1. It's almost impossible to find good information on anti-gravitons without getting pelted by a thousand geek-built websites on Star-Trek. It's frustrating when yer trying to figure something out.

We know that if you take an atom, and it's anti-equivalent, and combine them, they will annihilate each other. Their annihilation produces energy. This is great and all, but what happens when a graviton and an anti-graviton combine?

We would assume that the result would be energy, but as Einstein said, energy = mass. So essentially the annihilation would produce mass, but does that mean the anti-gravitons are being destroyed, leaving behind gravitons?

I probably need to poke at that some more, but any help would be appreciated! :-D

2.

3. Wow, not a single response. I'm disappointed.

4. Hmm, all the know-it-alls seem to be hiding in the theology section...

Anywho, to further my question:

If you could produce a mass wave or gravity wave, perhaps you could in theory produce gravitons through pair creation? That's assuming you could produce such a wave to begin with without already having gravitons or a mass.

Eagerly awaiting the cognition of others.

5. Considering that the graviton is only a hypothetical particle, any discussion of anti-gravitons probably belongs on the Star Trek web sites.

6. Originally Posted by Harold14370
Considering that the graviton is only a hypothetical particle, any discussion of anti-gravitons probably belongs on the Star Trek web sites.
on the other hand, you could always do a thought experiment

question 1 = what are the properties of the graviton ?
question 2 = in what sense would the anti-graviton be the opposite of the graviton ?

i can only pose the question, i don't know enough about particle physics to even have an inkling of an answer

7. I got this response from another forum:

Gravitons (if they exist) are their own antiparticles. A graviton and another graviton could annihilate and produce any particle which has a mass lower than that allowed by the graviton-graviton system. This does not, however, result in the creation of more mass, since any mass was already contained in the system
So it would appear that gravitons behave like neutrinos (which also don't have charges). Still wrapping my head around what interactions might be like, and where the lost mass goes (I'm assuming light) but this is progress. :-D

8. Originally Posted by Wolf
I got this response from another forum:

Gravitons (if they exist) are their own antiparticles. A graviton and another graviton could annihilate and produce any particle which has a mass lower than that allowed by the graviton-graviton system. This does not, however, result in the creation of more mass, since any mass was already contained in the system
So it would appear that gravitons behave like neutrinos (which also don't have charges). Still wrapping my head around what interactions might be like, and where the lost mass goes (I'm assuming light) but this is progress. :-D
Did the poster from the other forum know what they were talking about or were they just spouting gobbledygook. I don't know enough about the theory to say and I don't think you do either.

9. Probably, considering it was a forum specifically geared towards physics, with its own quantum physics section.

That, and they came right out and addressed the question head on.

It's all a deja-vu experience for me, kinda. I used to know a lot of this stuff, but haven't dealt with it in so long that those sections of my brain have gathered dust.

10. surely if a particle is its own anti-particle it's likely to be rather short-lived

11. Originally Posted by marnixR
surely if a particle is its own anti-particle it's likely to be rather short-lived
What it means is that there is no actual anti-particle.

In standard annihilation, you have positively charged particles, and negatively charged particles. Depending on yer perspective, one is the particle and the other the anti-particle. If the particle does not have a charge, it cannot have an anti-particle pair. Neutrinos are assumed to be such an example of particles without an anti-particle.

12. i don't mean to sound pushy or someone who knows something. Just a thought that gravitons don't have charges such like neutrinos... but we have observable evidence of graviton's properties that it pulls mass. Err~ why don't we try something like catching a graviton like the way we catch neutrinos ? and further testing about it's interactions with mass will later on conclude what it is..? Is that possible though?

I dunno about the neutrinos bit. But Just watched a documentary about some guys catching neutrinos under the water..~

13. Since the existance of a gravitron is still theoretical I'm just going off the most commonly accepted theory, The M(String) Theory. Which believes that the Graviton is a multidimentional particle, capable of not only traveling through any known object, but also through other dimensions, Also the graviton is believed to be massless, so study of it is very difficult. Because there is no know way of manipulating it or even affecting it for that matter. The current way that most hope to prove it's existance is with an atom smasher. They hope that the graviton will choose to switch dimensions at the point of impact and we will be able to prove it's existance with it's absence.

14. Originally Posted by marnixR
surely if a particle is its own anti-particle it's likely to be rather short-lived
No, photons are also considered as their own anti-particles. Gravitons would share this same characteristic.

15. So we have a hypothetical idea based on a hypothetical particle. Okay. Um. This has no discussion value whatsoever. Or do people enjoy intellectual masturbation? Anti-gravitons are nonsensical because the opposite of gravity is NO gravity. The same concept applies to, say, light. Anti-protons only work when there is something to counterbalance something else, such as electrical charges.

16. Originally Posted by Darius
Anti-gravitons are nonsensical because the opposite of gravity is NO gravity.
it isn't - if gravity attracts, the opposite of gravity should repulse

17. Gravity does is not ATTRACTION of objects (this is incidental), but rather is the CURVE in space caused by the presence of matter. The opposite of this would be the lack of curvature.

18. Originally Posted by Darius
The opposite of this would be the lack of curvature.
not necessarily : the opposite of positive curvature is negative curvature, not zero curvature

19. Curvature of space does not work on the basis of positive or negative, so your logic has an invalid premise.

20. Originally Posted by Darius
Curvature of space does not work on the basis of positive or negative, so your logic has an invalid premise.
Yes, it can. Positive curvature follows elliptical geometry while negative curvature follows hyperbolic geometry (zero curvature follows Euclidean geometry)

21. That's in 2D space. Space is not 2D! Argh!

22. Originally Posted by Darius
That's in 2D space. Space is not 2D! Argh!
No, it applies to all spaces. The rules of Euclidean and non-Euclidean geometries are not constrained to just 2-dimensional spaces.

23.

24. Um. Let me just be clear here: To create any sort of supposed "antigravity" you would have to create "antimass". Um. Yeah. Good luck with that. Although, really, the opposite of something is nothing. Antigravity? Space. this means the opposite of gravity...is the lack thereof.

25. Look. Space curvature is Einstein's idea; Relativity. Gravitons are predicted by quantum mechanics and made to work with M-theory. Both give exactly the same result.

26. It has come to my attention that there is a very "advanced" hypothesis regarding the existence of negative mass. While never observed (and I don't believe it ever will be because the logic behind it appears nonsensical), the hypothesis does exis.

In my view the opposite of something is nothing, not anti-something. Unless the universe works based on logical ternary.

27. Originally Posted by Darius
Unless the universe works based on logical ternary.
Maybe...

:P

28. Honestly, if it did, suddenly everything would make sense (By way of making absolutely no sense at all).

29. Did you get the joke? Ternary logic is True False and Maybe. Well, I thought it was funny...

30. Actually I was thinking +1, 0, -1.

31. That wouldn't have been as funny... :P

32. Maybe not as funny...but makes sense. 8)

Anyway, I agree with Darius, the opposite of something that is not tangable or physical would be nothing.
Anti-matter can only exist because of the rare quantity out in space where the two opposites will never meet. Anti-mass or anti-gravity make no sense unless you are referring to litterally "without mass" or "without gravity" which still doesn't make sense because they both are 'something', they are just not physical.

33. Originally Posted by marnixR
surely if a particle is its own anti-particle it's likely to be rather short-lived
[/quote]

That makes sense, if gravitons exist.

The fact it's so hard to detect them in the first place might make it difficult to go that extra step and start actually manipulating them.

Suppose we even get enough anti-matter in one place for them to generate a strong anti-gravity field, would the annihilation of gravitons and anti-gravitons even generate energy? If so, where is the mass/energy coming from?

As far as I know, the emission of gravitons by a massive body is not considered to use up any of its mass or energy, which would mean that the graviton itself doesn't actually have any mass or energy.

34. Well my post is going to be filled with nothing but conjecture, but since the graviton's existence itself is still only a theory anything that relates to it will be. Anyway, without further ado:

If you want to try and theorise about the properties of an anti-particle then you need to try and concisely think of what makes the original particle what it is? What are its defining factors?

For example, a common property that is associate with particles is their charge. If an electron has a negative charge then consequently a positron has a positive charge.

If we try and extend that to gravitons then the defining factor for the particle is its behavior with mass - it attracts it (of course, there are also valid theories that the graviton IS mass and attracts itself, but whatever). So in that respect, it conceptually acts in a similar way to charged particles and we can perhaps suggest that should an anti-graviton exist it would REPEL mass.

This would also satisfy the consideration that for anti-particles to exist they must somehow be isolated from their original counterpart; if an anti-graviton pushed mass away and a graviton pulled it towards itself, they would either have no interaction or they would be in a state of equilibrium (assuming no coincidental collision). In other words, unlike other particle/anti-particle relationships they wouldn't be bound to collide.

It's also possible they would actually repel one another directly if we if we give credence to the theory that the graviton is, or is responsible, for mass itself. This means there would be no general product from a collision as it would never occur. They'd essentially be opposite, in behaviour, from other particle/anti-particle relationships.

If you believe in the cyclic universe theory then that would be one potential situation where they would collide, and what would happen is anyone's guess. Personally I see two possibilities that could result from it, if we consider the cyclic theory to be true:

1. They would annihilate one another and this would produce mass.

2. More likely, in my opinion, is that they wouldn't annihilate one another under any circumstance, even a perceived singularity, and their behaviour would be like trying to push two repelling magnets together. Within an infinitesimal space the force of repulsion would be colossal enough to be an integral part of the Big Bang.

Number 2 poses a dilemma, or a suggestion at the particle's potential nature: In a cyclic universe, if a particle and an anti-particle don't annihilate each other then there's an infinite growth; if that anti-particle is consistantly being produced yet it can't be annihilated, that means there is an infinite flow of anti-matter being produced as there is no corresponding destruction to balance out its creation. The only potential balance to this would therefore be that anti-gravitons decay and eventually dissipate.

Of course, it's complete conjecture but that's the only way I can see an anti-graviton existing. What its purpose would be in a universe where every single particle contributes is beyond...other than establishing and maintaining gravitational stability on a galactic scale, or being a part of turning Big Crunch's singularity into a Big Bang explosion I can't think of one

35. Ok, I realize that I'm posting a reply more than a year after the last posting but if anyone still reads this thread here ya go...

First off I'm not a physicist, I'm actually a computer scientist with an interest in physics and cosmology so this post is only my understanding of gravitons and the general nature of gravity (so take it with a grain of salt).

Gravitons, as I understand, are gravity waves at typically very small scales (meaning high energy gravity waves like those which result from an exploding star or the merging of 2 black holes) - but essentially a graviton is simply a gravity wave.

A gravity wave is a structural deformation in the fabric of space-time.

Gravity waves (gravitons) are wave particles like photons (in the sense that they both act as a wave). Photons are light waves (waves of electromagnetic radiation). Light waves can be modified like any wave given certain conditions. A prime example is the red-shift of light waves that occurs when observing distant galaxies (the wave loses energy given enough time and it becomes stretched out and therfor the color of light shifts to the red end of the light spectrum).

Waves can also be cancelled when joined with another wave of inverse shape (or an identicle wave that has been phase shifted enough where the peak of one matches up with the trough of the other). A perfect example of wave cancellation is noise cancelling technology in headphone systems (they take background noise around you and emit inverse sound waves to cancel them out in the head phones).

So with that said, I believe in some way it would be possible to cancel out the behavior of gravity waves if a space-time distortion (graviton A) collided with another space-time distortion (graviton B) having an inverse wave pattern of the first distortion.

I believe in this case bending space-time in two directions in equal strength would result in the opposite behavior of normal gravity which in this case would be no bend in space-time at all (anti-gravity). I'm sure it's far-more complicated than this if anti-gravity through gravity wave interaction is possible - but that's my 2 cents.

One last thing I want to mention: a sort of "anti-gravity" does occur in nature all the time all around us in the form of dark energy. Where space itself expands pushing objects apart. I know it's not quite the same as anti-gravity in the context of this thread but perhaps it is close enough to merit further thought.

36. The only thing with that is, I think what you're describing is gravito-magnetism instead of gravity itself.

Electrically charged particles with opposite charges naturally attract in much the same manner as gravity. If one of these particles is moving relative to the other, it creates a magnetic effect. An alternating magnetic field is a radio wave/ light wave/ bunch of photons.

Gravito-magnetism is what happens when a gravity object moves relative to another, and if it exists (it's predicted to exist, but I don't think it's been proven yet), it would have that same trait of being wave-like. The positive portion of one gravito-magnetic wave could cancel with the negative portion of another gravito-magnetic wave if the two interacted.

37. Originally Posted by RandomGuy
Ok, I realize that I'm posting a reply more than a year after the last posting but if anyone still reads this thread here ya go...

First off I'm not a physicist, I'm actually a computer scientist with an interest in physics and cosmology so this post is only my understanding of gravitons and the general nature of gravity (so take it with a grain of salt).

Gravitons, as I understand, are gravity waves at typically very small scales (meaning high energy gravity waves like those which result from an exploding star or the merging of 2 black holes) - but essentially a graviton is simply a gravity wave.

A gravity wave is a structural deformation in the fabric of space-time.

Gravity waves (gravitons) are wave particles like photons (in the sense that they both act as a wave). Photons are light waves (waves of electromagnetic radiation). Light waves can be modified like any wave given certain conditions. A prime example is the red-shift of light waves that occurs when observing distant galaxies (the wave loses energy given enough time and it becomes stretched out and therfor the color of light shifts to the red end of the light spectrum).
The similarity between gravitons and photons goes deeper than that. Just like Photons are units of electromagnetic radiation, gravitons are units of gravitational radiation, and just like shining a flashlight on an object will not draw it towards you via the electromagnetic force, The waves produced by a gravity wave generator will not draw a mass towards it via the gravitational force. It is the electromagnetic field which is responsible for the electromagnetic force, and it is the gravitational field which is responsible for the gravitational force.

So why do you hear that the graviton is the force-carrying particle for gravity?

This is because in Quantum Electrodynamics, the quantum theory for the electromagnetic force, photons are considered the force-carrying particle. But here they are talking about virtual photons, not actual ones.

So in a quantum theory for gravity, you would expect virtual gravitons to be the force-carrying particle.

So far, the fly in the ointment is that no one has been able to come up with a workable equivalent to quantum electrodynamics for gravity. We don't have a quantum theory for gravity yet.

38. I think since gravitons have no apparent charge neither would Anti-gravitons but there is spin. One other thing, isn't there supposed to be particles with negative mass?

39. Originally Posted by Draco00942
I think since gravitons have no apparent charge neither would Anti-gravitons but there is spin. One other thing, isn't there supposed to be particles with negative mass?
I haven't heard of particles with negative mass!

40. Originally Posted by Draco00942
I think since gravitons have no apparent charge neither would Anti-gravitons but there is spin. One other thing, isn't there supposed to be particles with negative mass?
The graviton, if it exists, is its own anti-particle. This is also true of the photon. Since neither carries an electric charge, you are correct.

There is no known particle with negative mass/energy. There are exotic theories that allow such things but no evidence that they actually exist.

41. ANTI-GRAVITONS

42. Originally Posted by marnixR
Originally Posted by Darius
Anti-gravitons are nonsensical because the opposite of gravity is NO gravity.
it isn't - if gravity attracts, the opposite of gravity should repulse

Perhaps, this theoretical machine, can even control the amount of gravity being repulsed and enable it to move, or transfer from a mass (planet) to space.

43. this "anti-graviton" that many here are looking for is one with negative mass, not negative charge. Anti-particles generally refers to particles having the opposite electric charge of the original particle. Antimatter is matter in which the nucleus of the atom is comprised of antiprotons and is orbited by positrons. these are particles having opposite ELECTRIC charge.

If an object were to have negative mass AND negative energy, it would be exactly the same as a normal particle. Now, were it to have negative mass and POSITIVE energy, it would travel backwards in time. Thus, it would never be detectable as it would exist in a timeline moving in the opposite direction of the Big Bang. The only way to prove its existence would be to detect its ABSENCE in a collision that should yield its creation, assuming that it can be created entirely from particles with 'positive' mass. Otherwise, it would be safe to assume that, given a particle with 'negative' mass can exist, it all exists in its own universe in which all mass is negative and time moves backward from the origin.

Therefore, negative mass and positive mass could never collide except for once: the singularity from which the known universe has spawned.

So, if there is an equal magnitude of both positive and negative masses, there exists an equal amount on each side of the origin of time, and thus the equation balances and would explain how the universe could have come from no mass => there is still no NET mass, considering both directions of time.

This material could not be harnessed to build some sort of "anti-gravity" machine

44. Negative mass is stable at the state of high energy. So the “problem of the transition of the energy level of minus infinity” does not occur, and thus positive mass and negative mass can exist in the same space-time

1. Big bang simulation from the Zero Energy State!

2. Important reporting on the Dark Energy and Gravitational Potential Energy

3. Motion of the Negative mass

Have a nice day!

--- Icarus2

45. As has already been ( correctly ) pointed out by several contributors on this thread, a graviton - if it exists, for which currently there is no experimental evidence -, would be a massless spin 2 vector boson. It wouldn't carry any charge, and would not have an associated anti particle ( just like the photon btw ). The concept of an "anti-graviton" is not predicted or required by any current mainstream physical theory that I know of, and there is no experimental evidence for its existence.

46. an anti-graviton seems logical to exist as repulsion matter because how else would a pi^0 Meson (up and anti up quark) exist. The two quarks, working under normal strong nuclear forces, would attract towards each other and annihilate, as they have opposite charge and mass, but they don't due to the boson interaction, which would have to be repelling them and thus be an anti-graviton.

47. Originally Posted by Joepalubiski
an anti-graviton seems logical to exist
No. Gravitons, if they exist, would be massless spin-2 particles, so they are their own anti-particles. This is analogous to the photon.

because how else would a pi^0 Meson (up and anti up quark) exist
The existence of pi mesons has nothing whatsoever to do with gravitons.

The two quarks, working under normal strong nuclear forces, would attract towards each other and annihilate
That's exactly what happens - the neutral pion has an average life time of just 8.4*10^(-17)s, after which it decays electromagnetically into two photons, or via Dalitz decay into a photon, a positron and an electron. Again, this has nothing whatsoever to do with gravitons.

but they don't due to the boson interaction, which would have to be repelling them and thus be an anti-graviton.
Quarks aren't bosons, so I really don't know what you are saying here. In any case neutral pions aren't stable.

48. Originally Posted by DrRocket
The graviton, if it exists, is its own anti-particle. This is also true of the photon. Since neither carries an electric charge, you are correct.

There is no known particle with negative mass/energy. There are exotic theories that allow such things but no evidence that they actually exist.
I don't suppose I should quote a post from June 2011, but I always admired the good Doctor's ability in maths and physics.
DrRocket was always a stickler for accuracy so should he not have said "hypotheses" rather than "exotic theories" given that he states there is no evidence that particles with negative mass/energy exist.

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