Say you looking at a huge tvery own from much amethod on like a hillheight or a balcony…why does it seem that all the lights are flickering?-M

Obstructions in your check out such as water vapor, dust, heat, cause the lights to show up to flicker. I’m sure tbelow are more than likely several various other factors as well, however off the optimal o’ me head, that’s the main ones IIRC.


Anvarious other cause is the “nistagma” effect (I hope I spelled that right - I’m going from memory).

You are watching: Why do lights twinkle in the distance

Try to look at a dim single suggest of light for much longer than a few seconds (via the neighboring location dark). Your eye starts relocating to put the point of light on the more light (as opposed to color)sensitive external location of the retina. The stationary light resource shows up to start moving.

As much as far-away towns and also such, I think that the atmospheric disturbances that t-keela pointed out account for a lot of of the flickering. But if you are focusing fairly hard on a resource of light, your very own eyes will make it begin to relocate as well.

bbeaty July 15, 2003, 6:45am #4

Not obstructions.

It’s the very same thing that makes stars twinkle.

It’s the wind, wind plus patches of air of various temperatures. Amateur astronomers have a word for it: “Bad Seeing.”

Air is a transparent material favor glass, and also prefer glass it bends light in different ways at different temperatures (i.e. it’s refrenergetic index is not uniform as soon as its temperature is not unidevelop.) Patches of warm and also cold air create feeble prism and also lens impacts. The exact same thing happens in the warm air over a fire. This is happening all the moment in the atmosphere, yet it’s much even more feeble than the strong lens/prism impacts over a fire. Patches of various temperatures create the prisms/lenses. Wind transporting activities these prisms/lenses between you and the far-off objects.

So, why execute remote light sources twinkle, yet remote objects do not? Easy: point-sources of light are like lasers: they have actually high spatial coherence. (Easy?!!) In various other words, light from remote allude sources have the right to cast diffractivity fringes on your eyes as the light waves take slightly various paths via the hot/cold roiling windy air and also then recombine. The light shining on your challenge isn’t smooth, rather it’s frilly. The “fringes” are regions of wave-enhancement and also wave-subtraction. They typically look choose narrowhead parallel bars of light shadow. When they move throughout your eye, you watch a flickering.

Try this: look at distant flickering lights, then cross your eyes so you watch double. Look closely at the pairs of flickering distant lights. Often you’ll discover that the flickers of the 2 imperiods don’t match! This happens once the diffractivity fringes projected onto your challenge are shorter than the distance in between your eyes. As the parallel shadow bars rake throughout your eyes, one eye is seeing one pattern while your other eye sees a slightly different pattern. (This same crosseye trick works for twinkling stars.)

Perhaps the word obstruction might have actually been boosted on. IIRC my old astronomy/physics prof. dubbed it impediments.


Try this:

The twinkling (or scintillation) of stars is the outcome of the light rays being bent (refracted) and distributed from their direct route by passing with air of varying density. The twinkling of stars is strongest when the sky is clear and also it is windy, at least at higher altitudes. Stars nearer the horizon twinkle even more than those overhead because there is more atmosphere via which the light have to pass.

See more: Chantal Krev I Use To Carry The Weight Of The World On My Shoulders

Street lights in the distance may additionally twinkle and shimmer, but here thickness variations in the air a lot closer to the ground are responsible. Remember the bubbles of warmth air which create fair-weather cumulus? Well, they have weaker cousins which develop over urban locations, large bodies of water or rocky surdeals with at night. When these bubbles relocate in between us and low light resource, we see the far-off light shimmer and also twinkle – the further the light source, the better the effect.