How did the universe come into being?

1.Scientists believe it originated from an incredible big bang 13.7 billion years ago.This is an unimaginable energy explosion.It will take 12 billion to 15 billion years for light from the edge of the universe to reach the earth.The material emitted by the big bang drifted in space,and the huge galaxy composed of many stars was composed of these materials.Our sun is one of these countless stars.Originally,people imagined that the universe would not expand due to gravity,but scientists have found that there is a kind of"dark energy"in the universe that will produce a repulsive force to accelerate the expansion of the universe.
2.According to cosmology,the universe we observed was concentrated in a singularity with extremely small volume,extremely high temperature and extremely high density at the early stage of its gestation.About 14.1 billion years ago,the big bang occurred after the singularity,which began the birth of our universe.
3.0 or 01 seconds after the big bang,the temperature of the universe is about 100billion degrees.The main forms of matter are electrons,photons and neutrinos.After that,the material diffused rapidly and the temperature decreased rapidly.One second after the big bang,it fell to 10billion degrees.14 seconds after the big bang,the temperature was about 3billion degrees.After 35 seconds,at 300million degrees,chemical elements began to form.The temperature keeps falling and atoms keep forming.The universe is filled with gas clouds.Under the action of gravity,they formed a stellar system,which has evolved for a long time to become today's universe.