Jan 20, 2023 08:00:00

A cosmologist explains ``Where is the universe spreading?''

It is known that the universe is constantly expanding at a speed faster than the speed of light, and it is said that

human beings cannot reach the end of the universe, and experts are divided on whether there is an end to the universe in the first place. , there are many things that even modern science and technology do not know. Paul Sutter, an American cosmologist, explains how such expansion of the universe is happening.

What Is Our Universe Expanding Into? - Nautilus
https://nautil.us/what-is-our-universe-expanding-into-258168/

From Einstein's general theory of relativity and the results of actual observations of the universe, we know that the universe has continued to expand since the Big Bang occurred about 13.77 billion years ago. If you rewind time about 13.77 billion years, you will reach an infinitely small point that existed before the universe expanded, so it seems that it is considered to be the ``center of the expanding universe'', but that point is an existing theory. It becomes a 'singularity' that cannot be explained. Therefore, even if we say that the universe is expanding, it is difficult to think about where the universe is centered and where it is expanding.

What exactly is a black hole or a ``singularity'' at the beginning of the universe? -GIGAZINE

Sutter, a cosmologist at Stony Brook University in New York who studies the void space of the universe and the light of the Big Bang, asked the scientific journal Nautilus , 'Where is our universe expanding?' In response to the question, he replied, 'Very good question, but not a great question.'

According to Sutter, it is often said that ``the universe is expanding,'' but strictly speaking, it is ``expanding,'' not that it is expanding by stretching the edge of the center. Such expressions are not appropriate. Since the big bang occurred simultaneously in all places in the universe, the universe continues to expand from all places. Recognition such as 'the space is spreading' is a mistake.

Regarding the expression 'the universe is expanding,' Sutter said, 'If, for example, you can map multiple galaxies and record the distance between them, you should know that the distance is increasing after a year.' explains Mr. In other words, 'the universe is expanding' means that 'the distance between galaxies is increasing on average over time'. Therefore, it is said that there is no center or edge, and it is not true that the whole universe is spreading toward somewhere.

Similarly, if we focus on the Milky Way galaxy to which the Earth belongs, 'the whole universe seems to be expanding away from us.' However, when other galaxies are centered, they 'appear to expand as they recede' in the same way, and Sutter said, 'The universe does not expand toward anything or from anywhere. The universe is the universe. From itself, it expands into the universe itself.'