Asymmetry of matter & antimatter theories

[HoodedHero007]

I'm just asking what people's theories about asymmetry
Personally, I think it involves the density of the universe pre-big bang creating a gravity well, then a wormhole, with the universe in the center, due to being in 2 places at once, it explodes, matter on one end, antimatter on the other

[Grek]

I wonder it has something to do with the monodirectionality of time. Suppose there is an equal amount of antimatter and it's just on the opposite side of the Big Bang? Antimatter is already known to be the same thing as time reversed matter. The question of course is "How would we test this".

[-D-]

I wonder it has something to do with the monodirectionality of time. Suppose there is an equal amount of antimatter and it's just on the opposite side of the Big Bang? Antimatter is already known to be the same thing as time reversed matter. The question of course is "How would we test this".
No we dont. (http://physics.stackexchange.com/questions/391/is-anti-matter-matter-going-backwards-in-time)

[Kato]

I'm talking a bit out of my ass here but iirc correctly one simpler theory suggests antimatter has negative mass. Which means negative gravitational force. So if it gets enough of a head start it'll be repelled from normal matter and gather somewhere else, that is, somewhere which is by now far enough away...

sidenote: Yes, I'm too lazy to do my own research but what's the stance of antimatter interacting with electromagnetic waves?

[Chen]

I'm talking a bit out of my ass here but iirc correctly one simpler theory suggests antimatter has negative mass. Which means negative gravitational force. So if it gets enough of a head start it'll be repelled from normal matter and gather somewhere else, that is, somewhere which is by now far enough away...

sidenote: Yes, I'm too lazy to do my own research but what's the stance of antimatter interacting with electromagnetic waves?

We've created anti-matter (albeit at extremely low quantities). It doesn't have negative mass.

[erikun]

I'm just asking what people's theories about asymmetry
I frequently believe that the simplest solution is going to be the best place to begin looking.

If we assume that both matter and antimatter were created together at the beginning of the universe, then the two would've mostly annihilated each other at that point and whichever quantity was greater would've had some remain as the "regular" matter of the universe. Since it would be exceptionally unusual to have exactly equal quantities of matter and antimatter, it would be reasonable to assume that one of the types of matter would remain afterwards while the anti-particle version would be exceptionally rare.

That sounds like it describes the universe fairly well, including the idea that most of the matter/energy in the universe is not normal matter (since most would've been destroyed). Of course, I've not researched the topic, but that's just my impression and where I would start looking for refutations.


I would suspect that it's the same reason everything in the universe moves at the same relative speed to each other. If you had a bunch of matter zipping around at close to the speed of light relative to one another, then inevitable collisions would smash the matter apart and average everything out until most of the matter in the universe was moving at relatively the same speed. You do not, for example, find stars or comets moving at 90% c relative to the Earth, or any else, likely for that reason.

[Kato]

I frequently believe that the simplest solution is going to be the best place to begin looking.

If we assume that both matter and antimatter were created together at the beginning of the universe, then the two would've mostly annihilated each other at that point and whichever quantity was greater would've had some remain as the "regular" matter of the universe. Since it would be exceptionally unusual to have exactly equal quantities of matter and antimatter, it would be reasonable to assume that one of the types of matter would remain afterwards while the anti-particle version would be exceptionally rare.


No, it would not. Matter and antimatter are created in equal portions in certain processes. We know of no event that makes matter but not antimatter. Or we don't, as far as I know.


@Chen I'm not saying you're wrong but a quick search says while most scientists seems to agree with you, experimental results so far seem not conclusive. :smallconfused:

[Grek]

No we dont. (http://physics.stackexchange.com/questions/391/is-anti-matter-matter-going-backwards-in-time)
That doesn't look like it contradicts what I said? Antimatter has identical properties to what physics predicts time reversed matter should have. That doesn't necessarily mean that it is time reversed matter, but it's an interesting thought. And it would give an answer to how we could start with an equal amount of matter and antimatter at the big bang and yet still end up with a universe that seemingly contains more matter than antimatter.

[BannedInSchool]

Flavour changing neutrinos give insight into Big Bang (http://www.bbc.com/news/science-environment-36776167)

Explaining the results, Professor Tanaka said: "Our first results suggest that somehow the neutrino process [neutrino oscillations] happens more often than the anti-neutrino process."
So there's a possible lead into why there's matter if neutrinos and anti-neutrinos behave differently.

[wumpus]

No we dont. (http://physics.stackexchange.com/questions/391/is-anti-matter-matter-going-backwards-in-time)

I'd have to assume that you would need an experiment to determine if the entropy of a group of antimatter particles increased over time. That might take too many to be safe.

[gomipile]

I'd have to assume that you would need an experiment to determine if the entropy of a group of antimatter particles increased over time. That might take too many to be safe.

We already do experiments with a statistically large number of antimatter particles traveling in beams around accelerators. We haven't noticed anything odd about their thermodynamics in that context. That is, on the large scale they behave exactly like the more familiar charge-reversed versions of their antiparticles would be expected to behave.