Mars Express sends back stunning images of 'mysterious terrain' on Mars

The European Space Agency's (ESA) Mars Express rover has sent back new images of Mars' south polar region, capturing features known as “mysterious terrain” emerging from beneath the Martian frost.

The terrain at Mars' poles is covered in a mixture consisting mainly of carbon dioxide ice, with some water ice mixed in there. In the fall, when the planet cools, these gases condense around the polar caps, creating more ice. During the Martian winter, this causes the ice caps to grow significantly.

“By late winter they may reach a latitude of 55 degrees – roughly equivalent to the southern borders of Scotland and Denmark if translated to the Earth's northern hemisphere.” ESA explained In a blog post.

In the spring, the carbon dioxide ice does not melt, but rather sublimates, turning directly into a gas without any intermediate liquid phase, and so the cycle continues.

When we first started imaging Mars, we saw some unusual features. One of these terrains was simply called “Mysterious Terrain” because it was It defied explanation at the time. These features are areas of noticeably darker terrain, which really stand out compared to the rest of the Martian ice caps.

While these features were initially puzzling, scientists came up with a number of hypotheses, and now we have a good idea of ​​how they form.

“When sunlight penetrates the transparent ice layer of carbon dioxide in early spring, it warms the underlying surface,” ESA explains. “The ice at the bottom of the layer begins to sublimate, creating pockets of trapped gas. Pressure builds and the overlying ice suddenly cracks. Jets of gas explode across the surface, carrying dark dust from below. The dust returns to the surface in a pattern that forms depending on the direction of the prevailing winds.”

This is a similar mechanism to how scientists believe the famous “spiders on Mars” features likely formed, and indeed these “spiders” are only found inside the planet. Same area For the Red Planet (at least, as far as we know from images).

Once the dust settles, the dark spots absorb more light and begin to heat up, slowly sinking their way through the ice and creating a hole.

“Either fresh ice underneath will be exposed, or new frost may condense on top of the sinking dark grains, creating a bright fan in the place of the initially dark fan,” the ESA adds.

This mechanism is similar to that proposed for spiders on Mars, for which experimental evidence has recently been provided.

“In this model, sunlight penetrates the transparent ice sheets in the spring and high-wavelength thermal radiation is trapped, heating the regolith beneath the ice and causing the impermeable ice sheet to sublimate from its base,” explained a team studying this phenomenon in Their studies.

“Through this process, the spiders are supposed to be eroded by the high-velocity gas that cleans the regolith beneath the slab, while various fans and spots are scattered on the surface of the ice, deposited by a plume of dust and gas.”