357
Antimatter falls down, not up: CERN experiment confirms theory
(www.nature.com)
you are viewing a single comment's thread
view the rest of the comments
view the rest of the comments
this post was submitted on 27 Sep 2023
357 points (99.7% liked)
science
14595 readers
53 users here now
A community to post scientific articles, news, and civil discussion.
rule #1: be kind
<--- rules currently under construction, see current pinned post.
2024-11-11
founded 2 years ago
MODERATORS
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 ;)