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Warp Drive Might Be Less Impossible Than Previously Thought

Posted by Unknown on from the warp-seven-engage dept.

runner_one writes "Harold 'Sonny' White of NASA's Johnson Space Center said Friday (Sept. 14) at the 100 Year Starship Symposium that warp drive might be easier to achieve than earlier thought. The first concept for a real-life warp drive was suggested in 1994 by Mexican physicist Miguel Alcubierre, however subsequent calculations found that such a device would require prohibitive amounts of energy, studies estimated the warp drive would require a minimum amount of energy about equal to the mass-energy of the planet Jupiter. But recent calculations showed that if the shape of the ring encircling the spacecraft was adjusted into more of a rounded donut, as opposed to a flat ring the warp drive could be powered by the energy of a mass as small as 500 kg. Furthermore, if the intensity of the space warps can be oscillated over time, the energy required is reduced even more."

4 of 867 comments (clear)

  1. Re:What did I tell you? by Anonymous Coward · · Score: 5, Informative

    The energy argument was completely secondary. The main objection (which is barely touched on in the article) is that there are some fairly strong proofs that you need exotic matter in order to actually implement the drive. My understanding is that the space-time configuration necessary for the warp drive has been shown to be impossible to create without exotic matter.

    Exotic matter, by definition, requires violations of the known laws of physics. In other words, the currently accepted laws of physics indicate that you need to break the laws of physics to make the drive work. This means that while the results in this article might have alleviated some secondary concerns, the main problem with this type of warp drive is still completely unaddressed.

    Of course, there are some people who will waive their hands and say "abracadabra - QUANTUM MECHANICS" to try and get around the exotic matter problem. But you are now trying to combine general relativity with quantum effects, so there isn't any firm foundation to base your arguments on.

  2. Re:I'll believe it when I see... by Your.Master · · Score: 5, Informative

    Here is a relatively understandable explanation of why beating a photon to its destination implies time travel, even if you don't locally travel faster than light: http://www.theculture.org/rich/sharpblue/archives/000089.html. Basically, if you can pass stuff along at FTL between people at sub-light speed, and those people are moving relative to one another, you can send stuff into the past.

    There *are* workarounds. A fairly comprehensive list is here:

    http://www.physicsguy.com/ftl/html/FTL_part4.html#subsec:specialframe

    They're all kind of about relativity being wrong, and there's no evidence any of these are true. Mostly wishful thinking on the part of people that want to believe we can have an interstellar civilization but can't quite let go of causality. Briefly:

    1. FTL takes you to a parallel universe. So if you try to kill your past self, there's no paradox and you keep living because it was actually your counterpart in a different universe.
    2. There's some unknown physics that would prevent using FTL to violate causality. So even though there's technically time travel in some sense, it has no practical use and therefore you could say it isn't "really" time travel.
    3. A specific case of the above: perhaps the act of travelling FTL prevents any other FTL travel within a certain spacetime "radius".
    4. Violate relativity by having a "true" frame of reference with a "true" sequence of events. All FTL takes place in that context and is theoretically unlimited in speed. Within any other frame of reference, it looks like a speed limit, but still possibly faster than light speed.

  3. Re:What did I tell you? by Cyberax · · Score: 5, Informative

    There are no proofs that it's impossible to create a warp drive without exotic matter. It's just that we know several configurations of exotic matter that can produce warp drives.

  4. Re:What did I tell you? by khayman80 · · Score: 5, Informative

    "Exotic matter, by definition, requires violations of the known laws of physics."

    No, it doesn't. Antimatter is one valid type of "exotic matter", and it has been manufactured in labs in various (small) amounts for many decades now, without a physics violation in sight.

    Antimatter certainly isn't common, but it's not "exotic matter". Stable wormholes and the Alcubierre drive require using exotic matter that has negative mass-energy, which would violate the weak energy condition.

    "... we can see it in certain configurations of regular matter, such as the Casimir effect."

    What does the Casimir effect have to do with it? That is merely a demonstration of so-called "zero point" fluctuations. It isn't "negative energy", except to the extent that you have particles and their counter-particles spontaneously arising at the same time. Even so, in the case of the Casimir effect it exerts a net positive energy on the affected mass.

    The Casimir effect is the best known example of negative energy:

    Morris, Thorne and Yurtsever[4] pointed out that the quantum mechanics of the Casimir effect can be used to produce a locally mass-negative region of space-time. In this article, and subsequent work by others, they showed that negative matter could be used to stabilize a wormhole.