What is Alcubierre warp drive: Definition and 13 Discussions

The Alcubierre drive, Alcubierre warp drive, or Alcubierre metric (referring to metric tensor) is a speculative warp drive idea based on a solution of Einstein's field equations in general relativity as proposed by theoretical physicist Miguel Alcubierre during his PhD study at the University of Wales, Cardiff, by which a spacecraft could achieve apparent faster-than-light travel if a configurable energy-density field lower than that of the vacuum (that is, negative mass) could be created.Rather than exceeding the speed of light within a local reference frame, a spacecraft would traverse distances by contracting space in front of it and expanding space behind it, resulting in effective faster-than-light travel. Objects cannot accelerate to the speed of light within normal spacetime; instead, the Alcubierre drive shifts space around an object so that the object would arrive at its destination more quickly than light would in normal space without breaking any physical laws.Although the metric proposed by Alcubierre is consistent with the Einstein field equations, construction of such a drive is not necessarily possible. The proposed mechanism of the Alcubierre drive implies a negative energy density and therefore requires exotic matter or manipulation of dark energy. If exotic matter with the correct properties cannot exist, then the drive cannot be constructed. At the close of his original article, however, Alcubierre argued (following an argument developed by physicists analyzing traversable wormholes) that the Casimir vacuum between parallel plates could fulfill the negative-energy requirement for the Alcubierre drive.
Another possible issue is that, although the Alcubierre metric is consistent with Einstein's equations, general relativity does not incorporate quantum mechanics. Some physicists have presented arguments to suggest that a theory of quantum gravity (which would incorporate both theories) would eliminate those solutions in general relativity that allow for backwards time travel (see the chronology protection conjecture) and thus make the Alcubierre drive invalid.

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  1. Onyx

    A Proper Volume on Constant Hypersurface in Alcubierre Metric

    I'm wondering if there is a way to find the proper volume of the warped region of the Alcubierre spacetime for a constant ##t## hypersurface. I can do a coordinate transformation ##t=τ+G(x)##, where ##G(x)=\int \frac{-vf}{1-v^2f^2}dx##. This eliminates the diagonal and makes it so that the...
  2. S

    B Can We Create a Warp Drive for Light? - Josh's Curiousity

    Hello everyone, Preface: I'm hoping this doesn't violate the speculative or personal theories clause in the forum guidelines. It's really just a curiosity, I'm in no position to argue/develop/push the idea or anything. If this does violate that clause, would you be able to recommend a similar...
  3. T

    I Alcubierre Warp Drive: Spacetime Diagram Explained

    https://scipost.org/SciPostPhysLectNotes.10/pdf "Space expands behind the warp bubble and contracts in front of it, thus pushing the bubble forward at velocity v. The ship, which is at rest inside the bubble, moves along with the bubble at an arbitrarily large global velocity." If the ship...
  4. Quantum23

    A Energy condition respecting warp drives in Einstein Cartan theory

    I read this paper where if you take the alcubierre metric calaculations while including torsion in GR you get positive energy spin requirements instead of exotic matter. Here is the link: https://arxiv.org/abs/1807.09745 Could it be because a spinning quantum vacuum will be less stiff like a...
  5. DEvens

    A Alcubierre Warp Drive: Intro Paper for GR Students

    I would like to read about the Alcubierre warp drive. Is there a good introductory paper? I have done some GR, round about 8 months worth in undergrad [mumble] years ago. And my honors project was on interior solutions for stellar collapse. So I'm OK with GR at about the speed of Weinberg's...
  6. S

    I Is the Alcubierre Warp Drive possible?

    This Quora post seems to say that this type of warp drive could allow faster-than-light travel, but somehow I think this is junk science: https://www.quora.com/Will-humans-eventually-be-able-to-explore-the-galaxy-After-all-it-is-multiple-light-years-away-to-even-the-nearest-star (author is...
  7. E

    A Energy distribution on Alcubierre walls

    Hi, the trace of the extrinsic tensor K(Myu,Nu) in Alcubierre metric, relative to the foliation normal vector is non zero on the front x=rs+R and rear x=rs-R "walls". This is the normal volume component Tr =k(1,1)+k(2,2)+k(3,3) and should affect the Ricci tensor in Lorentzian/Minkowsky 4D. How...
  8. R

    I Alcubierre Warp Drive: 2nd Law of Thermodynamics Impossibility?

    It seems to me that if one had a functional Alcubierre drive and used it there would be some subluminal frame of reference in which time was going backwards for the spaceship which probably for it and for macroscopic objects in it which constitute a reasonably closed system would be a violation...
  9. B

    Alcubierre Warp Drive Physics Research

    Alcubierre Warp Drive With Rings Story Research I'm writing a new section in my science fiction novel and need a little help with the science of it. So, the general idea of the Alcubierre Warp Drive is that with 65 exajoules you can create a warp bubble by expanding spacetime behind you and...
  10. S

    Alcubierre Warp Drive: Debate and Discussions

    Alcubierre Warp Drive: Debate and Discussions (Force Fields; Dampners) I would like to first of all apologize if this is not in the correct location or if this thread violates any of the forum's rules. The purpose of this thread is to discuss, debate, and bounce ideas around regarding the...
  11. S

    Alcubierre warp drive as time machine.

    Hi. I heard it's possible to use an "Alcubierre warp drive" as a time machine, if they existed. But how, precisely, would that work?
  12. D

    What happens if an Alcubierre warp drive fails?

    If the warp drive is shut down either by its destruction or just plain turning it off, what happens? Does the vessel stop? Continue coasting forward? If so how would the time dilation factor at speeds several thousand times the speed of light?
  13. F

    Learn About the Alcubierre Warp Drive: A High Schooler's Guide

    I am interested in learning more about the Alcubierre warp drive. Although I've read every qualitative description imaginable plus Lillian Lieber's The Einstein Theory of Relativity, which gives a BRIEF introduction to the math behind GR, I am totally lost when it comes to the math. Although I...