Small Dark Formations on the Red Planet's Surface Appear Like Spider in Photos Captured by ESA's Mars Express

A Mars orbiter captured a bizarre sight on the Red Planet. In one photo, there seems to be a swarm of spiders crawling on the Martian surface.

Spiders on Mars?

In the new photo recently captured on camera by the European Space Agency's (ESA) Mars Express spacecraft, these "spiders" are seen scattered across the planet's hills near a formation known as the Inca City. The formation is called Angustus Labyrinthus because of its grid-like ridge network, which is reminiscent of the remains of Incan towns. It was originally observed in 1972 by NASA's Mariner 9 spacecraft.

It is still unclear to scientists how Inca City came to be. They speculated that it might have happened as a result of lava seeping through surface fissures on the planet or sand dunes gradually transforming into stone over time.

According to a different notion, Inca City may be situated inside a crater left by a previous impact, which caused faults to build throughout the surrounding area. The walls of the Inca City formation may have then been produced by lava seeping through these faults.

The animals in the picture are not real spiders. They are tiny dark spots that emerge from gas piercing through a layer of ice composed primarily of carbon dioxide on Mars' surface.

In 2020, the arachnoid scars were even more vividly photographed by ESA's ExoMars Trace Gas probe, another Mars probe that helped unlock the mysteries of these odd structures.

It is believed that the sun is responsible for these "spiders" because it warms layers of frozen carbon dioxide on Mars' surface. These spiders were found near the planet's south pole, where temperatures can drop as low as -243 degrees Fahrenheit, solidifying CO2 in the atmosphere into ice.

The bottom layers of carbon dioxide ice melt due to heat from the sun, forming gas that rises up like a shaken soda can and eventually bursts through the top layers of freezing CO2. Dark components from the earth are carried by the gas as it bursts outward, and dispersed between 150 feet and 0.6 miles from the starburst-shaped split in the ice. These odd formations resemble spiders when viewed from orbit.

There are other strange-looking formations on the surface of Mars besides these spiders. While the US Viking 1 orbiter and lander captured images of an odd face-like formation in 1976, the Mars Curiosity rover took a picture of the rock in 2015.

Other Strange Formations on Mars

Spiders aren't the only strange formation spotted on the Martian surface. In 2015, a spoon-shaped rock was also photographed by Mars' Curiosity rover. In January 2023, they also saw another bizarre geological formation on the planet that appears like the eyes of the "bear" and a V-shaped collapsed hill for its snout.

"There's a hill with a V-shaped collapse structure (the nose), two craters (the eyes), and a circular fracture pattern (the head)," the University of Arizona said in a statement. "This feature looks a bit like a bear's face."

On April 1, 2023, Curiosity also snapped spikes protruding from a rock lying at the base of the Gale Crater. Some compared it to a fish bone or branch from a fir tree.

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