• JackGreenEarth
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      3426 days ago

      Well, the names for different parts of the color spectrum are, I suppose. Wavelength of EM radiation, and how your brain interprets it as color, is ‘real’.

      • tate
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        326 days ago

        I think they were alluding to a different use of the word color.

        • JackGreenEarth
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          225 days ago

          What use? The only thing I can think of is ‘colourful’ language, which doesn’t seem to really make sense in this context.

  • @[email protected]
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    26 days ago

    OK I need someone to explain this to me cause AFAIK light speed is constant no matter how fast moving the source is

    • @captainlezbian
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      825 days ago

      So light is a wave. Shorter wavelengths are bluer longer wavelengths are redder. When you walk towards a wave you hit the peaks and troughs faster than had you been still. They come slower if you’re walking away from it. The Doppler effect is that but with light waves and velocities that make it relevant

    • Skalix
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      225 days ago

      Adding to the other comments; I once saw a interesting video of a visual demonstration of that effect and other weird things that happen close to the speed of light. It was this one if i remember correctly: https://www.youtube.com/watch?v=ge_j31Yx_yk

    • Björn Tantau
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      226 days ago

      Which is achieved by spacetime dilation which can in turn stretch or compress the light waves.

      • @[email protected]OP
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        225 days ago

        While it is true that space time dilation can cause red/blueshift, that is a distinct from the doppler effect which is the primary effect here.

        (dilation plays only a small role: without time dilation our answer going from 700nm to 350nm would be 0.5c instead of the 0.6c calculated below)

  • @[email protected]
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    1826 days ago

    How fast would the rose have to be going to blueshift that much? Someone please do the math

    • andrew_bidlaw
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      26 days ago

      Speed kills, coming down the mountain
      Speed kills, coming down the street
      Speed kills with presence of mind
      Speed kills, if you know what I mean