expansion of universe
Physics and electronics discussion, revision, exam and homework help.
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expansion of universethey always say in textbooks that after examining the red shift of galaxies we find the universe is expanding?
in my revision guide it says galaxies are moving apart due to evidence received from the redshift so the universe must be expanding
why is this so how do we know the galaxies are not just moving apart to another part of the universe that has already been created? why does the universe necesserily have to be expanding?Last edited by acapella34; 18-05-2012 at 21:52. -
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Re: expansion of universeBecause not only are the galaxies moving away from us, they are moving from each other. I.e. the space between galaxies is expanding.
The classic example is to consider points on the surface of a balloon. As the balloon is inflated, all the points move away from each other so whichever point you observe from, all the points appear to be moving away from you.
