Caves on Mars?! How Cool is That?!

Unclaimed Mysteries dropped this in my inbox the other day (thanks man!). And I'd gotten another version of the report from another grotto member from Lunar and Planetary Science XXXVIII (2007) so I wrote a little summary for the Grotto Newsletter that's due out in a couple days. For those of you who are grotto members this is a little preview:

Black spots have been discovered on Mars that are so dark that nothing inside can be seen. These spots (seven so far)might possibly be entrances to deep underground caves. The unusual hole pictured at left which is about the size of a football field was found on the slopes of the giant Martian volcano Arsia Mons and is so deep that it is completely unilluminated by the Sun. The photo was captured by the HiRISE instrument onboard the Mars Reconnaissance Orbiter currently circling Mars. The holes were originally identified on lower resolution images from the Mars Odyssey spacecraft. The Martian surface is virtually unprotected from UV radiation, solar flares and meteoroid bombardment so protected subterranean voids and skylights might be prime targets for future spacecraft, robots, and even the next generation of human interplanetary explorers because of their biological possibilities.

Also - for you non-cavers I guess I need to do a bit of translating of "BO!" to understand the photo (otherwise Bo of WmWms will be like why the @#%$ is the hole on Mars shouting my name?):

BO! - This single BO is used to signal a request for recognition. You should respond with a single BO. This is frequently used while ridgewalking to keep track of where everyone is on the mountain. You can usually tell the direction, distance, and identity of the person calling. This is also handy if you get separated from your friends in a cave. You can call BO! to one another to help you zero in on their location.

BO BO! - Two BOs mean that I am coming to you, wait for me.

BO BO BO! - Three BOs means for you to come to me. This is frequently used when people are spread out on a ridge looking for a cave entrance. If you hear this call, usually someone had found the entrance.

Here's to caving on MARS in the next couple hundred years! Where do I sign up? BO! BO!