1) Astronomer Edwin Hubble discovered that most celestial objects were moving away from each other, due to the red-shift of the light coming from them. This means that if you go back in time, all...
1. All the galaxies are moving away from each other, suggesting that they all came from the same place in space. 2. There is a uniform background radiation in space that was predicted by the big bang...
The main evidence for the Big Bang is the expansion of the Universe, as seen from the Doppler effect. That is, light from other stars or galaxies changes color depending on the relative velocity to...
(1) Red shift of light from galaxies correlates to their distance from us, which implies everything is flying apart, which implies everything was once in the same place.
(2) Microwave background...
Redshift of distant galaxies, attributed to the Doppler effect; and cosmic background radiation which agrees with certain predictions of the big bang model. I suggest you read the Wikipedia article...