Space Expansion

How can we see something from the origin of the universe? If light was emitted from that origin, it would travel out from it at the speed of light. Our Earth would evolve billions of years later, meaning the light of the big bang has long since passed us by.

The big bang didn’t happen at a single point in our universe but throughout all of space, which was at that time contracted to a single point. Therefore, light is not traveling “outward” from a single “center” but rather from all of space.

The expansion of the universe applies to intergalactic space but NOT the things in it, which are held together by the other forces of nature: gravity, electromagnetism and the strong force. According to Einstein’s Theory of Relativity, although things “in space” cannot travel faster than the speed of light, space itself is unrestricted and can expand beyond this “speed limit”. Entire galaxy clusters that are very, very distant may be “carried away” from us at faster-than-light speeds as the universe expands and in this case, we will never see them: their light itself is travelling slower than the expansion rate creating more distance between us per second than light can traverse in the same time. Such light has a losing battle trying to get to us, and therefore we will never see it. This “cosmic distance limit” defines the dimensions of our “Observable Universe”: all objects in the universe beyond that distance are undetectable.

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