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Inertial Mass Separate From Gravitational Mass?

Soulskill posted more than 4 years ago | from the what-an-interesting-mass-effect dept.

Science 405

CPerdue writes with this excerpt from the MIT arXiv blog: "The equivalence principle is one of the more fascinating ideas in modern science. It asserts that gravitational mass and inertial mass are identical. Einstein put it like this: the gravitational force we experience on Earth is identical to the force we would experience were we sitting in a spaceship accelerating at 1g. Newton might have said that the m in F=ma is the same as the ms in F=Gm1m2/r^2. ... All that changes today with the extraordinary work of Endre Kajari at the University of Ulm in Germany and a few buddies. They show how it is possible to create situations in the quantum world in which the effects of inertial and gravitational mass must be different. In fact, they show that these differences can be arbitrarily large."

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Next stop: Arisia (4, Funny)

The_mad_linguist (1019680) | more than 4 years ago | (#32570820)

Because once we have inertial drives, it's only a little while before we can colonize other planets.

The technology lens itself very well to that.

Re:Next stop: Arisia (5, Funny)

Anonymous Coward | more than 4 years ago | (#32570856)

The technology lens itself very well to that.

I sea what you mean.

Re:Next stop: Arisia (1, Funny)

c0d3g33k (102699) | more than 4 years ago | (#32570910)

Your comment will go over the heads of many, but ...

Dude. Nice one.

Re:Next stop: Arisia (1)

medv4380 (1604309) | more than 4 years ago | (#32571178)

Sorry I have to ask but my head hurts. Is this a good lensmen joke or just a convenient typo?

Re:Next stop: Arisia (1)

somersault (912633) | more than 4 years ago | (#32571456)

Look at the title..

Re:Next stop: Arisia (1)

somersault (912633) | more than 4 years ago | (#32571396)

You don't exactly need a magnifying glass to see the joke..

Re:Next stop: Arisia (1)

suomynonAyletamitlU (1618513) | more than 4 years ago | (#32571482)

Your comment will go over the heads of many

If you compensate for the refraction, you can still hit them.

General Relativity? (2, Interesting)

gyrogeerloose (849181) | more than 4 years ago | (#32570918)

I realize that this all works only at that quantum level but what implications, if any, does this have for Einstein's general theory of relativity?

Re:General Relativity? (4, Informative)

wurp (51446) | more than 4 years ago | (#32571062)

General relativity is known to be incompatible with quantum mechanics. People are still trying to come up with a theory that reconciles the two.

This is similar to the way we knew:
* the constant speed of light (regardless of reference frame) was incompatible with the classical laws of momentum and energy [resolved by Special Relativity]
* the equations for low energy blackbody radiation and high energy blackbody radiation were incompatible with one another [resolved by quantum mechanics]

I haven't RTFA, but if they have something testable, I would think this means we have a basis for making quantitative measurements of what happens where GR and QM collide. (And hence a basis for coming up with a unifying theory.)

No GR in Article (4, Insightful)

Roger W Moore (538166) | more than 4 years ago | (#32571698)

I would think this means we have a basis for making quantitative measurements of what happens where GR and QM collide.

Not quite. They make no assumptions about GR in the article, what they have done is come up with a way to test one of the assumptions of GR - assuming the article passes peer review, arXiv is just a preprint server. There are too possible outcomes to the test they propose: m_i=m_g or m_i!=m_g. In the first case nothing has changed and in the second case one of GR's core assumptions has been dismantled so GR cannot be a fundamental theory since there is a phenomenon which it cannot explain. Hence QM and GR will never 'collide' because GR will have disappeared to be replaced by something else - possibly something which QM has no problem with.

My personal guess is that any such experiment will show that m_i=m_g but it will be an interesting test to do and potentially result in a far more accurate test of the equivalence principle.

Re:General Relativity? (3, Informative)

maxwell demon (590494) | more than 4 years ago | (#32571256)

It allows new measurements to find potential deviation in the relation of inertial and gravitational mass. If no deviations are found, then this means nothing for general relativity (the equations would just contain the same quantity under two different names). If deviations are found, then it probably means that GR must be modified.

Re:General Relativity? (1)

Anonymous Coward | more than 4 years ago | (#32571362)

Absolutely nothing. In fact, the authors didn't even use general relativity. If they had, they would not have been able to demonstrate a difference between inertial and gravitational mass, because the fact that they are the same is essential to general relativity. Instead, they used Newtonian gravitation to prove that the equivalence principle isn't essential to Newtonian gravitation, something that everybody already knew.

tl;dr theoretical physicists are acting like theoretical physicists

Re:Next stop: Arisia (0, Redundant)

kg8484 (1755554) | more than 4 years ago | (#32570954)

The technology lens itself very well to that.

I see what you did there...

Re:Next stop: Arisia (1)

EdZ (755139) | more than 4 years ago | (#32571576)

The first comment is a veiled Bergenholm reference? My faith is Slashdot is restored!

Inertial Dampeners??? (5, Funny)

bfmorgan (839462) | more than 4 years ago | (#32570844)

Would this lead to science fictions "Inertial Dampeners"?

Re:Inertial Dampeners??? (4, Funny)

sznupi (719324) | more than 4 years ago | (#32571008)

I will take the option of seatbelts while sitting at the bridge of your spaceship, thank you very much.

Re:Inertial Dampeners??? (1, Funny)

Anonymous Coward | more than 4 years ago | (#32571310)

Why, so when it comes to a screeching halt, you are cut up into multiple pieces so you can get a nice scatter-shot pattern of paste on the window?

Re:Inertial Dampeners??? (3, Funny)

Surt (22457) | more than 4 years ago | (#32571500)

In space, no one can hear you screech.

Re:Inertial Dampeners??? (3, Interesting)

Ungrounded Lightning (62228) | more than 4 years ago | (#32571470)

I will take the option of seatbelts while sitting at the bridge of your spaceship, thank you very much.

Reverse engineering things like Star Trek to come up with plausible explanations is lots of fun.

My take on near misses with photon torpedoes making "bang" sounds and throwing people around the bridge (besides the needs of dramatic presentation).

  - Photon torpedoes are established as matter-antimatter nuclear bombs.
  - These can be expected to produce some extreme EMP as a side-effect of their detonation and the "gamma light" from it striking any nearby matter.
  - The artificial gravity / inertial compensation for multi-G impulse engine thrust (and any oddball forces from warp drive and changes to it) has to be variable to handle such variable conditions.
  - The EMP interferes with its control mechanism. Not enough to smear the crew like paint over a nearby bulkhead. But enough for a near-miss to throw them around in their seats and rattle the ship enough to create the "bang" sound in the air. (Perhaps also the "whoosh" of a passing spacecraft, due to an electromagnetic "wake" from its systems - though that was clearly established as use of artistic license after the soundless flybys in the first trial footage were unsatisfying.)
  - The engineers made the artificial gravity system VERY reliable. (Note that it keeps working when most of the ship's mechanisms, including other life support, is on the fritz.) And they made it good enough to keep the crew largely intact through "impacts" that seriously degrade the other systems and structural integrity of the ship. But they weren't able to get it down to no noticeable effect.
  - And the designers didn't add seatbelt-equivalents until the first movie (after Admiral Kirk, done with his five-year missino, had given them hell about it.) B-)

Re:Inertial Dampeners??? (1)

MobileTatsu-NJG (946591) | more than 4 years ago | (#32571620)

I will take the option of seatbelts while sitting at the bridge of your spaceship, thank you very much.

You'd rather be carried out in a bucket?

Re:Inertial Dampeners??? (1)

newcastlejon (1483695) | more than 4 years ago | (#32571106)

It wasn't until I started reading SF rather than just watching Star Trek that I realised how inertial dampeners would be useful. Of course being able to absorb an impact or two without turning the occupants to jelly would be nice but if you can lower the inertial mass of your spaceship can't you accelerate at ridiculous rates?

Holidays on Nereid, here I come!

Re:Inertial Dampeners??? (4, Informative)

Ungrounded Lightning (62228) | more than 4 years ago | (#32571258)

... if you can lower the inertial mass of your spaceship can't you accelerate at ridiculous rates?

See E. E. Smith's _Lensman_ series for an exploration of that.

My own take: All bets are off since the principles are currently unknown. But assuming that things like energy conservation and action/reaction remain valid, an "inertial damper" seems likely to function as a way to transfer thrust evenly from the engines to the matter of the ship, crew, cargo, etc. (Or deliberately unevenly to achieve a convenient artificial gravity without spinning the ship.)

Re:Inertial Dampeners??? (3, Informative)

Tetsujin (103070) | more than 4 years ago | (#32571298)

It wasn't until I started reading SF rather than just watching Star Trek that I realised how inertial dampeners would be useful. Of course being able to absorb an impact or two without turning the occupants to jelly would be nice but if you can lower the inertial mass of your spaceship can't you accelerate at ridiculous rates?

That was a key idea in "Lensman"... (And it's a pretty silly idea, though I enjoy how the books explore the exploitation of this idea)

Inertial dampeners don't imply that you're negating the mass of the passengers, however - just that you're translating external forces to make them also apply to the ship's contents. Whether this means some kind of accelerometer/tractor beam combo, or if you imagine some kind of pervasive force field acting to translate external forces smoothly and continuously onto everything inside the ship - the idea of an inertial dampener is beyond our technology, but it doesn't necessarily break conservation of mass.

Re:Inertial Dampeners??? (3, Informative)

Dragoniz3r (992309) | more than 4 years ago | (#32571340)

Indeed, and in fact this concept plays a large role in the middle book of the Revelation Space series by Alastair Reynolds (which I recommend that you read, if you have not).

Re:Inertial Dampeners??? (2, Informative)

sznupi (719324) | more than 4 years ago | (#32571738)

This was a fun read about inertia...
http://physics.fullerton.edu/~jimw/general/inertia/index.htm [fullerton.edu]

One of the probable explanations seems to be - inertia is equivalent to the gravitational force that acts on the body...from the rest of the Universe. With a disclaimer that this would need propagation of gravitational disturbances into and from distant future!

Which would be...most interesting. Possibly actually strenghtening speed limits present in our Universe, with those limits being probably even more crucial part of fundamental mechanisms of our world. OTOH with the potential to bring even more wild scenarios if it's possible to break away from said limits?

Re:Inertial Dampeners??? (5, Funny)

AdmiralXyz (1378985) | more than 4 years ago | (#32571166)

That's "dampers", unless you're talking about devices that make the bridge slightly moist when the ship is subject to acceleration.

Re:Inertial Dampeners??? (5, Funny)

demonbug (309515) | more than 4 years ago | (#32571344)

That's "dampers", unless you're talking about devices that make the bridge slightly moist when the ship is subject to acceleration.

We call those red-shirts around here.

Re:Inertial Dampeners??? (5, Informative)

Anonymous Coward | more than 4 years ago | (#32571368)

From Princeton's WordNet on the definition of "dampen":
# S: (v) dampen, damp, soften, weaken, break (lessen in force or effect) "soften a shock"; "break a fall"

A damper is either a movable iron plate to control the draft in a furnace, a device that decreases the amplitude of oscillations, or a depressing (as in emotional) restraint. Inertia is not a furnace, an oscillation, nor an emotion.

This post was brought to you by the Arrogant Pedants' Society.

Re:Inertial Dampeners??? (1)

Hatta (162192) | more than 4 years ago | (#32571648)

No, that's Tuvok.

Re:Inertial Dampeners??? (1)

Fumbili (1820232) | more than 4 years ago | (#32571268)

...butter toast strapped to a cats back.

Re:Inertial Dampeners??? (1)

somersault (912633) | more than 4 years ago | (#32571504)

I think you'd have to strap the toast to its feet actually

Re:Inertial Dampeners??? (1)

somersault (912633) | more than 4 years ago | (#32571520)

oh wait, I guess it depends on whether the butter is facing the cat or not..

Re:Inertial Dampeners??? (1)

DarrylM (170047) | more than 4 years ago | (#32571512)

Would this lead to science fictions "Inertial Dampeners"?

Not only that, but if we can establish a low-level warp field around the station, then we can move it to the mouth of the wormhole really quickly.

Show how it is possible to create? (-1, Flamebait)

Rogerborg (306625) | more than 4 years ago | (#32570848)

I do not think (at least) one of those words means what you think it means.

You can "show" it? Then show me. Until then, it's just a pretty theory.

Re:Show how it is possible to create? (5, Interesting)

jfengel (409917) | more than 4 years ago | (#32571022)

The "show" here is a proof, or rather, a calculation. They describe what kind of experiment can be used to test the calculation (on a Bose-Einstein condensate in free-fall).

The experiment isn't trivial, and these theoreticians won't be the ones doing it. They publish the theory, and everybody else looks at it to see if it's worth the time and money to set up an experiment. That's pretty much canonical science going on there, and doesn't merit being dismissed as "just a pretty theory".

Re:Show how it is possible to create? (1)

sznupi (719324) | more than 4 years ago | (#32571304)

"Free-fall" so, say, something as relatively trivial as "in orbit"?Y

es, there's some vestigal drag - just use high orbit or circumsolar one, and encase the experiment in "external" spacecraft, without physical contact between the two; the internal one being in as pure free-fall as we can get, the external one shielding the interior from miniscule drag by stationkeeping (that's not my ideas, that's actually a setup of some mission that's in the works already)

Re:Show how it is possible to create? (1)

Aladrin (926209) | more than 4 years ago | (#32571316)

Actually, until it's actually been proven, or at least many scientists have failed to disprove it, it -is- "just a pretty theory." THAT is science.

Re:Show how it is possible to create? (1)

Spatial (1235392) | more than 4 years ago | (#32571408)

Pretty hypothesis. When the data comes along you can have a theory. :p

Re:Show how it is possible to create? (0)

Anonymous Coward | more than 4 years ago | (#32571508)

Actually, no. Once there is
consistent supporting data and no inconsistent data, and it has been shown that there's an experiment to test it, it remains a theory until it is DISPROVEN. (That's why we have the theory of Universal Gravitation and the theory of Evolution.) Nothing is proven; it is simply proven falsifiable - ie testable - and remains under consideration until falsified. Now, THAT'S how science really works.

Re:Show how it is possible to create? (2, Informative)

abigor (540274) | more than 4 years ago | (#32571082)

They "show how it is possible to create situations", according to the summary. I think the experiment they outline in Appendix D of the paper satisfies that sentence.

Sure, here you go (1, Interesting)

scorp1us (235526) | more than 4 years ago | (#32571118)

Professor Fran De Aquino's Webpage [elo.com.br] explains in detail what is going on, and how to do it. He even has the paper "Engineering the Simplest Gravity Cell [elo.com.br] "

What he has discovered is that it is the PLASMA above the properly charged surface that creates a gravity shielding effect, and shielding includes inversion. Yes, -1g is possible.

One of the more awesome things is that when you are at +/-0.159g, you disappear from regular space-time because you are too weakly interacting with it, like a neutrino.

Handy side effect! (1)

StefanJ (88986) | more than 4 years ago | (#32571450)

"One of the more awesome things is that when you are at +/-0.159g, you disappear from regular space-time because you are too weakly interacting with it, like a neutrino."

A lot of grade school kids probably wish they could do that.

Of course, then the ring wraiths and Sauron could see them.

Re:Handy side effect! (0)

Anonymous Coward | more than 4 years ago | (#32571624)

"Ring Wraiths", you mean catholic priests?

Re:Handy side effect! (1)

scorp1us (235526) | more than 4 years ago | (#32571626)

Too true. In the Kinetic.pdf paper, he devises a "imaginary space-time imager", with "imaginary space-time" being where you go between +/-0.159g.

That would lead to quite a similar effect. You would be cloaked. But others in imaginary time without t he detector could see you.

Also, the paper goes on to explain faster-than light travel (because "light" is no in "imaginary space-time" and instant communications, again FTL.) Actually it solves a ton of mysteries regarding UFOs - how they could be here despite vast distances, how they could vanish and appear, how they can be agile without killing occupants, and how they can communicate with their home world in a meaningful way across the distance.

Re:Sure, here you go (0)

Anonymous Coward | more than 4 years ago | (#32571478)

Oh lord, is that the same Fran De Aquino that pulled the "System G" antigravity device out of his ass a decade ago and never proved his assertions?
I wouldn't believe anything this guy says.

Re:Sure, here you go (2, Informative)

somersault (912633) | more than 4 years ago | (#32571578)

What he has discovered is that it is the PLASMA above the properly charged surface that creates a gravity shielding effect, and shielding includes inversion. Yes, -1g is possible.

Except it don't work on water..

Re:Sure, here you go (1)

mako1138 (837520) | more than 4 years ago | (#32571590)

He also seems to have books on "The Physics of Miracles," "The Physics of UFOs," and "The Physics of Spirits."

Re:Sure, here you go (2, Insightful)

MozeeToby (1163751) | more than 4 years ago | (#32571690)

Seriously, how did that get rated up? Do the mods just say "oh that sounds interesting" and mod it up without even looking at the links or think about what the person is saying? Yes, I'm sure some random guy on the internet has come up with a convenient, easy, reproducible way to produce an anti-gravity device and it somehow slipped our attention. Thanks for filling us in GP!

Re:Sure, here you go (0)

Anonymous Coward | more than 4 years ago | (#32571642)

They must have some seriously fun drugs in Brazil. My favorite part of the paper was the references, where we discover that all of the most fantastical bullshit has "been shown" by other papers by the same guy. Solid science, that.

I would submit.... (5, Funny)

Count Fenring (669457) | more than 4 years ago | (#32570880)

I would submit, courteously, that your mother's inertial and gravitic masses are arbitrarily large.

Re:I would submit.... (4, Funny)

bistromath007 (1253428) | more than 4 years ago | (#32571050)

Thanks for spoiling Wednesday's xkcd, you dick. :/

Re:I would submit.... (5, Funny)

jspenguin1 (883588) | more than 4 years ago | (#32571228)

You mean this one [xkcd.com] from 2004?

Re:I would submit.... (1)

jspenguin1 (883588) | more than 4 years ago | (#32571254)

oops, I meant 2006.

Re:I would submit.... (0)

Anonymous Coward | more than 4 years ago | (#32571410)

It's ok. I was in a very (very) high speed centrifuge for a while too.

Re:I would submit.... (3, Insightful)

maxwell demon (590494) | more than 4 years ago | (#32571406)

The law of gravity says that fat people are more attractive than thin ones.

Quantum (1, Troll)

cytoman (792326) | more than 4 years ago | (#32570890)

No big surprise here...all kinds of crazy shit is possible at the quantum level. I would like to see this effect at the classical level.

Re:Quantum (1)

TomXP411 (860000) | more than 4 years ago | (#32571072)

No kidding... this would be the first step toward gravity control and drive systems based on inertial control.

Imagine if you could lift an aircraft carrier sized ship in to space with nearly no energy, then accelerate to .999 light speed with no more thrust than a model rocket.

What amuses me is how scientists say "this stuff is impossible", and not long later, someone comes along and says "Hey... here's some evidence that it is possible."

Re:Quantum (1)

TheKidWho (705796) | more than 4 years ago | (#32571244)

Would you rip your own arm off if you tried to move it?

Re:Quantum (1)

Nyeerrmm (940927) | more than 4 years ago | (#32571282)

When a scientist says "this stuff is impossible," they actually mean "given our best understanding, evidence and theories, we don't believe these things are possible."

They know that fundamental changes or misunderstandings or new discoveries can change that, it just doesn't make much sense to say that every single time. The qualifications are assumed.

Re:Quantum (0)

Anonymous Coward | more than 4 years ago | (#32571702)

The problem is that some say it with so much confidence that they tend to harm progress. Take for example the laws of thermodynamics. Mostly when they are mentioned people tend to just skip the part where all except the first one only can be applied on macroscopic scale. Once you start to track each particle instead of treating them as a statistical unit all bets are off and you may break the other laws as you see fit.

Re:Quantum (1)

The boojum (70419) | more than 4 years ago | (#32571374)

See <a href="http://en.wikipedia.org/wiki/Clarke%27s_three_laws">Clarke's First Law</a>.

Re:Quantum (0)

Anonymous Coward | more than 4 years ago | (#32571438)

Meh. Too quick on the button. I meant:

See Clarke's First Law [wikipedia.org] .

Re:Quantum (4, Interesting)

vlm (69642) | more than 4 years ago | (#32571422)

Imagine if you could lift an aircraft carrier sized ship in to space with nearly no energy, then accelerate to .999 light speed with no more thrust than a model rocket.

Note that one situation means low/zero gravitic mass, the other means low/zero inertial mass. You might be able to arbitrarily control both. You might be able to trade one off for another. Or maybe only modify one. Also, the problems with SR and QM are at a small scale, so your aircraft carrier might only be one atom in diameter or something.

Finally, I haven't read the paper, but it'll be interesting to see how it gets around various perpetual motion type problems. Right off the top of my head, extracting energy from a pendulum where gravitic and inertial mass are different and varying is going to be a serious issue.

Changing inertial mass would do pretty weird things to rotating flywheels. I suppose you could make a spinning flywheel break apart with immense violence at a very low rotational speed. Or rotate a spinning flywheel at insane speeds without it flying apart. All at the same stored energy level. Theres probably a perpetual motion machine that would involve extracting constant energy at a constant torque at high vs low RPMs.

Similar problems at a quantum scale. Otherwise it would be too easy to accelerate two beams of "reduced inertial mass" deuterium to an arbitrarily high velocity and then increase their gravitic mass at the collision point until they fuse.

Finally, the most interesting apps might be arbitrarily increasing inertial and gravitic mass. Increasing gravitic mass would make gravity wave detectors much simpler to make. The odds of increasing the gravitic mass of something small on a spacecraft to something large like a planet seem unlikely aka artifical gravity. Increasing inertial mass might be useful for weapons, armor, pretty much anywhere you use lead, tungsten, or DU.

Re:Quantum (1)

paulej72 (1177113) | more than 4 years ago | (#32571592)

My thoughts are that what we do not know about Physics is more than we know. It may be possible to do all of the stuff that is presented in Sci Fi.

Re:Quantum (2, Funny)

drdrgivemethenews (1525877) | more than 4 years ago | (#32571076)

We're unlikely to come up with anything better than crassical on this list.

Re:Quantum (1)

nine-times (778537) | more than 4 years ago | (#32571108)

Yeah, in abstract, I think of the quantum world as one where anything can happen and nothing makes sense. From that perspective, on a layman's level, this doesn't seem particularly interesting. Those weird quantum things cancel out by the time you get to our level.

However, I don't know if this has some kind of crazy/awesome implications.

Re:Quantum (0)

Anonymous Coward | more than 4 years ago | (#32571320)

[i]Those weird quantum things cancel out by the time you get to our level. [/i]

Maybe if you add up randomness alot it isn't random anymore?

Re:Quantum (2, Insightful)

Dragoniz3r (992309) | more than 4 years ago | (#32571426)

Yeah, I mean, quantum tunneling? Quantum confinement? Those effects totally just cancel out and never do us any good!

C'mon guys. I've never seen a response so short-sighted as to discard a physics breakthrough so quickly.

Re:Quantum (1)

vlm (69642) | more than 4 years ago | (#32571536)

Yeah, I mean, quantum tunneling? Quantum confinement? Those effects totally just cancel out and never do us any good!

It would be a heck of a lot of fun to reduce the inertial mass of some hydrogen ions so the can be accelerated to high speed with very little power, then increase their gravitic mass until the inevitably fuse into a cloud of an atom with an atomic number and atomic mass in the zillions, then shut "the magic field" off and watch the giant atoms fission releasing considerable energy to their surroundings.

AKA a perpetual motion machine, at least from the thermodynamic perspective.

Re:Quantum (1)

cytoman (792326) | more than 4 years ago | (#32571680)

hydrogen ions so the can be accelerated to high speed with very little power, then increase their gravitic mass until the inevitably fuse into a cloud of an atom with an atomic number and atomic mass in the zillions, then shut "the magic field" off and watch the giant atoms fission releasing considerable energy to their surroundings.

Duuuude!!! You have the kernel of an awesome SF novel here...what you describe seems to be the recipe for a "Big Bang" and the plot could involve a scientist trying to recreate the Big Bang and make a whole new universe.

Re:Quantum (1)

nine-times (778537) | more than 4 years ago | (#32571688)

Now I was sure to qualify those things. These things generally do cancel out by the time you get to our level. From the general layman's perspective of quantum physics being a field where "nothing makes sense", another thing that doesn't make sense isn't all that interesting.

I think this is a mistake that science-minded people sometimes make: they throw endless amounts of seemingly nonsensical theories at laymen which the laymen have little hope of really understanding, and try to get us all caught up in the cool-sounding implications. Oh, yes, quantum entanglement can be used for teleportation, but not teleportation of actual stuff and physical objects. It can't be used for faster-than-light transmission of information. But still, I swear! Teleportation!

Oh, and there's "dark matter" and "dark energy", which nobody can actually explain, but there are some equations that say it's there. Oh, and a scientist made a radio wave that travels faster than light, but it's really a composite wave traveling faster than light, which is essentially an illusion. But it's cool! You probably don't even know what the hell we're talking about, but trust us! IT'S AWESOME!

And yeah, after a while, laymen get overloaded and say, meh, whatever.

But sure, hopefully this will lead to something new, and maybe even practical applications.

Re:Quantum (0)

Anonymous Coward | more than 4 years ago | (#32571708)

You mean, you want the particles to wear togas while tested?

But Will It (0)

Anonymous Coward | more than 4 years ago | (#32570970)

run the Lithium Engine [google.com] ?

Yours In Ashgabat,
Kilgore Trout, P.E.

Tried to read the article (-1, Offtopic)

Anonymous Coward | more than 4 years ago | (#32570986)

Motivated by the seminal papers on neutron interferometry
[3–7] and the more recent, impressive matter wave experiments
[8–14], we address in the present paper the question
how the inertial and gravitational mass enter in nonrelativistic
quantum mechanics

"neutron interferometry"? Yeah. I definitely decided to stop reading at this point. Stop making me feel stupid, Slashdot!

Re:Tried to read the article (3, Informative)

maxwell demon (590494) | more than 4 years ago | (#32571342)

Neutron: Electrically neutral particle. One of the particles out of which atomic nuclei are built.
Interferometry: Measurement of the interference of waves. Remember that according to quantum mechanics, particles also show wave-like properties, especially interference.

Fr1s7 psot (-1, Troll)

Anonymous Coward | more than 4 years ago | (#32571090)

Ringworld (2, Interesting)

cats-paw (34890) | more than 4 years ago | (#32571120)

"But we had purchased a reactionless, inertialess drive from the Outsiders. You may have guessed their price. We are still paying in installments. "

I seem to remember that in one of his other stories, the figure is a trillion stars, which was the worth of an entire, technologically advanced, planet.

"can be arbitrarily large." (1)

Michael Kristopeit (1751814) | more than 4 years ago | (#32571136)

is anything with potential to happen ever not arbitrary in it's potential? it seem like they arbitrarily used the word arbitrarily.

Re:"can be arbitrarily large." (1)

Trepidity (597) | more than 4 years ago | (#32571394)

In nominal terms, it's rare for there to be an absolute bound, yes. But it's not always the case that anything that can diverge can diverge arbitrarily far in relative terms.

Re:"can be arbitrarily large." (1)

Michael Kristopeit (1751814) | more than 4 years ago | (#32571554)

see, you did it again... it's not arbitrarily far just because it's relative. being "far" from something is already implying relativity to something else. in what other ways can being far from something be arbitrary?

Re:"can be arbitrarily large." (1)

Trepidity (597) | more than 4 years ago | (#32571684)

"Arbitrarily far" means that there isn't a bound on how far it can be. Simply saying that two things are not always identical isn't the same as saying that they can differ by an unbounded ("arbitrarily large") amount; the 2nd is an additional, stronger claim.

Re:"can be arbitrarily large." (1)

Garble Snarky (715674) | more than 4 years ago | (#32571474)

Physical objects have the "potential" to move with a certain speed. There is a theoretical limit to the magnitude of such a speed. The speed of a physical object, then, can not be arbitrarily large. I haven't read the paper, but summary implies that there is no known theoretical limit to this magnitude of this mass non-equivalence phenomenon. So, the term "arbitrary" most definitely has meaning here.

Re:"can be arbitrarily large." (1)

Michael Kristopeit (1751814) | more than 4 years ago | (#32571740)

i'm not saying it doesn't have meaning, i'm saying that the meaning itself is arbitrary.

Re:"can be arbitrarily large." (1)

Hatta (162192) | more than 4 years ago | (#32571726)

No, it's entirely conceivable that inertial mass may only differ from gravitation mass by a limited amount. For instance contrast:

may differ by an arbitrary amount

with:

may differ by a factor of 10

Has tremendous importance, even if just sub-atomic (4, Informative)

gurps_npc (621217) | more than 4 years ago | (#32571156)

The rocket equation tremdously limits maximum speed. Even with an anti-matter powered rocket, the maximum theorectical speed would be 0.1 C (1/10th the speed of light).

In a gravity well, this explains why we need so much fuel to get out. But that assumes that inertial mass acts like gravitional mass. If we change that, then suddenly we use HIGH inertial mass but low gravitational mass as rocket exhaust, tremendously reducing the mass of the rocket's fuel, which has exponential gains in increasing the potential payload.

Re:Has tremendous importance, even if just sub-ato (-1, Troll)

Anonymous Coward | more than 4 years ago | (#32571240)

Wrong.

Re:Has tremendous importance, even if just sub-ato (1)

should_be_linear (779431) | more than 4 years ago | (#32571654)

I can't understand a word of what you are mumbling, but what does this mean for flying cars?

Dark matter? (3, Interesting)

jschen (1249578) | more than 4 years ago | (#32571226)

Assuming that these guys are right, would the presence of two different effects that we currently group together allow us to generate a model of the universe that doesn't require the vast majority of matter to exist as (currently) undetectable dark matter?

Johann Gambolputty (2, Funny)

hugi (878361) | more than 4 years ago | (#32571238)

de von Ausfern -schplenden -schlitter -crasscrenbon -fried -digger -dangle -dungle -burstein -von -knacker -thrasher -apple -banger -horowitz -ticolensic -grander -knotty -spelltinkle -grandlich -grumblemeyer -spelterwasser -kürstlich -himbleeisen -bahnwagen -gutenabend -bitte -eine -nürnburger -bratwustle -gerspurten -mit -zweimache -luber -hundsfut -gumberaber -shönendanker -kalbsfleisch -mittler -raucher von Hautkopft auf Ulm would be proud of his fellow citizen.

Let me interrupt you (1)

XanC (644172) | more than 4 years ago | (#32571464)

Let me interrupt you, Herr de von Ausfern -schplenden -schlitter -crasscrenbon -fried -digger -dangle -dungle -burstein -von -knacker -thrasher -apple -banger -horowitz -ticolensic -grander -knotty -spelltinkle -grandlich -grumblemeyer -spelterwasser -kürstlich -himbleeisen -bahnwagen -gutenabend -bitte -eine -nürnburger -bratwustle -gerspurten -mit -zweimache -luber -hundsfut -gumberaber -shönendanker -kalbsfleisch -mittler -raucher von Hautkopft auf Ulm, and ask you, just quickly...

reality separate from talknicians' hypenosys (-1, Offtopic)

Anonymous Coward | more than 4 years ago | (#32571264)

like the media(ahhaha) is reporting on things from an anti-gravity/morality/logic quantum. really it's (our take on things) just made up in new york & washington dc.

it's 'better' that most of US have no idea where we really are, where we're really going, or how close to departure we may be.

the corepirate nazi illuminati is always hunting that patch of red on almost everyones' neck. if they cannot find yours (greed, fear ego etc...) then you can go starve. that's their platform now. they do pull A LOT of major strings.

never a better time for all of us to consult with/trust in our creators. the lights are coming up rapidly all over now. see you there?

greed, fear & ego (in any order) are unprecedented evile's primary weapons. those, along with deception & coercion, helps most of us remain (unwittingly?) dependent on its' life0cidal hired goons' agenda. most of our dwindling resources are being squandered on the 'wars', & continuation of the billionerrors stock markup FraUD/pyramid schemes. nobody ever mentions the real long term costs of those debacles in both life & any notion of prosperity for us, or our children. not to mention the abuse of the consciences of those of us who still have one, & the terminal damage to our atmosphere (see also: manufactured 'weather', hot etc...). see you on the other side of it? the lights are coming up all over now. the fairytail is winding down now. let your conscience be your guide. you can be more helpful than you might have imagined. we now have some choices. meanwhile; don't forget to get a little more oxygen on your brain, & look up in the sky from time to time, starting early in the day. there's lots going on up there.

"The current rate of extinction is around 10 to 100 times the usual background level, and has been elevated above the background level since the Pleistocene. The current extinction rate is more rapid than in any other extinction event in earth history, and 50% of species could be extinct by the end of this century. While the role of humans is unclear in the longer-term extinction pattern, it is clear that factors such as deforestation, habitat destruction, hunting, the introduction of non-native species, pollution and climate change have reduced biodiversity profoundly.' (wiki)

"I think the bottom line is, what kind of a world do you want to leave for your children," Andrew Smith, a professor in the Arizona State University School of Life Sciences, said in a telephone interview. "How impoverished we would be if we lost 25 percent of the world's mammals," said Smith, one of more than 100 co-authors of the report. "Within our lifetime hundreds of species could be lost as a result of our own actions, a frightening sign of what is happening to the ecosystems where they live," added Julia Marton-Lefevre, IUCN director general. "We must now set clear targets for the future to reverse this trend to ensure that our enduring legacy is not to wipe out many of our closest relatives."--

"The wealth of the universe is for me. Every thing is explicable and practical for me .... I am defeated all the time; yet to victory I am born." --emerson

no need to confuse 'religion' with being a spiritual being. our soul purpose here is to care for one another. failing that, we're simply passing through (excess baggage) being distracted/consumed by the guaranteed to fail illusionary trappings of man'kind'. & recently (about 10,000 years ago) it was determined that hoarding & excess by a few, resulted in negative consequences for all.

consult with/trust in your creators. providing more than enough of everything for everyone (without any distracting/spiritdead personal gain motives), whilst badtolling unprecedented evile, using an unlimited supply of newclear power, since/until forever. see you there?

"If my people, which are called by my name, shall humble themselves, and pray, and seek my face, and turn from their wicked ways; then will I hear from heaven, and will forgive their sin, and will heal their land." )one does not need not to agree whois in charge to grasp the notion that there may be some assistance available to us(

boeing, boeing, gone.

Inertial mass must equal gravitational mass (2, Interesting)

selven (1556643) | more than 4 years ago | (#32571274)

Consider two giant bouncyballs in space, with the same inertial mass but where ball A has 4 times the gravitational mass of ball B. They start off some distance apart from each other, with velocity 0. As they attract each other, B will be accelerating 4 times faster than A since A has 4 times the gravity, and at one point they will meet. When they meet, A will have velocity -1 and B velocity +4. When they bounce off of each other, A will, naturally, have velocity +4 and B velocity -1. Now, B is still accelerating (or rather, decelerating) toward A 4 times faster than A is toward B, and when their relative velocity reaches 0, A will have velocity +3 and B will have velocity +3. Thus, each bounce accelerates the entire system by +3 with ZERO energy input, thus violating conservation of momentum and conservation of energy.

This is why any universe with a concept of conservation of energy and/or momentum must have the property inertial mass = gravitational mass. Now, if we can somehow break this rule with energy input, those of us interested in interstellar travel might have a completely new type of engine on our hands.

what about gradients? (1)

petes_PoV (912422) | more than 4 years ago | (#32571296)

When a body accelerates all its components are accelerated at the same rate. However, when body is subjected to a gravitational attraction, the part of the body nearest the attractor experiences a slightly larger attraction than is experienced by the other end of the attracted body (since the force experienced depends on the distance ** 2 from the attracting body). Unless you start talking about single point, infinitely small bodies, the difference in attraction across the gravity gradient will be real.

So in practical terms there is a difference, even if the effect is extremely small.

Re:what about gradients? (5, Insightful)

BradleyUffner (103496) | more than 4 years ago | (#32571514)

When a body accelerates all its components are accelerated at the same rate.

Not quite. Acceleration starts at a specific point and "pushes" its way through the object at the speed of sound in the material of the object. If you had a 10 mile long metal bar and were strong enough to shove one end, the other end wouldn't move instantly. Your force would start a compression wave along the metal bar, traveling at the speed of sound though the metal, until it reached the other end. Same with a rocket, the engines apply acceleration at their connection point and the acceleration pushes its way through the materiel. This is why they have to be built out of such strong stuff, it has to be able to withstand the compression forces of the acceleration without fracturing due to stress.

Re:what about gradients? (1)

maxwell demon (590494) | more than 4 years ago | (#32571570)

When a body accelerates all its components are accelerated at the same rate. However, when body is subjected to a gravitational attraction, the part of the body nearest the attractor experiences a slightly larger attraction than is experienced by the other end of the attracted body (since the force experienced depends on the distance ** 2 from the attracting body).

Yes. This effect is known as tidal force.

Unless you start talking about single point, infinitely small bodies, the difference in attraction across the gravity gradient will be real.

It suffices if the effect is below measuring accuracy, and therefore negligible.

So in practical terms there is a difference, even if the effect is extremely small.

A negligible effect can safely be neglected.

Superconducting You to Mars (0)

Black Gold Alchemist (1747136) | more than 4 years ago | (#32571348)

I had a similar idea a while back. I was calculating how much energy it would take to send a ship to Mars if it accelerated at 1G the whole time. There are two sources of energy use: gravity and acceleration. The result is that you basically blow up two nuclear bombs during the trip for a 100 ton ship. Most (>99%) of that energy is wasted accelerating the ship and slowing it down. Gravity is a small fraction of that energy (could easily be overcome by a nuclear reactor). That energy from acceleration is so huge because the Newtonian energy-momentum relationship is e=p^2/2m. However, in solid-state quantum systems (like silicon), the energy-momentum relationship (effective mass) is arbitrary. Sometimes it's just a constant times a Newtonian parabola, even a negative one. Sometimes it's a cubic function, others, a sine wave. The function is determined by the number and arrangement of particles in the system. This can be predicted by using quantum mechanics simulators to solve the Schrödinger equation for the system. If you could come up with a system that made the effective mass small enough, you could send the ship to Mars with a small battery (green spaceship!). Once you get this system (or maybe even before) you could move on to the Dirac equation. Then quantum mechanics and general relativity could fight each other, maybe even cancel each other out, and you could have quantum-based FTL.

Oh, another fun little problem. You're in space. You've got a gun that fires small bullets at really really high velocities - the bullets make up a trivial percent of your mass but have a noticeable effect on your velocity. It's an electric gun and puts the same amount of energy into every bullet. You fire the gun ten times. Do you get the same acceleration every time?

Extraordinary claims require extraordinary proof (1)

u19925 (613350) | more than 4 years ago | (#32571492)

The claim is extra-ordinary but unfortunately the proof is not. It is well known for a long time that the equations of quantum mechanics violates equivalence principle. Precisely for this reason, we don't have satisfactory theory of quantum gravity. So there is nothing new in terms of it. If I interpreted the contents of the paper right, the authors are suggesting a way to create an experiment which can show that m_i and m_g are indeed different, but these experiments have not been performed yet.

University of Ulm (1)

Megahard (1053072) | more than 4 years ago | (#32571502)

Does he know Johann Gambolputty de von Ausfern- schplenden- schlitter- crasscrenbon- fried- digger- dingle- dangle- dongle- dungle- burstein- von- knacker- thrasher- apple- banger- horowitz- ticolensic- grander- knotty- spelltinkle- grandlich- grumblemeyer- spelterwasser- kurstlich- himbleeisen- bahnwagen- gutenabend- bitte- ein- nürnburger- bratwustle- gerspurten- mitz- weimache- luber- hundsfut- gumberaber- shönedanker- kalbsfleisch- mittler- aucher von Hautkopft of Ulm?

building anti-grav spaceship in my garage now (3, Funny)

peter303 (12292) | more than 4 years ago | (#32571716)

The key part is the null-grav Bose-condensate at the base. When the temperature falls below 91 micro-kelvins, the resulting phase-change decouples inertial mass from equivalent mass and the gravitational force disappears.

There a few bugs to be worked out however. First, the grav-shield must be aligned within ten arc-seconds perpendicular to main gravitational body (Earth) or gravity leaks through. Second, stray cosmic rays have the disturbing habit of energizing the condensate about the phase-change temp and destroying the null-grav effect. I hope to have fixes by next week.
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