Expert: Ed - 10/11/2007

Question
hi
im curious as to how astronomers can estimate elevation of features of the moon by studying shadows on the moon during its different phases
thanks

Answer
Ammar,

The short answer is TRIGONOMETRY.

Here is a website which will help you to do this for yourself, if you'd like to try it.
http://www.tass-survey.org/classes/phys236/moon_mount/moon_mount.html

Before I forget, you might enjoy these links:
http://members.csolutions.net/fisherka/astronote/plan/craterdepth/CraterDepthsAp...

http://ntrs.nasa.gov/search.jsp?R=168475&id=9&qs=No%3D10%26N%3D4294903835

Basically, if they were only looking at images of shadows, they would not have enough data to estimate elevations.  However, in fact, they have more information than that.  We know exactly how far away the moon is.  Therefore, precise measurements of the length of shadows on the lunar surface can be used to determine the height of the object casting the shodow, such as mountains, or the walls of craters, or alien UFOs.  Just kidding on that last one.

i THINK THIS SHOULD BE HELPFUL.  pLEASE LET ME KNOW IF YOU'D LIKE TO DISCUSS IT MORE.

kEEP lOOKING uP!
--eD