APOD: Unusual Plumes Above Mars (2015 Feb 24)

[geckzilla]

http://exosky.net/exosky/?p=1700

Thanks for posting this, Wayne (and the rest of your post). I have to say that while these are more visually appealing overall, the cloud of [something] is easier to see in the image chosen for today's APOD, and that's what's important.

[bactame]

A snowstorm of carbon dioxide flakes.

[Donnageddon]

This guy.

[Evenstar]

I thought one of the orbiters around Mars was in a polar orbit to cover the entire planet? I still don't like fuzzy pictures several years old.

Go outside and angrily shake your fist at the sky, then. Earth's atmosphere likes to vacillate and blur ground-based imagery. These are actually very good amateur images of Mars despite being a few years old. An image taken tomorrow will look very much the same.

Shaking fist angrily...at Earth and at Mars mapping

[DavidLeodis]

It's quite an intriguing feature.

I wonder if anyone knows of a link to the individual frames used to compile the animation as there seems to be 5 frames that are then reversed but I'm unsure of that.

[kellogg]

Maybe it's the alien miners from Alnilam in pursuit of Lt. Cmdr Christopher Draper and Friday....

Scott Kellogg

(Or maybe, I've just watched "Robinson Crusoe On Mars" too many times...)

[BMAONE23]

Could also be Zodanga marching toward Helium

[Symbology]

I would guess that it is a result of the sun thawing a large deposit of water (or other) ice beneath the surface in a vast pocket. Every now and then the gas given off by this cause the ground over the pocket to swell up and eventually collapse, giving off a rush of methane or hydrogen that blows dust particles into the atmosphere.

Further to the above, the following Pingos and craters in Siberia can be over 250 ft across, and it would therefore seem possible that their collapse might trigger an upward blast of gas or other, causing the dust plumes :

"...A pingo, also called a hydrolaccolith, is a mound of earth-covered ice found in the Arctic and subarctic that can reach up to 70 metres (230 ft) in height and up to 600 m (2,000 ft) in diameter. The term originated as the Inuvialuktun word for a small hill. The plural form is "pingos"...."

"...When a massive and mysterious hole was discovered in Siberia last July (see pictures), social media users pointed to everything from a meteorite to a stray missile to aliens to the Bermuda Triangle as possible causes. But the most plausible explanation seemed to be the explosive release of melting methane hydrate—an ice-like material frozen in the Arctic ground—thanks to global warming.

Now, scientists are arguing that the methane theory is unlikely, based on new satellite surveys released by Russian researchers that found dozens of new craters in Siberia.

"The jury is still out" on the cause of Siberia's craters, says Carolyn Ruppel, chief of the U.S. Geological Survey's Gas Hydrates Project. But she and other scientists say the new satellite mapping suggests another explanation that has to do with the rapid melting of ice cores called pingos.

A pingo is a plug of ice that forms near the surface over time and has a small mound or hill on top.

When an ice plug melts rapidly—as many have been, thanks to unseasonably warm temperatures in Siberia over the past year—it can cause part of the ground to collapse, forming a crater. But that process alone isn't enough to explain the ejected rocks that have been found around the rim of the craters, which suggest some sort of explosion.

Instead, Ruppel theorizes that the craters were formed by a sudden release of natural gas that had been stored in the permafrost but was kept under pressure by the weight of the pingo.

This theory is bolstered by the Russian satellite data, which show pingos—they appear as small mounds—in the exact positions where the craters later formed...."

[Roberto Capacci]

Dust storm,I suppose.