a weird rainbow

April 4, 2005 6:16 PM

On a recent flight, I saw a weird circular 'rainbow' around the shadow of the plane (on a cloud). What's the physics behind this?

Sometimes I could see the 'rainbow' even before I could see the shadow, it was like a halo. The clouds were mostly irregular and white, ie non-water bearing.

posted by dhruva to Science & Nature (9 answers total)

It is called a pilot's halo. My dad brought back many photos of them from the Nam.

Let google do the rest.
posted by Baby_Balrog at 6:21 PM on April 4, 2005

A nice explanation.
posted by randomstriker at 6:23 PM on April 4, 2005

Glory, glory, hallelujah.
posted by Eideteker at 6:27 PM on April 4, 2005

Ya know...those google links are actually pretty useless.
Now I have to do some real research, dammit.
*scrounges around intertron for a while*

Aha! Here ya go. Not much physics, though...hmm.
Yes! Score! Physics! Boring shit! All about plane rainbows.

More cool stuff about planes and stuff in the sky that is pretty and can only be seen from planes.

*goes back to world of warcraft*
posted by Baby_Balrog at 6:28 PM on April 4, 2005

Narg! Scooped! I hate that.
posted by Baby_Balrog at 6:28 PM on April 4, 2005

They're also called "glories". My husband put together a nice little page on them here: glories.

Damnit, scooped by eideteker on "glory", but I'll let my link stand anyway. I've never heard the term "pilot's halo" before, btw. Interesting.
posted by livii at 6:29 PM on April 4, 2005

Best answer: Also check out Astronomy Picture of the Day (or "APOD"), they cover this, and many similar phenomena, with a good photo and explanation, with crosslinked and searchable archives, and something new to see every day. A lot of people I know who have little interest in astronomy still visit this page religiously because the photos and topics are so often just, well... damn cool. :)
posted by -harlequin- at 6:42 PM on April 4, 2005

Response by poster: Thanks everyone! I checked all the links and now I have something to look forward to on every flight :)
posted by dhruva at 7:05 PM on April 4, 2005

You can observe a similar phenomenon on a smaller scale without leaving the ground. Take a walk early in day when the sun isn't much higher than 45-degrees above the horizon and find a dewy lawn to cast your shadow on. Look at your shadow's head and you should see a halo around it.
posted by pmbuko at 12:24 AM on April 5, 2005