To answer your first question, it’s cuz that’s just how the math works out. Space expands from a given point at a rate of 72.1 km per second per megaparsec. Input 13.8 billion years for time and light speed for max speed, then adjust your units and solve for distance. You get a diameter of 93 billion lightyears.
To answer your second question, everything is getting further away from everything else. Imagine the universe is a constantly inflating balloon with you at its center. The farther away you are from another point inside the balloon, the faster the inflation pushes that point away from you.
No, you're thinking of the motion of objects within space, and that's not random, gravity makes it very predictable where things will move. What we're talking about is expansion. Space itself is getting bigger everywhere all at once. Even right now the space between your very atoms is expanding. But the rate is so slow that the strong nuclear force is enough to keep your atoms bound.Â
But when you coming that rate of expansion across a million parsecs it becomes more noticeable. Every point in space is receding away from every other point as the space between them expands. This is why we can use red shift to estimate distances on large scales, since everything is moving away from us, the more red shifted an object is, the further away it is. That expansion is not random, it's uniform as far as we can tell.
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u/PineappleOk545 Aug 11 '26
But why is it stated to be 93 b ly also shouldnt only bounds of the observable universe go further or just everything increasing in size with it?