Nasa scientists baffled after discovery of mysterious 'Skull Hill' rock formation on Mars

Scientists at Nasa have discovered an out-of-place rock formation that has left researchers baffled about its origins. Dubbed “Skull Hill,” the puzzling feature was picked up by the Perseverance rover as it descended onto Mars. It was spotted in an image on April 11 and is believed to be 45 kilometres wide.

Researchers also believe that the mysterious basin once contained a lake. The finding contrasts its surroundings so dramatically that it has led scientists to believe it may have originated elsewhere. The rest of the surface of the Martian landscape is light-coloured and extremely dusty. However, Skull Hill sticks out like a sore thumb with its intriguingly large and dark appearance.

The formation of the rock is very angular and covered in small pits. According to Margaret Deahn, a PhD student at Purdue University working with Nasa, it might have been "dropped there from somewhere else".

At the same time, the space rover saw numerous other out-of-place rocks in the area, which may have come from somewhere else, too.

Formations which differentiate from their origins are named “floats” by scientists, which suggest they have travelled away from their initial location.

Nasa has formed several theories about the origin of Skull Hill. One is that it was moved by erosion, an ancient impact or another substantial natural phenomenon.

Scientists also initially believed it could possibly be a meteorite. However, this theory was later ruled out after using Perseverance's laser-powered SuperCam to analyse similar rock.

It was noted that Skull Hill did not contain high enough levels of iron and nickel to classify it as a meteorite.

A separate theory suggests that the rock formation could be an igneous rock which was formed when lava or magma cooled down millions, or possibly billions, of years ago.

Ms Dean explained that the rover on Mars has “instruments that can measure the chemical composition of rocks”, which allows for certain theories to be ruled out.

The Perseverance rover will likely continue to conduct more tests to determine the rock's origins.