• Contramuffin@lemmy.world
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    7 days ago

    You’re confusing 2 different but related concepts. Blueshift and redshift does depends only on velocity. In the cosmological sense, redshift (the opposite of blueshift) occurs because everything is moving away from everything else due to the expansion of the universe, and so the distance of an object can be calculated based on how much redshift there is in the light. Basically, on a cosmological scale, distance and velocity are connected

    • Kongar@lemmy.dbzer0.com
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      7 days ago

      Right, I was thinking of redshift. But now I’m even more intrigued. How does a thing moving toward me shift light blue? It’s not like the space inbetween us is shrinking…. And the speed of light is constant…

      What the heck is blue shift? I need to go hit Google/wikipedia/something smarter than me ;)

      • protist@retrofed.com
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        7 days ago

        The speed of light is constant, however the frequency of light is variable. Similar thing with sound, high pitched and low pitched frequencies travel at the same speed in the same medium

        • Crazyslinkz@lemmy.world
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          7 days ago

          Yes! Ever heard a car horn coming at you and then going away? It’s the wave compressing and expanding.

      • Elting@piefed.social
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        7 days ago

        Red shift and blue shift are exactly the same thing. If you think about light as a wave, like sound, approaching objects have scrunched up waves (blueshifted light) and fleeing objects have spaced out waves (redshifted light). The exact same reason a car horn has higher pitch when it is approaching you and lower pitch when it travels away. The intensity of the effect is correlated to the speed limit of the medium so since light is so fast this effect is typically very small.

      • Kongar@lemmy.dbzer0.com
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        7 days ago

        Interesting, the interwebs just taught me that redshift does occur like the Doppler effect. Similarity blueshift in the other direction. I always thought it was just from space expanding.

        You learn something new everyday!