science
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But from the antimatter's perspective, it falls up.
Then it really is lost!
What happens to Australian antimatter?
it falls to the earth, like you would expect normal matter to do above the equator
Hmm interesting. I wondered if it would be attracted or repelled by matter. It does annihilate when it comes in contact with mater, right?
The reason antimatter is "anti" is that an antiparticle has the oppose charge of its non-anti counterpart. Electrons have a negative charge, while their antiparticles, positrons have a positive charge. And since opposite charges attract, well, I think you can figure it out from there.
And yes, matter/antimatter interactions result in annihilation.
What exactly does "annihilation" mean in this context. Do both "atoms" give off energy and convert to sub atomic particles? Does one atom kind of "win" over the other and undergo fission instead of complete annihilation?
Annihilation means exactly that - both particles destroy each other on contact, releasing the energy that composed them.
Isn’t “falling up” just another way of saying that it’s repelled by matter?
Yes
Why would anyone think it would fall up?
Because there is no theory of quantum gravity we have no idea how gravity could interact with anti matter. By showing that antimatter behaves just like matter when interacting with gravity we can learn a lot about it and cut the number of possible theories of quantum gravity in half.
Because things exist
(the antigravity hypothesis was an attempt to explain why matter and antimatter haven't annihilated each other)
Because one common assumption was that the universe might contain as much antimatter as matter.
Which begs the question: Where did it go? We would notice a huge amount of annihilation reactions in the solar system.
"Antimatter falls up" (is gravitationally repelled instead of attracted by normal matter) was an easy hypothesis to explain that.
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.
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 ;)
The Feynman–Stueckelberg interpretation states that antimatter and antiparticles are regular particles traveling backward in time.[18]
So just like in Tenet?
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
Duh. Negative mass doesn't exist. Antiparticles just have an opposite charge.