Twin Peaks Usenet Archive

Subject: Re: 4/11 *Black Box*
From: (Bernie Roehl)
Date: 1991-04-15, 12:01

In article <> (Ann Hodgins) writes:
> >Actually this has bugged me for a while.  What makes the moon light?  -
> >reflecting sun light. What causes the dark side?  - as far as I know it
> >is the earth interfering with the light getting to the moon.

Not exactly.  The light side of the moon is the side facing the sun, the
dark side is the side facing away from the sun.  As the moon orbits the
Earth, we see it from different angles and thus see different proportions
of its sun-facing and sun-away sides.

When the moon is between the Earth and the sun, we can't see the lit side
at all; when it's on the far side of the Earth, we see the full face (full
moon).  When it's "beside" the Earth, we see half-lit and half-unlit.

Lunar eclipses, on the other hand, occur when the full moon (on the far
side of the earth from the sun) happens to pass through the Earth's conical
shadow.  Solar eclipses occur when the moon passes between the Earth and
the Sun, and the moon's conical shadow hits the Earth wherever you happen
to be.

P.S. We missed you at the last Twin Peaks party, Ann!  Hope to see you at the
next (last?) one!
-- Bernie Roehl, University of Waterloo Electrical Engineering Dept Mail: OR BangPath: {allegra,decvax,utzoo,clyde}!watmath!sunee!broehl Voice: (519) 885-1211 x 2607 [work]