[X] My Assistant

[Guest_AlexBlackwell_*]

Two papers announcing new results of observations of Mars' south polar cap, Langevin et al. and Kieffer et al., are being published in the August 17, 2006, issue of Nature. See the Editor's Summary for a brief synopsis and links.

[Guest_AlexBlackwell_*]

See also:

Roaring Jets of Carbon Dioxide Solve Mars Mystery
By Sara Goudarzi
Staff Writer, Space.com
posted: 16 August 2006
01:00 pm ET

[ups]

Roaring Jets of Carbon Dioxide Solve Mars Mystery

Peculiar spots, fan-like markings, and spider-shaped features on Mars' southern ice cap are seasonal formations, researchers announced today.

The shapes are formed by thin layers of dark dusty material that are sprayed by roaring jets of carbon dioxide that erupt through the ice cap.

This dusty material may also be the reason that the southern ice cap doesn't reflect much light.

The mystery markings, generally 50 to 150 feet wide, appear every southern spring as the Sun rises over the red planet's ice cap. They last about three to four months.

"Originally, scientists thought the spots were patches of warm, bare ground exposed as the ice disappeared," said study co-author Philip Christensen of Arizona State University. But observations made with the Thermal Emission Imaging System (THEMIS), a multi-wavelength camera on NASA's Mars Odyssey orbiter, revealed that the spots were nearly as cold as the carbon dioxide ice, which along with water ice, make up the ice caps.

With more than 200 visible and infrared images from THEMIS, Christensen and his team studied an area of the southern ice cap from the end of winter in that region through the middle of summer.

Artist impression

full article

[Guest_AlexBlackwell_*]

NASA Findings Suggest Jets Bursting From Martian Ice Cap
NASA/Jet Propulsion Laboratory/Arizona State University
August 16, 2006

[DDAVIS]

The shapes are formed by thin layers of dark dusty material that are sprayed by roaring jets of carbon dioxide that erupt through the ice cap.


Now THERE'S a place to place a lander with a 30 frame per second video capability! (if the camera doesn't get sprayed)


Don

[mcaplinger]

The shapes are formed by thin layers of dark dusty material that are sprayed by roaring jets of carbon dioxide that erupt through the ice cap.

As usual, media coverage and summaries state a lot more certainty than many of us have. If these sprays are so large, how come we've never imaged one with MOC after years of trying?

[Guest_AlexBlackwell_*]

As usual, media coverage and summaries state a lot more certainty than many of us have. If these sprays are so large, how come we've never imaged one with MOC after years of trying?

Good point. The press hype would lead one to think the materials entrained in these jets would be just as visible as dust devils, and MOC certainly has no problem detecting the latter on a regular basis. Indeed, given the extensive imagery coverage in the solar polar regions, one would have to come up with a fairly good explanation on why MOC hasn't seen these jets.

[Bart]

Good point. The press hype would lead one to think the materials entrained in these jets would be just as visible as dust devils, and MOC certainly has no problem detecting the latter on a regular basis. Indeed, given the extensive imagery coverage in the solar polar regions, one would have to come up with a fairly good explanation on why MOC hasn't seen these jets.

Maybe they only happen at night.

[nprev]

Did anyone else notice the dendritic appearance of the purported plume ejecta fields? Those look a lot more like flow patterns than fallout areas...wonder if the CO2 sublimation might be triggering localized ice melting from compressional heating...?

[ups]

Agreed.

Nothing has been solved at this point about these strange formations.

[mcaplinger]

Maybe they only happen at night.

At these polar latitudes I don't think the sun ever sets at the season when they form. You would have to explain why they don't happen at 2 PM and 2 AM (for imaging on the other node) local time when MGS goes over.

[Guest_AlexBlackwell_*]

Maybe they only happen at night.

Or The Little Green Men have the ephemerides and orbital elements for the orbiters and know when they're overhead so they can turn off the jets.

[Bill Harris]

Levitating ice caps and dust geysers seem to be a bit of a stretch to me, too. But I can envision a gentler process where CO2 outgassing can entrain the very, very fine dust present on Mars and gently puff the dust onto the frosty surface.

--Bill

[stevo]

I'm with Bill. I think "roaring jets of CO2" may be an exaggeration, and somewhat misleading. Perhaps more in the nature of regular, gentle "burps". A mud pool instead of a geyser.

Steve

[Guest_gil nodges_*]

Actually, people have already claimed to see jets/plumes of material erupting into the atmosphere from MOC images on this forum:

http://www.unmannedspaceflight.com/index.php?showtopic=1495