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Inertial Mass Separate From Gravitational Mass?

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."

26 of 405 comments (clear)

  1. Next stop: Arisia by The_mad_linguist · · Score: 4, Funny

    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.

    1. Re:Next stop: Arisia by Anonymous Coward · · Score: 5, Funny

      The technology lens itself very well to that.

      I sea what you mean.

    2. Re:Next stop: Arisia by c0d3g33k · · Score: 1, Funny

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

      Dude. Nice one.

    3. Re:Next stop: Arisia by gd2shoe · · Score: 5, Funny

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

      Dude. Nice one.

      Oh, come on now. You must have meant "Nice won."

      --
      I won't join Slashcott. OTOH, If Beta goes live, I just won't be back until it's fixed. Sorry Dice.
  2. Inertial Dampeners??? by bfmorgan · · Score: 5, Funny

    Would this lead to science fictions "Inertial Dampeners"?

    --
    I hope this caused some synapses to fire.
    1. Re:Inertial Dampeners??? by sznupi · · Score: 4, Funny

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

      --
      One that hath name thou can not otter
    2. Re:Inertial Dampeners??? by AdmiralXyz · · Score: 5, Funny

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

      --
      Dislike the Electoral College? Lobby your state to join the National Popular Vote Interstate Compact.
    3. Re:Inertial Dampeners??? by Anonymous Coward · · Score: 1, Funny

      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?

    4. Re:Inertial Dampeners??? by demonbug · · Score: 5, Funny

      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.

    5. Re:Inertial Dampeners??? by Surt · · Score: 3, Funny

      In space, no one can hear you screech.

      --
      "Who is the Journal of Quantum Physics going to believe?" --Stephen Hawking
    6. Re:Inertial Dampeners??? by A+nonymous+Coward · · Score: 4, Funny

      That's a bloody good joke, sir.

    7. Re:Inertial Dampeners??? by Sir_Lewk · · Score: 4, Funny

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

      Trying to reconcile StarTrek's bullshit with physics is pointless masturbation.

      Color me baffled. Are you disagreeing with him or not? ;)

      --
      "linux is just DOS with a UNIX like syntax" -- Galactic Dominator (944134)
    8. Re:Inertial Dampeners??? by sznupi · · Score: 3, Funny

      Hm, maybe you're onto something - that could, maybe, account for exploding control panels... (not to later problems with repairing them, though)

      --
      One that hath name thou can not otter
  3. I would submit.... by Count+Fenring · · Score: 5, Funny

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

    1. Re:I would submit.... by bistromath007 · · Score: 4, Funny

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

    2. Re:I would submit.... by jspenguin1 · · Score: 5, Funny

      You mean this one from 2004?

    3. Re:I would submit.... by darkmeridian · · Score: 1, Funny

      Dude, seriously, that's fucked up. This xkcd man must be a genius or something. Holy fucking shit! LOL. LOL. LOL.

      --
      A NYC lawyer blogs. http://www.chuangblog.com/
  4. Re:Quantum by drdrgivemethenews · · Score: 2, Funny

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

  5. Johann Gambolputty by hugi · · Score: 2, Funny

    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.

  6. building anti-grav spaceship in my garage now by peter303 · · Score: 3, Funny

    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.

  7. Re:Sure, here you go by grimJester · · Score: 3, Funny

    Now, it is possible for the first time to write down a single equation (Eq.1 of Mathematical Foundations of the Relativistic Theory of Quantum Gravity. See T-shirt below) that can explain all the laws of physics( including the Einstein's equations), all the forces of nature - the proverbial "theory of everything".

    The standard crackpot "a single equation" makes me want to cry, but the "see t-shirt below" part more than makes up for it.

  8. This Can't Be by DynaSoar · · Score: 2, Funny

    If he's right, they'll call it that "Kajari Drive". That just doesn't ring for me. We need someone else to refine this and make it go. An Archer maybe, or a Cochrane. Now those are names a real space drive can wear. Hell even inter-compartment conduits get names like Jefferies Tubes. Kajari? No way. He can have an episode of his own when they serialize history (as we know they have, so we can see it but consider it fiction thus avoiding paradox), but not the name of the drive.

    --
    "I may be synthetic, but I'm not stupid." -- Bishop 341-B
  9. Re:Dark matter? by Dahamma · · Score: 4, Funny

    More importantly, it means that one pound of dark matter COULD weigh over ten thousand pounds!

  10. Re:Sure, here you go by maxwell+demon · · Score: 3, Funny

    Oh, I can easily write all equations of Physics into one equation.

    To see how it works, let's assume I want to "unify" the Schrödinger equation and Einsteins field equation (don't worry about the fact that the Schrödinger equation is non-relativistic ...).

    Schrödinger: i hbar d/dt psi = H psi [d here should be the partial derivative sign]
    Einstein: G = 8 pi gamma/c^4 T [gamma here is the gravitational constant, because G is already used for the Einstein curvature tensor]

    The first step is to bring all terms to the left side:

    Schrödinger: H psi - i hbar d/dt psi = 0
    Einstein: G - 8 pi gamma/c^4 T = 0

    Note, however that the "0" in the first equation is a null vector in the quantum mechanical Hilbert space, while in the second equation, it's a tensor in spacetime. Those are not compatible. However, in both cases, we can choose a norm (in the first case, the standard Hilbert space norm can be used; in the second case, any matrix norm will do). Note that the norm need not to make physical sense; the only thing we need is that it maps to the non-negative real numbers, and only the zero object of the respective quantity is mapped to the real number zero. Denoting both norms with ||...||, we get:

    Schrödinger: ||H psi - i hbar d/dt psi|| = 0
    Einstein: ||G - 8 pi gamma/c^4 T|| = 0

    Now we have two non-negative real numbers which shall be zero. Their sum is zero exactly if each one of them is zero. Therefore we can combine the equations into one:

    ||H psi - i hbar d/dt psi|| + ||G - 8 pi gamma/c^4 T|| = 0

    From this equation, one can easily derive both Einstein's field equation and Schrödinger's equation. Therefore I just unified quantum mechanics and general relativity. :-)

    --
    The Tao of math: The numbers you can count are not the real numbers.
  11. Re:The really important question ... by Anonymous Coward · · Score: 1, Funny

    Yes.

  12. Cartman by Hognoxious · · Score: 2, Funny

    I don't have a lot of gravitational mass ... it's my bones that have a lot of inertia.

    --
    Confucius say, "Find worm in apple - bad. Find half a worm - worse."