From NASA: Potentially, A Breakthrough (Understatement of The Century)
Last edited Fri Aug 1, 2014, 12:26 PM - Edit history (4)
The word "breakthrough" has been so diluted by decades of Silicon Valley bullshit that when we hear it, we tend to think it means some company has found a way to increase cellphone battery life by 2%, or that a car gets 5 more miles per gallon, etc. etc. This...is not that. This is potentially something else entirely. Potentially, something more familiar in science fiction novels and TV series.
Now, when I say that, the intelligent skeptic will imagine something more ambitious than the above examples, but still relatively rooted in the status quo: Perhaps a practical battery capable of powering commercial aircraft? Perhaps a telescope with a hundred times better optics at the same cost? A solar cell with twice the performance at half the cost and twice the lifetime? Nope. Still too conservative. Once again, this is potentially something else entirely.
And I would stress the word potentially lest our imaginations run away with us at this point (and I have been tempted in that direction by this news, let me tell you). A lot of review, experimentation, and theoretical discussion has to take place before it's clear whether the breakthrough in question has actually occurred...but the first experimental results by NASA indicate that it has. Again, don't let your imagination run wild just yet. So first, some scientific background to explain what may potentially have been discovered.
Theoretically, according to quantum mechanics, "empty" space is permeated by a froth of quantum particles that pop into and out of existence in negative/positive pairs so that the net mass-energy of the universe never changes (i.e., each pair together has a net mass-energy of zero, so they don't technically exist when they stay together, but if you separate them they become "real" particles that can interact with things). In the normal course of events, random fluctuations in this froth can briefly separate particle pairs and create very, very small transient forces in otherwise empty space, and these forces are called quantum fluctuations or vacuum energy.
Now, that energy is not "something from nothing" - the net change in the universe is still zero. The fluctuations merely separate the positive mass-energy virtual particle from the negative mass-energy virtual particle, creating temporary and localized forces that together add up to nothing. But suppose you could harness just one side of that equation and let the other side fly off and do whatever, basically mooching off the universe and letting it handle its own bookkeeping to pay for your activity? This is the basis of a variety of speculative technologies that occur frequently in science fiction literature, in particular as they concern advanced in-space propulsion concepts that don't require propellant mass because they tap into transient forces that are omnipresent throughout the universe.
These concepts were theoretically plausible, but none of them had any foundation in applied science. Until now, that is. Potentially. According to a very cautiously-worded paper released from a team at NASA Johnson Space Center, one of these theoretical technologies appears to work: A "radio-frequency (RF) resonant cavity" designed to selectively transform quantum fluctuations into momentum in one direction while being unaffected by them in the other direction. If I understand the concept properly (and my understanding is far from professional), basically it's a box whose internal shape and material properties are such that one side is supposedly reflecting vacuum energy while the other side is designed to be transparent to it, resulting in a net acceleration in one direction.
According to the paper, NASA scientists, after devising a careful experiment to eliminate outside influences and confounding factors, detected just such acceleration in a not one but two different RF resonant cavity test articles with different configurations. The effect is small but large enough to be detected unambiguously. In other words, they built a couple of boxes a certain way, isolated them from the environment as best they knew how, and without putting any outside momentum into the boxes, somehow the boxes had a net acceleration and the scientists were unable to account for it through normal electromagnetic processes.
But again, don't let your imagination run wild just yet. Science has the excruciating but utterly necessary habit of finding very subtle, non-obvious reasons why things that appear to hint at radical new possibilities...don't. Five NASA scientists have done their best to disprove quantum thruster technology and have been unable to do so, but now their work and the theories surrounding the concept will be studied and discussed in-depth by the entire global physics community with subsequent experiments sure to follow. For a dash of cold water, just remember that a team of world-renowned physicists were recently unable to disprove their detection of faster-than-light neutrinos, and were only able to find the mundane explanation when the world scientific community focused on the topic.
So, the greatest likelihood per Occam's Razor is that some very subtle but nonetheless ordinary, non-quantum effect is producing the observed acceleration in a way that does not make it a useful technology. However, given the results and high credibility of the experiment, the likelihood that this is a real phenomenon is nontrivial - it has gone from "sheer speculation" to "observationally significant," and is now in the domain of the empirical rather than entirely theoretical.
Having made clear the limits of the finding, now we can go crazy and imagine the potential that may have opened up. If the effect is real, a spacecraft utilizing it - even at the likely very low efficiencies that this bleeding-edge test article achieves - could theoretically reach Alpha Centauri in a matter of decades rather than 70,000 years at Voyager speeds, because the effect would allow spacecraft to accelerate indefinitely to a substantial fraction of the speed of light. It could propel spacecraft to anywhere in the solar system in matters of weeks rather than years, potentially opening up every planet and moon in the solar system to human exploration and settlement. We would still need traditional rockets to land on and take off from surfaces, but traveling across the vast expanses of space between worlds would be downright easy.
Here's another thing: Since vacuum energy permeates all space, there is no practical limit to the mass you could transport. It makes no difference whether you're sending a little probe or a skyscraper-sized spaceship with thousands of people in it - you would just have to build a bigger RF cavity as the engine. A bigger empty box. Not the most staggering engineering challenge one could imagine, that. Of course, you'd still have to design decent life support, radiation shielding, etc. etc., but with transit times measured in weeks rather than years and mass no longer a limitation, those challenges become easily (and I do mean easily) surmountable. In other words, if these results prove out, a future just short of Star Trek opens up very quickly (short of it since you're still kept below light speed, but don't worry, NASA's working on that too).
There could possibly also be consequences for power generation here on Earth, although that's a good deal more questionable given the low power levels involved. Power is all about cramming as much energy into as short a time as possible, while the benefit of this potential technology is that it consistently provides a small amount of energy per unit area indefinitely. Solar energy is probably vastly more powerful, but perhaps it could be augmented? Ironically, the less profound potential applications (Earth-based gadgets and surface transportation) are far more dubious than the seemingly pie-in-the-sky possibilities of space travel that could be rapidly realized if this technology proves to be genuine.
So, as weird as it seems, if this turns out to be real, we could very well still be struggling to switch to electric cars and build up solar power infrastructure here on Earth at a time when we're swarming around the solar system in giant reactionless space cruiseliners. The very idea of the latter sounds ludicrous, but...that's the potential. And even if the devil-in-the-details proves the technology real but less useful than hoped, even intermediate possibilities are pretty staggering. Maybe there are mass limits, so instead of Carnival Cruise ships flying from Earth orbit to Neptune and back in a month, it's only mid-sized yachts with a hundred people. Or maybe the speed limit is lower than imagined, so instead of a month, it's three months (as opposed to ten years).
Either way, the very worst possible outcome of this news is that it's an illusion and changes nothing, while almost every single other scenario quickly turns into a science fiction novel. And I do mean quickly. Remember, we're talking about an empty box with a precisely-built internal shape, not some ultra-complex machine requiring an army of Lockheed employees and years of testing. Universities that today build their own small satellites could, in a matter of years, be constructing their own interplanetary and interstellar engines. Maybe.
But again, (and I'm speaking to myself as much to anyone else) one experiment is not a discovery, and eventual disproof remains the most likely outcome. Still, it's hard not to smell The Future in this news. If someone told you there was a 1% chance of the world ending tomorrow, you'd be pretty terrified. If someone told you there was a 1% chance you would become a billionaire tomorrow, you'd be pretty excited.
Well, without knowing the exact numerical probability, let's arbitrarily say there's a 1% chance that this proves out, and you will wake up one day soon and people will be on the Moon again; wake up the next day (figuratively speaking) and they will be on Mars and orbiting Venus; the next day, they're swarming around the Asteroid Belt; the next day, the moons of Jupiter; the next day, Saturn; on, and on, and on. And before you've repaid your mortgage from that first day, your species is headed to Alpha Centauri, Tau Ceti, and Epsilon Eridani when the day before that first day the world had almost given up on the very idea of space travel. Quickens the pulse, doesn't it?
I'll be monitoring the scientific community's response to these findings very closely. Hopefully the NASA experiment's results can be replicated in relatively short order.
Update: Here's a brief article on the PBS website about the potential breakthrough:
http://www.pbs.org/wgbh/nova/next/space/improbable-thruster-seems-work-violating-known-laws-physics/
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