According to the big bang theory, the universe was squeezed in to a very small volume and then began expanding explosively about 13.7 GA. Identify three main evidence that supports this theory?
1. Cosmic microwave background radiation: One of the key pieces of evidence for the big bang theory is the existence of cosmic microwave background radiation, which is a faint glow of radiation that fills the universe. This radiation is believed to be leftover from the initial hot, dense state of the universe and matches the predictions made by the big bang theory.
2. Hubble's Law: Observations of the redshift of distant galaxies by Edwin Hubble in the 1920s showed that galaxies are moving away from us, and the farther away they are, the faster they are moving. This is consistent with the idea that the universe is expanding, as predicted by the big bang theory.
3. Abundance of light elements: The big bang theory also predicts the abundance of light elements such as hydrogen, helium, and lithium in the universe. Observations of the elemental composition of stars and galaxies match these predictions, providing further evidence for the theory.