PAllen's latest activity
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PPAllen replied to the thread Undergrad Does the Alcubierre drive shorten distances?.Yes, I agree with you.
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PPAllen replied to the thread Undergrad Does the Alcubierre drive shorten distances?.I don’t think that works. I tried that. Remember f is a function (hidden within r) of all 4 coordinates. That means zeta must be as...
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PPAllen replied to the thread Undergrad Does the Alcubierre drive shorten distances?.My current view is back to the idea that you can have synchronous, but not diagonal. However, the trick used by Hiscock for...
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PPAllen replied to the thread Undergrad Does the Alcubierre drive shorten distances?.True, but if you switch to coordinates that manifest the orthogonality, then the Eulerian world lines do have constant spatial...
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PPAllen replied to the thread Undergrad Does the Alcubierre drive shorten distances?.good catch, I'll fix.
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PPAllen replied to the thread Undergrad Does the Alcubierre drive shorten distances?.I would like to summarize conclusions scattered across this thread. The following are key references: The main document that...
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PPAllen replied to the thread Undergrad Does the Alcubierre drive shorten distances?.A curve orthogonal to all Eulerian world lines it touches must have zero t component. But one that is orthogonal to just one need not...
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PPAllen replied to the thread Undergrad Does the Alcubierre drive shorten distances?.This I don’t believe. One thing that is confusing about the notation in some of these papers is that f is a function of all 4 spacetime...
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PPAllen replied to the thread Undergrad Does the Alcubierre drive shorten distances?.There is always a geodesic orthogonal to any world line at any point. What happens is the spacetime geodesic and the slice geodesic are...
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PPAllen replied to the thread Undergrad Does the Alcubierre drive shorten distances?.Just to take up a detail discussed earlier: whether There is a difference between computing distance using a geodesic of a Euclidean...
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PPAllen replied to the thread Undergrad Does the Alcubierre drive shorten distances?.Before the full solution, I can put an upper bound on the odometer reading. It is easy to compute, using the full metric, rigorously...
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PPAllen replied to the thread Undergrad Does the Alcubierre drive shorten distances?.So, the easy part is as follows: my traveler has reached the left edge of the right bubble wall at t (coord time) of 4.95, z of 16.295...
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PPAllen replied to the thread Undergrad Does the Alcubierre drive shorten distances?.So, my choice for traveler world line is very convenient. It turns out it produces a constant integrand for the odometer integral of .1...
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PPAllen replied to the thread Undergrad Does the Alcubierre drive shorten distances?.So it is quite easy to analyze that light gets trapped in the wall in the original coordinates. Using my proposed diff.eq. for traveler...
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PPAllen replied to the thread Undergrad Does the Alcubierre drive shorten distances?.Note that this section is using v constant and superluminal, which is not what we want. This basically says that if the bubble never...