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Cake day: July 9th, 2023

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  • This is hard to truly eli5, so I’ll have a go too, in case the others haven’t cleared it up for you.

    The spot on the moon that moves isn’t a real thing, it’s the effect of photons hitting the left side, then other photons hitting the right side. The ‘reason’ or ‘cause’ for those photons comes from earth very much at light speed. But the left side of the moon can’t cause an effect in the right side, that fast. It just experiences a thing right before the right side experiences something similar.

    Like if two cars drive from London to Manchester and Liverpool, arriving within seconds of each other. It doesn’t mean you can drive from Manchester to Liverpool in seconds.

    There’s an SMBC I love on this: “The shadows of reality go as fast as they like.” https://www.smbc-comics.com/comic/superluminal


    Bonus: IIRC, any two events that are too close in time for light to travel from one to the other, can be viewed from a different “inertial reference frame” (someone else moving fast and analysing things with the same physics) as being the other way round. I.e. the right observer could see the right hand side of the moon get lit up before the left hand side. But the chap on earth wiggling the laser pointer is still wiggling it slower than the speed of light, so this observer would still see the laser pointer move from left to right. How does that work?






  • milicent_bystandr@lemm.eetoScience Memes@mander.xyzMultiverse
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    27 days ago

    More or less. There’s a bit more nuance to it, and I was thinking particularly of the case of entangled particles at a distance rather than a self-interfering particle through a slit - but it probably resolves down to much the same mathematics.

    Bell’s inequality proves the simple (‘realist’, above) option can’t be true, but the Copenhagen Interpretation is the most accepted interpretation of the alternative. Wikipedia lists three such interpretations, and IIRC “many worlds” is a separate one to the Copenhagen Interpretation. Though again, it’s a bit more nuanced. When I was studying, I think they basically assumed Copenhagen, though not treating that entirely as settled fact, and leaving other interpretations as niche.


  • milicent_bystandr@lemm.eetoScience Memes@mander.xyzMultiverse
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    27 days ago

    I see. Thank you for your more explanatory reply. I must not hang out in the right circles, because I haven’t seen that enough to see it as a cliché. Perhaps the commenter was not dismissing multiverse theory because of a gut reaction, but because they’re fed up themselves with popular and un-falsifiable speculation being treated as science.

    The incredible thing with these weird results is they are falsifiable - this “spooky action at a distance” that famous pre-redditor Albert dismissed as nonsense. Bell’s inequality, that lies at the heart of the trouble, is experimentally demonstrable.

    But there’s a gap between that science and the interpretations of it. And maybe coming from they popular end, it’s easy to see the wilder speculations as nothing more than unprovable imagination.

    But in the end, after re-writing much of my comment, I have to concede the point. I feel you’ve made a bit of a straw man to attack, but I agree a thing can seem unapproachable scientifically - non-falsifiable - but still be valid science. Even in this area, IIRC, part of the debate over the main quantum mechanics interpretations is quite whether they can be falsified or experimentally differentiated: and that itself takes time and logic and mathematics… it takes science!




  • You mean the post at the top? Or the comment you replied to? Either way I don’t really see the cliché.

    Do you mean that something being non-falsifiable making it non-scientific is a cliché? That’s how science works: by having theories that can be differentiated with experiment.

    Or, of the post, that multiverses contain every conceivable universe, then why anti-intellectual, when it’s just a silly joke?