— It is also called as expanding universe hypothesis.
— According to this theory the space between the galaxies is increasing.
— Though the space between the galaxies is increasing, the size of the galaxies is constant.
Stages of development of universe:
- In the beginning, all matter forming the universe existed in one place in the form of a "tiny ball" with extremely small volume, infinite temperature and infinite density.
- Around 13.7 billion years before the present, the tiny ball exploded violently. This lead to huge expansion.
- Within 3,00,000 tears from the Big Bang, temperature dropped to 4,500 K (Kelvin) and gave rise to atomic matter.