Dry ice 'smoke' carves up dramatic sand dunes on Mars, Reconnaissance Orbiter shows

The seasonal thawing of carbon dioxide ice near Mars' north pole carves grooves in the red planet's sand dunes, new research has found.

Researchers using NASA's Mars Reconnaissance Orbiter see seasonal changes on far-northern Martian sand dunes caused by warming of a winter blanket of frozen carbon dioxide, NASA said in a statement.

Earth has no naturally frozen carbon dioxide, though pieces of manufactured carbon-dioxide ice, called "dry ice," sublime directly from solid to gas on Earth, just as the vast blankets of dry ice do on Mars.

A driving factor in the springtime changes where seasonal coverings of dry ice form on Mars is that thawing occurs at the underside of the ice sheet, where it is in contact with dark ground being warmed by early-spring sunshine through translucent ice. The trapped gas builds up pressure and breaks out in various ways.

Transient grooves form on dunes when gas trapped under the ice blanket finds an escape point and whooshes out, carrying out sand with it.

The expelled sand forms dark fans or streaks on top of the ice layer at first, but this evidence disappears with the seasonal ice, and summer winds erase most of the grooves in the dunes before the next winter.

The grooves are smaller features than the gullies that earlier research linked to carbon-dioxide sublimation on steeper dune slopes.

"It's an amazingly dynamic process," said Candice Hansen of the Planetary Science Institute.

"We had this old paradigm that all the action on Mars was billions of years ago. Thanks to the ability to monitor changes with the Mars Reconnaissance Orbiter, one of the new paradigms is that Mars has many active processes today," said Hansen, lead author of the first of the three new reports.

With three Martian years (six Earth years) of data in hand, the researchers report on the sequence and variety of seasonal changes.

... contd.

Please read our terms of use before posting comments
TERMS OF USE: The views, opinions and comments posted are your, and are not endorsed by this website. You shall be solely responsible for the comment posted here. The website reserves the right to delete, reject, or otherwise remove any views, opinions and comments posted or part thereof. You shall ensure that the comment is not inflammatory, abusive, derogatory, defamatory &/or obscene, or contain pornographic matter and/or does not constitute hate mail, or violate privacy of any person (s) or breach confidentiality or otherwise is illegal, immoral or contrary to public policy. Nor should it contain anything infringing copyright &/or intellectual property rights of any person(s).
comments powered by Disqus