Re: Rays of Sunshine

[Bob Sciamanda <trebor@VELOCITY.NET>]

Consider an airplane's vapor trail.  This is not the path of a light ray,
it is the locus of scattering centers.  The light which you see is
scattered from each point along the vapor trail into your eyes.

Bob Sciamanda (W3NLV)
Physics, Edinboro Univ of PA (em)
trebor@velocity.net
http://www.velocity.net/~trebor
----- Original Message -----
From: "Roger Haar" <haar@PHYSICS.ARIZONA.EDU>
To: <PHYS-L@lists.nau.edu>
Sent: Monday, August 18, 2003 11:19 AM
Subject: Rays of Sunshine


> Hi,
>
>         Here is something for which I have not been able
> to think up a proper explaination.
>
>         On a partly cloudy day, one often sees DIVERGING
> rays of sunshine, something like the Japanese flag
> or the Arizona flag.  I think these rays are
> visible because of scattering in the atmosphere
> and they appear to diverge from the sun.  But for
> most of their path rays of light coming from the
> sun are in outerspace and are scattered very
> little.
>
>         At first thought the solution is that the
> sunlight passes through a hole in a more distant
> cloud and is heavily scattered into a broad range
> of angles.  This scattered light then passes
> through holes in nearer clouds to produce the
> rays.  The problem with this is the rays would
> appear to diverge from the hole in the first cloud
> rather than the sun.
>
>         Any thoughts.
>
> Thanks
> Roger Haar