The warp drive: hyper-fast travel within general relativity · HackerPapers discussions

The warp drive: hyper-fast travel within general relativity — mentioned by otrahuevada

Wed, 15 Dec 2021 18:56:00 GMT

It does not need /negative matter/ or energy, though. What is needed, in the original, non-scammer-friendly version by Alcubierre is /something/ that can push spacetime in the opposite direction that mass and energy do. At least the original Alcubierre solution, he basically lays out the mechanism and says, paraphrasing: "hey, the numbers do work out. We just need something that doesn't make sense, or something that makes /the thing/ happen" We see then that, just as it happens with wormholes, one needs exotic matter to travel faster than the speed of light. However, even if one believes that…

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The warp drive: hyper-fast travel within general relativity — mentioned by yellowapple

Tue, 30 Mar 2021 17:52:41 GMT

Welp, looks like this turned sour again. Whoops! But hey, I tried, I guess. > Can recommend again that you turn to books on this subject Got any recommendations? In fact, I asked you this already, the last time you dickishly suggested I go read books (as if I haven't done that already). > This sentence is pure gibberish Then go read Alcubierre's paper[1]. Expanding spacetime on one side of an object and contracting it on another is exactly what's being described. Maybe "without acceleration in the local frame of reference" rather than "without movement" makes more sense to you? > The math…

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The warp drive: hyper-fast travel within general relativity — mentioned by yellowapple

Tue, 30 Mar 2021 07:30:50 GMT

So first, I'd like to say thanks for bearing with me here. I know it's probably frustrating when someone you're talking to just... ain't... getting... it... ...which is why I hate to say that I still ain't getting it, lol > Along the path actually taken need not be the case, we are reasoning about the endpoints of the communication independent of the means. So the means doesn't matter at all? It doesn't matter that as far as the endpoints are concerned they're at a fixed distance from one another? That seems hard to believe - not to mention contrary with the math presented in that…

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The warp drive: hyper-fast travel within general relativity — mentioned by raattgift

Fri, 05 Mar 2021 16:50:02 GMT

Causality violations probably aren't really that much of a problem for mathematical physics. Geroch (a very well known and highly cited relativist) takes a shot at this in a short paper considering a "democracy of causal cones" rather than simply the one that matches light: "All systems, and their cones, are on an equal footing: No one set of fields, or one set of causal cones, has priority over any others." Geroch's argument is that one can still do initial-value-formulation physics even in the presence of causal cones whose width is different -- including wider -- than that of light.…

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The warp drive: hyper-fast travel within general relativity — mentioned by raattgift

Sat, 28 Nov 2020 11:05:48 GMT

If we build heavy Casimir plates near a Cavendish experiment, the latter will point to the former as a normal gravitational source. Rather than claiming that there is a tiny Cavendish apparatus deviation for heavy Casimir plates held close together and in parallel vs the same plates with a different orientation or separation, one should really show it in a lab. (One might also try to use a Casimir setup to lift some heavy object off the floor, or do other gravimetry experiments). The usual explanation for the Casimir results involves modes in the fields of the Standard Model, all of which…

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The warp drive: hyper-fast travel within general relativity — mentioned by raattgift

Sat, 28 Nov 2020 10:22:53 GMT

I don't know about those exact examples or how to compare them, because the subject doesn't really interest me enough to peruse the material when and if it is ever published, and unlike Bee I don't have a copy to read (or much motivation if I did). The lack of interest hangs on the fact that we have highly-tested descriptions of our universe which have relativity baked right in. Even Alcubierre's "drive" paper [1] is written in the language of relativity. And thus we have to take seriously the problem that we have in relativity no obvious way to induce a warp bubble onto a patch of flat…

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The warp drive: hyper-fast travel within general relativity — mentioned by raattgift

Tue, 14 Aug 2018 06:11:12 GMT

> space expansion and the speed faster than c as a result is possible. Without exotic matter, etc. Except that in order to get the observables right, dark energy is required to keep the galaxy clusters running away from each other faster over time. It's a heavy price that no physical cosmologist is really happy about, but the concordance cosmology gets its name from how it is explicitly constructed to match ("concord with") observation (and it is consequently updated from time to time). It is not really surprising that some energy is required to keep the warp bubble from dissipating away from…

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The warp drive: hyper-fast travel within general relativity — mentioned by raattgift

Tue, 14 Aug 2018 04:02:39 GMT

Agreed. The pattern could range practically forever, with "B"s appearing for any "A": A: It's a static solution; the warp bubble is eternal. There is no recipe for turning it on or off. A: It's a vacuum solution; there is no "ship" inside, and no matter outside. It is everywhere exactly flat except for the compact region of spacetime in the bubble wall. The only way to decide whether it is even meaningfully moving in the sort of way intended is to add something else to the spacetime. One could make a more complicated vacuum solution with a qualitatively similar compact region, or "stitch"…

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The warp drive: hyper-fast travel within general relativity — mentioned by yk

Mon, 22 Jul 2013 20:51:41 GMT

Your third paragraph is a nice way to think about FTL. Actually it causes quite interesting problems to define FTL, since nothing special happens locally. > But one thing I could not really figure out is whether this so-called FTL travel has the potential to violate causality, because I don't fully understand how causality and FTL are related. They are not directly related, as I wrote above, nothing special happens except you find a 'shortcut.' So at every point there is still a nice lightcone ( locally) and every event is caused by events in its past lightcone. However, you can have global…

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The warp drive: hyper-fast travel within general relativity — HN submission

Mon, 02 Jun 2008 14:31:44 GMT

The warp drive: hyper-fast travel within general relativity

1 point; 0 discussion replies on HN. Paper and source history. A submission is not an endorsement.