Comment on Speediest little fella.

Tb0n3@sh.itjust.works ⁨1⁩ ⁨year⁩ ago

• Vilian@lemmy.ca ⁨1⁩ ⁨year⁩ ago

  well, if it get reflected and change direction it going to be at light speed, so it can be interpreted (probably incorrectly lol) that it “accelerated instantly to the other direction after the reflection”?

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  • kogasa@programming.dev ⁨1⁩ ⁨year⁩ ago

    This is an interesting question. Instant acceleration is mathematically implausible, but I don’t know if there’s a better physical interpretation for what happens to a bouncing photon.

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    • Entropius@lemmy.world ⁨1⁩ ⁨year⁩ ago

      As a rule, it’s probably best to avoid “random” internet sources on matters of how light works because there’s so much confidently parroted misinformation out there. For example, this is completely wrong: youtu.be/FAivtXJOsiI See here for correct answers to that issue: youtu.be/CiHN0ZWE5bk

      For how mirrors work see this: scientificamerican.com/…/what-is-the-physical-pro… youtu.be/rYLzxcU6ROM

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    • sj_zero ⁨1⁩ ⁨year⁩ ago

      There's a hard rule about quantum physics. It goes: "it's all fun and games until you're at the Quantum level, then everything is all fucked up"

      According to what we know, electrons don't "move between" energy states on an electron, they're just in one one moment and another the next. That's so disconnected from reality we perceive it still breaks my brain.

      • callyral@pawb.social ⁨1⁩ ⁨year⁩ ago

        wait, so it’s like a floating-point precision error but with quantum mechanics?

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• AlwaysNowNeverNotMe@kbin.social ⁨1⁩ ⁨year⁩ ago

  This is acceleration with no mass and no resistance to medium.

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  • Neato@kbin.social ⁨1⁩ ⁨year⁩ ago

    Photons are born and die at c. They experience no time and have no frame of reference.

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    • hansl@lemmy.world ⁨1⁩ ⁨year⁩ ago

      The loneliest of experience.

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  • Tb0n3@sh.itjust.works ⁨1⁩ ⁨year⁩ ago

    wtamu.edu/…/how-does-a-photon-accelerate-to-light…

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• trash80@lemmy.dbzer0.com ⁨1⁩ ⁨year⁩ ago

  They change direction and speed, right?

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  • ziggurism@lemmy.world ⁨1⁩ ⁨year⁩ ago

    The fact that light cannot change speed is one of the core axioms of relativity

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    • trash80@lemmy.dbzer0.com ⁨1⁩ ⁨year⁩ ago

      Light doesn’t travel the same speed in water or glass as in a vacuum.

      In a medium, light usually does not propagate at a speed equal to c; further, different types of light wave will travel at different speeds. The speed at which the individual crests and troughs of a plane wave (a wave filling the whole space, with only one frequency) propagate is called the phase velocity vp. A physical signal with a finite extent (a pulse of light) travels at a different speed. The overall envelope of the pulse travels at the group velocity vg, and its earliest part travels at the front velocity vf.

      en.wikipedia.org/wiki/Speed_of_light#In_a_medium

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      • Neato@kbin.social ⁨1⁩ ⁨year⁩ ago

        That's light as an aggregate wave. Photons, actual light, always travel at c. What's happening in a medium is the rapid absorption and readmission of photons. The probability of admission is based on structure of material causing things like lens or mirrors to work.

        You can think of it as the photons having to jump between platforms before the can continue running at c.

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      • there1snospoon@ttrpg.network ⁨1⁩ ⁨year⁩ ago

        But doesn’t relativity explicitly state that c is the speed of light in a vacuum, and travelling through other mediums explicitly changes and is explained by relativity?

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  • marcos@lemmy.world ⁨1⁩ ⁨year⁩ ago

    No, they don’t. They can get absorbed and re-emitted, and the space they are moving though can compress sideways. But they can’t make curves at all.

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    • trash80@lemmy.dbzer0.com ⁨1⁩ ⁨year⁩ ago

      Do lenses absorb and re-emit light?

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      • marcos@lemmy.world ⁨1⁩ ⁨year⁩ ago

        That’s basically all that refraction is. A dead giveaway is that light doesn’t move at the speed of light in them.

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      • Neato@kbin.social ⁨1⁩ ⁨year⁩ ago

        Yes.

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