Alcubierre drive, could it cause inconsistencies?

[Gerinski]

The Alcubierre drive is a very interesting theoretical idea, if only as a thought experiment. It might in principle allow travel even faster than light speed (according to some external frame of reference).

But we know that faster than light propagation could lead to history inconsistencies, and the universe abhors inconsistencies, it will not allow them (that is probably the deepest law in the universe, consistency between events must hold).

Should we infer that an Alcubierre drive is physically impossible?

 

[Dale]

We probably should consider it impossible because it requires exotic matter with negative energy density.

 

[tom aaron]

The Alcubierre drive is a very interesting theoretical idea, if only as a thought experiment. It might in principle allow travel even faster than light speed (according to some external frame of reference).

But we know that faster than light propagation could lead to history inconsistencies, and the universe abhors inconsistencies, it will not allow them (that is probably the deepest law in the universe, consistency between events must hold).

Should we infer that an Alcubierre drive is physically impossible?

Yes. Impossible. Much ado about nothing when the actual physics are examined.

 

[bcrowell]

But we know that faster than light propagation could lead to history inconsistencies, and the universe abhors inconsistencies, it will not allow them (that is probably the deepest law in the universe, consistency between events must hold).

IMO this is not nearly as strong an argument as you seem to think. See:

• Friedman, 1990; Cauchy problem in spacetimes with closed timelike curves, http://authors.library.caltech.edu/3737/

• Echeverria, 1991, Billiard balls in wormhole spacetimes with closed timelike curves: Classical theory, http://authors.library.caltech.edu/6469/

You may be interested in this thread: https://www.physicsforums.com/threads/could-a-warp-drive-work-as-a-time-machine.720433/

Keep in mind that the Alcubierre spacetime is actually nothing like Star Trek-style warp drive. The WP article has a good discussion of this.

 

[rootone]

I see the idea of Alcubierre drive as an artistic implementation of mathematics, but physically unlikely, (extremely so).
Then again, I am told that Einstein considered black holes to be unlikely to exist in actuality, although relativity did allow for that possibility.

 

[tom aaron]

I see the idea of Alcubierre drive as an artistic implementation of mathematics, but physically unlikely, (extremely so).
Then again, I am told that Einstein considered black holes to be unlikely to exist in actuality, although relativity did allow for that possibility.

What is the connection between Alcubierre drive being possible and Einstein's opinion on Black Holes?

 

[phinds]

What is the connection between Alcubierre drive being possible and Einstein's opinion on Black Holes?

rootone's statement seems totally straightforward to me. I don't get why you have a problem with it. He's comparing his point of view about the drive w/ E's point of view about black holes and saying that E was wrong about BH's and he may be wrong about the drive. He's not saying, as far as I can tell, that the drive exists, only that as far as he can tell it MIGHT exist.

I think that's wrong and the drive doesn't exist but that doesn't make his statement logically inconsistent.

 

[tom aaron]

rootone's statement seems totally straightforward to me. I don't get why you have a problem with it. He's comparing his point of view about the drive w/ E's point of view about black holes and saying that E was wrong about BH's and he may be wrong about the drive. He's not saying, as far as I can tell, that the drive exists, only that as far as he can tell it MIGHT exist.

I think that's wrong and the drive doesn't exist but that doesn't make his statement logically inconsistent.

By that logic then anything can be used.

Einstein was wrong about Black Holes so Leprechauns might be real.

Please explain the physics of how the Alcubierre drive is not fantasy. Everything we know about the Standard model of physics shows it to be no more possible than Leprechauns.

 

[Nugatory]

Let's see if I'm understanding... Phinds is saying that the drive doesn't exist, despite the theoretical possibility that it might; and you're saying that the drive is no more possible than that leprechauns exist (also a theoretical possibility, albeit remote); and you two are arguing? That "thunk" noise that you just heard is the sound of a thread being locked.