Spiderlike formations formed by the action of sublimating carbon-dioxide frost on the surface of Mars


We're not talking about "The Rise and Fall of Ziggy Stardust and the Spiders From Mars," that 1972 concept album by David Bowie.

These spiders are actually geologic features from the South Pole region of Mars, captured by the University of Arizona's HiRISE camera during the six-year mission of the Mars Reconnaissance Orbiter.

A series of papers published this week in the journal Icarus are a  photographic tour de force of the big revelation of the HiRISE mission — that Mars, contrary to previous understanding is not geologically static.

Mars undergoes widespread seasonal changes caused by the freezing and thawing of carbon dioxide and some water frost at its polls.

The lead author of the first paper is Candice Hansen, deputy investigator on the HiRISE camera, who is now affiliated with the Planetary Science Institute. Co-auhors of all three new papers include principal investigator Alfred McEwen and co-investigator Shane Byrne, leaders of the long-running project at the UA's Lunar and Planetary Lab.

NASA/JPL has produced a cool video of the changes.