When the night falls, we can see countless stars in the sky, and their radiance brings a little light to the dark night sky, which is also a beautiful landscape. In ancient times, people didn’t know what the stars in the sky were, so there are various legends about stars.
But with the continuous progress of human civilization and entering the age of science and technology, we finally know that most of the stars in the sky are actually stars like the sun. It is only because they are too far away from the earth that they look so small.
At the same time, we also understand that the reason why the earth has bright daylight, light and heat, all come from the sun. Without the sun’s rays, there would be no light on the earth, no suitable temperature, no life, and no human beings would be born. People in ancient times also often thought about a question: Why does the earth have day and night? Isn’t it possible that it is always daytime? In fact, almost everyone knows that this problem is because the earth is rotating.
The stars in the night sky are all stars far away from the earth, and they are all fixed luminous points. In the Milky Way, there are hundreds of billions of stars, while in the vast universe, the number of stars is too large to be counted. And we all understand that when countless luminous points can be gathered in one place, this place must be very bright.
The sun can illuminate the earth precisely because the countless photons of the sun have reached the earth, so there are also countless stars in the universe. Why can’t the light from them illuminate the earth? I believe that many friends have thought about this issue. Why is this? If there are only a very small number of stars, it is normal that the gathered light cannot light up the earth. However, there are countless stars in the vast universe. Theoretically speaking, these photons can reach the earth, but why do they not? Light up the earth?
In fact, this question was raised by a scientist from Germany more than 200 years ago. He regarded the universe as a static world, so the universe’s total space and time are infinite, and the number of stars in the universe, They are also evenly distributed. Eventually, all the lights can gather together to reach the earth. Then, theoretically speaking, even if there is no sun on the earth, the earth should not have night.
This view is also known as the “Obers paradox”, and according to data, as early as 1610, scientists have put forward this view and also derived another view, because there is a dark night on the earth, so The universe is not static. This view can also be used as one of the evidences of the Big Bang. This shows that the universe is always in expansion, and the distance between galaxies is constantly increasing due to the expansion. The farther.
Seeing this, I believe many of my friends have already understood why there are so many stars in the universe, but the light gathered together cannot light up the earth? The reason is actually very simple, that is, the universe is expanding rapidly, and this expansion speed exceeds the speed of light.
We all know that the universe originated from the Singularity Big Bang 13.8 billion years ago. There were no celestial bodies in the universe at the beginning of the Big Bang. At that time, only energy began to continuously transform into the initial hydrogen and helium. One billion years later, hydrogen and helium continued to accumulate to form the first early stars. Before the stars were born, the universe was also dark without any light.
It was not until the birth of the first stars that the universe had a little temperature and light, and the birth of stars also directly affected the evolution of the universe. The star itself is a refining plant, which can continuously convert hydrogen into other elements, and the various heavy elements that continue to appear later are also closely related to the stars.
It can be said that the star is the biggest contributor to the universe that can evolve to the present state. Without it, there would be no terrestrial planets, no living planets, and no intelligent life. After the Big Bang, the universe did not stop, but showed a rapid expansion. This expansion rate was the fastest in the early stage of the Big Bang, far exceeding the speed of light.
Even now, the farther away the galaxy is from the earth, the faster it will move away from us. The reason why we cannot observe galaxies tens of billions of light-years away is because the galaxy here has moved away faster than the speed of light. The speed of photons is only the speed of light, so photons from distant galaxies can never reach the earth.
It can be seen that although the number of stars in the universe is unlimited, the stars that can send their own light to the earth are limited. Therefore, even if the number of stars is very large, the light they gather is far from enough to light up the earth, and the light of the earth still needs the sun to maintain.
The contribution of the sun to the earth is too great. Many people worry that if one day the sun no longer shines and heats up, what should the earth do? Indeed, if the sun no longer shines and heats one day, then the earth will be plunged into darkness and endless cold. That would be a catastrophe for life on earth. If the earth is just an ordinary life planet without human beings with intelligent life, then the ultimate destiny can only be the end.
But the earth gave birth to human beings with intelligent life and became a civilized planet, and then the fate may change. We all know that the power of science and technology is infinite, as long as we can enter the age of nuclear fusion, then the artificial sun is nothing. We all understand that the sun is actually a huge nuclear fusion reactor, and it uses nuclear fusion to convert hydrogen into helium.
If we achieve controllable nuclear fusion, we can also create a small artificial sun. Even if the sun no longer emits heat, we can still use the artificial sun to maintain the light and heat of the earth, and the earth will not fall into the boundless darkness and heat. In the endless cold, life can continue to survive and multiply.
Of course, this is just our own imagination. In fact, the sun will not go out before nuclear fusion stops. Only when the combustion of hydrogen and helium in the sun is exhausted, then the mission of the sun will be completed, and it will enter the final stage of destruction. At this time, the current position of the earth will be insecure, and it can even be said that the entire solar system will be insecure.
At that time, the only way out for the earth and mankind to be preserved was to leave the solar system. If the technological strength at that time was strong enough, perhaps we could also transform the earth into a mobile spacecraft and take the earth out of the solar system. Then go to a new stable galaxy to make a home. In short, as long as human technology can advance and develop rapidly, we can deal with any disaster in the future, and humanity can continue forever.