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- science@lemmy.ml
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Huh I didn’t know antimatter was a completely confirmed thing.
After making a thin gas of thousands of antihydrogen atoms, researchers pushed it up a 3-metre-tall vertical shaft surrounded by superconducting electromagnetic coils. These can create a kind of magnetic ‘tin can’ to keep the antimatter from coming into contact with matter and annihilating. Next, the researchers let some of the hotter antiatoms escape, so that the gas in the can got colder, down to just 0.5 °C above absolute zero — and the remaining antiatoms were moving slowly.
The researchers then gradually weakened the magnetic fields at the top and bottom of their trap — akin to removing the lid and base of the can — and detected the antiatoms using two sensors as they escaped and annihilated. When opening any gas container, the contents tend to expand in all directions, but in this case the antiatoms’ low velocities meant that gravity had an observable effect: most of them came out of the bottom opening, and only one-quarter out of the top.
You may have heard of a “PET scan” used in medicine. This uses a type of antimatter called a positron.
https://bigthink.com/hard-science/positron-emission-tomography-antimatter-cancer/
The complexity behind this is fascinating.
Just wait until you find out about MRI :)
That’s pretty awesome too, but they don’t need molecules with atoms that were modified using particle colliders just minutes/hours before you need them.
Still much more complex than PET conceptually, and much more versatile.
That might be dark matter you’re thinking about
Maybe!
Not only does it exist, but bananas give off a fair bit of antimatter due to their decaying potassium isotopes.
Allegedly, im not smart enough to verify it
Would an anti-banana give off normal matter?
Does it matter?
I don’t think it would antimatter
Argument anihilated!
AFAIK, yes, you might wanna look into β± and β־-decay
AFAIK, yes.
There are some very small differences between matter and anti-matter, but I don’t think any of them affect radioactivity.
Bananas produce antimatter, but just barely. The main radioactive material in bananas is Potassium-40. A banana is about 0.358% potassium in all. About 0.012% of naturally occurring potassium is the radioactive Potassium-40. Only 0.001% of all radioactive decay events in postassium-40 produce an antiparticle (a positron).
An average banana produces a single positron about every 75 minutes.
Brb. Making a fruit-based matter-antimatter annihilation power plant.
You kid but as a kid when I learned about potatoes and lemon batteries I was like “SCALE THIS UP NOW!”
…if only…
That’s fucking awesome.
El psy kongroo
They say if you microwave bananas, you will get green gel bananas
^dont ^actually ^try ^that
We need a Far Side where ape scientists are colliding two bannanas at high speed
Antimatter was first observed physically back in 1932. A positron, more specifically. Its existence has been confirmed, and accepted, for ages, and some of our technology already operates using antimatter to do its tasks.
anti-matter? ya, we have been observing it for quite a while (testing is difficult for reasons), it naturally accumulates in parts of the Van Allen belt.
Dark matter on the other hand is still completely up for question
The Large Hadron Collider wouldn’t work if antimatter wasn’t confirmed.
Why wouldn’t it work?
Because it involves colliding protons and antiprotons.
No, it either does proton-proton collisions or heavy ions, both regular matter. At TeV energies the added energy from anihalating matter with antimatter isn’t that much of a contribution anymore that it would justify the added complexity.
Its predecessor collided positrons with electrons though. But the LEP was more for precise refinement of known interactions and not so much about reaching the highest possible energies.
Sure, but it doesn’t just collide protons and antiprotons, does it?
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How? Pro doesn’t mean positive. If anything they’d be called contons.
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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 opposite 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?
At this tiny scale, energy and mass are essentially equivalent. So when we say that matter annihilates, we mean that they transform into pure energy (in this case, as photons of light). They don’t break into subatomic particles, because that still counts as mass. They just simply cease to exist.
As a side note, the “conversion rate” of mass into energy (and vice versa) is governed by Einstein’s E=mc^2. All this equation means is that it takes a ridiculous amount of energy to create a small amount of mass, and vice versa, it only takes a small amount of mass to create a ridiculous amount of energy. Because antimatter annihilates completely (ie, 100% of its mass, as well as 100% of the regular matter’s mass, gets converted into energy), antimatter is currently the most explosive thing known to mankind
Ok that makes sense.
Man that’s pretty wild to think about. If antimatter was created at the same time as matter in the same quantity and distribution, then why are we here. Why didn’t the entire universe essentially cancel itself out? Was there some factor that benefited regular matter or hindered antimatter? Is there some level of chaos on the atomic or subatomic scale that played in regular matter being the dominant? Has some crazy philosophical implications.
You’re describing the matter-antimatter asymmetry problem
https://home.cern/science/physics/matter-antimatter-asymmetry-problem
I mean if you just thought of all those questions on your own, that’s damned impressive. You just summarized one of the greatest mysteries in particle physics. Here’s a story about that exact question - what was the process that gave preference to creation of matter over antimatter?
https://www.scientificamerican.com/article/why-is-there-more-matter-than-antimatter/
The universe very nearly did cancel itself out entirely. That’s why it is as empty as it is. The matter you see is the slight surplus there wasn’t enough antimatter to annihilate. Why this surplus? It’s one of the great remaining problems.
I think there’s an extreme form of the anthropogenic principle we can apply here. Universes may pop into existence constantly and destabilize into nothing because their physical laws aren’t fine tuned for stability, or because they don’t have an uneven amount of anti/matter. Perhaps universes are part of some extra-cosmic superstructure that’s just frothing like mad. Some bubbles last a little longer than others before they pop. We could be one of those. Perhaps the multiverse is a little bit of suds in some leviathan child’s bathtub.
Oh snap, you know this is a good point. What if the reason lies in other universes? Didn’t we detect a possible fingerprint of a collision with another universe In the cosmic heat map looking thing? What if we had a collision at just the right time that caused the destruction of just enough anti-matter to throw off the balance.
If I understand it correctly, annihilation is a 100% efficient process that converts all the matter into energy. After the process is complete there is no matter left over and only energy in the form of light, heat, and other energy forms that go way over my head remains.
For the simple case of electron-positron annihilation, they transform into high-energy photons, whose total energy is equal to the total mass-energy of the electron and positron. See: https://en.wikipedia.org/wiki/Electron–positron_annihilation
Annihilation means exactly that - both particles destroy each other on contact, releasing the energy that composed them.
While atoms can be comprised of antimatter the interactions are generally on a subatomic level, i.e. electron/positron, and proton/antiproton. Since particles/antiparticles are identical to their counterparts aside from charge any such interactions are total with nothing left over other than the resulting energy release usually in the form of photons. The results of an atom reacting with an anti-atom could have a variety of results depending on the differences in weight between the two. Exactly what those results might be is a bit beyond my lay-understanding of the process.
Isn’t “falling up” just another way of saying that it’s repelled by matter?
Yes
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?
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.
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Duh. Negative mass doesn’t exist. Antiparticles just have an opposite charge.
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.
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