13.8 billion years ago, the balance of singularity was broken by some unknown reason, and a huge explosion occurred in , and time and space were born, and at the same time, it also brought about all the matter in the universe today.
At the beginning of the explosion, matter could only exist in the form of elementary particles such as electron photons and neutrino . After .5 million years, the hot radiation gradually cooled down to , and the background temperature dropped to about 3,000 degrees Celsius. At this time, the neutral atoms were no longer ionized, and gravity began to play its dominant role.
At this time, the main component in the universe was gaseous matter, among which hydrogen element accounted for 92% of the total amount of cosmic matter, and the rest were helium element and less than 1% of lithium elements. There were very few metal elements in the early universe, which determined that the metal abundance of stars born at that time would be very low. they were collectively called the first generation of stars in the universe.
stars are different in their mass, and the degree of destruction and the remains left behind. Stars with a mass greater than 8 times the sun will produce supernova explosion after death. is one of the strongest energy release activities in the universe today. The energy released in the moment of explosion is equal to the sum of energy released by the sun in its lifetime, and the explosive matter will spread outward at one tenth of the speed of light, which can instantly destroy any creature within 50 light years.
However, due to the special composition of the first generation of stars, the mechanism and remains of ordinary supernova explosions are very different from those of ordinary supernova explosions. At the same mass, the energy released by the first generation of stars in the Chinese supernova explosion is 10 to 100 times that of ordinary supernova . The way they die is that the current universe cannot reproduce.
Most of the first generation of stars only exist about 1 to 300 million years after the birth of the universe. It is difficult to see the first generation of stars in today's universe. is because they have long disappeared, but it is difficult not to mean it is impossible. Through the space telescope, we can also see the light from tens of billions of years ago.
When astronomers used the Gemini telescope in the North Sky to observe a very distant quasar , found that there was a strange interstellar cloud cluster in the universe around it, and its chemical characteristics were different from that of the current conventional cloud cluster.
quasar looks very similar to a star, it emits super light, but it is not a star. It is essentially a galaxy with an supermassive black hole at the center. Generally speaking, the volume of a quasar is smaller than that of a galaxy. However, the black hole will release huge energy during the swallowing of matter, and its power is enough to reach thousands of times that of an ordinary galaxy, so that the telescope can observe it tens of billions of light years away.
The quasar discovered this time comes from a distant 13.1 billion light years away, which means that the light it emitted took 13.1 billion years to reach the earth, , and what we see is , tens of billions of years ago, at that time, less than 700 million years have passed since the creation of the universe.
When researchers observed the cloud cluster around it, they found that the ratio of chemical element iron and magnesium in the cloud cluster was abnormally high, and is about 10 times that of in the conventional state. Based on this, scientists believe that this cloud cluster is the remains of the first generation of stars in the universe after the outbreak.
The first generation of stars lacks metal elements, so they can only perform nuclear reactions through the p-p chain . The capacity efficiency of this reaction chain is relatively low. The star core will continue to shrink and increase the center temperature. The higher temperature of causes the helium 3a reaction process to start , synthesizing a small amount of heavy elements, so as to maintain itself in the stage of main sequence star .
Therefore, the internal temperature and surface temperature of the first generation of stars will be higher, and the high-energy part in the spectrum will also account for a larger proportion.
According to estimates, the mass of this first generation star is about 3300 times that of the sun. The big explosion at the end of his life made it an unstable supernova.
Ordinary supernova explosion is the internal nuclear fusion stop, which cannot resist the explosion caused by its own gravity collapse inward. Finally, it leaves a neutron star or black hole, and and unstable supernova are different.
The unstable supernova also collapsed inward at the beginning, but the situation behind it was different. collapsed caused excessive compression of the core, and the internal photon decayed into electrons and positrons pairs. The overpressure caused nuclear splitting to get out of control. nucleus in a few seconds completely burned , creating a thermonuclear explosion, and the overall starts to collapse rapidly, and more heat energy releases beyond gravity potential energy.
In the end, the stars were completely destroyed, without black holes and neutron stars, all the wreckage of was thrown into space , becoming a diffuse cloud.
According to existing theory, the early universe did not support the appearance of dust and heavy elements. Instead, unstable supernova will throw metal elements outward when they explode. This means that some ancient galaxies today are descendants of the first generation of stars . The dust and elements in them all come from the energy released by the first generation of star supernova after the explosion.
Early first generation stars were generally relatively large in mass, and the internal nuclear fusion reaction was faster, so their lifespan was relatively short.
However, there are some exceptions, forming a generation of stars with small mass, some of these small mass stars can reach tens of billions of years , and some of them can reach tens of billions of years . Some red dwarf star even has a lifespan of hundreds of billions of years, and there are still traces of them in the universe.
