# Does anti matter have matter?
**URL:** https://boards.straightdope.com/t/does-anti-matter-have-matter/781313
**Category:** In My Humble Opinion
**Created:** [March 3, 2017, 4:59pm UTC](https://boards.straightdope.com/t/does-anti-matter-have-matter/781313 "2017-03-03T16:59:15Z")
**Posts on this page:** 20
**Page:** 1
### Author:  [@HoneyBadgerDC](https://boards.straightdope.com/u/HoneyBadgerDC)
#### Post date: [March 3, 2017, 4:59pm UTC](https://boards.straightdope.com/t/does-anti-matter-have-matter/781313/1 "2017-03-03T16:59:15Z")
Can anti matter travel any faster than matter? Is their an opposite of c? Would re recognize it if we saw it?
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### Author:  [@Grey](https://boards.straightdope.com/u/Grey)
#### Post date: [March 3, 2017, 5:29pm UTC](https://boards.straightdope.com/t/does-anti-matter-have-matter/781313/2 "2017-03-03T17:29:24Z")
Antimatter is effectively matter with a different change. So a positron is the anti-matter equivalent of an electron. An antiproton is the antimatter equivalent of a proton. In both cases the antimatter particle has the same mass as it matter partner.
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### Author:  [@Grey](https://boards.straightdope.com/u/Grey)
#### Post date: [March 3, 2017, 5:40pm UTC](https://boards.straightdope.com/t/does-anti-matter-have-matter/781313/3 "2017-03-03T17:40:34Z")
Though if I remember right Richard Feynman described antimatter as matter traveling backwards in time - sort of.
Yep - [Theory of Positrons](http://journals.aps.org/pr/abstract/10.1103/PhysRev.76.749)
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### Author:  [@Darren\_Garrison](https://boards.straightdope.com/u/Darren_Garrison)
#### Post date: [March 3, 2017, 5:43pm UTC](https://boards.straightdope.com/t/does-anti-matter-have-matter/781313/4 "2017-03-03T17:43:33Z")
In theory and [to the best that we can determine experimentally](http://www.zmescience.com/science/physics/matter-antimatter-same-properties-043243/), antimatter and matter are identical in all respects other than charge.
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### Author:  [@Riemann](https://boards.straightdope.com/u/Riemann)
#### Post date: [March 3, 2017, 6:00pm UTC](https://boards.straightdope.com/t/does-anti-matter-have-matter/781313/5 "2017-03-03T18:00:36Z")
In principle, entire distant galaxies could be made up of antimatter. They would look and behave no differently. The presence of antimatter would only be obvious if it were in proximity to matter, when annihilation would release a lot of energy.
The ISS has an experiment running designed (in part) to test this notion by looking for antihelium nuclei among cosmic rays.
> **[Alpha Magnetic Spectrometer](https://en.wikipedia.org/wiki/Alpha_Magnetic_Spectrometer)**
>
> The Alpha Magnetic Spectrometer (AMS-02) is a particle physics experiment module that is mounted on the International Space Station (ISS). The experiment is a recognized CERN experiment (RE1). The module is a detector that measures antimatter in cosmic rays; this information is needed to understand the formation of the Universe and search for evidence of dark matter.
> The principal investigator is Nobel laureate particle physicist Samuel Ting. The launch of Space Shuttle Endeavour flight STS-1...
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### Author:  [@HoneyBadgerDC](https://boards.straightdope.com/u/HoneyBadgerDC)
#### Post date: [March 3, 2017, 6:10pm UTC](https://boards.straightdope.com/t/does-anti-matter-have-matter/781313/6 "2017-03-03T18:10:26Z")
If something like light were traveling backwards would there be any way to distinquish backwards from simply a different direction?.
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### Author:  [@Der\_Trihs](https://boards.straightdope.com/u/Der_Trihs)
#### Post date: [March 3, 2017, 6:13pm UTC](https://boards.straightdope.com/t/does-anti-matter-have-matter/781313/7 "2017-03-03T18:13:58Z")
> [@HoneyBadgerDC](#):
>
> If something like light were traveling backwards would there be any way to distinquish backwards from simply a different direction?.
Yes; since its speed isn’t infinite, it just has to be noted where a light impulse appears at first.
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### Author:  [@John\_Mace](https://boards.straightdope.com/u/John_Mace)
#### Post date: [March 3, 2017, 8:00pm UTC](https://boards.straightdope.com/t/does-anti-matter-have-matter/781313/8 "2017-03-03T20:00:41Z")
Do you mean: Does anti matter have mass?
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### Author:  [@HoneyBadgerDC](https://boards.straightdope.com/u/HoneyBadgerDC)
#### Post date: [March 3, 2017, 8:09pm UTC](https://boards.straightdope.com/t/does-anti-matter-have-matter/781313/9 "2017-03-03T20:09:07Z")
> [@John\_Mace](#):
>
> Do you mean: Does anti matter have mass?
I thought that was what I said until I went back and reread my post.
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### Author:  [@Tom\_Tildrum](https://boards.straightdope.com/u/Tom_Tildrum)
#### Post date: [March 3, 2017, 9:49pm UTC](https://boards.straightdope.com/t/does-anti-matter-have-matter/781313/10 "2017-03-03T21:49:32Z")
It has anti-mass!
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### Author:  [@John\_DiFool](https://boards.straightdope.com/u/John_DiFool)
#### Post date: [March 3, 2017, 10:35pm UTC](https://boards.straightdope.com/t/does-anti-matter-have-matter/781313/11 "2017-03-03T22:35:38Z")
> [@Riemann](#):
>
> In principle, entire distant galaxies could be made up of antimatter. They would look and behave no differently. The presence of antimatter would only be obvious if it were in proximity to matter, when annihilation would release a lot of energy
If that were the case, then, when opposite galaxies collided, they should emit tons of energy (how much exactly I’d dare not speculate, and yes most of the matter in both would NOT collide directly, but would have substantial gravitational effects at least).
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### Author:  [@friedo](https://boards.straightdope.com/u/friedo)
#### Post date: [March 3, 2017, 11:04pm UTC](https://boards.straightdope.com/t/does-anti-matter-have-matter/781313/12 "2017-03-03T23:04:24Z")
> [@Tom\_Tildrum](#):
>
> It has anti-mass!
Nah, it has perfectly ordinary regular mass.
Sometimes physicists like to posit what would happen if you stick unexpected things in the equations. Negative matter (completely different from antimatter) is hypothetical matter that has negative mass. But it causes all sorts of problems with various energy conditions. (IOW, it breaks the law a lot.) So negative matter probably doesn’t exist.
We’ve observed antimatter, though, so we know it exists. It’s the behaves exactly the same as regular matter in all respects, except its charges are different. So positrons are electrons with positive charge, antiprotons are protons with negative charge. Antineutrons are still neutral, but made up of antiquarks.
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### Author:  [@Riemann](https://boards.straightdope.com/u/Riemann)
#### Post date: [March 3, 2017, 11:06pm UTC](https://boards.straightdope.com/t/does-anti-matter-have-matter/781313/13 "2017-03-03T23:06:55Z")
> [@John\_DiFool](#):
>
> If that were the case, then, when opposite galaxies collided, they should emit tons of energy (how much exactly I’d dare not speculate, and yes most of the matter in both would NOT collide directly, but would have substantial gravitational effects at least).
Yes, but the absence of such an observation apparently does not definitively rule out antimatter galaxies, given the stated objectives of AMS. I don’t know the theory, but presumably the distribution might be such that collisions between matter & antimatter galaxies (or any detectable regions of annihilation) are rare. It seems that the presence or absence of antihelium nuclei in cosmic rays is the definitive test.
[https://science.nasa.gov/science-news/science-at-nasa/2009/14aug\_ams](https://science.nasa.gov/science-news/science-at-nasa/2009/14aug_ams)
> **[Alpha Magnetic Spectrometer | Antimatter](https://en.wikipedia.org/wiki/Alpha_Magnetic_Spectrometer#Antimatter)**
>
> Experimental evidence indicates that our galaxy is made of matter; however, scientists believe there are about 100–200 billion galaxies in the observable Universe and some versions of the Big Bang theory of the origin of the Universe require equal amounts of matter and antimatter. Theories that explain this apparent asymmetry violate other measurements. Whether or not there is significant antimatter is one of the fundamental questions of the origin and nature of the Universe. Any observations of ...
> [@](#):
>
> In 1999, AMS-01 established a new upper limit of 10−6 for the antihelium/helium flux ratio in the Universe. AMS-02 will search with a sensitivity of 10−9, an improvement of three orders of magnitude over AMS-01, sufficient to reach the edge of the expanding Universe and resolve the issue definitively.
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### Author:  [@Riemann](https://boards.straightdope.com/u/Riemann)
#### Post date: [March 3, 2017, 11:12pm UTC](https://boards.straightdope.com/t/does-anti-matter-have-matter/781313/14 "2017-03-03T23:12:33Z")
> [@friedo](#):
>
> Nah, it has perfectly ordinary regular mass.
>
> Sometimes physicists like to posit what would happen if you stick unexpected things in the equations. Negative matter (completely different from antimatter) is hypothetical matter that has negative mass. But it causes all sorts of problems with various energy conditions. (IOW, it breaks the law a lot.) So negative matter probably doesn’t exist.
>
> We’ve observed antimatter, though, so we know it exists. It’s the behaves exactly the same as regular matter in all respects, except its charges are different. So positrons are electrons with positive charge, antiprotons are protons with negative charge. Antineutrons are still neutral, but made up of antiquarks.
But actually not yet confirmed experimentally.
> **[Gravitational interaction of antimatter](https://en.wikipedia.org/wiki/Gravitational_interaction_of_antimatter)**
>
> Onia
> The gravitational interaction of antimatter with matter or antimatter has been observed by physicists. As was the consensus among physicists previously, it was experimentally confirmed that gravity attracts both matter and antimatter at the same rate within experimental error.
> Antimatter's rarity and tendency to annihilate when brought into contact with matter makes its study a technically demanding task. Furthermore, gravity is much weaker than the other fundamental forces, for reasons...
> [@](#):
>
> The gravitational interaction of antimatter with matter or antimatter has not been conclusively observed by physicists. While the consensus among physicists is that gravity will attract both matter and antimatter at the same rate that matter attracts matter, there is a strong desire to confirm this experimentally.
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### Author:  [@HoneyBadgerDC](https://boards.straightdope.com/u/HoneyBadgerDC)
#### Post date: [March 3, 2017, 11:24pm UTC](https://boards.straightdope.com/t/does-anti-matter-have-matter/781313/15 "2017-03-03T23:24:08Z")
If gravity pushed it away instead of attracting it could that help to explain why they usually occor on opposite sides of the universe?
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### Author:  [@ekedolphin](https://boards.straightdope.com/u/ekedolphin)
#### Post date: [March 3, 2017, 11:30pm UTC](https://boards.straightdope.com/t/does-anti-matter-have-matter/781313/16 "2017-03-03T23:30:53Z")
I’m curious, no sarcasm intended. Has antimatter actually been proven to exist?
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### Author:  [@Riemann](https://boards.straightdope.com/u/Riemann)
#### Post date: [March 3, 2017, 11:34pm UTC](https://boards.straightdope.com/t/does-anti-matter-have-matter/781313/17 "2017-03-03T23:34:36Z")
> [@ekedolphin](#):
>
> I’m curious, no sarcasm intended. Has antimatter actually been proven to exist?
Yes.
> **[Antimatter](https://en.wikipedia.org/wiki/Antimatter#Natural_production)**
>
> Onia
> In modern physics, antimatter is defined as matter composed of the antiparticles (or "partners") of the corresponding particles in "ordinary" matter, and can be thought of as matter with reversed charge, parity, and time, known as CPT reversal. Antimatter occurs in natural processes like cosmic ray collisions and some types of radioactive decay, but only a tiny fraction of these have successfully been bound together in experiments to form antiatoms. Minuscule numbers of antiparticles can ...
> **[Antimatter](https://en.wikipedia.org/wiki/Antimatter#Artificial_production)**
>
> Onia
> In modern physics, antimatter is defined as matter composed of the antiparticles (or "partners") of the corresponding particles in "ordinary" matter, and can be thought of as matter with reversed charge, parity, and time, known as CPT reversal. Antimatter occurs in natural processes like cosmic ray collisions and some types of radioactive decay, but only a tiny fraction of these have successfully been bound together in experiments to form antiatoms. Minuscule numbers of antiparticles can ...
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### Author:  [@Darren\_Garrison](https://boards.straightdope.com/u/Darren_Garrison)
#### Post date: [March 3, 2017, 11:48pm UTC](https://boards.straightdope.com/t/does-anti-matter-have-matter/781313/18 "2017-03-03T23:48:56Z")
> [@ekedolphin](#):
>
> I’m curious, no sarcasm intended. Has antimatter actually been proven to exist?
Antimatter isn’t something that you run across every day, but is easy enough to generate [to be used in medicine](https://en.wikipedia.org/wiki/Positron_emission_tomography) (the “P” in PET scan is antimatter.)
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### Author:  [@wolfpup](https://boards.straightdope.com/u/wolfpup)
#### Post date: [March 4, 2017, 12:01am UTC](https://boards.straightdope.com/t/does-anti-matter-have-matter/781313/19 "2017-03-04T00:01:42Z")
> [@Darren\_Garrison](#):
>
> Antimatter isn’t something that you run across every day, but is easy enough to generate [to be used in medicine](https://en.wikipedia.org/wiki/Positron_emission_tomography) (the “P” in PET scan is antimatter.)
Well, damn, I thought a PET scan was when a CAT scan was done on your dog! 😉
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### Author:  [@Grey](https://boards.straightdope.com/u/Grey)
#### Post date: [March 4, 2017, 1:04am UTC](https://boards.straightdope.com/t/does-anti-matter-have-matter/781313/20 "2017-03-04T01:04:42Z")
> [@HoneyBadgerDC](#):
>
> If gravity pushed it away instead of attracting it could that help to explain why they usually occor on opposite sides of the universe?
Lets leave aside the idea of opposite sides of the universe - what makes you think that matter and antimatter occur on opposite sides of the universe?
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