Comment on To cosmic shreds, I say!

• victorz@lemmy.world ⁨2⁩ ⁨days⁩ ago

  Imma go ahead and postulate that beyond the observable universe is a wall of anti matter, that keeps eating our universe’s matter and neutralizing it.

  Prove me wrong! (Don’t.)

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  • naeap@sopuli.xyz ⁨2⁩ ⁨days⁩ ago

    Isn’t that the opposite of what we’re “seeing” now with the expanding universe and dark matter (not anti matter) being the reason for space to grow?

    Anti matter and matter live inside the space, that dark matter is “producing”

    At least that’s my layman interpretation of looking at some videos and reading some stuff

    So, I have no clue ;⁠-⁠)

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    • victorz@lemmy.world ⁨1⁩ ⁨hour⁩ ago

      My mind just melts when I try to understand dark matter and an expanding universe. And I’m a big astronomy guy, I eat that shit up! I even grasp time dilation to some extent. But the expanding universe, I just can’t get my mind around it fully.

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      • naeap@sopuli.xyz ⁨37⁩ ⁨minutes⁩ ago

        Yeah, me too…

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• sbeak@sopuli.xyz ⁨2⁩ ⁨days⁩ ago

  There is, afaik, no explanation why there is more matter than anti matter, so maybe we just don’t see it

  Like, dark side of the universe or something ;⁠-⁠)

  This is the baryon asymmetry problem, and indeed, one of the proposed solutions is an “anti-universe” that flows backwards in time. The theory goes that all the antimatter travelled backwards in time while matter travelled forward from the Big Bang, creating a mirror anti-universe. However, there has been experimental evidence against this theory, as antiparticles seem to move forward in time, just like their matter counterparts.

  There are a bunch more theories on how matter dominated the universe, like electroweak baryogenesis and leptopgenesis! Those are a bit more complicated though and are difficult to explain in an internet comment.

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  • CheeseNoodle@lemmy.world ⁨1⁩ ⁨day⁩ ago

    iirc the experiment was verifying that anti-matter falls downward in gravity? otherwise it still functions physically rather like time-reversed matter. Unless anti-matter is time-reversed and has reversed gravity in which case it would also seem to obey normal gravity because we would see it under the effect of anti-gravity but backwards?

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• DevDave@piefed.social ⁨2⁩ ⁨days⁩ ago

  I thought Madam Wu’s experiment provided a starting point for explaining why the universe exists despite its best efforts to annihilate itself. Disclaimer, I have passing interest in physics but I have no formal education on any of it.

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  • sbeak@sopuli.xyz ⁨1⁩ ⁨day⁩ ago

    Yeah, CP violation is a big focus when it comes to the research of baryogenesis, the theoretical process that produced the baryon asymmetry! Her experiment established that parity symmetry (P) can be broken through weak interactions, and later experiments showed that the combined CP symmetry (charge conjugation + parity) can also be broken, again through weak force shenanigans.

    CP violation is one of the three Sakharov conditions (which were proposed by and named after Soviet physicist Andrei Sakharov) of dynamic baryogenesis, as it would mean that matter and antimatter can behave differently in certain processes. If they behaved identically, no asymmetry would be produced and they would both annihilate. However, there was one extra baryon for every million antibaryons (we know this through measurements of the CMB and the quantities of light elements produced in Big Bang nucleosynthesis), and this slight difference allowed matter to dominate the universe.

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  • naeap@sopuli.xyz ⁨2⁩ ⁨days⁩ ago

    Don’t know about that
    Can you provide me some more words to search for it or even a link?

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    • DevDave@piefed.social ⁨1⁩ ⁨day⁩ ago

      https://en.wikipedia.org/wiki/Wu_experiment

      Wu was one of the few female physicist on the Manhattan project. Absolutely amazing what she accomplished despite having the double whammy of having to overcome racism as well as sexism. Currently on my watch list is a veritasm video that talks about her experiment.

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      • naeap@sopuli.xyz ⁨1⁩ ⁨day⁩ ago

        Ah, I see, thank you!

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