• Codex
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        51 year ago

        Indeed, many would argue that water can’t be wet, only things that water gets on/in.

    • @[email protected]
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      21 year ago

      Wait, how do you make the laser pointer travel at the speed of light? I assume it has some mass.

    • @[email protected]
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      201 year 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?

      • @[email protected]
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        181 year 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.

        • @[email protected]
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          341 year 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
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            71 year 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.

    • @[email protected]
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      41 year 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

  • Morphit
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    81 year ago

    I think they’ve changed the headline, but not the embedded video:

    • @[email protected]
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      111 year ago

      I mean, the video one makes a little more sense, as it’s about destroying things at the speed of light rather than just firing the laser.

    • @[email protected]
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      101 year ago

      This is incorrect by well over a century. The error is likely a conflation of information transmission with mass in context of relativity.

      Thomas Young’s 1801 double slit experiment demonstrated the wave particle duality of light. The modern scientific explanations aren’t found in relativity, instead quantum mechanics.

      The title is just crap. Don’t try to defend it, especially not like this.

  • @[email protected]
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    221 year ago

    Honestly I’d be more impressed by the Star Wars kind that go about thirty miles an hour.

    • Jolteon
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      91 year ago

      Those aren’t lasers. They’re contained plasma projectiles.

  • Julian
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    241 year ago

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

  • Dyskolos
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    701 year 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.