home *** CD-ROM | disk | FTP | other *** search
- Newsgroups: sci.physics
- Path: sparky!uunet!haven.umd.edu!darwin.sura.net!wupost!sdd.hp.com!elroy.jpl.nasa.gov!ucla-cs!ucla-ma!news
- From: geoff@math.ucla.edu (Geoffrey Mess)
- Subject: Re: Noah's formation: The rainbow
- Message-ID: <1992Jul23.001559.5946@math.ucla.edu>
- Sender: news@math.ucla.edu
- Organization: UCLA, Mathematics Department
- References: <2A6DEF17.1804@ics.uci.edu>
- Date: Thu, 23 Jul 92 00:15:59 GMT
- Lines: 27
-
- In article <2A6DEF17.1804@ics.uci.edu> bvickers@valentine.ics.uci.edu
- (Brett J. Vickers) writes:
- > peterk@public.sub.org (Peter Kittel) writes:
- > >Is it only me or does the sky beneath a rainbow also appear lighter
- > >to others than the sky above a rainbow (or wait, was it the other way
- > >around?)?
-
- > Optical illusion? Two fields of the same color, separated by a line
- > of a brighter or darker color, give the optical illusion that one half
- > is lighter than the other. The trick is to cover the line and see that
- > they are the same. I've never tried this with a rainbow.
-
- Not an optical illusion. Above the primary bow of the rainbow is
- Alexander's dark band, first
- described by a philosopher Alexander [not the Great] in Hellenistic times.
- There's a Scientific American reprint volume on atmospheric optics which
- explains this and other features of the rainbow (I don't have the
- reference handy.) There's also a Dover book "The nature of light and
- colour in the open air" (approx. title); I've never seen it but it's
- probably a good place to look for information on atmospheric optics.
-
- --
- Geoffrey Mess
- Department of Mathematics, UCLA
- Los Angeles, CA.
- geoff@math.ucla.edu
- NeXTmail welcome.
-
