NASA has found a series of interesting looking erosion features on Mars that may be infant versions of larger features called “spiders”.
What are these exactly? Well, carbon dioxide trapped by ice under the surface can be released in the Martian spring season when the ice thaws. The gas builds up pressure and eventually erupts out, picking up sand and dust and eroding the ground.
The sand and dust falls back to the ground, appearing as dark streaks (or channels) on the surface. The channels range in size from tens to hundreds of meters across, and they often converge at a central pit, making them look a bit like a spider from above.
The whole process takes about 1,000 Martian years (1,900 Earth years), so it’s not exactly quick. But now, for the first time, scientists have seen infant spiders forming and growing over a number of years. Images of the process were obtained by the Mars Reconnaissance Orbiter, and the findings were published in the journal Icarus.
An animation of the images, taken on August 5, 2009; August 9, 2011; and May 25, 2015. NASA/JPL-Caltech/University of Arizona
"Much of Mars looks like Utah if you stripped away all vegetation, but 'spiders' are a uniquely Martian landform," said co-author Candice Hansen of the Planetary Science Institute in Tucson, Arizona, in a statement.
One interesting quirk of these spiders is that they appear only in the south polar region of Mars, and not in the north. The reason may be that there is less sand in the south, so the channels that form are less likely to be filled in.
"There are dunes where we see these dendritic [branching] troughs in the south, but in this area, there is less sand than around the north pole," said lead author Ganna Portyankina of the University of Colorado, Boulder, in the statement.
The research sheds further light on how carbon dioxide plays a key role in shaping Mars. And the spiders look rather nice, too. Who said Mars was a barren, dead world?