@mikeymojo,
mikeymojo wrote:
That's where Ptolemy messed up. He created the concept of earth being the center of the universe before the proper technology was around to confirm his claim. And it was deemed truth for most of civilized history. His concept turned something that really is (earth is not the center of the universe) into something it's really not (earth is the center of the universe). And people believed it without any evidence but Ptolemy's, which obviously wasn't correct, as technology has proven.
http://math.ucr.edu/home/baez/physics/Relativity/GR/centre.html (is suggest you read the whole article).
Where is the centre of the universe?
There is no centre of the universe! According to the standard theories of cosmology, the universe started with a "Big Bang" about 14 thousand million years ago and has been expanding ever since. Yet there is no centre to the expansion; it is the same everywhere. The Big Bang should not be visualised as an ordinary explosion. The universe is not expanding out from a centre into space; rather, the whole universe is expanding and it is doing so equally at all places, as far as we can tell.
In 1929 Edwin Hubble announced that he had measured the speed of galaxies at different distances from us, and had discovered that the farther they were, the faster they were receding.
This might suggest that we are at the centre of the expanding universe, but in fact if the universe is expanding uniformly according to Hubble's law, then it will appear to do so from any vantage point.
If we see a galaxy B receding from us at 10,000 km/s, an alien in galaxy B will see our galaxy A receding from it at 10,000 km/s in the opposite direction. Another galaxy C twice as far away in the same direction as B will be seen by us as receding at 20,000 km/s. The alien will see it receding at 10,000 km/s:
A B C
From A 0 km/s 10,000 km/s 20,000 km/s
From B -10,000 km/s 0 km/s 10,000 km/s
So from the point of view of the alien at B, everything is expanding away from it, whichever direction it looks in, just the same as it does for us.
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So, in a sense everyone and everything is at the center of the universe and in this sense those who say we are not are incorrect. Anywhere in this uniform distribution can be classed as being the center... because of that one can also say that there is no center but that is not what most think was refuted i.e. Ptolemy.. they say we are on the outer arm of an insignificant galaxy and that cannot be the center of the universe 'because' of that fact... but that understanding is now defunct.
