'Smiley Face' Could Solve Mars' Big Mystery

The European Space Agency's Mars Exploration Rover captured an interesting image on Mars, with a circular shape resembling a smiling face.

Astronomers recently spotted a strange "smiley face" glowing from the surface of Mars as they surveyed the red planet's landscape in a new study.

Sharing a picture of the "smiley face" on its Instagram page, the European Space Agency (ESA) said that this interesting shape is made up of an ancient strip of chloride salt , originating from a meteorite crater.

An image from an infrared camera shows a chloride salt deposit on the surface of Mars shaped like a smiling face facing the spacecraft (Photo: ESA/TGO/CaSSIS).

Normally, these deposits are indistinguishable from the rest of the Martian surface. However, thanks to the infrared camera equipped with ESA's ExoMars Orbiter , the salt deposits appear as pink or purple images.

Using images from the ExoMars Orbiter, researchers have created the first catalogue of chloride salt deposits on Mars , with a total of 965 different deposits scattered across the planet. On average, each deposit ranges in size from 300 to 3,000 meters.

The ExoMars Orbiter has also been analyzing concentrations of methane and other gases in Mars' thin atmosphere since 2016.

Finding salt deposits on Mars is particularly important, the researchers say, because they could provide optimal conditions for biological activity and preservation, as well as create targets for astrobiological exploration.

Mars was once a water world with lakes, rivers, and a shallow ocean similar to Earth's. But between 2 billion and 3 billion years ago, the water on Mars dried up due to severe climate change.

The cause of this change is still being clarified. Some theories suggest that this phenomenon occurs because Mars lost its magnetic field, causing solar winds to "blow away" most of the planet's atmosphere.

This resulted in most of the liquid water freezing or evaporating into space, turning Mars into the arid planet it is today.

However, the salt deposits left behind after the last water source disappeared will decipher the planet's past and evolutionary history. They may even have great implications for the search for evidence of ancient life on Mars.