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ChrisHallquist comments on Open Thread, November 1 - 7, 2013 - Less Wrong Discussion

5 Post author: witzvo 02 November 2013 04:37PM

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Comment author: ChrisHallquist 04 November 2013 03:54:30PM 2 points [-]

The energy blasts as usually depicted break conservation of energy; with a bit of physics trickery you can get time travel out of that.

Wait, explain that? What is "a bit of physics trickery" here?

I know in HPMOR, Harry points out that violations of conservation of mass in magic imply FTL signaling, and I know from relativity FTL implies time travel, but Harry doesn't even consider running off to get time travel from common spells. Assumed turning the theory into practice would be far from straightforward.

Heck, it's not even obvious to me how you turn FTL travel into time travel in practice, if you don't have control over what frame of reference you're FTL in.

Comment author: So8res 07 November 2013 02:24:17AM 1 point [-]

To make a time machine out of an FTL drive, simply travel somewhere at near lightspeed and FTL back. Now you're where you started, before you left.

Comment author: [deleted] 05 November 2013 03:25:06PM 1 point [-]

In the approximation of the True Laws Of Physics which is in use today --- The Relativistic Standard Model --- FTL (and subsidiarily time travel) is nonsense. Like, it's gibberish. It is a description of a situation which not only does not happen, but which is a mathematical falsehood. It is impossible. It is like violation of conservation of energy, or violation of entropic developments.

The maths plainly states that assumptions like that leads to a contradiction, and we do in fact know that the Standard Model is complete and consistent (i.e. cannot encode formulas as objects).

Any hypothetical scenarios involving time travel will invariably be contrite, non-causal, and require classical mechanics. It is fiction, make of it what you will.

Comment author: Armok_GoB 05 November 2013 09:33:39PM 1 point [-]

Oooh, that's even better: from a contradiction, anything can be proved. Thus, if we can break conservation of energy we gain literal omnipotence.

Comment author: [deleted] 10 November 2013 02:56:46PM 1 point [-]

... I am pretty sure that is not how it works.