Message from @TastefulH8r
Discord ID: 444892065655160852
GR is the best example
It requires no discrete lengths in space or time basically so that you can for any given curvature in space create a locally “flat” thing called a spacetime metric
To do that the world has to be continuous in time and space, so infinitely divisible
It’s really analogous with epsilon delta I think it’s callled from calculus one. Which is why infinities are also required there
I understand the necessity of it, but I fail to see how this correlates with infinity with regards to creation? While I certainly hold no credentials, and that should be apparent, how does this figure into the Lemaitre-Tolman-Bondi model?
I mean how can accelerated expansion be believed in an infinite understanding?
Perhaps I'm misunderstanding the model.
Let me look that up tbh I haven’t heard of it. Are you saying howncould they theorize that the universe expansion is accelerating indefinitely?
The expansion of the universe, and the theory of it, seem to contradict the idea of an infinite universe. I mean, how could infinity expand infinitely? That makes no sense.
Oh the ltb metric is inhomogenous which our universe isn’t
Again that's why I brought up Lemaitre and Edwin Hubble, that was their bread and butter
Yeah they are describing an inhomogenous universe which ours isn’t. But as for how infinity can expland that depends on a few things. We can pm about it if you want because my background is actually in GR and I feel like people here won’t really care
So the idea is that the universe is expanding at an accelerated rate flies in the face of the theory that the big bang is just an infinitely recurring event in the history of the universe, right?
Yes it does
An infinite universe can expand though
So is in inhomogeneous and also not isotropic?
Expansion means that the space between the points has become greater. Not that more “points” have been created. That’s one of the big confusing points in GR
Our universe is homogenous and isotropic
Oh I misread what you said my bad.
Meaning the average energy density is the same roughly everywhere, and the universe looks the same from wherever you are in it
I mean, I was taught, albeit in high school, that galaxies could be moving away from the Earth.
And that would just kind of never end?
Yes but it’s worth noting that most people don’t believe in the cyclical universe. And yes there are galaxies that move away from us due to expansion, and then there are some closer ones that move towards us regardless of expansion
The further away something is, the more the expansion has an effect. That’s why we have an “observable universe”. Beyond that point the space between us and objects there expands faster than light so we could never interact
I'm still not understanding how expansion of the universe can be at all possible when its infinite.
So what does that say about the state of the universe before the big bang?
Sure so for one we don’t know if it’s infinite. But if it were, the way it would expand is by the space between points expanding.
What could have caused the big bang if it's not possible that things retracted to that state
contracted*
We don’t really deal with that in physics. A philosophers opinion on what happened “before” the Big Bang is just as valid as a physicists
To me it doesn't sound very plausible that time existed infinitely before that
god damn this server gay nowadays
Yeah the argument goes “how could infinite time have passed for us to be here” but we pass through infinities every day if we assume space is continuous
poster below is gay
You mean like how matter or time is infinitely divisible?
^^^^poster above is gay
Not matter but space and time
joe fuck off and fire up your charcoal grill
The boomer is mad continue on
Because if it is you walked from point a to b and covered an infinite amount of points in space. So that same argument can be applied to the time thing.