NASA has shared a landscape view of a surface on Planet Mars that features what appears like crawling spiders.
Image of the Day
The image, which the U.S space agency posted as part of its Image of the Day series on Friday, was taken at the South Pole of the Red Planet on May 13.
The image shows a carbon ice cap that enveloped the region during the winter as the sun returns in the spring. It shows what appears like silhouettes of spiders emerging from the Martian surface.
These arachnid-like features, however, are not actual spiders. These features are what scientists call "araneiform terrain." The mounds form when carbon dioxide ice beneath the surface heats up and is released.
NASA said that the active seasonal process involved does not occur on Earth, but like dry ice on our planet, the carbon dioxide ice on Mars sublimates when it warms, causing it to change from solid to gas and become trapped below the surface.
How Araneiform Terrains Form On The Surface Of Planet Mars
The trapped carbon dioxide gas eventually builds up in pressure overtime and later becomes strong enough to break through the ice as a dust-spewing jet. The gas is then released into the atmosphere, but the darker dust may get deposited around the vent or winds may transport it to produce streaks. The loss of the sublimated carbon dioxide results in the spider-like features in the surface.
"There are radially organized channels on Mars that look spider-like, but we don't want to confuse anyone by talking about 'spiders' when we really mean 'channels,' not 'bugs,'" NASA said.
"Gas flows through these channels until it encounters a vent, where is escapes out to the atmosphere, carrying dust along with it. The dark dust is blown around by the prevailing wind."
Mars Reconnaissance Orbiter
The image was taken by the Mars Reconnaissance Orbiter (MRO). The $720 million spacecraft launched more than a decade ago in 2005 was designed to conduct reconnaissance and exploration of the Red Planet from orbit.
The HiRISE camera that the spacecraft carried onboard has captured stunning images of the Martian surface, which include the Matara Crater that feature gullies running through the sand dunes on the arid world and classic barchan dunes on Mars' Lyot Crater region that appear like blue dunes in an enhanced image NASA shared last month.