PeterDonis's latest activity
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PeterDonis replied to the thread Undergrad Does the Alcubierre drive shorten distances?.Please, read all of my latest posts before responding. -
PeterDonis replied to the thread Undergrad Does the Alcubierre drive shorten distances?.Note, though, that by this definition, using the notion of "length" of "spacelike distance along a horizontal line in the diagram", the...
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PeterDonis replied to the thread Undergrad Does the Alcubierre drive shorten distances?.More precisely, in the coordinates used in the paper I've been referencing, with the diagram in Figure 3 that I posted about in post...
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PeterDonis replied to the thread Undergrad Does the Alcubierre drive shorten distances?.As I said, the "calculation" was simple: inside the bubble, spacetime is flat, so "distance equals speed times travel time" works fine...
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PeterDonis replied to the thread Undergrad Does the Alcubierre drive shorten distances?.See my post #63 just now, which crossed yours in the mail, so to speak. The diagram I was relying on in that paper isn't actually...
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PeterDonis replied to the thread Undergrad Does the Alcubierre drive shorten distances?.Hm. The diagram does show that, but looking at the math in the same paper, I'm not sure the diagram shows the light cones correctly...
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PeterDonis replied to the thread Undergrad Does the Alcubierre drive shorten distances?.Well, my answer was based on both Earth and Alpha Centauri being inside the bubble at some point, which you objected to. Inside the...
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PeterDonis replied to the thread Graduate Gravitons.@Josiah you already have a thread open on what is basically this same topic. Duplicate threads on a topic are not permitted here...
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PeterDonis replied to the thread Undergrad Does the Alcubierre drive shorten distances?.And then, in the very next paragraph of the same post, you said: What @PAllen is telling you is that, so far, you have given no...
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PeterDonis replied to the thread Undergrad Does the Alcubierre drive shorten distances?.What path in spacetime is this integral taken over? You've described this integral as giving a distance, which would imply that it's an...
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PeterDonis reacted to Dale's post in the thread Undergrad Does the Alcubierre drive shorten distances? with
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The problem is that the "length of the path" is ambiguous in a curved spacetime. Here is the main issue: When you talk about the... -
PeterDonis replied to the thread Undergrad What effect do gravitons have on electrons?.These two things have nothing to do with each other. Consider the analogy with electromagnetism: the number of photons hitting...
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PeterDonis replied to the thread Undergrad Does the Alcubierre drive shorten distances?.Yes.
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PeterDonis replied to the thread Undergrad Does the Alcubierre drive shorten distances?.The diagram in Figure 3 of the lecture notes linked to in the OP of this previous thread would seem to me to show that there are...
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PeterDonis replied to the thread Undergrad Does the Alcubierre drive shorten distances?.My question is whether the sum (integral) that is being implicitly done here actually evaluates to the distance that was claimed...