May 21 is celebrated all over the world – International Space Day! (photo)

According to Einstein’s theory of relativity – the Universe has arisen from a certain point with a very high density and an infinite amount of energy – the Big Bang.

There are other theories, but at the moment there is no way to test any of them.

Astrophysicists believe that the universe is the same everywhere. Today, more than 1 million galaxies and quasars are known. Distance from Earth – up to 15 billion light years. They are evenly distributed in space, and their movement does not have a clearly defined direction.

According to one hypothesis, if the space-time geometry is closed, and the Universe is like a sphere, then in the future it will certainly be compressed. If the Universe is open, then it will expand forever. While observations of astronomers confirm the theory of an open universe.