Physics Photo of the Week
September 9, 2005
Moon Photos by Astronomy class
The astronomy class at Warren Wilson
College made photographs of the moon through a telescope on Thursday,
September 8, 2005, when the moon was a crescent phase. This is
Molly Sternberg's image. The moon phase was about 5 days after the new
moon. The moon was seen in the southwestern sky soon after
sunset. The sun was below the horizon to the lower right in the
photo. The reason the moon is crescent shaped is NOT due to the
earth's shadow, but because of the angle between the sun, moon, and
earth. Most of the moon's surface on the side facing the earth is
on the "night" side of the moon. The moon is in its own shadow,
not the earth's shadow!
On Molly's photo above notice the
details of the craters near the terminator - the boundary between the
sunlit part of the moon and the darkness. That is because the
craters and mountains cast long shadows on the moonscape.
The image at left, made by Bo Collins,
zooms in on the crater Theopilus. Notice the central peak in this
crater. The central peak in this crater and in many other craters
on the moon is caused by the rebound effect when the crater was created
millions of years ago by a catastrophic impact from a comet or small
asteroid. Cosmic impacts melt the material of the planet or
satellite due to the enormous kinetic energy of the impacting
body. The material of the moon rebounded immediately after the
impact and formed the peak. This is similar to the rebound splash
when a stone is thrown into a pond.
The reddish color of these photos is
due to the moon's position low in the sky. The moonlight travels
through a larger thickness of haze which "reddens" the moon - similar
to the red sun at sunset.
Photo of the
published weekly during the academic year on Fridays by the Warren
Wilson College Physics
feature an interesting phenomena in
the world around us. Students, faculty, and others are invited to
submit digital (or film) photographs for publication and
explanation. Atmospheric phenomena are especially welcome.
Please send any photos to email@example.com.
here to see all Physics Photo of the Week for 2005