• Glowstick@lemmy.world
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        5 months ago

        Actually, c is the speed of light in a vacuum, but light travels slower through a medium, like air. So lasers shot through air will actually travel slower than c.

        • Evil_Shrubbery@lemm.ee
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          5 months ago

          Yes, ofc - but we’re talking about a weapon here, the air is implied as a medium, and the very-near-c with it.

          But a weapon that would construct some sort of structure or a tunnel between it’s position and the target would be something else indeed.

        • dev_null@lemmy.ml
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          5 months ago

          It’s still travelling at c, it’s just bouncing around the medium’s particles on the way. It arrives later because it’s not going in a straight line.

          • qjkxbmwvz@startrek.website
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            5 months ago

            I don’t think that’s a great way of thinking about it. I think you’re describing something more like scattering — or maybe absorption and stimulated or spontaneous emission — which does indeed happen, but is distinct from the index of a medium.

            If it were indeed “bouncing,” optics wouldn’t really work, as any n > 1 medium would cause the light to go every which way.

            • SirSmokeAlot@lemmy.ml
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              5 months ago

              If you fire a laser that goes first through vacuum, then through a lens, then again in vacuum, at what speed is the light travelling on the other side?

              • qjkxbmwvz@startrek.website
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                5 months ago

                It’s same as it was at first. The speed of light depends on the index of refraction of the medium it’s in, but doesn’t depend on its “history.”

                • SirSmokeAlot@lemmy.ml
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                  5 months ago

                  I didn’t write it out, but what I was trying to get at was that if it would “slow down”, then it would be slower on the other side. The explanation that the light travels longer through a medium with the same speed would therefore make sense to me.

                  But then again, how it wouldn’t shoot out in every direction, that doesn’t make sense to me.

                  I don’t know much about light, that’s why i’m asking. And i’m sure some article or paper would have anwers for that question, I might search it on my own.

    • Lad@reddthat.com
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      5 months ago

      Imagine if they made it fire so slow that you could just do a dark souls dodge roll to avoid it

    • Jumuta@sh.itjust.works
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      5 months ago

      just shine a laser through a thing of zircon (n=index of refraction=1.923~2)

      so speed of the laser in the zircon = c/n ~c/2

    • RandomVideos@programming.dev
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      5 months ago

      The laser pointer can travel the light of speed? If you turn it on, does the laser not come out of the laser pointer?

      • OneWomanCreamTeam@sh.itjust.works
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        5 months ago

        The laser and the laser pointer are both traveling away from each other at the speed of light, so from the pointer’s perspective the laser is traveling at twice the speed of light.

        • AlolanYoda@mander.xyz
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          5 months ago

          You are being downvoted as if your point was offensive or harmful. You are wrong, but it’s totally counter intuitive and I think this is a mistake that everyone makes when studying introductory physics. This would be correct for anything moving at relatively low speeds. But when you’re talking about light, or anything that goes so fast that “percentage of the speed of light” starts being a useful unit to describe their speed, this concept starts being a bit weirder.

          This is actually the basic principle of Einstein’s theory of relativity: the speed of light (in a vacuum) is the same for all observers, regardless of their frame of reference. That means that if the laser pointer emits a laser, the light is moving away from the pointer at the speed of light. If the pointer itself is moving at a speed reeeeeally close to the speed of light… Then the laser will STILL be traveling away from the pointer at the speed of light. And if you, an observer in a frame, see the pointer moving at near the speed of light emit a laser… The laser that the laser emitted is also traveling at the speed of light from your point of view.

          And there’s no wordplay here. I don’t mean that it’s light, so of course any speed it travels at is the speed of light. I mean that if you measure its speed from any reference frame, you will get around 300000000 m/s, or around 671 million miles per hour. No matter if you are also traveling at near light speed.

          • dream_weasel@sh.itjust.works
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            5 months ago

            I think you’ve got to be a little careful how you say what you mean here:

            In light’s own reference frame, this is true-ish from a pure special relativity perspective. Velocity is sort of undefined in that case because at c, Lorentz transformations bring all distances to zero, meaning that the photon is everywhere at the SAME time. Or said another way, it’s everywhere on its own simultaneity curve. Maybe this is splitting hairs on the definition of “undefined” because, mathematically yeah you’re right, but a rock also moves zero distance in zero time. Its more like it’s velocity doesnt make sense to compute.

            From the outside though (as in a non photon frame) this is not true at all. Using laws of refraction you can compute, and even photograph and verify a real, defined speed for a photon in a medium.

    • Akasazh@feddit.nl
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      5 months ago

      That’s impressive. Having a non-photon mass traveling at the speed of light would break our understanding of physics. Get that laser pointer to the lab ASAP

  • Dyskolos@lemmy.zip
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    5 months ago

    Impressive. The future is awesome! Can we maybe apply this to regular light too? Maybe even green light? Or purple? I’m so excited.

  • Julian@lemm.ee
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    5 months ago

    Wait until they see the speaker that makes noise at the speed of sound.

    • RandomVideos@programming.dev
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      5 months ago

      There was an auction that started at the price of 69420 USD on the 1st of april of 2022

      . .

      .

      .

      (The lightsaber is real, selling an extremely dangerous weapon was the joke)

  • Annoyed_🦀 @monyet.cc
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    5 months ago

    Have you not seen those Blaster from the galaxy far far away that fire laser half the speed of sound?