From the surface of Mars, a salt deposit in the shape of a smiley face was spotted as astronomers conducted a survey of the landscape with a spacecraft.
The smiley face can only be seen under certain conditions. It is the remnant of an ancient lake that dried up billions of years ago and could hold signs of former life on the Red Planet.
On September 7, the European Space Agency (ESA) shared an image of the smiling face via Instagram.
The shape consists of a ring of chloride salt deposits with a pair of crater eyes that were made by meteor strikes.
The image was captured by the ESA’s ExoMars Trace Gas Orbiter. Since 2016, the spacecraft has been analyzing the levels of methane and other gases in Mars’ atmosphere.
Such deposits usually would be indistinguishable from the rest of the planet’s surface. But when infrared cameras are used, the salts appear violet or pink.
The photo was taken as part of a new study in which researchers created the first robust catalog of chloride salt deposits on Mars.
Overall, the research team identified 965 different deposits that ranged in size from 1,000 to 10,000 feet wide. Currently, it is unclear exactly how large the smiley face is.
The deposits are important because they can provide the ideal conditions for biological activity and preservation, so scientists are always interested in exploring them.
Andrii IURLOV – stock.adobe.com – illustrative purposes only
Mars used to be covered with rivers, lakes, and a shallow ocean that was similar to the ones on Earth.
However, between two billion and three billion years ago, severe climate change caused the waters to dry up.
The climate change was likely driven by the loss of Mars’ magnetic field. As a result, the solar wind gradually wore away at much of the planet’s atmosphere and led most liquid water to freeze or evaporate into space. As the last water vanished from Mars, the salty deposits were left behind.
The researchers think that as the water started to disappear on Mars, the remaining liquid became extremely salty.
Because of this, the water was able to stay in liquid form even though temperatures were as low as -40 degrees Fahrenheit, according to the ESA.
The last salty puddles could have kept surviving microbes alive. Their remains may have accumulated in the deposits as the water dried up completely.
The salt would act as a preservative, possibly safeguarding the evidence of these extinct lifeforms for billions of years.
Recent discoveries on Mars have also revealed that the planet may contain much more water than previously thought.
For example, in June, astronomers found at least 150,000 tons of water frost on some of the tallest volcanoes on Mars.
And in August, scientists discovered that a vast hidden ocean might be located beneath the planet’s surface.
The new study was published in the journal Scientific Data.
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