Scientists are puzzled by mysterious “smiles” inside a crater on Mars

Mars holds many great mysteries. Did microbial life once exist on it? Are there hidden liquid lakes under the polar cap? But the Red Planet also has mysteries that can be seen in pictures from space, such as the mysterious formations inside the craters in the northern part of the planet. NASA’s Mars Reconnaissance Orbiter spotted unusual shapes.

Відкладення на дні кратеру у формі посмішки
Smile-shaped deposits at the bottom of a crater. Image credit: NASA/JPL-Caltech/UArizona

According to MRO team member Paul Geissler, the images intrigued and puzzled scientists. A team of researchers suggests that the smile-like formations in Martian craters may be traces left by ice that has slowly melted over millions of years.

Ice terraces

The deposits were found only inside craters on the northern plains of Arabia Terra, a large and highly eroded cratered region north of the equator. It is interesting that the mysterious deposits on the bottom appear only on the southern sides of craters whose diameter exceeds 600 m. Smaller craters do not have them.

Повний погляд на один із кратерів із дивними відкладеннями
A full view of one of the craters with strange deposits seen by MRO’s HiRise camera. Photo: NASA

Geissler and his team suspect that these mysterious patterns are caused by ice-rich material that has melted and turned into gas over time, with each terrace representing a different stage of the process. Scientists believe that Mars was once covered with water, which later turned into ice that seeped onto the arid surface of the planet over billions of years. This is consistent with the theory that Mars once had large reserves of water that later turned into ice and then evaporated.

The disappearance of Martian ice led to formation if a variety of fascinating landscapes, which look really mysterious. Other craters, such as the “Happy Face” found in the icy region of the south pole of Mars, are believed to have formed by sublimation of ice over many years.

Earlier, we reported on MRO device capturing a stunning phenomenon on Mars.

According to the materials of Uahirise