Someone asks if the sun has burned for so long, is it full of oxygen, what do you think?
Why the sun can burn for so long? Is there enough oxygen in the sun?
The glow of the sun is not a general combustion, but nuclear fusion.
The sun is a plasma, that is, at high temperatures, some of the atoms' extranuclear electrons are lost, and the atoms become ions, but the lost electrons have not completely left the nucleus, but have been rippling around the nucleus, forming a mass to maintainElectrically neutral "plasma", this is the plasma.
The plasma state of the sun is not formed by the high temperature of the chemical combustion of oxygen, but originates from the huge energy released by the fusion of hydrogen in the core area, so that the gas on the surface of the sun is completely ionized. Such a flame of the sun does not require oxygenParticipate in burning, it becomes a dazzling light ball we see.
The ball of the sun is mainly composed of hydrogen and helium, and the proportion of hydrogen by mass is 73.46%, the proportion of helium is 24.85%, and there are about 1.69 other elements, including oxygen 0.77%, carbon 0.29%, iron 0.16%,Neon 0.12%, nitrogen 0.09%, silicon 0.07%, magnesium 0.05%, sulfur 0.04%, etc.
Only 21% of the atmospheric oxygen element on our planet will help to ignite enough flames. From the perspective of the composition of the sun, only 0.77% of oxygen can be burned by oxygen?
Plasma is the fourth state of matter, and stars are the main body of the visible universe, so we can see that the universe is mainly composed of plasma, which is the most material form in the world.
Why does the sun fusion?
The sun is the only parent star in our solar system, and its mass reaches 1.9891x10^30kg, accounting for 99.86% of the entire solar system, which is 330,000 times the mass of our earth.
According to the law of universal gravitation, the greater the mass of the celestial body, the greater the gravitational force. This gravitation is not only the mutual attraction outside the surface of the celestial body, but also the tendency to continuously collapse toward the center, thus forming a huge inward gravitational pressure. For exampleOn the earth, the central pressure reaches 3.6 million sea-level atmospheric pressure, and for a huge object like the sun, the core gravitational pressure reaches 300 billion atmospheric pressure, which is more than 80,000 times the geocentric pressure. Under this pressure, the core temperature reaches 15 million degrees.
The conditions of nuclear fusion are high temperature and high pressure. The temperature of the core of the sun is not high, so the main reason for stimulating nuclear fusion is high pressure.
The hydrogen atoms of the sun's core are stripped into free electrons under high temperature and high pressure, and the nuclei are barely exposed. They are fused together under huge pressure, which is fusion into a helium nucleus. In this fusionIn the process, 0.7% of the mass will be converted into energy, which is the source of the sun's huge energy.
According to estimates, the sun converts 600 million tons of hydrogen into 595.8 million tons of helium per second, of which 4.2 million tons of mass are all converted into energy. According to Einstein's mass-energy equation E=MC^2, we canIt is concluded that this energy reaches 3.78x10^26J.
What is this concept? That is, the energy emitted by the sun per second is about 1.05 trillion kilowatt-hours of electricity, which can be obtained by burning more than 300 billion tons of coal. This energy is continuously radiated from the center to the outside, after radiationThe area, the troposphere, the photosphere, and the chromosphere are finally emitted into space by means of electromagnetic radiation, and our earth also gets a fraction of 2.2 billion.
However, this point of the earth reaches 1.72x10^17J per second, which is equivalent to 48 billion kWh, which is the total power generation of 15 million Three Gorges dams, or the energy of more than 3,000 Hiroshima atomic bomb explosions per second.
So, how many years can the sun burn in this way of nuclear fusion?
Many people are worried that if the sun burns like this, even if it is so nuclear fusion, it will consume 600 million tons of hydrogen per second, won't it hollow out and die soon? Let's calculate it.
The sun is a yellow dwarf star. The typical lifespan of this mass star is about 10 billion years. Now the sun is about 5 billion years old and has a lifespan of 5 billion years. So how much hydrogen can be burned in these 10 billion years?How much mass is consumed? This is a simple elementary school arithmetic body, and we can all calculate it if we eat melons. 1 hour 3600 seconds, 24 hours a day, a Julian year in astronomy is 365.25 days, which is 31557600 seconds. 100100 million years is about 3.16x10^17 seconds.
600 million tons of hydrogen consumed per second, 10 billion annual consumption: 3.15576x10^17x6x10^8≈1.89x10^26 tons.
About 18.9 billion tons of hydrogen is consumed in 10 billion years. The mass of the sun is 1.9891x10^27 tons. What is the ratio of hydrogen consumed in 10 billion years to the mass of the sun? That is: 1.89x10^26/1.9891x10^27 ≈0.095
That is, in 10 billion years, the total consumption of the sun’s conversion from hydrogen to helium accounts for less than one-tenth of the total mass of the sun. If you want to calculate the mass of its actual conversion into energy, the consumption is even less, just this0.7% of the total consumption is 0.00067% of the mass of the sun.
So, some friends always worry that the sun will burn out is completely unnecessary.
Actually, in the late stage of the sun's evolution, not the entire solar hydrogen has been converted, but only the core hydrogen has been converted. The sun will expand into a huge red giant star. The outer mass of this red giant star will gradually dissipate into the universe.The part converted to helium will undergo helium fusion under the gravitational high pressure after stopping nuclear fusion, and eventually become a dense carbon ball, which is the home of the sun ~ white dwarf.
White dwarfs are only about the size of the earth, but the mass is about 0.5 times that of the sun, and the density of the above material reaches 1000~10000kg/cm^3.
This is another topic, just stop here.
Thank you for reading and welcome to discuss.
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