Mars never ceases to amaze us. The Martian landscape often exhibits otherworldly features that we never imagined could exist.
Over the last decade, we’ve been able to explore some of the uncanny scenery on the Red Planet thanks to NASA’s Mars Reconnaissance Orbiter (MRO), which has been circling our planetary neighbor since 2006.
The photos it beams back from Mars’ orbit have offered a wealth of data on what goes on under the Martian atmosphere, and they just keep getting more and more bewildering.
After sharing an exciting series of eye-catching snapshots of the Martian landscape in June — including the famous “blue dune” at the bottom of the Lyot Crater, the colorful bedrock of Hale Crater, and the wild image of a meteoroid-triggered avalanche on Mars — NASA continues to keep us on the edge of our seats in July with yet another dramatic photo release, courtesy of the MRO.
Showcased on the agency’s website under the “Image of the Day” category (where all the best snapshots are displayed), the new MRO photo reveals strange “spiders” creeping across the Martian landscape.
“As the sun warms the terrain in the South Pole, spiders begin to emerge. Wait, what?” the orbiter’s famous high-resolution camera, HiRISE, tweeted on Tuesday, a few days ahead of the NASA photo release.
NEW: Jamming with the “Spiders” from Mars— HiRISE (NASA) (@HiRISE) July 10, 2018
As the sun warms the terrain in the South Pole, spiders begin to emerge. Wait, what?
NASA/JPL/University of Arizonahttps://t.co/1ZN8LcHLiU#Mars #science pic.twitter.com/PmFZtVHNhu
Captioned “Jamming with the ‘Spiders’ from Mars” — a witty reference to David Bowie’s backing band in the early 1970s — the image unveils fantastic spider-looking features that can only be seen on the Mars, specifically at the planet’s South Pole.
Taken by HiRISE on May 13, exactly two months before it was released on the NASA website, the photo captures “spider-like radiating mounds” stretching on the Martian terrain.
These peculiar features are “radially organized channels on Mars that look spider-like,” NASA explains, and only come out during the Martian winter, when the carbon dioxide ice beneath the planet’s surface gets warm and turns into gas.
The same thing happens to dry ice on Earth, which also sublimates as it warms, changing from solid to gas. In the case of the Martian carbon dioxide ice, the gas it releases remains trapped under the planet’s surface, building up pressure until it eventually bursts through the ice “as a jet that erupts dust,” notes the space agency.
“The loss of the sublimated carbon dioxide leaves behind these spider-like features etched into the surface.”
This seasonal process that ends up setting “spiders” loose on the Martian surface is all the more captivating considering we’ve never seen it on our own planet.
Because the mounds it produces share a resemblance to Earth’s arachnids, this type of winter landscape on Mars has been dubbed “araneiform terrain,” said NASA.
“The south polar terrain on Mars contains landforms unlike any that we see on Earth, so much that a new vocabulary is required to describe them,” the space agency pointed out.