Talk:Gravitational interaction of antimatter

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LEP Observations[edit]

I don't know if it has ever been published, but in 1993 in LEP it was found we had to adjust our calculations for the beam orbits to take into account the moon. We actually observed tidal effects on the positron and electron beams. The calculated corrections where done assuming gravitational attraction of positrons, and noticeably improved the agreement between predictions and observation. I remember this was mentioned when they discovered a 1% correction to the beam energies. I'm not certain how much of the 1% correction was the tidal corrections... I doubt anyone at the time thought to run the calculations reversed to see if the effect was significant enough difference to prove the gravitational attraction of positrons to ordinary matter. In fact since the work was done by graduate students, I would not be surprised if they did the calculations and then just assigned the +/- sign to match the experimental results. However, chances are the answer to this question if positrons are attracted by matter exists within the LEP data.Bill C. Riemers, PhD. (talk) 21:42, 22 December 2010 (UTC)

  • I'm not a physicist, but from my reading of the paper [1] I think that the change in beam energy was due to tidal forces deflecting the equipment, and not the beams directly. 74.183.177.42 (talk) 20:04, 13 November 2011 (UTC)

Measurement of antimatter's relationship with gravity?[edit]

Are you seriously suggesting that antiprotons and positrons (very common compared to anti-matter) have never been tested for susceptibility to gravity? The Antiproton page claims that they know that the antiproton interacts with gravity; is it true no one has demonstrated whether the sign of that interaction is positive or negative? Then one must assume they have never demonstrated any interaction at all.

Is anyone seriously suggesting that combining a positron with the antiproton will flip its sense of gravity?

This speculation about the gravitational interaction of antimatter is unserious. The interesting question is whether, once we know how gravity arises, we'll find a symmetrical set of particles (gravity reversed protons, anti protons, etc.). As for the sort of antimatter formed by antiproton-positron pairs, I'll think you'll find we already know the answers.

Someone with access to journals will have to find the relevant cites.

76.126.215.43 (talk) 17:40, 9 July 2009 (UTC)

These are extremely difficult experiments; I don't think any of them have been done. The antiproton article doesn't say that the gravitational interaction has been experimentally observed, just that it's predicted. From "antiprotons and positrons (very common compared to anti-matter)" it sounds like you think that antiprotons and positrons aren't antimatter. They are. -- BenRG (talk) 21:11, 20 July 2009 (UTC)
I do not have a source, but I seem to remember that anti-protons and positrons have been weighed and found to have positive weight. That is, they are attracted gravitationally to the Earth. But this only measures their passive gravitational charge. Measuring their active gravitational charge (whether matter is attracted to them) is probably effectively impossible. JRSpriggs (talk) 11:10, 21 July 2009 (UTC)
As far as I know, it should be a relatively simple (Though expensive) experiment - you get an antiparticle, put it in a vacuum and isolate it from any external electromagnetic fields, and 'drop' it (By removing the field supporting it, of course). Then whether it goes up or down (Detectable by the annihilation event, as it releases heat.) should present the answer for us. I'm surprised no one has apparently done this yet. Xander T. (talk) 08:07, 22 July 2009 (UTC)
The problem is that you need to cool individual atoms of antihydrogen to millikelvin temperatures in order to do this. Otherwise, they're moving quickly enough to swamp any gravitational effect on their motion. Last I heard, the best we could do was to cool antiprotons down to eV energy scales (thousands of K) to allow formation of antihydrogen.
The best way I can think of to test the response of antimatter to gravity would be to look at a cosmic ray source that produces both matter and antimatter and that appears to pass behind the Sun as Earth moves in its orbit. If the matter and antimatter parts of it cut off at the same time, they're affected the same way by the Sun's gravitational lensing effect. If antimatter is repelled by the Sun's gravity, lensing would cause the antimatter component to cut off earlier and the matter component to cut off later.
Moot point for now, though. What I'd really like to see is a citation attached to the statement claiming that it's been measured. If it's been measured reliably, there'll be papers about it. If there aren't any, then it probably hasn't been measured reliably. --Christopher Thomas (talk) 20:04, 22 July 2009 (UTC)

(Unindent) It's been a while since someone added a comment here. I'd like to refer anyone reading this to the exotic matter article, where one of the things talked about is "negative mass". It seems to me that that stuff would be a much better candidate for exhibiting gravitational repulsion with ordinary matter, than anti-matter. To better understand that involves two steps. First, remember that that standard equations for gravitation do not incorporate Quantum Mechanics, but almost certainly they some day will (that's the goal of Grand Unified Theories, after all). Anyway, when it happens that gravitational equations do incorporate QM, that's when they will incorporate Planck's Constant. The second step here is to closely examine the Definition of Planck's Constant. It has the "dimensional units" (see dimensional analysis) of "energy multiplied by time". Now look again at the Planck's Constant article, and notice that the first equation in it describes the association of the energy of a photon with its wavelength. That's a photon of ordinary energy, and so Planck's Constant includes ordinary energy in its dimensional units. Which means, if we wanted to equivalently describe a photon of negative energy, the energy "dimension" of Planck's Constant should be negative, not positive. The net effect of this is, when we get to the gravity equations that incorporates Planck's Constant, for negative mass, some key sign-reversals will occur. For example, with an ordinary Planck's Constant two negative masses are predicted to generate an attractive gravitational force between them, and will respond by accelerating away from each other. But with a negative Planck's Constant in the equations, two negative masses are predicted to generate a repulsive gravitational force between them, and will respond by accelerating toward each other. That "accelerating toward each other" is of course identical to the gravitational behavior of two ordinary masses. I leave open the question of what value of Planck's Constant to use when an ordinary mass gravitationally interacts with a negative mass, but the result of "accelerating away from each other" does not appear to be impossible. So, like I wrote near the start, negative mass could be a much better candidate than anti-matter, when one wants to explain such things as the accelerating expansion of the universe. Especially since, per the "E=mc² argument", anti-matter is very likely only ordinary, in terms of mass-energy, and General Relativity has a lot to say about the gravitational behavior of ordinary mass-energy. V (talk) 17:42, 30 December 2009 (UTC)

Maybe I am simple, and I am surely no physicist, but if antimatter produced an opposite to gravity, antimatter would gravitate together and would repel matter. paulbuchholz22 —Preceding unsigned comment added by Paulbuchholz22 (talkcontribs) 02:54, 27 May 2010 (UTC)

There is a discrepancy in terminology here. two groups use the term anti-matter in two slightly different ways. The article on antimatter describes it in analogy to the relation between regular matter to regular sub-atomic particles. That is, it is neutral stable matter which when brought into contact with regular matter will annhilate. I understand that some would say that antimatter was discovered in 1932 and pronounce that an anti-particle is antimatter. While I do not favor equating ANY sub-atomic particle with matter, it is certainly moot. What is NOT moot is that there are two different definitions of antimatter, one essentially sub-atomic (on up) and one restricted to atomic matter (on up) and clearly this difference should be explained in this article. It is especially important now that we are creating antihydrogen with significant life-times in the laboratories.71.31.152.112 (talk) 04:15, 4 October 2010 (UTC) I should add that it seems that no one commenting here has any idea how incompetent we are at creating a vacuum. Before people go off making wild claims about how easy it is to measure a antiatom's gravitational interaction by "just putting it into a vacuum" please check to see what the neutral atom density IS in the very best vacuums we are able to create. Some of you will be chagrined - at least SHOULD be.71.31.152.112 (talk) 04:23, 4 October 2010 (UTC)

Interesting analogy from semiconductors says anti-matter falls up.[edit]

General relativity predicts anti-matter falls down, and it probably does. However, I find the close analogy between electron/hole pairs and electron/positron pairs fascinating. Holes fall up, because the electrons above fall down. When electron/hole pairs meet, they annihilate each other, often giving off a photon, just like electron/positrons. Electron/holes are created in pairs, never just on their own, just like matter/anti-matter.

It's a weak analogy, but if gravity is caused by warping of space, can we compare that to how electrons and holes warp a crystal lattice? Electrons cause a crystal lattice to expand to make room for them, and this expansion causes other electrons to be weakly attracted to them. At very low temperatures this results in Cooper pairs, which likely explains super-conductivity. Holes in a silicon lattice similarly attract each other, because they cause the local lattice to contract. There are papers on the web that mention the possibility of Cooper pairs made of holes. Electrons are repelled by the lattice contraction caused by holes, just as holes are repelled by the lattice expansion caused by electrons. Could matter/anti-matter be similar? WaywardGeek (talk) 04:20, 8 March 2012 (UTC) 68.188.203.251 (talk) 02:06, 29 August 2012 (UTC) Interesting when applied to the plasma W Thornhill says is active. I think of this radial compression our heliosphere is under (NASA says squish is vertical expanding horizontally) caused by an expansion in our cosmic space outside the Oort cloud. A sudden release would have to be due to ? And here you are.....the expansion due to anti-matter (electrons) and sudden release of compression due to hole contraction. Non scientific mind thinking feel free to erases me.

Santilli[edit]

Do we really want to reference Santilli here? Consensus seems to be that he's a nutter. See also http://www.sptimes.com/2007/05/09/news_pf/Hillsborough/Snubbed_by_mainstream.shtml — Preceding unsigned comment added by 71.93.61.178 (talk) 20:16, 20 April 2014 (UTC)

The reference is to Santilli's work, which in this case has been published by an ISI journal. The reference should thus stay in, regardless of the majority opinion about Santilli as a person.213.34.152.77 (talk) 09:49, 22 May 2014 (UTC)
I noted that the paragraph about Santilli's work had been removed. Although I am not a fan of Santilli, the source here is his paper in a well-reputed physics journal. It is then nothing but an ad hominem argument to remove this paragraph because Santilli is allegedly a crackpot: this is a blatant violation of the neutral point of view policy. The main point for keeping this paragraph in is that Santilli's paper (whether you like it or not) was historically the first one in the peer-reviewed literature that is consistent with repulsive gravity. 213.34.152.77 (talk) 08:08, 12 June 2014 (UTC)

The paragraph on Santilli's work as it stands is preposterous. The notion of "isodual" numbers cannot possibly contribute any physical understanding, as they are identical to the real numbers except for a trivial change of notation: see http://mathoverflow.net/questions/33351/what-are-santillis-isonumbers [1] for example. Comments on that page by subject experts say further that the alleged mathematical properties of isonumbers (e.g., to provide instant proofs of the Riemann conjecture, which would be a global sensation deserving the highest recognition if true) are "quackery" and observe that the papers on them have been published in journals controlled by Santilli and remain un-peer-reviewed online.

It is not possible to say that Santilli's paper is consistent with anything, when he is appealing to a special mathematics which is either (a) not able to sustain his appeal or (b) itself inconsistent. Any peer review of the physics of this paper must have been irresponsibly lax when the mathematics does not stand up. I know nothing about the editorial standards of the journal in which it was published, but this fact about first publication belongs in a page, if there is one, about controversies over ISI. It contributes nothing to understanding the topic of this page. I will remove the reference to Santilli now and consider it should stay removed with extreme prejudice.

(On edit: I see the conversation above is the result of previous attempts to remove this content that have been reverted on the grounds of "Neutral point of view". It cannot be the case that neutrality towards sources must mean allowing informative pages to become congested with preposterous material. If it must remain, it should be very strongly flagged as controversial.)

— Preceding unsigned comment added by 2.27.182.56 (talk) 08:44, 2 October 2014 (UTC) 
The reference to Santilli's work has to stay in. His paper is published in a peer-reviewed journal with rigorous standards (note that the journal is not controlled by Santilli). Calling Santilli a crackpot is not an argument against his paper, neither is some talk by some sophomore on some forum. Just google "Witten charlatan"; you will find out that quite some people call Ed Witten, the number one theoretical physicist of the moment, a charlatan. Are you now also going to remove all pages on Wikipedia on Ed Witten? I don't think so. The theory of isodual numbers is consistent, even though it is only a notation. The point is that there exist an isomorphy between the real number field and the isodual number field: of course that doesn't make the isodual number field inconsistent. If you do not understand what that means, then you should ask yourself this question: am I the right person to edit this page on Wikipedia? I mean calling Santilli a nut and then removing a reference to his work *because* you have called him a nut is of course a crap argument. As to that discussion on Santilli's work on some forum: this was about someone else's book, in which he made several possibly untenable claims. But that has nothing to do with the work of Santilli to which this Wiki-page refers. If I here and now claim that string theory cures cancer (look: I just did!), which of course is a false claim, are you then going to remove all references on Wikipedia to string theory? Of course not, you quack. The point is this: Santilli's work is historically the first peer-reviewed paper that predicted a repulsive gravity between matter and antimatter and for that reason it has to stay in. If you want to remove the paper, write a scientific comment, get that published in the peer reviewed literature (and not on some quack forum), and even then you only get to say that Santilli's work has been contended in the literature. — Preceding unsigned comment added by 217.64.255.44 (talk) 23:48, 11 January 2015 (UTC)
I have removed the Santilli paragraph. The claim that Santilli was the first to conjecture that antimatter is repelled my ordinary matter is false. Morrison and Gold published work hypothesizing that exact thing back in 1957; see [2] Reyk YO! 06:47, 12 January 2015 (UTC)
No, the Santilli paragraph has to stay in. Morrison and Gold only investigated the implications of repulsive gravity, they didn't publish any principles according to which it is possible. It remains the case that the Santilli paper in Int.J.Mod.Phys. (which is a serious journal) is the first paper that proposed a theory of repulsive gravity. That's fact, not opinion: this is is independent of one's personal opinion of Santilli. The purpose here is to make a factual lemma in an encyclopedia, not to ventilate one's opinion about person's. ~If the Santilli paragraph is removed once more, then we will have to report an editing war. 77.170.125.44 (talk) 11:46, 14 May 2015 (UTC)
No. Even if you disregard this paper (for no good reason), here [3] is another from 1995, which discusses gravitational repulsion in the framework of Dirac's equations and predates Santilli. It also cites even earlier papers mentioning gravitational repulsion between matter and antimatter. From the abstract: "...the equation serves to extend Dirac's deduction of antimatter parameters to include the possibility of gravitational repulsion between matter and antimatter." This settles the issue. Santilli was not the first to have this idea. I have removed the paragraph. Of course you have the right to report an editing war to any venue you feel appropriate, but I do not think you will be successful. Reyk YO! 12:37, 14 May 2015 (UTC)
Hey Reyk, finally you come up with a decent argument. The paper that you refer to is from 1996, so probably Santilli didn't know about it when he submitted his own paper. But now we can improve the section by adding a paragraph on Kowitt's theory. Then we get three theories on repulsive gravity: one based on quantum theory, one based on GR, and one fundamentally different from modern physics. Nice. 77.170.125.44 (talk) 17:48, 15 May 2015 (UTC)

A de Guerin's argument[edit]

I removed this section as it appears to be original research, see WP:OR. This theory is not supported by any reliable sources, see WP:RS. The only sources given are: a blog posting; a 2006 arxiv paper (never published); and an online National Geographic news article that does not make any statements directly supporting this theory. Aldebaran66 (talk) 17:06, 3 May 2014 (UTC)

Hi, I see that the additions I made to "Gravitational interaction of antimatter" have been removed. I appreciate that my additions may constitute some original research but upon consulting the original archived copies of Dr. Tajmar's work it appears that my hypothesis could indeed be correct. Will let you know when my paper is published, hopefully this will be rectified shortly.185.16.69.238 (talk) 17:38, 3 May 2014 (UTC)Conundrum84720

Modifications supported by recent observations suggest that ball lightning may be closely linked to antimatter production in thunderstorms and linked to TGFs. If so and Feynman's hypothesis is correct then BL is actually antimatter returning to the storm that created it in the future, all the observed effects could be simple thermodynamics (ie nature balancing its books). The negative gravity experienced by antimatter would be canceled out by normal gravity under most conditions so would be very hard to observe in the laboratory, but may be indirectly documented by examining distant galaxies, black holes etc. — Preceding unsigned comment added by 185.3.100.28 (talk) 05:11, 29 July 2017 (UTC)

Section related to William Fairbank[edit]

If "William Fairbank" is supposed to be William M. Fairbank, there is already a Wikipedia link for him. It should be put in place if confirmation is made. Also that section could use some references! TonyMath (talk) 23:22, 13 December 2015 (UTC)