Thread: Another question about light

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?

I'm guessing the size of the light also plays a factor, after all I've seen red and green airplane lights.

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

As far as the question about firefly lights goes, I'm not sure how to explain that. How many were there? how many times did you see them?

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.

I'm guessing there was more than one doing this (to make it seem like it jumped). But I only saw one appear at a time, and the others did not reappear. It traveled in a path by "Blinking out".

When I first saw it, I thought it was like a comet, but it had a thick trail like someome took a marker and slashed the sky slowly. It also turned around and went into the trees.

There was fireflies that night, and that's the only explanation I can come up with.

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.

haven't you ever seen a red star? Light doesn't lose its color at a distance.

From where I live there are few stars. Can't say that I seen a red star, plenty of white ones though.

Originally Posted by Xaqaria

haven't you ever seen a red star? Light doesn't lose its color at a distance.

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.