Why Are We Made of Matter?

StartsWithABang (3485481) writes "The Universe began with equal amounts of matter and antimatter after the Big Bang, and yet when we look out at today's Universe, we find that, even on the largest scales, it's made of at least 99.999%+ matter and not antimatter. The problem of how we went from a matter-antimatter-symmetric Universe to the matter-dominated one we have today is known as baryogenesis, and is one of the greatest unsolved problems in physics. Where are we on the quest to understand it as of April, 2014? A wonderful and comprehensive recap is here."

Re:Something From Nothing.

[bunratty]

Actually, the big bang theory simply says that the universe started in a hot, dense state and expanded into a cold, sparse state. It doesn't even try to explain how the universe came to be in that hot, dense state. It is similar to how evolution does not even try to explain how life started, just how species evolve once they exist.

Re:easy

[Smallpond]

Why do people think these simple questions are hard???

I agree. It's almost as if they don't read past the headline.

Re:Matter-Antimatter Explosions

[Jaime2]

Read the article. It explains that if there were anti-matter regions, we should be able to detect gamma rays from the explosions. The number of gamma rays we detect are far too few for there to be large regions of antimatter.

Re:What if there is no reason?

[Bengie]

As far as we can tell, the Universe is symmetrical, so stating that we didn't have equal parts indicates that our physics is wrong or matter/anti-matter are an exception to all other particles, which is the opposite of Occam's Razor.

Re:Ah, antimatter

[Immerman]

Nope. Antimatter is still basically "normal" matter, just with the opposite charge. We've created a fair bit of it in the lab, especially anti-hydrogen and various anti-subatomic particles The mass appears to be the same, and it interacts with light and other EM fields just as normal matter does. The only real difference is that when you bring a matter particle together with its antimatter twin they mutually annihilate.

Dark matter on the other hand would have to interact only via gravity, no electromagnetism to promote "clumping" into atoms or larger structures, nor any absorption or emission of light or we would be able to see evidence of its existence in the spectrum and brightness of distant stars.

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