Mustard Lun 25 Déc 2006 - 21:07
Tout ce que j'ai c'est ça:
A trough wanders between two hills in the Tartarus Colles region of Mars in this HiRISE image from Mars Reconnaissance Orbiter. The trough most likely began as a covered lava tube, but most of the roof has collapsed over time. One tiny remnant of lava tube roof has been left behind as a 25-meter-wide bridge, a natural arch over the trough below. The dusty slope to the west of the trough shows dark slope streaks due to dust avalanches, which fade over time. The visible area is 2 by 1 kilometer in size. Clicking to enlarge shows the image at 1 meter per pixel, a quarter the full resolution of the original. Credit: NASA / JPL / U. Arizona
source ici: http://planetary.org/blog/article/00000793/