Why is the night dark?

In fact, the world we live in is full of amazing problems. Although the times are progressing, science and technology are more and more developed, and people have successfully landed on the moon and Mars, in fact, the universe is unknown and amazing, and human beings still need to explore. Many people are curious about why the night is dark. Most people will think of a very simple answer to this question. They think this may be because the earth rotates day and night and the sun moves to another place at night. Without sunshine, the earth will turn black. In fact, this is just a very simple point of view, and the real answer is related to BIGBANG's theory.

The night is black not only because of the rotation of the earth, but also because of the rotation of the earth. However, on the moon, whether there is sunshine or not, we can find that the sky photographed by astronauts is black, while on the earth, there is bright moonlight and starlight at night, but we can find that the sky is still black. The universe is infinite. So far, people can't know exactly how big the universe is. That is to say, the radius of the universe is infinite, and the brightness should also be infinite. If you look at the starry sky from the earth, the night should be very bright.

Olbers's paradox is a very famous question in astronomy, about why the night is dark. One of the most popular ideas is that the universe is expanding, and then there are galaxies that you can't see moving. This situation is called Olbers Paradox. Olbers's paradox is that the universe is full of galaxies, and after a long time, the universe is full of light. Although some interstellar matter may absorb light and glow when heated, what we humans see is darkness, which means that the universe is constantly expanding, and the expansion speed of the universe is very fast, and then it will offset the generated light, which is also a kind of BIGBANG theory.

At present, astronomy can't fully explain this problem, because the night is dark. It can be said that this question is very troublesome, but Olbers's paradox is also a highly recognized answer.