# How does gravity react with anti matter?
**URL:** https://boards.straightdope.com/t/how-does-gravity-react-with-anti-matter/778983
**Category:** Factual Questions
**Created:** [February 4, 2017, 3:14pm UTC](https://boards.straightdope.com/t/how-does-gravity-react-with-anti-matter/778983 "2017-02-04T15:14:05Z")
**Posts on this page:** 20
**Page:** 3
### Author:  [@Hari\_Seldon](https://boards.straightdope.com/u/Hari_Seldon)
#### Post date: [October 4, 2023, 7:31pm UTC](https://boards.straightdope.com/t/how-does-gravity-react-with-anti-matter/778983/41 "2023-10-04T19:31:25Z")
> [@xtenkfarpl](#):
>
> Or I’d settle for a spindizzy.
There’s one on 23rd Street (although it can flaky at times).
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### Author:  [@OldGuy](https://boards.straightdope.com/u/OldGuy)
#### Post date: [October 4, 2023, 8:21pm UTC](https://boards.straightdope.com/t/how-does-gravity-react-with-anti-matter/778983/42 "2023-10-04T20:21:58Z")
> [@EdwardFound](#):
>
> It’s just unfortunate that someone back in the day happened to choose the prefix “anti”, which gives lay folk (and SF writers) the impression that these particles are bizarro, opposite-matter.
There was another name, contraterrene matter. I don’t know how widespread that name was, but Jack Williamson referred to antimatter by that name in his two science fiction novels _Seetee Shock_ and _Seetee Ship_ published in the 1940s and 1950s. Seetee was the pronunciation of CT
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### Author:  [@xtenkfarpl](https://boards.straightdope.com/u/xtenkfarpl)
#### Post date: [October 4, 2023, 8:27pm UTC](https://boards.straightdope.com/t/how-does-gravity-react-with-anti-matter/778983/43 "2023-10-04T20:27:50Z")
> [@Hari\_Seldon](#):
>
> > [@xtenkfarpl](#):
> >
> > Or I’d settle for a spindizzy.
>
> There’s one on 23rd Street (although it can flaky at times).
And then the big pivot one on 60th: blew out at a strategic moment, I recall…
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### Author:  [@CalMeacham](https://boards.straightdope.com/u/CalMeacham)
#### Post date: [October 6, 2023, 2:46pm UTC](https://boards.straightdope.com/t/how-does-gravity-react-with-anti-matter/778983/44 "2023-10-06T14:46:31Z")
> [@OldGuy](#):
>
> There was another name, contraterrene matter. I don’t know how widespread that name was, but Jack Williamson referred to antimatter by that name in his two science fiction novels _Seetee Shock_ and _Seetee Ship_ published in the 1940s and 1950s. Seetee was the pronunciation of CT
The magazine **Popular Astronomy** used the term “contraterrene matter” in the 1930s and 1940s. They had some articles wondering if the Tunguska Meteorite was a case of Contraterene Matter (an idea that was independently proposed at least two more times).
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### Author:  [@LSLGuy](https://boards.straightdope.com/u/LSLGuy)
#### Post date: [October 6, 2023, 5:51pm UTC](https://boards.straightdope.com/t/how-does-gravity-react-with-anti-matter/778983/45 "2023-10-06T17:51:43Z")
Had we settled on “Contraterrene matter” as the real term I wonder how the unfortunate coincidence of “CT matter” and Conspiracy Theories would have played out.
I can imagine some very wild CTs involving oddball sorts of matter that control minds, lead to wormholes, cause JFK to be killed by the Mafia, prevent lunar landings, etc.
We may have dodged a civilizational bullet right there. 😉
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### Author:  [@xtenkfarpl](https://boards.straightdope.com/u/xtenkfarpl)
#### Post date: [October 6, 2023, 6:03pm UTC](https://boards.straightdope.com/t/how-does-gravity-react-with-anti-matter/778983/46 "2023-10-06T18:03:36Z")
You think the Eddorians were wiped out at the end of the Lensman saga?
No, they just went underground. I had a beer with Gharlane just the other day… he’s not a bad fellow, buys his round like any normal chap…
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### Author:  [@Qadgop\_the\_Mercotan](https://boards.straightdope.com/u/Qadgop_the_Mercotan)
#### Post date: [October 10, 2023, 3:16pm UTC](https://boards.straightdope.com/t/how-does-gravity-react-with-anti-matter/778983/47 "2023-10-10T15:16:09Z")
> [@xtenkfarpl](#):
>
> I had a beer with Gharlane just the other day… he’s not a bad fellow, buys his round like any normal chap…
But Lan and Amp of the Eich rarely if ever stand a round. I’ve never had either of them pick up my tab for even the smallest neutronium cocktail.
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### Author:  [@xtenkfarpl](https://boards.straightdope.com/u/xtenkfarpl)
#### Post date: [October 10, 2023, 7:13pm UTC](https://boards.straightdope.com/t/how-does-gravity-react-with-anti-matter/778983/48 "2023-10-10T19:13:34Z")
I guess you don’t get paid well being a minion. The Eich were far from being the Top Dogs of the bad guys: there was a whole hierarchy with at least the Ploorians between them and the Eddorians.
Or were they? Somehow the Ploorians seem to have been… strangely… edited out of references on the Internet… could they have been the real puppet masters, perha
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### Author:  [@Qadgop\_the\_Mercotan](https://boards.straightdope.com/u/Qadgop_the_Mercotan)
#### Post date: [October 10, 2023, 7:18pm UTC](https://boards.straightdope.com/t/how-does-gravity-react-with-anti-matter/778983/49 "2023-10-10T19:18:17Z")
> [@xtenkfarpl](#):
>
> could they have been the real puppet masters, perha
I think you’ve been dexitroboped! That Pilinixi is a rascal.
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### Author:  [@HoneyBadgerDC](https://boards.straightdope.com/u/HoneyBadgerDC)
#### Post date: [November 4, 2023, 6:44pm UTC](https://boards.straightdope.com/t/how-does-gravity-react-with-anti-matter/778983/50 "2023-11-04T18:44:58Z")
From what I understand we have approximately equal parts of matter and anti-matter. Does this support the theory that everything came from nothing? It would seem that if you took something from nothing you would have a negative on the other side that would still equal nothing if recombined.
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### Author:  [@OldGuy](https://boards.straightdope.com/u/OldGuy)
#### Post date: [November 4, 2023, 6:52pm UTC](https://boards.straightdope.com/t/how-does-gravity-react-with-anti-matter/778983/51 "2023-11-04T18:52:07Z")
> [@HoneyBadgerDC](#):
>
> From what I understand we have approximately equal parts of matter and anti-matter.
We don’t. One of the most basic unsolved problems in cosmology and particle physics is why there is so much more matter than antimatter.
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### Author:  [@Chronos](https://boards.straightdope.com/u/Chronos)
#### Post date: [November 4, 2023, 7:13pm UTC](https://boards.straightdope.com/t/how-does-gravity-react-with-anti-matter/778983/52 "2023-11-04T19:13:34Z")
Or, if “we” do “have” an equal amount of antimatter, it’s all tens of billions of lightyears away, more distant than we can see. There are no large concentrations of antimatter anywhere in the visible Universe, because if there were, we would be able to see them.
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### Author:  [@EnolaStraight](https://boards.straightdope.com/u/EnolaStraight)
#### Post date: [November 5, 2023, 4:22am UTC](https://boards.straightdope.com/t/how-does-gravity-react-with-anti-matter/778983/53 "2023-11-05T04:22:07Z")
THIS is the thread I’m replying to.
A _really_ old thread of mine on the subject
[antimatter - Factual Questions - Straight Dope Message Board](https://boards.straightdope.com/t/antimatter/58240)
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### Author:  [@xtenkfarpl](https://boards.straightdope.com/u/xtenkfarpl)
#### Post date: [November 6, 2023, 5:00pm UTC](https://boards.straightdope.com/t/how-does-gravity-react-with-anti-matter/778983/54 "2023-11-06T17:00:14Z")
> [@Chronos](#):
>
> Or, if “we” do “have” an equal amount of antimatter, it’s all tens of billions of lightyears away, more distant than we can see. There are no large concentrations of antimatter anywhere in the visible Universe, because if there were, we would be able to see them.
I don’t really doubt the conclusion that the universe is overwhelmingly composed of matter rather than antimatter. But I do just wonder how we can be really sure of this?
As far as we know matter and antimatter behave similarly in almost all ways including, with the recent results, response to gravity.
So can we be ‘absolutely’ sure that distant galaxies are not composed of antimatter? The light from them would be similar in all ways including spectral lines etc.
Granted, it is hard to envision a mechanism which would segregate matter and antimatter like that.
And if they both existed in significant quantities there would probably be regions where they were annihilating, which would produce characteristic radiation. Which we do not observe.
I am not an astrophysicist, but interested in the physical evidence…
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### Author:  [@Babale](https://boards.straightdope.com/u/Babale)
#### Post date: [November 6, 2023, 5:09pm UTC](https://boards.straightdope.com/t/how-does-gravity-react-with-anti-matter/778983/55 "2023-11-06T17:09:27Z")
> [@xtenkfarpl](#):
>
> And if they both existed in significant quantities there would probably be regions where they were annihilating, which would produce characteristic radiation. Which we do not observe.
This is the main problem with that theory. Space isn’t _completely_ empty, and even a handful of particles and anti-particles annihilating every few square kilometers in border regions should be observable.
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### Author:  [@xtenkfarpl](https://boards.straightdope.com/u/xtenkfarpl)
#### Post date: [November 6, 2023, 5:40pm UTC](https://boards.straightdope.com/t/how-does-gravity-react-with-anti-matter/778983/56 "2023-11-06T17:40:14Z")
> [@Babale](#):
>
> Space isn’t _completely_ empty, and even a handful of particles and anti-particles annihilating every few square kilometers in border regions should be observable.
Right, the annihilation photons would be in the gamma ray region of the spectrum. Like 0.511 Mev for electron-positron collisions, more for heavier particles.
I hope that astrophysicists looking at results from gamma ray space observatories have taken a look for this… it’s a pretty obvious thing to check. Assuming that the existing observatories are sensitive to that part of the spectrum?
Guess I need to go and look at some NASA specs…
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### Author:  [@OldGuy](https://boards.straightdope.com/u/OldGuy)
#### Post date: [November 6, 2023, 5:50pm UTC](https://boards.straightdope.com/t/how-does-gravity-react-with-anti-matter/778983/57 "2023-11-06T17:50:09Z")
> [@xtenkfarpl](#):
>
> Right, the annihilation photons would be in the gamma ray region of the spectrum. Like 0.511 Mev for electron-positron collisions, more for heavier particles.
Of course if the regions are very far away, and I’d think they’d have to be, then the gamma rays would be red shifted like everything else far away. So there would be a broad spectrum of results.
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### Author:  [@xtenkfarpl](https://boards.straightdope.com/u/xtenkfarpl)
#### Post date: [November 6, 2023, 6:10pm UTC](https://boards.straightdope.com/t/how-does-gravity-react-with-anti-matter/778983/58 "2023-11-06T18:10:52Z")
> [@OldGuy](#):
>
> Of course if the regions are very far away, and I’d think they’d have to be, then the gamma rays would be red shifted like everything else far away. So there would be a broad spectrum of results.
Oh, right. I hadn’t thought of that. So maybe we need a more comprehensive investigation across the electromagnetic spectrum?
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### Author:  [@LSLGuy](https://boards.straightdope.com/u/LSLGuy)
#### Post date: [November 6, 2023, 7:09pm UTC](https://boards.straightdope.com/t/how-does-gravity-react-with-anti-matter/778983/59 "2023-11-06T19:09:42Z")
Said another way, that’s already being done. The fact you (or me or any other interested amateur) just thought of it at a glance is pretty well proof positive the PhDs in the field thought of it long ago.
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### Author:  [@xtenkfarpl](https://boards.straightdope.com/u/xtenkfarpl)
#### Post date: [November 6, 2023, 7:26pm UTC](https://boards.straightdope.com/t/how-does-gravity-react-with-anti-matter/778983/60 "2023-11-06T19:26:48Z")
You’re almost certainly right.
I, and probably you, have a good university science education.
But I’d still like to hear from professionals working in the field willing to give us first hand experience.
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