[Nmcaver] A Hole in Mars

[Lee H. Skinner]

The Astronomy Picture of the Day for May 28, 2007 is of the one of the 
cave entrance recently discovered on Mars:

http://antwrp.gsfc.nasa.gov/apod/ap070528.html

Like typical Earth karst, you'll notice the usual lack of surface 
drainage, and you'll also see the numerous other smaller depressions in 
the area.  :-)

I wonder if a meteorite could have caused the collapse to occur.

Lee Skinner