be attracted to the Earth is not the same. After all, the greater the mass of a given body, the greater the force with which the body is attracted to the Earth.
Definition of force
With such interaction of bodies with each other, their speed will change differently. So, for example, a body can not only start moving, but also stop or even change the direction of speed. As a rule, we practically do not touch upon the question of the influence of any particular body on a given body, but only mention that the body’s speed changes under the influence of force. So, let's define force.
Force is a physical quantity that characterizes the force of change in speed.
There are 4 criteria for the action of force on a body. Let's look at them in more detail. So, what are these forces?
Firstly, this is when the body's force values change;
Secondly, when the body can change direction of movement;
Third, when changes in body size may occur;
Fourthly, changes in the shape of a given body can also occur.
Body deformation
It is also important to emphasize that a change in speed may not occur in the entire body, but only in some of its parts. For example, if you take and squeeze a foam ball, you and I will see that only some of its parts begin to move. This means that deformation has occurred with this ball.
Let's define deformation:
Well, now let's look at an example of the movement of a body that is thrown horizontally. To do this, attach a chute to a tripod and launch a ball along it. From this example we see that the trajectory of the ball is not straight, but its movement is uniform. Let's now try to figure out why this happens. And the reason for this movement is that all bodies located on the surface of the Earth tend to be attracted to the Earth. This could be a person who is bouncing on the surface of the Earth, and an object that is raised above the surface of the Earth, since all bodies are attracted to the Earth.
In addition, it is worth noting that not only bodies are attracted to the Earth, but also all these bodies have the ability to attract the Earth to themselves.
Each of you knows that twice a day you can watch big waves rise on the seas and oceans. Now let's remember why this happens. The reason is that the Moon has an effect on the Earth. It would be more correct to say that there is interaction between them.
This interaction was first described by the English physicist Isaac Newton. According to him, all bodies in the Universe have the ability to attract each other. He also determined that the higher the mass of interacting bodies, the greater the force of their interaction. According to Newton's calculations, it follows that the higher the distances between these bodies, the less force of interaction will be.
Interesting facts about gravity
From the topic we have covered, you already know that gravity refers to the force that pulls everything around to the center of the Earth. This is such an incredible force that any object can fall, but cannot fly into space on its own. Thanks to this force, the Moon rotates around the Earth.
Did you know that not only the Earth, but also all other planets and stars have an attractive force. What’s also interesting is that the larger a planet is, and if it is close to another object, then the greater the gravitational force it has.
But the Sun, although located quite far from the planets, due to its enormous size, is capable of holding these planets around itself and forces them to rotate around its orbit.
