THE BIG BANG THEORY

  1. Cosmic Inflation - When the universe was a trillionth of a trillionth of a billionth of a second old, it underwent a burst of expansion known as a cosmic inflation.

  2. The universe cooled to about 10 billion degrees, allowing primordial matter to form. Universe consisted of a plasma of radiant energy, electrons, protons, neutrons, and extremely light particles called neutrinos.

  3. Over the next few seconds, protons that are hot enough continuously fuse together, forming nucleus of the next heavier element, helium. When the Universe was less than 1.5 minutes old, it was so hot that helium nuclei were blasted apart almost as soon as they formed. After 10 minutes, the Universe was so cool that fusion could no longer occur. Thus, the formation of helium nuclei, called the Primordial Nucleosynthesis, occurred over a time span of 8.5 minutes.

  4. The universe continued to expand, and cool to a few thousand degrees by about 300,000 years after the big bang. Electrons became attached to the hydrogen and helium nuclei forming the first atom.

  5. After 1 billion years, galaxies finally form and continuously evolve. Our solar system is estimated to have been born 9 billion years after the big bang.

A hydrogen nucleus consists of a lone proton. At the right temperature, 4 protons (a hydrogen nuclei) fuse together to form a nucleus of the next-heavier element, helium.

Hot protons also fuse with hot neutrons to form deuterium, an isotope of hydrogen to make helium.

EVIDENCES

  1. Galaxies moving away.

  2. Abundance of light elements.

  3. Presence of cosmic microwave background radiation.

Cosmic Microwave Background Radiation:

  1. If the universe was initially unimaginably hot, then researchers should be able to detect the remnant of the heat.

  2. In 1964, Arno Penzias and Robert Wilson discovered this microwave radiation which is found to fill the entire visible universe.