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Hyperdrive Propulsion Could Be Tested At the LHC
KentuckyFC writes "In 1924, the influential German mathematician David Hilbert calculated that a stationary mass should repel a particle moving towards or away from it at more than half the speed of light (as seen by a distant inertial observer). Now an American physicist has pointed out that the equal and opposite effect should also hold true: that a relativistic particle should repel a stationary mass. This, he says, could form the basis of a 'hypervelocity propulsion drive' for accelerating spacecraft to a good fraction of the speed of light. The idea is that the repulsion allows the relativistic particle to deliver a specific impulse that is greater than its specific momentum, an effect that is analogous to the elastic collision of a heavy mass with a much lighter, stationary mass, from which the lighter mass rebounds with about twice the speed of the heavy mass. Unlike other exotic hyperdrive proposals, this one can be tested using the world's largest particle accelerator, the LHC, which will generate beams of particles with the required energy (abstract). Placing a test mass next to the beam line and measuring the forces on it as the particles pass by should confirm the theory — or scupper it entirely."
"calculated that a stationary mass should repel a particle moving towards or away from it at more than half the speed of light"
So, how do I slow down while going half he speed of light?
I see the advent of a new industry: space crash landings
"Our goal each year should be to increase the number of goals we set for ourselves!"
Where hyperspeed was possible unless there were ships or asteroids nearby. In that case you became "mass locked" So it turns out that more than just a gimmick to skip the boring bits of the game, mass does indeed interfere with fast moving objects.
How about Impulse Drive?
The ONLY exception to this is the "solar sail" concept, which relies on an external source of propulsion.
I believe the idea here is to have a particle accelerator in orbit that will be fired past the spacecraft it is accelerating, so it is analogous to a laser-pumped solar sail. It's also best to think of this as a potential tool for accelerating really low-mass instrument packages intended to do fly-bys of nearby stars, which could be scientifically useful.
The rest of your post sounds remarkably like statements by people back in the '70's that we'd never be able to image the disk of even nearby stars, much less discover or image planets around them.
It may be that what the author is proposing is impossible. There are a number of things in the paper that look highly sketchy to me, but GR ain't my field. Even so, while this method of acceleration for interstellar exploration may not work, the one method that is certain not to work is never bothering to try.
Blasphemy is a human right. Blasphemophobia kills.
I totally agree! If it works - its historic.
General Relativity has only a few real direct tests: bending of light, perihelion shift (such as of mercury), gravitational waves, gravitational red-shift... Maybe a few more.
It also has some indirect supporting results such as the indirect discovery of black holes in the center of galaxies. No one has visited those holes, we believe they are there based on the behavior around them.
In cosmology, GR is the only theoretical model that is widely accepted; the main game in town.. But it has some challenges with the discoveries of the "accelerating expansion of the universe" and the dark matter & dark energy debates. Some people try to explain these mysteries with non-GR theories and who knows - they may be right.
Note that none of these are experiments you can do isolated in a terrestrial lab! They are all astronomical. So if this idea works, it would be the first purely terrestrial test of GR. Its Nobel-prize material.
Sounds like Tom's Repelatron ...
The white side reflects light, the black side absorbs it...
Once you reach the same temperature as your surroundings, you'll radiate as many photons as you absorb on the black side, and not go anywhere. If there's any anisotropy in the surrounding radiation field, you can use that to move around (but that's just called a solar sail for the common dipole case).
Of course, your example just shows you don't know what he's talking about. You build the solar collectors in orbit around Mercury, and then aim the laser at the solar sail in deep space.
Robert Forward even showed how you can use one of them to decelerate when you get where you're going - basically, you release about 3/4 of your lightsail, and focus that section so that the laserlight, reflected off the larger section of lightsail shines on the smaller one, decelerating it relative to your start point.
"I do not agree with what you say, but I will defend to the death your right to say it"
The point of the drive is not that it enables light speed, or that it saves energy, because it doesn't do either.
The point of the drive is that it would accelerate you and you *don't* feel it!
The drive would accelerate you by gravity. Just like the International Space Station astronauts are still falling towards the Earth, but they can't feel it- you can't feel relativistic gravity either.
So you could accelerate at 1000 times the Earth's surface gravity if you wanted, and not even spill your coffee (potentially, if it works, and it should do).
Of course scaling up an effect that is only faintly sensed on an accelerator the size of the LHC is left as an exercise to the reader ;-), but it's fundamental research and you never know where it could lead.
-WolfWithoutAClause
"Gravity is only a theory, not a fact!"A colleague of mine asked if I thought this was possible or hokum. The authors own "paper" (unpublished preprint, linked above) contains a rather lot of self-references to other unpublished preprints, usually a sign of some level of crack-pottedness. Also, his own numbers in the abstract for this idea (an acceleration of 3 nm/s^2 for 2 ns) make this completely unworkable. That corresponds to a displacement of a test mass of 1.5 x 10^-35 m. The most sensitive displacement detectors are the laser gravitational wave observatories, each of which are a pair of perpendicular 10km Fabry-Perot cavities. These detectors have a sensitivity of about 10^-18 m. That's seventeen orders of magnitude difference. On an amusing note, that displacement is actually the same order of magnitude as the "Planck length". I can't help but wonder whether the author engaged in some silly numerology in order to get it to work out that way.