Sublime Fractures

  • Released Tuesday, December 2, 2014
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Looking for weird and wonderful landforms that are truly out of this world? Mars has you covered. The planet's south pole is littered with spidery cracks and other peculiar patterns produced by seasonal deposits of frozen carbon dioxide, or dry ice. As spring thaws the south pole each Martian year, the ground warms up faster than the ice, heating it from below. The ice turns directly into a gas through a process called sublimation and starts to accumulate. Rising pressure forces the gas to the surface by carving channels into the ice and underlying terrain. The channels linger long after the ice has melted, growing bigger over time. Explore the images for views of these formations taken by the HiRISE camera aboard NASA’s Mars Reconnaissance Orbiter spacecraft.

Scientists observe most “spider” formations like these near the south pole of Mars, under dry ice up to a meter thick.

Scientists observe most “spider” formations like these near the south pole of Mars, under dry ice up to a meter thick.

The formations range from tens to hundreds of meters in diameter and grow bigger every winter.

The formations range from tens to hundreds of meters in diameter and grow bigger every winter.

When rock particles get caught in the gas, they rain down on the icy surface in “fan” formations shaped by the wind.

When rock particles get caught in the gas, they rain down on the icy surface in “fan” formations shaped by the wind.

Sometimes, spiders and fans appear together, forming figures like impressionistic trees.

Sometimes, spiders and fans appear together, forming figures like impressionistic trees.



Credits

Please give credit for this item to:
NASA's Goddard Space Flight Center
Images courtesy of NASA/JPL/University of Arizona

Release date

This page was originally published on Tuesday, December 2, 2014.
This page was last updated on Wednesday, May 3, 2023 at 1:50 PM EDT.