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Science

Why Are We Made of Matter? 393

Posted by timothy
from the better-than-the-alternate dept.
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."
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Why Are We Made of Matter?

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  • by bunratty (545641) on Sunday April 06, 2014 @02:03PM (#46677521)
    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 (Score:5, Informative)

    by Smallpond (221300) on Sunday April 06, 2014 @02:48PM (#46677869) Homepage Journal

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

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

  • by Jaime2 (824950) on Sunday April 06, 2014 @03:01PM (#46677989)
    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.
  • by Bengie (1121981) on Sunday April 06, 2014 @03:10PM (#46678067)
    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 (Score:5, Informative)

    by Immerman (2627577) on Sunday April 06, 2014 @04:24PM (#46678559)

    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.

  • Re:Ah, antimatter (Score:2, Informative)

    by geoskd (321194) on Sunday April 06, 2014 @07:56PM (#46679681)

    Ah, the obligatory /. cheap shot at religion

    Maybe if it weren't for the fact that organized religion is a form of tribalism/conformity, which is the sole cause of war. Without such anti-social behaviors, wars would be impossible.

Never try to teach a pig to sing. It wastes your time and annoys the pig. -- Lazarus Long, "Time Enough for Love"

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