May 23, 2007, HiRISE release Options

[bdunford]

I don't know if this is news to anyone, but FWIW, after a similar amount of interest about this image on my site, I asked the MRO team for some more info, and received this reply from Nathan Bridges on the HiRISE team, via Suzanne Smrekar:

"1. Yes, HiRISE is planning to image this again. We can't do much about the Sun angle because MRO's orbit is close to 3:00 P.M. and we are near the equator. Seasonal variations mostly affect the solar azimuth at this latitude, not the angle above the surface. However, we can change the angle that MRO looks at the target. So, for our 2nd observation, we will do a large roll to the east in the hopes of seeing the west-facing wall.

2. The two prevailing hypotheses is that this feature is either a deep collapse pit or a "skylight" ( opening) into an ancient lava tube. The location is between Pavonis and Arsia Mons, two large shield volcanoes, so a volcanic origin is appealing."

[Juramike]

...I imagine it's just a function of prevailing wind and topography. Wind blowing over a lage flat area suddently finding a big hole is going to get chucked up a bit - you might even find that the area under the hole is at a slight negative pressure relative to the surrounding area because of it.

What would it sound like next to the hole? Would it whistle in the wind?

How fast would the wind have to go past the hole to get any sound at all?

(High frequency or low frequency? How would it compare to a similar setup on Earth? Is the frequency dependant on the absolute depth and inner structure?)

Any wild guesses?

-Mike

[ngunn]

Good one thinking of my photo, I didn't even do that, but yes, there are definitely similarities in the spatial lay-out!

Yes, and thanks for the additional image. The only difference between this and my sketched geometry is that I have replaced the spherical internal shape of the Pantheon with a horizontal cylinder representing the inferred lava tube. The internal illumination pattern then depends on the azimuth difference between the illumination direction and the cylinder axis, as well as the sun's altitude.

[Guest_AlexBlackwell_*]

Are There Giant Caves on Mars?
Planetary Radio
Monday, June 18, 2007

[ustrax]

Wow! They were able to actually get the bottom of a pit out of the dark!
http://www.universetoday.com/2009/03/19/hi...ars/#more-27497

Nothing new here...done it two years ago...
http://www.unmannedspaceflight.com/index.p...ost&p=90761