ElliosRile t1_ix75hdg wrote
Reply to comment by IronSmithFE in Someone tell me how the Big Bang began 13 billion years ago, yet the *observable* universe is 83 billion light years apart? by novacks0001
Imagine you have a balloon, and you have a bunch of dots on it. Things can travel along the surface of the balloon up to a certain speed in any direction. You can define the balloon based on where all the dots are and the surface in between them. However, if someone starts inflating the balloon, then everything is going to spread out and the surface is going to stretch. Since the expansion of the balloon isn’t travel along the surface of the balloon, it’s not subject to the same speed limit, so your dots can move away from each other faster then things can travel along the surface if the balloon.
IronSmithFE t1_ix9sa75 wrote
k, but the stars don't and can't move at near the speed of light and even if they did and two stars were traveling in opposite directions the furthest they could have expanded from each other in the fastest scenario assuming they did each move at the speed of light would still only be 26 billion lightyears. in your balloon scenario, they wouldn't move near the speed of light except in relation to each other and even then they would be unlikely to reach the speed of light in relation to each other.
ElliosRile t1_ixa069r wrote
I want to clarify, this isn’t “my scenario”, it’s a non-mathematical explanation of what we actually observe right now. When we measure the speed of galaxies far away from us, they’re receding at faster then the speed of light. You have to keep in mind that we are not talking about movement “within” the universe, where stars and matter don’t move anywhere near the speeds of light, we’re talking about reality itself expanding in all directions. We can actually observe the light emitted from those distant galaxies change its color, as the expansion of space causes the actually wavelength of light to expand.
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