this post was submitted on 27 Sep 2023
357 points (99.7% liked)
science
14697 readers
113 users here now
just science related topics. please contribute
note: clickbait sources/headlines aren't liked generally. I've posted crap sources and later deleted or edit to improve after complaints. whoops, sry
Rule 1) Be kind.
lemmy.world rules: https://mastodon.world/about
I don't screen everything, lrn2scroll
founded 1 year ago
MODERATORS
you are viewing a single comment's thread
view the rest of the comments
view the rest of the comments
So then it is not really antimatter in the sense that it is completely opposite?
So antimatter still has positive mass?
In my limited understanding, antimatter just means the particles have the opposite charge of normal matter. All other attributes are not part of the definition of antimatter.
Charge isn't the right word, although I'm not sure what the right word is. Otherwise you've got it right.
No, charge is the right word. But i was wrong about charge being the only difference, apparently antimatter's "parity" and "time" are also opposite of normal matter. Whatever that means.
https://en.m.wikipedia.org/wiki/Antimatter
The word is charge-parity. All physical systems (at least I'm quantum physics, I cant speak for other fields) are symmetric (nothing changes) if you change C(harge), P(arity) and T(ime reversal) at the same time. This is called CPT symmetry, see https://en.m.wikipedia.org/wiki/CPT_symmetry
As antimatter can be described as normal matter going back in time (see the other comment), it means antimatter can also be described as normal matter transformed under the C and P operators. If T(particle) = antiparticle and CPT(particle) = particle then CP(particle) = antiparticle also.
And the reason you can reverse time is because most of the equations are quadratic: they have a positive and negative solution, one describes particles moving forward in time, the other solution describes antiparticles going backward in time.
NB: in quantum field theory it gets slightly more complicated, lets leave that as homework ;)
So just like in Tenet?
Antimatter can interact with matter and create an explosion of energy that annihilates both.
If you take some antimatter out of its containment cabinet and do that with it 5 minutes from now, you’ve done that in its “past” which means it can’t be there for you to procure in the first place.
Or did you, in reverse time, cause a bunch of energy to converge and become matter and anti-matter, and then walk over and put the antimatter away in the cabinet?
It’s reverse entropic as fuck but I guess that’s anti-time for you. Maybe this is how the Big Bang was caused. Anti-entropic flow of anti-matter into a highly ordered state in one point. Fuck.
Would that mean that they're not falling, but rather actually rising?
What... How...
EDIT
i asked chatgpt if antimatter travels backwards in time, and this was the reply:
Some physicists have proposed that antimatter is actually matter moving backwards in time, based on a mathematical equivalence that emerges from quantum field theory. This idea was first suggested by Richard Feynman, who wondered if all electrons could be the same electron bouncing back and forth in time. However, this is not a widely accepted interpretation, and there is no experimental evidence to support it. In fact, most physicists do not believe that antimatter is really moving backwards in time, because it is not clear what that would mean physically.
One way to test this idea is to see how antimatter responds to gravity. If antimatter falls upwards instead of downwards, that would imply that it has a negative mass and a negative energy, which could be interpreted as moving backwards in time. However, a recent experiment at CERN has confirmed for the first time that atoms of antimatter fall downwards, just like normal matter2. This means that antimatter and matter have the same gravitational mass and the same sign of energy. However, this does not rule out the possibility that antimatter and matter might fall at different rates, which would still indicate a difference in their behavior under gravity.
So, to answer your question, antimatter does not travel backwards in time, at least not in any obvious or observable way. It behaves very similarly to normal matter, except for having opposite charges and other quantum numbers. The mystery of why antimatter and matter did not cancel each other out completely in the early universe remains unsolved, and requires further investigation and experimentation
Thanks for the source. Looks like I have some learning to do.
Duh. Negative mass doesn't exist. Antiparticles just have an opposite charge.