The apparent symmetry between matter and antimatter is puzzling scientists at the European Organization for Nuclear Research (CERN):
One of the great mysteries of modern physics is why antimatter did not destroy the universe at the beginning of time.
To explain it, physicists suppose there must be some difference between matter and antimatter – apart from electric charge. Whatever that difference is, it's not in their magnetism, it seems.
Physicists at CERN in Switzerland have made the most precise measurement ever of the magnetic moment of an anti-proton – a number that measures how a particle reacts to magnetic force – and found it to be exactly the same as that of the proton but with opposite sign. The work is described in Nature [open, DOI: 10.1038/nature24048] [DX].
"All of our observations find a complete symmetry between matter and antimatter, which is why the universe should not actually exist," says Christian Smorra, a physicist at CERN's Baryon–Antibaryon Symmetry Experiment (BASE) collaboration. "An asymmetry must exist here somewhere but we simply do not understand where the difference is."
Previously: Evidence Mounts that Neutrinos are the Key to the Universe's Existence
Matter-Antimatter Asymmetry Confirmed in Baryons
LHCb Observes an Exceptionally Large Group of Particles
Possible Explanation for the Dominance of Matter Over Antimatter in the Universe
(Score: 2, Informative) by khallow on Thursday October 26 2017, @03:10PM (3 children)
In current theory, antimatter has the usual mass and usual attraction of gravity.
There's a couple of problems with that approach. Why wouldn't it attract to itself? And if it does get fired off into the void, why don't we see it in the voids? They're far less dense than if they had a bunch of antimatter present.
(Score: 3, Insightful) by tfried on Thursday October 26 2017, @07:56PM (2 children)
... and therefore this speculation is rather pointless, but to jump in on it:
If antimatter attracted to antimatter but repelled matter, we would absolutely expect to see very quick separation, much like drops of grease in you soup. Then, why shouldn't the observable universe be drop of matter in a soup of antimatter, or vice versa? (Also, any remaining "small" droplet of antimatter inside our observable drop of matter could be expected to be annihilated over time.)
(Score: 1) by anubi on Thursday October 26 2017, @09:28PM
Do we know that other galaxies are matter, not antimatter?
"Prove all things; hold fast that which is good." [KJV: I Thessalonians 5:21]
(Score: 1) by khallow on Thursday October 26 2017, @10:36PM