We can sometimes see some particles floating in the air from a headlight or a cinema-projector, What are they?
442332
They are residues left from dust or sand, but more they are particles of air that reflect the light on various ways they are being projected to our eyes and that's what we see..
790315
It's an optical effect called a halo
628295
Could be "floaters".  Are you pretty short-sighted?  You'll see them more often then.  Good idea to go to your optician or doctor to get them checked out, though.
516515
I have the same problem dude. I'm thinking you have what is commonly called 'floaters', that is, you have small particles floating withing the fluid of your eye. You see these lines and dots because they float over your retina and block light, casting a shadow. Usually this is a non-issue (nothing to worry about), and only appears when looking into a bright light (I.E. a microscope) or staring an uncommonly bright image, or paper. It could be a sign of retinal detachment (a very serious issue) if it is  persistant (constant), or distracts you from everyday things such as driving, or working. \n\nIf you are really worried, check with your Eye-Doctor or Physician, they'll tell you if it is completely harmless, or if you should take further action
160214
They also occur as a circle, if you're in a plane (i was in a microlight) above mist/cloud it's the most spectacular sight, I looked down and there was a circular rainbow. It has to do with the fact that you're viewing it from one point, all the rainbow is relative to you.
193329
The technical term is "floater".  This is material from the retina (the light detecting portion of the eye) that has made its way into the vitreous fluid of the eye (the jelly-like material that fills up much of the eye).  These can be cholesterol plaques, old blood, or some of the cells that line the retina.  While the majority of these are benign and will clear themselves (usually takes several months), it is recommended that you talk to a doctor about them as they can be a warning sign of more serious medical problems.
231866
Fact... ive seen plenty of things in my lifetime. balls of floating light,doors shutting when there is no breeze, noises when nobody but me is here.. other people in my family have heard these things too.. ghostly sights in my house...
259241
Because there are no atmospheric particles for the light beams to bounce off of. You know how light bends(i.e. slows down) when traveling through water? Some light particles bounce off the water and others go through it. Its the same with the air. So that is why when you look at pictures of space you can actually see some things, because the light is bouncing off of them. The rest is void. Or mostly anyhow.
172088
I know the new Mercury and Lincoln vehicles with the LED's don't seem to flicker much, but I agree it seems that Cadillac's have a bit of flicker to them. Maybe they should put one of those epilepsy warning stickers on the back of 'em!
429574
gas emitting visible light as a result of being heated
439947
u might have something in your car drawing extar power which is making them dim, or the lens that covers the headlights might be yellowed from the sun.
961174
When the suns rays heat up the air above a surface and the heated air is appearing to shimmer (different index of refraction) then that can appear as a mirage (for water for example). I think some mirages (along the highway) are pure imagination and others (water in the desert) are also partly wishful thinking.
1057033
It probably has to do with a mix of light pollution and regular pollution
422752
Smoke or fog will work.  There are also 100mW red lasers out there (wickedlasers.com should do the trick) that have some visibility in daylight, but this always depends on there being something (even the tiniest amount of dust) in the air to scatter off of.
1051141
Atmospheric interference.
1061413
I don't know but I have seen some weird stuff in the sky. I saw this light go back and forth very fast a couple of times then disappear straight up into the sky. I also used to see these weird upside down arch shape clouds in the sky just barely moving. Bonafide Alien Space Craft or Aerial Government Experiment, I don't know.
485222
I think its bcoz of some lyophobic particles present... im not sure..... jus guessin...