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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."
I think most/all of us take the term "hyperdrive" to imply FTL speeds.
This technology doesn't claim to achieve that.
It could be tested at the LHC if it ever manages to stay working for more than a month at a time, that is. :(
"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!"
Apart from being a potential nifty space drive, it would also provide a new test of General Relativity. This is far more likely to get it done as a real experiment at the LHC, than a new space drive.
Unless we use a Bussard Ramjet to collect interstellar dust...
It pays to be obvious, especially if you have a reputation for being subtle.
And now they're getting the theory down for building it.
Its only a matter of time (pun intended) till this plays out and turns into the world's first hyperdrive.
While testing this on the ground, just make sure you're not actually moving the Earth...
------ The best brain training is now totally free : )
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.
um... no?
kinetic energy doesn't follow that formula at relativistic speeds, which the article is explicitly about.
In fact, you could accelerate a million ton spacecraft up to .5 c with half a kilogram of propellent if you could put enough energy into it.
The question then becomes, how much does that amount of energy weigh?
That's the classical formula, which is asymptotically accurate at speeds much below the speed of light.
The real formula is messier, as you'll see at the Wikipedia article. There's currently no way around that one, but we might find a more precise formula later.
If the classical formula was completely correct, then the kinetic energy of a particle at lightspeed would be half the relativistic energy of its rest mass, and therefore modern particle accelerators (which can be seen as adding kinetic energy to particles) would achieve speeds far faster than light. This doesn't happen.
There's no inherent limit to the amount of kinetic energy we can put into a particle of any mass. The issue for interstellar travel is getting the energy, not applying it. Energy on that scale has an awful lot of mass.
"When you have eliminated the unacceptable, whatever is left, however improbable, must be the truthiness" - Holmes
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.