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I've been reading a number of online "pop-sci" articles on the subject of "warp drive" - derived from work done initially by Alcubierre.

Some of the most recent articles say that there are researchers at NASA who have found theoretical basis for not only "warping" space in the manner described by Alcubierre, but that estimates on the quantities of "exotic" matter required to make it work are far more reasonable than initially thought (~500kg instead of ~1 Jupiter mass), and that there is bench-top experimentation under way to validate it all. Furthermore, that it would easily permit an interstellar trip of say, 20 light-years to be completed in only a couple of months. Some statements have been made that we may be only a few decades away from a real spacecraft capable of such a voyage.

My question is: What has really been accomplished, proven or disproven to-date?

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  • $\begingroup$ I think my question really had two fundamental parts (1) establishing the credibility of claims in regard to theoretical/experimental research based on the "Alcubierre Metric", and if credible, (2) where does that work fall on the path to implementable technology. I agree, my question(s) probably belong more on the physics SE than here. $\endgroup$ – Anthony X Aug 5 '13 at 19:08
  • $\begingroup$ This can be a coherent single question if left to strictly focus on legitimacy. The question at hand is if research into faster-than-light (FTL) travel is legit. Some people use definitions of "warp" to deflect. FTL travel is easily definable, and violates special relativity by definition. The answer is two-part, 1) that Alcubierre metric is not necessarily FTL and 2) FTL travel is not possible. $\endgroup$ – AlanSE Aug 5 '13 at 20:57
  • $\begingroup$ This is confusing to me because I thought the key point is that Alcubierre had found a "loophole" in relativity effectively permitting a form of FTL travel (no speed limit on expansion or contraction of space), and that the theory is sound, leaving only questions of feasibility of implementation. $\endgroup$ – Anthony X Aug 5 '13 at 21:30
  • $\begingroup$ See also this recent question on Skeptics: Did a 19 year old Egyption student invent a new space propulsion system?. $\endgroup$ – gerrit Aug 6 '13 at 9:52
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    $\begingroup$ The alcubierre drive requires a negative mass. So far there is no reason to believe that matter with negative mass exists. 500kg of stuff which doesn't exist isn't more reasonable than 1 jupiter mass of stuff which doesn't exist. $\endgroup$ – Philipp Jan 5 '14 at 1:09
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Original Answer

Given Alcubierre's math, and White's calculations, it's a viable avenue of research to pursue.

Whether or not it is practical as FTL, and given the expected maximum apparent speed of about 10 times the speed of light (White), and that the math says it should be able to be done, an attempt to implement a prototype series should be of immense benefit. Even if the drive fails to work, the drive testing will provide interesting measurements.

Therefore, investigations of Alcubierre's Warp Drive equations in a practical (rather than theoretical) mode are of use scientifically.

Also note: Any measured effect, even if not what is predicted, will lead to improvements in the theory.

Further, NASA is allowing White to pursue a practical experiment.

Note that Warp Drive, even if it doesn't allow for FTL (or as Alcubierre's theory notes, apparent FTL by STL movement of the craft within STL movement of the space the craft is moving through), a STL version will still massively reduce travel times. A 0.01C drive puts Mars a mere few hours away. At furthest distance, Mars is about 18 light minutes away; 1800 minutes travel time is 30 hours - not even 2 days.

Note that, for logistical and health purposes, a roughly 60-90 day mission (round trip) is about the limit. White has implied that he expects 10 C to be practical - this puts Alpha Centauri, home of the nearest detected extrasolar planet, at 156 days travel time. So, for practical purposes, a 10 C drive isn't an interstellar one. At 40 C apparent velocity, the Alpha Centauri system becomes reasonably practical. This means that, unless apparent speeds higher than White's worked 10 C examples are practical, the Warp Drive is going to still be an in-system drive.


2015 Update

It is worth noting that, as of May 2015, NASA thinks the EM-Drive may in fact be generating an Alcubierre warp, and is in fact generating thrust in a vacuum. Dr. White is working on the team testing this drive.

NASA has yet to release any data that this author can find on Dr. White's approved tests of a pure Warp Drive, but if the EM-Drive is generating a warp field, this may be a result of two lines of unrelated research converging.


References

White, Harold "Sonny", Warp Field Mechanics 101 (http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20110015936_2011016932.pdf) Retrieved 5 August 2013.

Peckham, Matt, NASA Actually Working on Warp Drive (http://techland.time.com/2012/09/19/nasa-actually-working-on-faster-than-light-warp-drive/) Retrieved 5 August 2013.

José Rodal, Ph.D, Jeremiah Mullikin and Noel Munson, Evaluating NASA's Futuristic EM-Drive, (http://www.nasaspaceflight.com/2015/04/evaluating-nasas-futuristic-em-drive/), Retrieved 3 May 2015.

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  • $\begingroup$ Any info on what experiment White will be attempting? $\endgroup$ – System Down Dec 30 '13 at 19:18
  • $\begingroup$ The paper implies passing a laser through a low-power field off a benched rig and checking for displacement and modulation, but I've no hard evidence. $\endgroup$ – aramis Dec 31 '13 at 6:23
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    $\begingroup$ @aramis why is 'a 160 day each way trip is a nightmare'??? I mean, in human terms that seems to be a pretty small cost to be the first to get to another solar system! In logistical terms, without knowing how the drive actually works aren't we jumping the gun? $\endgroup$ – NPSF3000 Oct 23 '14 at 11:39
  • $\begingroup$ The issue is one of cabin fever and food supplies. 160 days is past the point where most crews suffer morale breakdowns. Any meaningful trip needs to have more than just the crew needed to keep the ship going, but then you get into "how do we keep them busy and sane during the trip" $\endgroup$ – aramis Oct 25 '14 at 19:04
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This is a repository community-wiki post with references to current work on Alcubierre drive at NASA (Harold White) and in other places.

The original work:

Limitations:

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Exotic matter is an area that is worth looking at. The geometry of warp drive (or equivalently, Krasnikov tubes) is not really as interesting for FTL travel as people believe: Something that usually gets overlooked is the causality of the matter-geometry dependency. You need the matter to be deployed first on a space-like region between a home and a destination, and then the space-time will change to allow FTL travel.

It is clear that if you are in Earth, even if you had the exotic matter in adequate quantities, you'll still need some way to deploy it along the road, otherwise there will be no warp!. So, in summary, you need a FTL drive in order to deploy the matter that will enable a warp drive. It still could find other applications though. For instance, could be applied (in principle) for exceeding the bounds of computation rates imposed by the speed of light on local information exchange between different regions of a computer.

A more reasonable proposition for spaceflight applications is researching micro-wormholes that might become stable and large enough to be observable if exotic-matter can be made to persist above the constraints imposed by the weak and dominant energy conditions. Eric Davis is looking into parabolic mirrors that focus high quantum fluctuations in a confined volume. That should be interesting to test the general validity of the energy conditions

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