Interesting Facts About Gravity

When it comes to gravity, we inevitably return to memories of elementary school, where we first learned about this unusual force. We were told that it is what keeps us on Earth, but that is not its only function.

Gravity is just a theory, not a law

There is an idea that gravity has nothing to do with scientific laws. If you enter the word "gravity" into any search engine, you will see countless articles about the law of gravity. In reality, the concepts of "law" and "theory" in the scientific world have significant differences. A law is based on certain data from the results of factual research. A theory is an idea that explains the existence of a phenomenon.

Understanding these concepts makes it clear why gravity cannot be called a law. At the moment, scientists cannot measure its impact on every celestial body. Voyager 1 (an automatic probe exploring the Solar System and its surroundings) explored the Solar System at a distance of approximately 21 billion kilometers from Earth and even briefly went beyond its limits. Voyager 1 has been "on a business trip" for 40 years now, but the Universe is too vast to explore it thoroughly.

There are gaps in the theory of gravity — and that's a fact

The theory of gravity is imperfect, but some of its gaps are not noticeable from Earth. For example, according to the theory, the force of gravity from the Sun should be stronger on the Moon than on Earth, but then the Moon would orbit the Sun, not the Earth. By observing the movement of the Moon in the night sky, we can accurately determine that it revolves around the Earth. In school, we were also told about Isaac Newton, who discovered gaps in the theory of gravity. He also introduced a new mathematical term "fluxion," which later developed into the theory of gravity. The concept of "fluxion" may seem unfamiliar, today it is called a "function." Anyway, we all study functions in school, but they are not without flaws either. Therefore, it is quite likely that in Newton's "proofs" of the theory of gravity, not everything is as smooth as it seems.

Gravitational Waves

Albert Einstein's theory of relativity, also known as the theory of gravity, was introduced in 1915. Around the same time, the concept of gravitational waves emerged, the existence of which was only proven in 1974. Gravitational waves are vibrations in the spacetime continuum that arise from the movement of masses in the Universe due to the collision of black holes, the rotation of neutron stars, or the occurrence of supernovae. When any of these events occur, gravitational waves create ripples similar to circles on water from a stone thrown onto the surface. These waves travel through the Universe at the speed of light, which is why proving the existence of gravitational waves took almost 60 years. For the first 40 years, scientists observed waves generated by two stars that began to orbit each other due to the force of gravity. Over time, the stars moved closer and closer to each other in accordance with calculations based on Einstein's theory. This became evidence of the existence of gravitational waves.

Black Holes and Gravity

Black holes are one of the most mysterious phenomena in the Universe. They form when a star self-destructs and a new one is born, which ejects parts of the old star to a considerable distance, creating a place where gravity is so strong that no object that enters it can escape back. Gravity itself does not form a black hole, but it helps scientists understand the essence of black holes and detect them in the Universe. Since the gravitational force around a black hole is very strong, many stars and gases gather around it, which helps detect the black hole. Sometimes the gases around a black hole emit light, forming an aura. Without the super-powerful gravity in black holes, we would never have known about their existence.

Theory of Dark Matter and Dark Energy

Approximately 68% of the Universe consists of dark energy, while 27% consists of dark matter. However, neither dark energy nor matter have been deeply studied. Nevertheless, we know that dark energy has many properties. Einstein's theory of relativity played an important role in understanding dark energy and its ability to expand and create more space. Initially, scientists assumed that gravity restrained the expansion of the Universe, but in 1998, with the help of the Hubble Space Telescope, it was established that the Universe is expanding faster and faster. Thanks to this fact, it became clear that the theory of relativity cannot explain what is happening in the Universe. Scientists hypothesized the existence of dark matter and dark energy, which allow the Universe to continue to grow.

Gravitons

Everything we are taught in school about gravity being a force of attraction, but is it really? If we imagine gravity itself as a particle and call it a graviton (or a quantum of the gravitational field), then it turns out that gravitons form the force of attraction. True, physicists have not been able to confirm the existence of these particles, but there are many reasons why they should exist. The first reason is that gravity is just a force (one of the four fundamental natural forces), and its main element cannot be defined. Even if gravitons exist, determining them is very difficult. Physicists purely theoretically assume that gravitational waves consist of gravitons. It is quite easy to detect gravitational waves; it is enough to create reflections of light beams in mirrors and see their splitting. But such a method is not suitable for determining the change in distance between gravitons.

Formation of Wormholes

Wormholes (spacetime tunnels in the hypothetical model of the Universe) are truly fascinating phenomena. What if it were possible to travel through a cosmic tunnel at the speed of light and find oneself in another galaxy? If wormholes exist, then this is quite possible. To date, there is no confirmation of the existence of such tunnels, but physicists are seriously considering their creation. Using Einstein's theory of relativity, physicist Ludwig Flamm described how gravity can distort time and space to make the creation of a wormhole possible. Of course, this is not the only theory of the origin of such tunnels.

Planets Also Attract the Sun

It is well known that the gravitational force of the Sun affects the planets of our solar system, which is why they orbit around it. Similarly, the Earth attracts the Moon. However, every celestial body with mass also affects the Sun with a gravitational force, the power of which depends on the mass of the objects and the distance between them. And since the Sun has the strongest gravity in our Galaxy, all planets orbit around it.

Zero Gravity

We have all seen photos and heard stories about there being no gravity in space, so astronauts can float in weightlessness. Nevertheless, there is still gravity in space, but it is so small that it is even called microgravity. It is thanks to this that astronauts appear to float in the air. If there were absolutely no gravity in space, then planets could not orbit the Sun, and the Moon around the Earth, simply because the greater the distance, the weaker the gravitational force.

Time Travel

The possibility of time travel has always deeply fascinated humanity. Numerous theories, including the theory of gravity, can explain the possibility of time travel. The force of gravity creates a curvature in time and space, which causes objects to move in a spiral, resulting in these objects moving faster than on the surface of the Earth. For example, clocks on artificial satellites in space shift only by 38 microseconds per day because the force of gravity in space causes objects to move faster than on Earth. For this reason, any astronaut returning from orbit can be considered a time traveler; it's just that the effect is not strong enough for them to feel it. The main question remains the possibility of time travel as depicted in movies, but there are currently no answers to it.