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Joined 10 months ago
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Cake day: August 4th, 2023

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  • 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


  • 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






  • Picking a higher density of the material just means the one gram would occupy less volume, it doesn’t affect how much energy that gram is equivalent to in terms of E=mc2. For that calculation, as the equation implies, only the mass matters; a gram of feathers is equivalent to the same amount of energy as a gram of lead for that equation. Now, this equation is in fact a simplified assumption; if you launch your feather at relativistic speed, then we’re talking