Spring dawns at the Mars' South Pole and spiders emerge from the landscape, as shown in a curious photo taken on May 13.
Astronauts may not have found life on Mars just yet, but the natural landscape is alive and dynamic nonetheless.
Taken by the Mars Reconnaissance Orbiter, this photograph of so-called spiders lets the public peek into the mysterious workings of Mars' environment. As the seasons change in the Red Planet, "bugs" come crawling out of the ground.
Spiders Pop Out From The Martian Landscape
NASA explains that these creepy crawlies aren't actually spiders, but what's called "araneiform terrain." These mounds are produced when the carbon dioxide ice underneath the surface of Mars heats up and releases during spring.
This icy carbon dioxide goes from solid to gas as it gets exposed to the heat, the same way dry ice behaves on Earth. The resulting gas is trapped beneath the ground where it builds more and more pressure until it finally bursts through the ice as dust.
The gas is released into the atmosphere, but dark dust may also be left deposited around the vent. The wind may also play a role in creating streaks of dust.
On the ground, the loss of the carbon dioxide gas leaves a spider-like shadows.
It's an interesting phenomenon not just because it leaves marks on the Red Planet's ground that can be spotted and photographed, but also because araneiform terrain does not occur on Earth. The two neighboring planets may share plenty of features and natural events — such as the dunes constantly seen on Mars — but there are also major processes unique to each.
More On Mars' Surface: Water
Much about Mars is still a puzzle, but scientists are piecing together their knowledge on the planet slowly, but surely. One of the areas of study in Mars is the planet's water.
Earth's neighboring planet shows evidence of having once had water, demonstrated by what appears to be scars of running water on the surface, according to Space.com. Scientists have long wondered about the source of this water, whether it stemmed from rainwater or from underground ice melting.
Using geometry and comparing the Martian landscape to Earth's, a trio of scientists determined that the Red Planet's landscape resemble those that are arid such as Arizona's deserts. In the paper published in the journal Science Advances, the team reveals that there must have been sporadic heavy rainfall for a prolonged period to carve the Martian landscape into the complex network of valleys it became.