in principle, distance doesn't affect doppler shifting. It's the speed difference of the emmitter and the reciever. I imagine that if you saw red and green airplane lights, then they really were red and green |
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Can fireflies appear like white dots only a few meters away? Sort of like blinking stars? I know stars do this but how far does light need to be to loose its color? |
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in principle, distance doesn't affect doppler shifting. It's the speed difference of the emmitter and the reciever. I imagine that if you saw red and green airplane lights, then they really were red and green |
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Previously PhilosopherStoned
My nephew and I saw white lights in the sky about two days ago. They blinked like small sparks from fireworks and sat still in the sky. Sometimes they blinked out and reappeared a couple of meters away. And other times they were so bright they looked like small lightning strikes. |
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In the dark, it'd be hard to see the fireflies' bodies. So, yes, you'd only see the little white light. You can also sometimes see fireflies from a surprising distance away. They don't flash very often, which could explain why they didn't happen to flash at the same time as another one. |
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haven't you ever seen a red star? Light doesn't lose its color at a distance. |
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Art
The ability to happily respond to any adversity is the divine.
Dream Journal Shaman Apprentice Chronicles
From where I live there are few stars. Can't say that I seen a red star, plenty of white ones though. |
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That's not true. Light doppler shifts. If the source of the light is approaching you at speeds that are not neglibable compared to the speed of light, it will shift in a blue direction. If it's moving away from you at non trivial speeds, it will shift in the red direction. This is one of the ways that we prove that the universe is expanding. |
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Previously PhilosopherStoned
While we're talking about light, I've been thinking about something: |
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It would be "black". If there's nothing behind it that reflects the blue light to let you see the silhouette, then it will be "invisible", in that you'll see nothing but blackness. |
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Last edited by Forsaken; 08-06-2009 at 03:13 AM.
I disagree but not definitively. The red object is absorbing the blue light that it doesn't reflect. The atoms do this and it moves the electrons in the atoms into a 'higher' orbit. They will decay into a lower orbit and conservation of energy demands that they release a photon to do so. The frequency of this photon will depend on the atom that is in question. Given atoms only have particular orbits open for an electron to occupy and moving between them 'costs' a discrete amount of energy that gets tranformed into the photon. The amount of energy determines the color of the photon. |
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Last edited by PhilosopherStoned; 08-06-2009 at 05:50 AM.
Previously PhilosopherStoned
The doppler shift has nothing to do with light 'losing color' at a distance. No matter how far away a light source is, the shift in frequencies will only be dependent on how fast the source is moving away from/towards the observer. |
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Last edited by Xaqaria; 08-06-2009 at 07:39 AM.
Art
The ability to happily respond to any adversity is the divine.
Dream Journal Shaman Apprentice Chronicles
that's what I said and that's doppler shifting. |
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Last edited by PhilosopherStoned; 08-06-2009 at 02:39 PM.
Previously PhilosopherStoned
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