Physics Photo of the Week

Warren Wilson College

<>

March 4, 2005

Waxing Moon Phases in February
February 17, 2005 photo by Anna Shoemaker.
Processed by BJ Scofield.
February 22, 2005 Photo by Ellenor Moore. 
Processed by Kevil Murray.
<>
During the recent two weeks of evening moon visibility, there were only two nights suitable for photography by students in Physical Science Class.  Notice the drastic difference in appearance 5 days makes!

The moon was a little more than half full in the Feb. 17 image. The sun illuminates the moon from the right (west). The mountains and craters near the terminator are highly pronounced due to the shadows.  These shadowed areas are the "sunrise" on the moon. The arc of mountains in the upper left of the Feb. 17 image are the Apennine mountains with Mare Imbrium half obscured by the terminator left of the Apennines.

The moon was nearly full in the Feb. 22 image when the sun is illuminating the moon from almost behind the observer.  With the sun angle in line with the observer, notice there are no shadows - hence the relief features are barely noticeable during the full moon.  On the other hand, notice that several craters show rays of ejecta as lighter lunar material was excavated during the catastrophic impact events and dispersed as rayed deposits in all directions.  The most recent event formed the crater Tycho very promiment in the lower center of the full moon photograph.  This event is believed to have occured "only" 100 million years ago (http://stardate.org/resources/gallery/gallery_detail.php?id=5).  Can you find Tycho on the Feb. 17 image? 

Other features to note are: Mare Crisium near the right-hand limb of the moon and the nearly circular Mare Serenatatis in the upper center of the moon. 

Physics Photo of the Week has published other student moon photos.  See Oct. 8, 2004 and March 12, 2004.


Physics Photo of the Week is published weekly during the academic year on Fridays by the Warren Wilson College Physics Department.  These photos 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 dcollins@warren-wilson.edu.

Click here to see all Physics Photo of the Week for 2005

Click here to see all Physics Photo of the Week for 2004.