What is the Olbers Paradox, one of the world-class paradoxes?

The specific question of Olbers's paradox is: Why is the background color of the sky black at night? Astronomers realize that if the universe is uniform and infinite, you will see light from countless stars no matter where you look. Staring at any point in the night sky, our eyes will eventually pass through countless stars and receive infinite light. Therefore, the night sky should be bright. The fact is that the background color of that night is black, which contradicts the above speculation.

This paradox has puzzled many astronomers or astronomy enthusiasts, the most famous of which is Kepler. At that time, he could not explain this paradox well. He can only speculate that the universe is limited and surrounded by a shell, so only limited light can reach our eyes. There is also Olbers's view that the light shining on the earth is absorbed by the dust clouds in the universe, otherwise the temperature of our earth will be too high to survive.

Obviously, this conjecture cannot explain Olbers's paradox well. In our opinion, there are indeed thousands of stars shining in the universe. When dust clouds absorb the same temperature as the body, they will also emit the same light, which is the absorption and propagation of light in the universe. In this way, light can still shine on the earth through the dust cloud.

In fact, the first person to solve this paradox is American writer edgar allan poe, who is also an astronomy enthusiast. He wrote in the article: The invisible background is so far away that no light can reach here. He pointed out the key to solving the problem. The universe is not infinitely old, so the final answer for subsequent scientists is that the sky at night is actually not black. Due to the red shift of light caused by the expansion of the universe, the light emitted by stars is elongated into electromagnetic waves with lower frequency, and even becomes infrared and microwave. If our eyes can see microwave radiation more or less, not just visible light, we will see the radiation of the Big Bang filling the night sky.