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Cake day: June 17th, 2023

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  • Whilst I’ve heard this idea said plenty of times by scientists as a way of demystifying the double slit and similar experiments, it doesn’t really do justice to the weirdness of the quantum world.

    Firstly in the “default” interpretation there’s no mechanism or explanation for how an observation causes wavefunction collapse, it’s just a rule that it just does that. And the collapse doesn’t correspond to a change in momentum of a particle or any other change in classical physical state, but something else entirely.

    In the double slit experiment a detector at one slit somehow seems to affect the particle as it leaves the source, before it reaches the detector (so the effect is backwards in time!) And without the detector it goes through both slits at once.




  • At the risk of explaining what everyone here already gets: I like how the bottom picture could literally be a diagram of a 4-way deadlock where the buses are threads of execution and the roundabout exits are object locks.

    Whereas in top picture there are no passengers and I’m fairly sure the buses aren’t moving. Which probably says something about the state of the documentation




  • I have a grain of crack here for those who are interested.

    You don’t need to do many calculations to see that the AI has gone slightly wrong. Since water covers roughly twice as much of the Earth’s surface as land does, lowering the oceans 1 inch should raise the land by about 2 inches, assuming that the volume of dirt isn’t changed by the process of moving it.

    More precisely: Area of the oceans = 361,000,000 km2
    1 inch = 2.54cm = 0.0000254 km
    Volume of dirt = 361000000 * 0.0000254 = 9169.4 km3
    Area of land on Earth = 149,000,000 km2
    Height of dirt spread over land = 9169.4 / 149000000 = 0.0000615 km = 6.15 cm = 2.4 inches

    Not going to say how many Everests as estimates for the volume of Everest seem to be all over the place. But the point stands that it’s a huge amount of material making the idea somewhat impractical.












  • This is interesting because the most “realistic” (i.e. still not realistic) depictions of time travel in fiction involve travelling through a singularity or wormhole. So you probably have to be in space to start with, but also both ends of the wormhole have mass so they can be orbiting a planet or star and stay within a stable distance of it. It solves this particular problem (just leaving the other usual problem of causality!) It also proves your point since it does allow travelling in space, in fact it allows travelling faster than light.

    I think the converse is true as well, that if faster than light travel is possible then time travel must be possible, at least if you take relativity at face value. As others have pointed out there’s no universal reference frame, and for any journey that is faster than light in one reference frame, there is another frame in which the journey goes backwards in time.