Expansion Theory
The expansion theory of the universe states that the Galaxies found throughout space are flying away from each other, as if from an explosion 'the Big Bang'. Nothing too difficult so far. Astronomers can measure the speed at which the galaxies are travelling by studying the red shift in their light. This I can still get my head round.
They have found that this speed increases by about 15 miles for every extra million light years of distance. This roughly equates to, one light year equaling 8 million million miles. I know this is called Hubble's Law. This all began 15,000 million years ago, again I have no problem understudying that also.
What I don't understand is what the universe is expanding into? If it is expanding into somewhere else, then the somewhere else must be getting smaller.
I also don't understand what caused the 'Big Bang'. Was there a place for the 'Big Bang' to go off in the first place? If there was where did it come from?