/sci/ - Science & Math

The Big Bang is an explosion.
Which made our universe expand.
How do we observe it expanding?
We only observe galaxies moving away from us in redshift and coming closer to us in blueshift.
But I don't think that proves anything, if you think it does prove anything isn't the center of the universe towards the point of blueshift as those galaxies are ''moving'' behind us from the central explosion point? Or am I wrong here?
And yes I did not include gravity in this hypothesis, I know gravity pulls everything with mass, but with the velocity of moving galaxies which is relatively slow compared to light.