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StrawberryWaste3012 t1_iszszr2 wrote

How could we observe expansion beyond the existing matter?

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gwardotnet t1_iszyy7a wrote

Can't. It's expanding faster than speed of light. We'll never be able to see the big bang or the border of the universe.

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kldload t1_it0on32 wrote

This is not true. Only very distant objects expand at away from us at apparent faster than light speeds. Nothing is moving faster than light in its own reference frame. The speed of light is\ 73 kilometers per second per megaparsec. That means its only the effects of the change in distance that appears to be faster than light could travel. In essence, the objects are receding away from us at speeds exceeding the distance light could cross for the same unit of time.

This is because each "point" in space is expanding at the rate above. The more "points" in space you have between you and a distant object, the faster it expands.

If there are two megaparsecs between you and an object, it will appear to recede at 146 km/s/mpc.

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Works out to about 4100 mpc between you and object to exceed c.

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