eli5 If nothing can travel faster than C, then how does the fabric of space time expand faster than light?


My only explanation in my thought process would be that space itself isn’t an *object* and thus isn’t actually “traveling?” I’m not sure.

In: 0

Basically, yes.

The rate of expansion *of* the universe is not limited by the rules governing matter *within* the universe.

Is this is a simulation and we are all brains in a vat, the rules of the simulation are not derived from the physical rules governing the vat.

1: you say “the fabric of space time” but you mean “the universe”

2: the universe isnt moving, its expanding. That part is difficult to visualize but its critical.
Point A and point B aren’t moving away from each other. The space between them just becomes larger.

Point A and point B aren’t moving. But the distance between them is increasing.

Space time is not moving. There is just more space being created, and it gives the illusion of moving.

Ill use an analogy with a tennis ball.

If i stand 1 meter away from the ball, and then it increases to 2m, it will appear to me as if that thing has moved away from me.

But whats actually happened, is that neither me or the ball has moved. 1m of space has popped into existance between us.

The rule of light speed is that no information can travel faster than light. But the universe expanding does not transmit information. As in, we cant use this expansion to send stuff to other places faster than light.

If i jumped away from the earth, i would not speed away from the earth at lightspeed at some point, while at the same time approaching another galaxy at lightspeed. I would instead be moving away from both. Since there is space being created both inbetween me and the earth, but also inbetween me and the other galaxy i jumped toward.

Imagine an ant walking on a rubber sheet. Stretch that rubber sheet, and for that ant’s perspective, its walking speed hasn’t changed. There’s just more of rubber sheet to walk on.

>My only explanation in my thought process would be that space itself isn’t an object and thus isn’t actually “traveling?” I’m not sure.

That’s pretty much exactly it the space isn’t travelling, it’s simply increasing. You couldn’t ride the expansion of space from point A to point B – you’d always stay at point A, and point A would in fact get further from point B.