PeterDonis's latest activity
-
PeterDonis replied to the thread I Question about discussions around quantum interpretations.Why would that be a reason not to read it? Even if it wasn't written by Feynman, strictly speaking, it's still about him, and has a lot... -
PeterDonis replied to the thread B Need help understanding particle physics and quantum physics.What would count as such a measurement, if all the measurement results we already have that confirm the predictions of our best current...
-
PeterDonis replied to the thread B Trying to calculate proper time of worldlines using rotating frames.You are misinterpreting what that coordinate restriction means. The Born ##\phi## coordinate of the rotating observers the OP is using...
-
PeterDonis replied to the thread I Question about Parallel Transport.I think what you mean by "regular Euclidean space" here is actually "Newtonian physics". Basically you're saying that in Newtonian...
-
PeterDonis replied to the thread I Question about Parallel Transport.Ok, so it's not a matter of the analogue to F-W transport not existing in Riemannian manifolds, it's a matter of whether it's considered...
-
PeterDonis reacted to Orodruin's post in the thread B Matter density right after the decoupling with
Like.
Free-streaming means that the (average) density of matter is so small that the mean-free path exceeds the size of the Universe. The... -
PeterDonis replied to the thread A three month long summer vacation from public school seems stupid.I agree that both alternative views should be presented, or neither. This being GD, I think it's ok to opt for "both" at least for a...
-
PeterDonis replied to the thread A three month long summer vacation from public school seems stupid.I don't think this is true. US corporations can increase their profits by investing in poorer countries to make them richer. But doing...
-
PeterDonis replied to the thread B Trying to calculate proper time of worldlines using rotating frames.The OP already did that. @JimWhoKnew was just checking to see that the answer the OP got in the rotating frame is consistent with the...
-
PeterDonis replied to the thread B Trying to calculate proper time of worldlines using rotating frames.Unfortunately PF doesn't have a way to automatically insert LaTeX tags or delimiters.
-
PeterDonis replied to the thread B Trying to calculate proper time of worldlines using rotating frames.Ah, yes, that's right. I was implicitly thinking of it that way. Good catch!
-
PeterDonis replied to the thread B Trying to calculate proper time of worldlines using rotating frames.Both work, but the double pound signs and dollar signs are definitely easier and quicker to type, and easier to keep track of. :wink:
-
PeterDonis replied to the thread I Question about Parallel Transport.Generally yes, since it's generally used in a relativity context along worldlines. However, the definition only makes use of path...
-
PeterDonis replied to the thread I Question about Parallel Transport.While I know what you mean by this, I would point out as a caution that the term "geodesic deviation", at least in a GR context means...
-
PeterDonis replied to the thread B Trying to calculate proper time of worldlines using rotating frames.Your ##d \phi d t## cross term isn't quite right; the factor in front should be ##2 \omega r##, not ##2 \omega r^2##. (When doing these...