The sun is a star, and the star is a planet that can emit light and heat by itself. The principle of its light emission is as follows:
According to the observation and analysis of scientists, we know that the sun is a huge fireball composed of hydrogen atoms and helium atoms. Inventors have some doubts about this: scientists separated hydrogen and helium from the sun's light spectrum. But sunlight comes from the surface of the sun. The sun is so big, can we really see through its components? Is it possible that only the surface of the sun or only a certain depth is hydrogen and helium? And it's a different situation inside? Or is the original material of BIGBANG hidden in the core of the sun? What makes scientists so sure that it must be hydrogen and helium? Inventors are very skeptical about the truth of this point. Because we don't know exactly what matter is in the core of the earth where we live. Not to mention the distant sun? This is a digression. Write it here for your reference.
The reason why solar energy glows and heats is because there is a strong thermonuclear reaction inside it. Thermonuclear reaction is a reaction that converts light nuclear fusion into heavier nuclei at extremely high temperature and releases a lot of energy. The thermonuclear reaction of the sun is that four hydrogen atoms are aggregated into one helium atom, and in this process, the mass is reduced (about one and a half times) and becomes energy, and the energy radiates around it in the form of light and heat. This is how the light and heat on our earth come from. The sun's light and heat on our earth are only one-second of them.
according to theoretical estimation, it takes more than 5 million degrees or even hundreds of millions of degrees to transform hydrogen nuclei into helium nuclei to realize uninterrupted thermonuclear reaction. At present, the artificial thermonuclear reaction realized is the explosion of hydrogen bomb, which makes it possible to fuse hydrogen into helium nuclei by using the high temperature generated at the moment when uranium (235U) or plutonium (239Pu) explodes during fission. This is how the hydrogen bomb exploded in our country.
From the above statement, you already know that the mass of the sun is getting smaller while it is constantly emitting light and heat, but this is a very slow process. According to scientists' speculation, it has been about five billion years since the sun was just born. And it will take at least five billion years for the sun to burn out completely, and the sun will not disappear within the lifetime of you and me.
You can rest assured that when you wake up tomorrow morning, you will surely see the warm sun.