refraction of light?

Comments and questions about the APOD on the main view screen.
jcoll

refraction of light?

Post by jcoll » Fri Dec 31, 2004 3:51 am

I am a glider pilot and have observed an unexpected 'pheomena" of apparent refraction of light. I have queried many people including scientists but still have no satisfactory explanation. Perhaps someone out there can help.
Observation:
When flying a glider on a sunny day and late in the afternoon, I often look at the ground where I expect to see a shadow of the glider.
I do NOT see a shadow, but a bright concentration of light where I would expect to see a shadow.
It appears that the glider is acting as a long focus lens with a positive refractive index to produce this surprising observation.
I have heard of astronomers using the term "micro lensing" which refers to the refraction of light around a celestial object to determine presence or distance of astronomical objects, is this what is happening here?
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BMAONE

Post by BMAONE » Fri Dec 31, 2004 6:17 pm

THE ANSWER LIES IN DR LEWINS THREAD. IT IS A SIMILAR PHENOMENON
TO THE ONE BEING DISCUSSED THERE, IN DEPTH.

Mary Celest

Re: refraction of light?

Post by Mary Celest » Tue Jan 04, 2005 3:52 pm

jcoll wrote: It appears that the glider is acting as a long focus lens with a positive refractive index to produce this surprising observation.
I have heard of astronomers using the term "micro lensing" which refers to the refraction of light around a celestial object to determine presence or distance of astronomical objects, is this what is happening here?
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No microlensing (one word) is caused by massive objects like stars. In these cases the gravitational potential well deflects the path of the light. A glider does not have sufficient mass to cause this at anywhere near a perceptable level.

BMAONE stop shouting.
Can't you find the caps lock key?

crosscountry
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Joined: Mon Dec 20, 2004 3:24 pm
Location: St. Louis, MO

Post by crosscountry » Wed Jan 05, 2005 3:17 am

Mary Celest is right. microlensing does not work for small objects.

you didn't say where you glide? is it over a desert or what?