Tuesday, February 2, 2016

Faster Than Light Travel: Now There Is a Way Forward

Faster Than Light Travel: Now There Is a Way Forward

Many years ago, when NASA decided it should fund a blue-sky open-ended effort to look for workable concepts for faster than light (FTL) travel, Marc Millis, who ran the program, invited me to be the National Science Foundation partner. At that time, it was basically too speculative for NSF, and even for me. The goal was a worthy goal,  and one might ask: “How can we ever have any hope of finding an answer if we don’t devote at least SOME effort to thinking about the question?” At that time, however, my response to the question was: “We won’t ever have any real chance at this until and unless we make a whole lot of progress in updating our very basic understanding of basic physics. Until we do more of that, it is premature to expect any kind of specific, concrete way forward.”

But now – that has changed, at least for me. I have done a lot to update my knowledge of basic physics this past year, and, as part of that – I now see a reasonable, more concrete way forward to TRY to achieve FTL. When it comes down to political and economic constraints – I can’t guarantee that humans will ever learn to tie their shoelaces, but from an objective scientific viewpoint, I do see a way forward on FTL which is far more solid and plausible than earlier approaches (though the new approach draws heavily on previous work). Until I get to publish all the many aspects of what I have learned this past year, is it premature for me to say what it adds up to? Maybe, but I can’t be sure I will live long enough to dot all the i’s and cross all the t’s as normal practice demands.

1. Space-Bending spacecraft in general versus other approaches *****************************

The most mainstream approach to achieving FTL starts with the question: “Now that Einstein has shown that space can be bent, can we bend space in a way that lets us build FTL spacecraft?”  That is the approach I will discuss here, but probably I should briefly review more of what this means.

There are other folks who like to hope for “hyperspace craft,” which assume that our cosmos has more than just the three dimensions of space and the dimension of time, linked to each other as Einstein described (3+1-D).  In fact, many very serious mainstream physicists argue strongly for superstring theories or brane theories which assume the existence of such additional dimensions. However, I view that as speculative stuff, because I see no real empirical data at all yet in science to give us any practical understanding of what those additional dimensions would really be like, if they exist at all.  Yes, that is a valid area for research, to try to get past speculation, but for a concrete way forward now I would only assume the 3+1-D dimensions that we now know well. (That also applies to concepts like exploiting the “digital universe” as in the wonderful novel Moving Mars by Greg Bear.)

To bend space in 3+1-D, one needs a mathematical model of bending space. Einstein’s General Relativity (GR) is the obvious model, but FTL is not so easy in GR. Thus it makes a lot of sense to support research which really probes GR for possible changes, possible gaps in the theory, especially the kind of gaps which might make FTL easier. It still makes a lot of sense to intensify such efforts ... but at present, it looks ever more speculative that gaps will be found. A year or two ago, there seemed to be growing hope that a model like Moffat’s model of gravity might supersede GR, even though some of the key terms look suspiciously odd. GR requires the weird concepts of dark energy and dark matter to explain some of the basic observations we made a few years ago, but Moffat’s model was predicting them without dark matter or dark energy. But new information has come in on dark matter and dark energy, and the complexities of Moffat’s model no longer seem helpful of justified. And so, the practical way forward now is to aim for space-bending spacecraft, bending space exactly in accord with what GR allows.

How mainstream can one get? In fact, the famous guys at CalTech talk both about space-bending spacecraft and about wormholes as mainstream, GR-based approaches to FTL. The spacecraft approach and the wormhole approach are somewhat related; one might even view the spacecraft approach as a step towards wormhole capabilities (just as low cost RLV may be viewed as a prerequisite to “space elevators”, for those folks who like space elevators more than RLVs).

2. A New Way Forward with space-bending spacecraft ****************************************

The word “Alcubierre” is maybe the best google search term to get into the serious literature on how to build space-bending FTL spacecraft. It all goes back to Alcubierre himself, who found a solution to the equations of GR (i.e. a state of the world allowed according to GR, a design) in which space is bent around a spacecraft enough to allow it to travel faster than light. The Alcubierre solution generated a lot of rightful excitement, but it entailed two overwhelming obstacles, which kept it from being a practical way forward for now, even for folks like me who usually support high-risk high-benefit technologies: (1) it requires the use of “exotic matter,” i.e. matter or energy whose mass/energy density is negative; and (2) it requires a huge amount of that.

There was great excitement a few years ago when a physicist at NASA published a variation of the Alcubierre solution which appeared to get (2) under control. With a new design, much less exotic matter is needed. I have not looked up the details, but I remember an email from someone involved in that saying something vaguely like: “Before, we needed a hunk of exotic matter as big as Jupiter. Now we only need something as big as the Edmonton Mall, something we could actually build.” (We could even AFFORD to build something as big as the Edmonton Mall in space, if our politicians would allow us to build the low-cost RLV which previous work at Boeing, at AF and at NASA has validated, using off-the shelf technology and data!)  That was nice – but at the time I sadly grinned: “Too bad we don’t have ANY exotic matter, not even a thimble full, let alone a Mall full.”

But now, it looks better. Maybe even much better. There is a way forward to check and even to do if the checks work. If I still had a government funding mandate, and were allowed to go international and so on... but whatever.

“Where is there ANY exotic matter?”  I did give Marc Millis a recommendation to give special priority to that question....

Folks like Puthoff funded by Marc Millis offered a possible answer: “Why not squeeze the vacuum?”  Strictly speaking, exotic matter/energy does not really require that energy density be zero in an ABSOLUTE sense. It only requires that we create a zone of energy or matter where the average energy is LESS THAN the average density of the outer space we are traveling through. Many mainstream physicists believe that ordinary outer space is already at a very high level of energy density, because of “zero point fluctuations (ZPE).” For example, even Weinberg’s authoritative book the Quantum Theory of Fields,  has section explaining and endorsing ZPE as a way to explain the Casimir effect. “Squeezing the vacuum,” they suggest, is baiscally just a matter of excluding those vacuum fluctuations from a region of space.

As it happens, I don’t believe in that mainstream Feynmann ZPE theory. The logic seems very clear to me, but, since it is heresy and since new heresy takes many years to percolate through the ever more complex and bureaucratic systems of our world, I simply posted a paper giving the logic at vixra.org this year. For those capable of logic, that should be enough, but for those who must watt for endorsements from Ginsparg or from the President of Liberty University, it is too early. The ZPE theory implies that there is a truly immense amount of energy out there in the vacuum of outer space, something like 10**120 somethings per cubic centimeter of free space.

But could there still be some vacuum energy out there in reality, at a level we could use?

That is what I find most exciting here. At an elite workshop at Princeton in May 2015, I was delighted to learn about the work of the group of Alfred Leitenstorfer, which has since been published in a number of credible places like Nature and Science and PRL. My vixra paper gives specific citations. I disagree with their conclusion that they have measured vacuum energy as large as what ZPE implies; if they lower the temperature of their measurement crystal (EOX), I predict a much lower energy density, energy density more like that of dark matter and dark energy (also discussed in the vixra paper). But that energy density is already very large and very serious!

 By combining a more general Boltzmann equation in the space of density operators, together with any variant of electroweak theory capable of explaining the existence of elementary particles, I predict a vacuum density of subquantal fluctuation of the well-established B and W fields roughly on the same order as what is needed to explain observations on dark energy. (The vixra paper cites a recent review of that data.) That is a substantial energy density; recall that dark matter is many times denser than ordinary matter.

Of course, “way forward” does not mean “yes we can.” Lots of numbers to be checked, and not lightly. For example, consider that the energy density of light now on its way out from the sun, not yet beyond Pluto, is a VERY tiny fraction of the mass-energy of our solar system, but still of some use to technology (the very basis of all earth life!). The subquantal B/W component of dark matter may likewise be “small and big at the same time.”  There is an amusing possibility that we will find that FTL is practical in a way WITHIN spiral arms, but much more difficult across Rifts. Leitenstorfer’s group appears sanguine about the possibility of “squeezing the vacuum’; lots of approaches may work, but I suspect it will take a lot of effort and reasonable creativity to find the most cost-effective way.  The EOX technology is probably one part of what it will take. But there is a way forward. (Perhaps also... or in parallel... quantum separators and coherent baryon number changers may also feed into strengthening such new technology, e.g. providing more energy... and perhaps someday I will post that last work of Schwinger, which is risky but maybe important on this path.)

Best of luck...

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