• cmgvd3lw
    cake
    link
    fedilink
    English
    arrow-up
    2
    ·
    7 months ago

    If it is viewed from far and on a high altitude, would the light appear red shifted?

      • cmgvd3lw
        cake
        link
        fedilink
        English
        arrow-up
        3
        ·
        7 months ago

        1000024983 I was reading on this aurora phenomenon and saw that in some parts of Himalayas, aurora was seen red.

        • phcorcoran@lemmy.world
          link
          fedilink
          English
          arrow-up
          1
          ·
          7 months ago

          That’s a cool photo, thanks for sharing.

          For more context why this wouldn’t be related to redshift, redshift is a concept in physics for light that’s analogous to the Doppler shift for sound. The typical example of Doppler shift is the EEEEE-OO-UUUUUM sound a car makes when moving fast past you. When the car is speeding away from you, the sound pitch is noticeably lower

          Similarly, when a light emitter moves away from you at extremely fast speeds (i.e. hundreds of millions of meters or yards per second), the light you see reaching you will be shifted down in frequency, towards red in visible light. This can happen in other more complicated relativistic situations too but they are less easy to explain and also not applicable here

          I don’t know why the people in the photo see this beautiful red aurora but redshift is almost certainly not a related concept here

          • cmgvd3lw
            cake
            link
            fedilink
            English
            arrow-up
            1
            ·
            7 months ago

            Oh I think I got things confused there. I was referring to the phenomenon where the sky looks red-pinkish on evenings because the Rayleigh scattering.

            • phcorcoran@lemmy.world
              link
              fedilink
              English
              arrow-up
              1
              ·
              edit-2
              7 months ago

              Yeah I would say that one could explain the picture here

              Ultimately, the phenomenon is happening much much higher up in the atmosphere, so being a few kilometers closer vertically won’t make a difference; but by being further up on the ground, you could see an aurora from further away and through a lot more molecules that could scatter non-red light