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  • Hello and welcome to: I Don't Think That Means What You Think It Means

  • where we look at bits of scientific theory that have wiggled their way into popular culture

  • and have taken on a life of their own.

  • Today we're talking about Schrodinger's cat; A famous thought experiment devised by

  • the Austrian physicist Erwin Schrodinger who helped piece physics back together

  • after Einstein and his crew blew a giant freaking hole in it back in the early 20th century

  • Sorry to overstate how much of a giant crap circus the nineteen twenties were for physicists.

  • Until then everything had pretty much just been good old fashion Newtonian Physics

  • where you could observe objects moving and predict to how they react to various forces.

  • But then along comes all this new research into subatomic particles

  • that shows that they dont act predictably at all!

  • In fact, sometimes stuff seems to be two different things at once like an electron and

  • a beam might act like a particle sometimes and like a wave at other times.

  • And to make things even more... GAA! --

  • The more you try to observe and measure these particles, the less naturally they behave.

  • Say what now?!

  • My friends, I shall now introduce you to one of the biggest mind-flogs of quantum mechanics.

  • It's called, Superposition.

  • The idea that a particle can exist in all of its theoretically possible states at the same time.

  • So Schrodinger came up with this thought experiment to help everybody understand it.

  • So you have a cat, and you put the cat into a steel chamber for an hour

  • with a vial of deadly gas, a Geiger counter, a hammer, and a tiny bit of something radioactive.

  • Bear with me here.

  • Now say that there's a fifty-fifty chance that one of the radioactive atoms is going to decay

  • and release some radiation within that hour.

  • If one of the atoms decays, the Geiger counter is going to trigger the hammer,

  • shattering the vial of poisonous gas. Really Schrodinger?

  • This is not the best way to get people behind the idea of funding the sciences.

  • So, there is a fifty percent chance that at the end of the hour that vial has been broken and the cat is dead

  • and an equally good chance that the vial hasn't been broken

  • and the cat's just kickin' it wondering 'What's for supper?'

  • But, what's actually happening in the box?

  • According to quantum mechanics, any one of those radioactive atoms would be in a superposition

  • of being both decayed and not decayed at the same time.

  • Because that's how quantum objects act.

  • So then, that decayed atom will have both killed and not killed the cat, right?

  • Well that's the logical conclusion but a cat... a cat isn't a quantum object.

  • A cat is a big, normal thing that obeys nice, old-fashioned Newtonian Laws

  • so it, just like every other cat in history, is EITHER alive OR dead.

  • Schrodinger's point, at least one of them,

  • is that the two objects are subject to two separate sets of laws that can't be reconciled.

  • In order to know whether the atom has decayed or not and whether the cat is dead or not

  • you have to open the box and see. But in quantum mechanics, the state of superposition can't be observed.

  • So, when the evil mad scientist finally opens the chamber to observe

  • the superposition collapses and the outcome is ensured.

  • Today, Schrodinger's cat is often talked about as some kind of undead zombie cat

  • or discussed as if the cat is actually both alive and dead in the box.

  • But Schrodinger's point wasn't to prove that you can make a cat be both alive and dead,

  • but instead to prove that the quantum world

  • doesn't mesh together well with the, you know, like, normal world.

  • And alternatively the point is that the universe is pretty frickin' weird.

  • There are other interpretations of quantum mechanics that might resolve the paradox

  • but none of them are particularly easy to test.

  • My favorite, of course, is the many worlds interpretation that states that at the end of the experiment,

  • and at the end of every superposition, new alternate universes are created!

  • In this case, one in which that cat is alive and one in which the cat is dead.

  • And to be clear, I don't like this interpretation because I think it's the most likely one

  • I like it because I think it's such an excellent plot device for science fiction novels.

  • If you have any questions, and I'm sure you do,

  • ask them in the comments below and I'll, you know, do my best.

  • Also, if you have an idea for "I Don't Think That Means What You Think It Means"

  • please let us know about that too.

Hello and welcome to: I Don't Think That Means What You Think It Means

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IDTIMWYTIM:薛定諤的貓。 (IDTIMWYTIM: Schrodinger's Cat)

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