3 ms·

> The density of stress-energy, for matter (or radiation, since you asked about light) is the same with the scale factor slightly smaller and the energy density

> The density of stress-energy, for matter (or radiation, since you asked about light) is the same with the scale factor slightly smaller and the energy density slightly higher, as with the scale factor slightly larger and the energy density slightly smaller. So you are saying, there is a semi-reversible process where energy and volume are correlated? That's what I've started with. Should there actually be some specific amount of energy in place in order this density-to-scale transmutation to happen? What kinds of energy participate in it in our real world scenario? Does it depend on the specific local density (though I've already asked that)?

pdonis 2y ago
> So you are saying, there is a semi-reversible process where energy and volume are correlated? My original objection was to you thinking of it as a "process", or at least a process involving energy and volume. It's a relationship between stress-energy and spacetime geometry. > Should there actually be some specific amount of energy in place in order this density-to-scale transmutation to happen? There is no such "transmutation". That's not what's going on. Your questions aren't answerable because they are based on false premises. At this point I've done my best to explain what is and isn't going on. All I can do is recommend reading more detailed treatments, which you can find in any cosmology textbook, or in briefer form in most GR textbooks. Sean Carroll's lecture notes on GR are available for free online [1], and Chapter 8 discusses the basics of our best current model of the universe in cosmology. [1] https://arxiv.org/abs/gr-qc/9712019 https://arxiv.org/abs/gr-qc/9712019
DEADMINCE 2y ago
At this point why not interact with an LLM to get a better base understanding? Disagreeing with someone more knowledgable whose answers you can't properly grok isn't a great way to learn, surely?
- pdonis 2y ago
  I would not advise trying to learn physics (or any subject, for that matter) from an LLM. They will confabulate confident sounding nonsense just as easily as they will give you reasonable information--and if you don't already know the subject, you won't be able to tell the difference.

pdonis 2y ago

> So you are saying, there is a semi-reversible process where energy and volume are correlated? My original objection was to you thinking of it as a "process", or at least a process involving energy and volume. It's a relationship between stress-energy and spacetime geometry. > Should there actually be some specific amount of energy in place in order this density-to-scale transmutation to happen? There is no such "transmutation". That's not what's going on. Your questions aren't answerable because they are based on false premises. At this point I've done my best to explain what is and isn't going on. All I can do is recommend reading more detailed treatments, which you can find in any cosmology textbook, or in briefer form in most GR textbooks. Sean Carroll's lecture notes on GR are available for free online [1], and Chapter 8 discusses the basics of our best current model of the universe in cosmology. [1] https://arxiv.org/abs/gr-qc/9712019 https://arxiv.org/abs/gr-qc/9712019

DEADMINCE 2y ago

At this point why not interact with an LLM to get a better base understanding? Disagreeing with someone more knowledgable whose answers you can't properly grok isn't a great way to learn, surely?

pdonis 2y ago
I would not advise trying to learn physics (or any subject, for that matter) from an LLM. They will confabulate confident sounding nonsense just as easily as they will give you reasonable information--and if you don't already know the subject, you won't be able to tell the difference.