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Antimatter falls down, not up: CERN experiment confirms theory
(www.nature.com)
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this post was submitted on 27 Sep 2023
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Antimatter still has a positive mass. It's not some exotic negative mass matter.
Well, yes, as far as our theories go. But we also "knew" that light was a wave that traveled through the luminiferous aether, which permiated all of space... Until we tested that theory with the Michelson-Morely experiment, and it turned out our theories were completely wrong and physics as we knew it was completely upended.
Point being, it's important to actually test our theories instead of assuming they're completely correct just because most of their predictions are accurate.
Science advances by testing the limit cases. You do it and you do it until one day you get an unexpected result. That result, and the subsequent understanding of why it happens, is what leads to Nobel Prizes.
Aether was a fudge and pretty sure Einstein knew it. Forgot the exact history, but it was made up from whole cloth to make the math work out.
Well yeah. The concensus at the time was that light is a wave, and waves need a medium to travel through, so they just made up some stuff that must be everywhere and called it the aether. The null result of the interferometer experiment is part of what led to the discovery that light is a particle that acts like a wave, and so doesn't need a medium.
The medium for the electromagnetic field is space time
Dark energy is a fudge in a similar way. Eventually we'll know what it actually is and no longer need it, kinda like alchemy was to chemistry.
A mistake plus kelevin gets you home by seven.
I'm pretty sure every physicist in existence knows that. It's just a simple principle that's really hard to test, so actually testing it is pretty cool. Like dropping a steel ball and a feather on the Moon.
Those are pretty expensive experiments. Are you sure they do them just because they are cool?
We choose to go to the moon and to do the other things, not because they are easy, but because they make me hard
giggity
Haha I missed it the first time.
It is possible to do something cool and something that furthers science at the same time. Deep down, doing cool stuff is probably why most research scientists exist. Because it isn't for the mad stacks of cash, I can promise you that.
Let the science people do their pew-pew-pew thing with the fancy toys and pretend they're in Star Trek. At least they're enjoying themselves while helping the rest of us out!
It's also an excellent proof of concept for how to test with antimatter. Anyone who designs a test using anti hydrogen will look back at their methodology.
You think they get rich off them?
It makes me sad that dudebro science has become so prevalent that people forget the main reason we do this stuff. Saying you're into science to discover things and not to blow shit up is like saying you go to a monster truck derby to watch people drive and not run over cars.
It has a positive mass, and in every other way it acts just like normal matter going backwards in time (cpt inversion).
If, despite its positive mass, it was pushed back by gravity, then it would have given even more weight to the theory that antimatter is just matter moving backwards.
Since gravity is such a wonky interaction, I'm not even sure this result disproves the time-reversal theory entirely!
Why would inverting charge make particles go backwards in time? Electrons have opposite charge to protons and they don't seem to. Positrons have the opposite charge to electrons and as far as I know they don't go backwards?
I think you're misinterpreting cpt reversal symmetry, which is if you mirrored the universe in terms of charge, time and parity it would essentially evolve the same
It's been many years since I was invited with particle physics, so it's a bit muddled in my memory... i could be wrong on the details here. It could be the CP symmetry instead of the CPT symmetry.
It's not that positrons go back in time, but more like "if an electron went backwards in time, it would look exactly like a position". The Feynman diagram of an electron and position annihilaton is the same as that of an electron bouncing on photons, expect the angle is rotated such that the electron bounces backwards in time.
https://commons.m.wikimedia.org/wiki/File:Feynman_EP_Annihilation.svg#mw-jump-to-license
Ah yeah makes more sense
I believe a crucial detail here is mirroring a particle vs the whole universe. Mirroring the whole universe you get the same dynamics described by our laws due to CPT symmetry. If you mirror a particle alone, I think you get an anti-particle.