Give the two Major Era of the evolution of the Universe
Answers
The Big Bang theory does not, by itself, say why there was a Big Bang, only that there was a Big Bang. By looking at the way galaxy clusters are receding from us, and by looking at the background radiation, and by similar lines of evidence, astrophysicists conclude that all the matter we can see was essentially all in the same spot, in a high-pressure, high-temperature mass, and from that state, it exploded out into radiation and gas, which went on to condense into the universe we see today. That explosion is the Big Bang.
There are many ideas about why the explosion happened, all very speculative.
The Radiation Era and the Recombination Epoch are two major epochs in the evolution of the universe.
Explanation:
Because the universe is expanding, it has evolved from a dense concentration of matter to its current widely dispersed distribution of galaxies.
- The Age of Radiation: After the early nucleosynthesis epoch, radiation ruled the cosmos. The Radiation Era refers to the time in the evolution of the cosmos when radiant energy had a much higher density than matter. During the Radiation Era, the cosmos was tremendously hot. Atoms cannot be stable at such a high temperature. If a proton and electron were to combine to create an atom during this time, the atom would be ripped apart relatively rapidly by a powerful photon or a collision with another particle.
- The Recombination Epoch: After the Big Bang, the universe's temperature dropped to the point where it was transparent to light, which took roughly 400,000 years. Because the cosmos expanded sufficiently to spread the free electrons far enough apart, light could travel faster and further without being scattered. Thinning a heavy fog would be similar to this.
- As the temperature dropped, radiation and collisions no longer had enough energy to break apart neutral atoms that had formed from the merging of nuclei and electrons.
