since ancient times, humans looking up at the sky, to feel the endless curiosity.glittering stars and hot sun, full of mystery.for astronomers, the sun is just a are dying star.but for others, the sun is a ball of fire burning, for we can provide the light and heat.
stars the sun is located in the center of the solar system, it is almost a thermal plasma and magnetic field of mixed with a perfect sphere.the sun's diameter is about 1392000 km(1.392 x 10 ⁶), equivalent to 109 times the diameter of the earth;volume is about 1.3 million times of the earth;its quality is about 2 x 10 after ⁰ kg(330000 times) of the earth.from the point of chemical composition, the mass of the sun now is about three-quarters hydrogen, the rest are almost helium, including oxygen, carbon, neon, iron and other heavy elements quality less than 2%, with the method of fusion release of light and heat into space.
the sun has been burning for about 5 billion years, what is in maintaining the sun burn?we all know, there is no air in space, and therefore no oxygen can be used for the burning of the sun.in our everyday experience, the familiar is the only burning flame.in essence, this is a kind of oxidation reaction of emit heat and light.but this is not the only type of response.the sun is in"combustion", but it is a kind of nuclear reaction, rather than a chemical reaction.
1, the sun is a fusion method to provide energy.essentially it can use all smaller than the atomic weight of iron element as fuel, synthetic heavier elements, huge nuclear fusion energy released.used most widely, of course, the sun is hydrogen fuel, it is the 90% of the time of life is burning hydrogen, just not ordinary hydrogen chemical burn, chemical energy that is just a drop in the bucket, in fact the fusion between the sun's use hydrogen-hydrogen energy, thousands of times higher than that of hydrogen combustion energy.
2-hydrogen fusion produce helium, hydrogen, hydrogen consumption after changed to 3 helium fusion to produce carbon, and then continue to fusion can produce silicon carbon, oxygen, and a series of atoms, but the fusion arrived in synthetic iron chain after they arrived in the sun at last time.
3, because the iron is nuclear power the lowest and most stable elements, whether iron nuclear fusion or nuclear fission, all need to absorb energy rather than release energy, so when the sun burning to the stage of silica, iron, began to iron accumulation and stop nuclear fusion, the fate of the sun is depends on the initial quality.
4, small quality become boring white dwarf stars, yin cold die, massive stars end life in the big bang, core neutron star or black hole.
5, but don't look down upon this final stage of the supernova explosion, although is very short for an instant, but really the most meaningful in the universe, the big bang all the constituent parts of life elements heavier than iron are at the moment, can say no supernova explosion, there would be no life.
early scientists didn't understand, why can the sun in such a long period of time, produce so much energy.
in the early 19th century, scientists assume that the sun is like a fire on the earth, using a fuel, like coal burning slowly, however, this theory has a serious problem:the fuel.
if you in front of a fire, if you want to keep burning, to constantly add wood.if it is like the sun so big of a pile of wood, in ensure that there is enough oxygen to burn cases, also can only be maintained for about 5000-6000.although for a long time, but it was not enough to support life on earth.
in the early 20th century, the study of the earth's rock and fossil carbon-14 dating confirmed that when the sun in 3 billion years ago already exists in the temperature of enough to maintain life, obviously, there must be some other way to supply the sun.
the sun for hydrogen fuel, 73% of the mass of the sun is made up of this chemical element.the sun's light and heat from its center area, where the temperature is as high as 15 million degrees celsius, pressure as high as 300 billion earth's atmosphere.under such extreme high temperature and high pressure, four hydrogen atoms to gather into a helium atom, and release energy.therefore, hydrogen fusion without oxygen,"combustion"of the sun without oxygen.
the sun to burn about 4.26 million tons of hydrogen atoms, according to einstein's equation e=mc^ 2, the power of the sun can be calculated as 3.85 * 10^ 26 watts, equivalent to 9.19 * 10^ 10 tons per tnt explosion.
the sun will eventually put out
the sun will eventually burn out, but also for a very long time, because the sun fuels are abundant.since birth billions of years, the sun has burned half of hydrogen fuel.
the scientists estimated that its life and about 50 to 6 billion years.after that, the sun's interior have run out of hydrogen and its core will collapse, cause temperature rise.know the sun began to focus the helium into carbon, stops the phenomenon.to after the new element, the mass of the sun will be decreased, which leads to the earth or mars is farther from the sun.and the sun's outer layer will be extended to the earth or mars's orbit at present.
so, in summary, the sun is very large, volume and quality is still very long, it's powerful energy generated by nuclear fusion, the main fuel is hydrogen, also do not need oxygen burning process.