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Gravity and anti-matter

  1. Jun 16, 2004 #1
    okay, the electromagnetic force affects antimatter and matter oppositely. (and i'm just guessing the same could be said for the electroweak and weak forces as well.)
    Now, does gravity affect antimatter the same way it affects matter?

    Or, maybe i should say, does gravity act as a repellant force between one matter particle and one anti-matter particle and as an attractant force between two matter or antimatter particles?

    Here's another interesting little question: does antimatter have antimass or just mass?
  2. jcsd
  3. Jun 16, 2004 #2


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    Ductaper -- Experiments done in the late 60s or early 70s indicated that matter and antimatter sufer the same gravitational force, always attractive. I apologise, I dont' recall the specifics, but I think either Schalow at Stanford, Rebke and Pound at Harvard. You should be able to find out the specifics on the net.
    Reilly Atkinson
  4. Jun 16, 2004 #3


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    Electromagnetic force action depends on the charge, not whether or not it is matter or antimatter. For example, it has no effect on neutrons or anti-neutrons. For protons and electrons, the corresponding anti-matter particles have opposite charge.
  5. Jun 17, 2004 #4
    Where can I get anti-matter?
    Anyone have some to spare?
  6. Jun 17, 2004 #5


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    This is a question I have been pondering as well. I did not think any experiment had been done with sufficiently sensitive equipment to measure the effect of gravity on the tiny amounts of antimatter we have managed to produce.

    There is additional confusion in the study of Hawking radiation. The part of the virtual partical pair that falls into the BH is often reffered to as the "antipartical". This antipartical is said to fall into the EH, where its negative energy cancels out some of the positive energy therein. The reason this is confusing is because negative energy and antimatter are two very different things. Negative energy does indeed have negative mass and is therefore repelled by gravity, so negative energy should not be able to enter the EH. But antimatter is made of positive energy, just like ordinary matter, so it has positive mass, and should react normally to gravity.
  7. Jun 17, 2004 #6


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    I'm guessing. When high energy physics experiments involving positrons or antiprotons are carried out, I suspect that the forces being applied to keep particles on track must include compensating for gravity, and I would be very surprised if they didn't work to overcome falling, not rising.
  8. Jun 17, 2004 #7
    electron gravity

    In electron acceleration experiments, where an electron is directed at a target - is the electron effected by gravity as it travels to the target? Is the weight of the electron compensated by magnetics to keep it in line with the target?

  9. Jun 18, 2004 #8
    I'm guessing as well, but considering that gravity is many orders og magnitude weaker than electro magnetism, I'd be surprised if they had to do anything at all to counter gravity. We're talking particles moving at 99.999% of c in approximately 15000m/3e8m/s = 0.00005 seconds (long linear accelerator). On this path the particles is boosted about 1000 times by magnets ...
  10. Jun 18, 2004 #9
    Gravity Gauge...

    All known matter in the Universe (including dark matter), is based upon 'positive mass', regardless if such mass is exotic (neutrino) or anti-matter (opposite mass monopolarity) and attracts only due to the negative warping effect that all mass has on the fabric of space-time.

    However, there is a hypothetical mass called 'negative mass' which theoretically repells all other negative masses, however, negative mass has not been discovered and probably does not exist in the current Universe.

    Hypothetically, 'gravitational monopolar' positive masses attract only and monopolar negative masses repel only, therefore monopolar positive and negative masses probably attract also, because only alike monopoles attract or repel only and unlike monopoles propably attract only.

  11. Jun 22, 2004 #10
    To make it very short, anti-matter and matter are exactly the same except their charge, antiprotons and protons for example have teh exact same mass, and every other property is the same except their net charge. Photons emitted from antimatter are exactly the same as photons from matter, an anti- piano will sound exactly the same as a normal piano, and finially....gravity will act on anti-matter exactly the same as it will on matter, the anti-matter wont "float" up or get repelled in a gravitational field.
  12. Jun 22, 2004 #11
    This is only partially true. Other quantum numbers such as baryon number, lepton number, z component of isospin, strong hypercharge Y, etc. change sign also between matter and anti-matter.
    Last edited: Jun 22, 2004
  13. Jun 22, 2004 #12
    Thats cool, im not gonna argue with ya, because i myself dont know nearly as much as others on this site, im still in high school, 17 years old. :P
  14. Jun 25, 2004 #13
    We currently view matter as having various properties that are dependent on the type of matter we are referring to. Somewhere along the path of science, a concept of opposites came into being as an explanation of various phenomena. This concept has been applied to matter such to state we have positive particles of matter, negative particles of matter and neutral particles of matter. We also have ordinary matter and antimatter. The ideas spawned by the concepts of opposite types of matter, has advanced our technologies to amazing heights; but they have done nothing to assist our understanding of the real physical nature of existence. The universe has only one type of matter – the rest is all smoke and mirrors of nature.
  15. Jun 25, 2004 #14
    antimatter reacts to curvature of spacetime in the same way ordinary matter does, therefore it falls down.
  16. Jul 2, 2004 #15
    Do you have any evidence at all to support this opinion?
  17. Jul 3, 2004 #16
    Right. Because we are humans we always need to "touch it" and play with it to be sure. Antimatter is not an exclusion.
  18. Jul 3, 2004 #17
    You guys should go talk to Antonio Lao in the Theory Development Forum, he is having some trouble believing antimatter doesn't create anti-gravity.
  19. Jul 8, 2004 #18
    Mate, show me then how
  20. Jul 8, 2004 #19
    Gravity will remain in darkness untill we catch a gravitone if there is such thing, the preposition that antimatter may create antigravity comes from the well known quantuum understanding " cliche' " of our world prevailing from the times of Einstein. If there is a gravitone we cannot catch it because, maybe, it is either too fast or is eaten up by virtually anything that has to do with mass too fast. We cannot catch it because it practically doesn't seem to exist in real world, i.e. being "consumed" and "re-emmited" and then "consumed" at really "unreal" speeds (gravity seems to be always there) as an interaction particle by anything that has "mass" or can be involved in a gravitational interaction... Because gravity seems to be always there without a delay like in the electromagnetic case, we wonder what it's speep may be like.... and of course gravity is more common than light or EM waves, it's just everywhere... If, following the above "quantuum cliche", the presence of other objects hit "gravitons" out of yet other objects then the energy and time required to achieve that are proximate to zero.
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