From: Henry Spencer <firstname.lastname@example.org>
Subject: Re: IR cooling throught IR window to space
Date: Sat, 21 Mar 1998 22:48:41 GMT
In article <351222FC.C403E9E8@www.nbtel.nb.ca>,
Dale Trynor <email@example.com> wrote:
>...it should cool to temperatures of
>air in much a higher level with some help from the cold of actual space
>itself but to a very small amount and only on clear nights...
Yes, this has been known for a long time. The Romans made ice in the
desert that way: insulate the container with a thick layer of straw
during the day, expose it to the sky at night (unless it's cloudy),
repeat as necessary. A clear night sky is very cold.
>But what I
>thought would be most interesting would be is if this could be made to
>work even during daylight...
Nope, too much scattered sunlight.
>...remember being told that if you looked up from a long chimney you could
>even see the stars during the day...
Unfortunately, that's a myth. The inability to see stars during the day
is not just because the bright light desensitizes the eye (although it
does). The incoming sunlight scatters off air molecules; a clear daytime
sky really is glowing bluish-white, just like it looks. It's much
brighter than any normal star.
On the Moon it would work.
Being the last man on the Moon | Henry Spencer
is a very dubious honor. -- Gene Cernan | firstname.lastname@example.org