A supernova explosion is an extremely intense celestial activity that occurs in the universe and releases enormous amounts of energy in an instant, so how did a supernova explosion form?
Supernova explosions occur after the end of the main sequence of stars, but not all stars will have supernova explosions, such as the sun we are most familiar with does not undergo a supernova explosion process.
The sun is only a yellow dwarf star, is a medium-mass star, the reason why it can stably emit light and heat, is because the outward radiation expansion pressure generated by hydrogen fusion and the gravitational effect of the center have been balanced, but with the depletion of hydrogen elements on the sun, the outward radiation expansion pressure weakens, the sun under the action of the central gravity, the internal pressure is further increased, so the helium fusion is ignited, at this point, the sun from the hydrogen fusion stage into the helium fusion stage, after that, nuclear fusion will continue to advance to heavier elements, Until carbon or oxygen stops, the Sun collapses into a white dwarf.
Collapse into a white dwarf is the end of the Sun, but not the end of all stars, and if a star reaches a mass of more than 8 times the mass of the Sun, it can advance nuclear fusion to iron after the end of the main sequence star stage.
Iron element is the final point of stellar nuclear fusion, because before the iron element, fusion will release energy, and the fusion of iron element will not release energy, but will also absorb energy, when the nuclear fusion on the star is advanced to iron element, the outward radiation expansion pressure will be sharply reduced, so the entire star will collapse sharply to the center under the action of huge gravity, and the huge mass will fall sharply to the core, making the activity of the star become extremely intense, so that in an instant it will release a huge amount of energy. This energy is equivalent to ten times the sum of the energy released by stars in their lifetime, and this phenomenon is called a supernova explosion. Only stars with a mass greater than 8 times the Mass of the Sun can produce supernova explosions.
The energy released by stellar nuclear fusion is huge, taking the sun as an example, the energy released by the sun every second can meet the energy needs of all mankind for 250,000 years, and the amount of solar energy we can collect on Earth is almost zero.
The sun can release such a huge amount of energy in one second, and the supernova explosion releases ten times the energy released in a single star's lifetime, and its power can be imagined. Scientists believe that the spread range of supernova explosions can reach about 50 light-years, that is, with the stars in which the supernova explosion occurs as the center of the circle, all planets within a radius of 50 light-years will be wiped out. Our Planet has been around for 4.6 billion years, so has earth ever been affected by a supernova explosion during these long years? Probably happened. We know that in the late Devonian period, 377 million years ago, there was a series of extinction events, and this series of events is also considered the dividing line between the Devonian and Carboniferous periods.
During the extinction events of the late Devonian period, about 70% of invertebrate organisms disappeared, so what caused such a huge biological loss?
Previously, scientists thought that the Devonian mass extinction was caused by the lava activity of the earth, when a large amount of lava flowed out of the ground, and the violent volcanic eruption completely changed the ecological environment of the earth, resulting in a large number of biological deaths, but now scientists have some new understanding.
Fields, a professor in the Department of Astronomy at the University of Illinois, and his research team found some clues in plant spore fossils. They found signs of ultraviolet destruction in fossil spores of the late Devonian period, and this sudden increase in ultraviolet light was most likely caused by supernova explosions in distant stars, and when a large number of high-energy particles came near Earth, they penetrated the Earth's atmosphere and seeped into the oceans and soil, causing a large number of Earth creatures to go extinct. Fortunately, the star with the supernova explosion is far away from Earth and should be 65 light-years away.
If a supernova explosion had occurred within 50 light-years of Earth, then Life on Earth would have been completely extinct, and we would not have existed, fortunately the star is more than 65 light-years away from Earth, so Life on Earth has not suffered a devastating blow.
Supernova explosions are so powerful, will something so terrible happen in the future within 50 light-years of Earth? For now, scientists haven't found stars that could explode in supernovae within 50 light-years of Earth, so we're safe now. Even if there are stars within 50 light-years that will have supernova explosions, at least our generation does not have to worry, because nothing in the universe can happen instantaneously, whether it is the propagation of light or the action of gravity, it takes time. So even if the energy released by the supernova explosion travels at the speed of light, it will take 50 years to reach Earth, when we are all dying of old age or covered with loess.