In space, as we know, every object is in motion – planets revolve around stars, and star systems in turn revolve around galaxies. Galaxies are also constantly moving. There are different reasons for this. For example, scientists have concluded that 13.8-17 billion years ago, the Big Bang occurred, which led to the super-fast expansion of the Universe from an infinitely dense single point. This led to the emergence of everything we observe today, and the expansion is still ongoing. However, the Big Bang cannot explain all the types of motion that we know.
Everything in the universe is in motion, from atoms to galaxies. Photo source: gazeta-proregion.ru
Why the universe moves not only because of the Big Bang
People once believed that the Earth was motionless and the center of the universe. However, with the development of science, scientists have managed to find out that our planet is one of countless bodies in the Universe that revolve around stars and galaxies.
We now know that our entire Universe is in motion, from individual atoms to giant galaxy clusters. According to Edward Gomez, an astrophysicist and employee of the Las Cumbres Observatory, the reason is that motion was built into the Universe at its creation. As mentioned above, the Universe began to expand from the very beginning as a result of the force of the Big Bang. Therefore, motion is a kind of imprint of the beginning of everything.
However, the Big Bang only caused the expansion of the Universe, which means that it causes motion on a very large scale. As Edward Gomez explains, the effects of the Big Bang are noticeable only on objects that are very far from each other. Over time, the space between them becomes larger and larger.
Stars rotate like planets, but around their own galaxy. Photo source: spacegid.com
However, objects are in motion on much smaller scales as well. For example, the Earth's motion around the Sun, and the Sun's motion around the galaxy, cannot be explained by the Big Bang theory and the expansion of the Universe. However, rotation is also an integral part of the Universe, since there is nothing that does not rotate.
Why do all objects in the Universe rotate
The rotation of objects in orbits around other objects occurs due to angular momentum. That is, if two objects approach each other but do not crash, their mutual gravity begins to attract, which leads to rotation. That is, the cause of rotation is actually gravity.
This phenomenon concerns absolutely all objects in space, from dust to giant galaxies. For example, our Milky Way galaxy actually revolves around the Andromeda galaxy, or more precisely, both galaxies revolve around each other. True, at the same time, they are approaching each other. After about 4.5 billion years, the two galaxies will collide, but that is a topic for another conversation.
The solar system is shaped like a disk. Image source: theidealist.ru
Due to angular momentum, not only do different objects rotate around each other, but they are also stretched into a disk. For example, the solar system is stretched into a disk like pizza dough, which is spun by professional craftsmen to get a “pancake” of uniform thickness. Any other systems in the Universe are stretched in the same way.
By the way, the Solar System was originally a mass of gas and dust that merged into a star and planets. At the same time, the angular momentum ensured its eternal rotation as long as it exists. However, this has nothing to do with the rotation of the planets around their axis, since its cause is inertia.
The Riddle of the Galaxy's Rotation
Scientists have noticed that the galaxy does not rotate as one would expect from an object made up of individual components. It behaves as if it were solid and solid, like the aforementioned pizza dough. Given that the galaxy is a cluster of different objects, the stars that are on the outskirts should rotate more slowly than those in the center. But for some reason, this does not happen.
The galaxy rotates like a solid object. Photo source: naked-science.ru
According to scientists, this is proof that there is something in the Universe that is not visible, but it affects objects. Scientists began to call this something “dark matter”.
Dark matter cannot be seen, since it does not interact with light. Accordingly, it cannot be detected in telescopes. However, it has mass and is able to interact with other objects that have mass as a result of gravity. In particular, dark matter also has angular momentum. And this, according to scientists, is another reason why everything moves in space.
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To summarize all of the above, movement is a fundamental feature of the universe, due to which it has the form that we know. Something is constantly happening in it – all sorts of chemical reactions, physical processes, etc. The most basic form of energy is movement, the causes of which, as we found out, are different.