Astronomers have discovered a smiley-face-shaped structure on Mars – and it could be more than just a planetary quirk.

Researchers believe that it may be harboring signs of past life on the Red Planet.

This grinning formation is made up of a pair of crater eyes and rings of ancient salt deposits.

These deposits are the remains of an ancient body of water that dried up long ago, leaving behind this emoji-like remnant that is only visible when viewed with an infrared camera.

The European Space Agency (ESA) – which snapped the pH๏τo – said: ‘These deposits, remnants of ancient water bodies, could indicate habitable zones from billions of years ago.’

Scientists aren’t sure exactly how big the smiley-face is, but it’s one of 965 other salt deposits that have recently been catalogued on Mars’ surface, which range in size from 1,000 to 10,000 feet wide.

Salt deposits are accumulations of salt – or chloride – found on a planetary surface. On Mars, they are the remnants of ancient bodies of water that dried up when the planet underwent a major climatic shift eons ago.

Before the last puddles of Mars’ liquid water disappeared, they may have been a ‘haven’ for microbial life, according to the ESA.

These puddles would have been extremely salty, and thus the remains of microbes that once lived in them may still be preserved to this day – hiding in deposits like this smiley face.

The ESA captured this image using their ExoMars Trace Gas Orbiter, which has been measuring the levels of methane and other gases in Mars’ atmosphere since 2016 to help scientists understand possible biological or geological activity on the Red Planet.

Normally, salt deposits on Mars’ surface are invisible.

But the orbiter’s infrared cameras allow us to see them glowing pink or violet – revealing the smiley-face.

The pH๏τo was published as part of a study in the journal Scientific Data.