Burning for 4.6 billion years, what does the sun use for fuel?

2022-05-02 0 By

The 3.8 billion years of life on earth, in essence, are due to the “selfless dedication” of the sun. Almost all the celestial bodies in the solar system are the main source of energy from solar radiation.Given the mass of the Sun, such stars have a life span of at least 10 billion years. The sun has been burning for 4.6 billion years, which is “barely middle age,” and will burn for another five billion years.In chemistry class, we learned that combustion is a chemical reaction energy release process, with three main elements “combustible, oxygen, ignition point”, but for the burning sun, it seems not so, a matter burning for 4.6 billion years is also very exaggerated and unrealistic.What exactly does the sun use for fuel?Stars are very core celestial bodies in the universe. They are formed in primitive nebulae, and the sun is one of them. The sun is the core of the solar system, with its mass accounting for about 99.86% of the entire solar system, and the rest are eight planets, dwarf planets, asteroids, and various comets.The Sun is neither a rocky object like Earth or Mars, nor a gaseous object like Jupiter or Saturn. It is an ideal sphere of magnetic fields interwoven with hot plasma, about 1.3 million times the size of Earth.The sun consists mainly of 75 percent hydrogen and nearly 25 percent helium, plus less than 2 percent oxygen, carbon, iron and other heavy elements.What is the fuel of the sun?Hydrogen seems to be the best answer. Although the sun is glowing like a fireball, the fireball is not really burning. The sun is glowing because it is undergoing nuclear fusion, a process that is not technically a chemical reaction but takes place inside the nucleus of an atom.What happens is that the hydrogen nuclei are floating around in the core of the sun, and in the heat and pressure, they’re moving very fast and they’re colliding and they’re fusing, and they’re forming helium.There is a loss of mass in such a reaction, and according to Einstein’s equations of mass and energy, this loss of mass eventually becomes energy, propagating outward as light and heat.The reaction at the core of the sun is the ideal form of energy that humans are currently pursuing. It’s called controlled nuclear fusion, but we only have the ability to trigger it instantaneously, in the form of hydrogen bombs.If it’s fusion, why doesn’t it explode instantaneously like a hydrogen bomb?Instead of ordinary combustion, the sun’s interior is fusing about 600 million tons of hydrogen every second, resulting in 595 million tons of helium, a loss of 5 million tons of mass in the process, which is converted to energy according to Einstein’s mass-energy equations.Although the sun does undergo nuclear fusion, it doesn’t explode like a hydrogen bomb and release its energy instantaneously.There are two main reasons for this: The Sun is big and has a lot of fuel. If we can think of the sun as burning, at least it has plenty of fuel. After all, the sun makes up more than 99% of the solar system’s mass.Even if the reaction rate of nuclear fusion is fast, when the raw material is abundant, the fusion process is not instantaneous, but continuous.02, high fusion reaction conditions, didn’t happen overnight now many countries are carrying on the project “man-made sun”, is simply a controlled nuclear fusion technology of verification and implementation, if successful, then the human future depend on the energy in the form of more efficient, especially in space exploration may be on a big step,It is no longer a dream for human beings to go into space or even to other celestial bodies.But mastering the wild horse of nuclear fusion is no easy task, and the sun is uniquely suited to do so.Under the gravitational collapse of the sun itself, an extreme environment of high temperature and high pressure is formed in its core (about 0.2 radius from its center). Under high pressure, the density can reach at least 150 times that of water, and the temperature can reach at least 15 million degrees Celsius, which is much higher than 5000-6000 degrees Celsius on the surface of the Sun.High temperatures make hydrogen nuclei move faster, and high pressures bring them closer together, two conditions that make fusion more likely.The sun and the kernel of gravitational collapse of its nuclear fusion is actually a process of mutual balance, when the collapse in the upper hand to an inward force, so the sun of the kernel in nuclear fusion reaction will be more intense, it will produce a larger outward force to resist the sun’s gravitational collapse, the result is to reduce the kernel of the fusion reaction rate.So it’s like a spring, it’s in dynamic equilibrium, so it’s not like the sun’s nuclear fusion just explodes like a hydrogen bomb.What happens when the sun goes down?Of course, even if the sun is big and has a lot of fuel, it will eventually go out. When the sun comes to the end of its life, what will happen to the Earth?What will be the end of humanity?Life on Earth does not live forever, and natural bodies that seem to last forever do in fact reach the end of their lives.That’s what the sun is like, it’s glowing and it’s hot right now, but in another five billion years, the sun will end up as a red giant, shedding its excess material and becoming a less active White Dwarf.Before that happens, the earth faces two changes:First, the sun accumulates helium in its core as it fuses, which is a much harder process, but as the amount of helium increases, it reaches a point at which the core begins to fuse violently, releasing energy instantly, and scientists speculate that if that happens,The energy released by the sun would destroy the four nearest rocky planets at once, while pushing the four more distant planets out of their previous orbits.Then the sun enters the age of a red giant, and its outer edge expands rapidly. Astronomers speculate that eventually the sun’s outer edge will reach the orbit of Mars, which means that even if earth survives the sun’s helium shock, it will eventually be swallowed up by the Sun, and the end of humanity will be over.In the end, of course, it may be too early to worry about the future of the sun, since human civilization has only been around for millions of years, and the jury is still out on how far it can go.The dinosaurs that had ruled the earth for 160 million years were all wiped out. Five billion years is probably too long for civilization.The big problem is that the sun has given us plenty of time as the earth’s climate changes, leading to more extreme weather events that may eventually trigger extinction events.Black hole, images from the Internet.