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Lamp halo

  1. Apr 26, 2005 #1


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    i was walking along somewhere and i see this street lamp.


    lol anyway so this street lamp is like ish bright, like you can look straight at it w/o hurting your eyes but its still bright. and i noticed that when you look at it, theres this like spherical shell around it, (when its dark outside). and that the shell is smaller if ur close and bigger when ur far away. it looks sortof like a soap bubble. in the spirit of scientific discovery i observed it very closely, and here are my measuremeants: lamp is about 10 cm x 10 cm, halo about 1 foot in radius when standing like 5 meters away. and the shell looks perfectly spherical. if you go like 1 meter farther the shell is noticeably bigger. im really not sure why you see this funny shell/halo/something. im guessing it has something to do with your eyes.

    any thoughts?
  2. jcsd
  3. Apr 27, 2005 #2


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    There can be some fuzziness associated with impaired eyesight, so that might have something to do with it. Most likely, though, it's entirely resultant of particles (mostly water) in the air reflecting and to some extent refracting the light. The apparent size varies with distance because a higher percentage of the light is directed away from you as you get closer. Think of it as a little-bitty sundog.
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