What does the sun use as fuel, and why hasn't it burned out for 4.6 billion years? How long can it still burn?

When it comes to the sun, we all know that it is the source of life, it selflessly "burns" itself, emits light and heat, and nurtures billions of lives. But when it comes to how the sun "burns", I am afraid that most people can only say "nuclear fusion" based on their impressions, so I don't know if you have ever thought about why the hydrogen bomb explosion that also uses nuclear fusion can only maintain Just a few seconds, but the sun can "burn" for tens of billions of years?

Although the sun uses nuclear fusion technology like the hydrogen bomb, the level of science and technology contained in it is very different. Just inside the red sun above our heads, there is a star that all scientists have been striving for but has always been difficult to reach. Crown - Controlled Fusion .

The so-called controllable nuclear fusion technology actually refers to making the energy released by nuclear fusion controllable and usable, rather than just causing blind destruction. Once the research in this direction is successful, the 400,000 tons of deuterium stored in the oceans of the earth can be fully utilized, and this energy is enough for the current human beings to use for tens of billions of years.

Controllable nuclear fusion is still like a dream for the current human beings, and there is not only a single form of nuclear fusion, like the nuclear fusion inside the sun is a typical proton qualitative change , a simple overview is four separate hydrogen Atoms will fuse into a helium atom. This kind of fusion is not violent, but it will also release a lot of energy, and the accumulation of small amounts of energy will create the dazzling light of the sun.

Explained why the sun "burns", I'm afraid everyone still can't understand why the sun can burn stably for tens of billions of years, but if we want to find the answer to this question, we have to start from two aspects, one is " balance ", two is " reserves ".

First, let's talk about "balance".

What I want to popularize here is that although the sun looks like a red sphere to us, nuclear fusion does not occur in all positions, but only occurs inside it, which also leads to the sun's nuclear fusion. Energy radiates from the inside out, and eventually spreads to all parts of the universe.

This kind of emanation from the inside out is somewhat similar to the explosion of a hydrogen bomb, and it is also a release of energy. But completely different from the hydrogen bomb, the sun itself is a supermassive planet with a great gravitational force inside. This gravitational force finally restricts the outward diffusion of energy inside the sun, and finally makes it in a certain part of the sun. A kind of "balance" is formed, which is the main reason why the sun will not burn out all at once, but can slowly glow and heat for tens of billions of years.

The light we usually see and the heat of the earth actually come from the energy generated by nuclear fusion inside the sun, but these energies eventually include many high-energy particle flows, wandering in the universe as "solar wind", and finally successfully reach Earth's, but only one in 2.2 billion , almost nothing. Only 1/10000 of this small amount of energy can be used by human beings, but even this meager amount of light and heat has also benefited us a lot.

Next, let's take a look at "reserves".

We also said earlier that the mass of the sun is far beyond what the earth can match, and greater mass often means greater "reserves". Like the combination of hydrogen nuclei that occurs on the sun, it is actually quite rare Yes, because the process is too difficult, but the mass of the sun is too large and the reserves of hydrogen nuclei are too large, which eventually makes the so-called "small probability events" become "commonplace".

You may not be able to understand it just by using an empty "big" to describe it. Here we will use the earth as an example to make a comparison.

From the perspective of diameter, the sun is about 109 times that of the earth. After converting to volume, the sun is equivalent to 1,295,029 earths . what is this concept? This means that the earth is almost as tiny as a speck of dust in front of the sun.

But it is such a "dust", after the deuterium contained in the ocean inside it fuses, the energy released is enough for human beings to use for tens of billions of years. From this, we can see the energy contained in the sun. How vast is it? With such vast energy, why is it so strange that the sun "burns" for 10 billion years?

Having said that, it is quite difficult for the sun to react as violently and quickly as a hydrogen bomb. Because the conditions for hydrogen bomb explosion are quite harsh, in order to create its high temperature and high pressure conditions, people can only detonate the atomic bomb first to prepare for it. The detonation temperature is at least hundreds of millions of degrees, and this condition is only 15 million degrees The sun is far away, and because of this, the "burning" of the sun and the "explosion" of the hydrogen bomb have their own advantages and disadvantages.

As far as the current situation is concerned, the sun has been burning for 4.6 billion years, and it will still burn for 50 to 6 billion years in the future. However, this time is too long for human beings, and it is unfounded for human beings to worry about the lifespan of the sun, because according to the calculations of scientists, if human beings cannot find a new way out, they will not live in the sun at all. The day that goes out.

This is not to say that there are insufficient resources on the earth, or the limitation of land space, but that as the sun continues to burn, its external radiation is also increasing, which means that the temperature on the earth's surface will slowly rise High, eventually reaching a terrifying level.

Take the moon as an example. The temperature on the side of the moon exposed to direct sunlight is as high as 100 degrees, while the temperature on the side facing away from the sun is minus 100 degrees. In such an extremely harsh living environment, human beings simply cannot survive normally; The scary thing is that sooner or later the earth will be the next moon, which is why we say we have to "escape" the sun and find a new way out.

In any case, the burning of the sun will not be shifted by human will, and if we want to ensure the continuation of the species in the vast universe, we must continue to explore and make breakthroughs, and finally find a way out in the sky above our heads. And the sun will continue to burn in this galaxy.