Rolling stones left strange grooves on Mars moon: Study
thanks: Express Tech
Researchers simulated the paths of the boulders ejected from Stickney, taking into account Phobos’ shape and topography, as well as its gravitational environment, rotation and orbit around Mars. (Image Source: NASA)
Phobos’ grooves, which are visible across most of the moon’s surface, were first glimpsed in the 1970s by NASA’s Mariner and Viking missions.
Strange grooves that crisscross the surface of the Martian moon Phobos were likely made by rolling boulders blasted free from an ancient asteroid impact, a study has found. The research, published in the journal Planetary and Space Science, used computer models to simulate the movement of debris from Stickney crater, a huge gash on one end of Phobos’ oblong body.
The models show that boulders rolling across the surface in the aftermath of the Stickney impact could have created the puzzling patterns of grooves seen on Phobos today. “These grooves are a distinctive feature of Phobos, and how they formed has been debated by planetary scientists for 40 years,” said Ken Ramsley, a planetary science researcher at Brown University in the US. “We think this study is another step toward zeroing in on an explanation,” said Ramsley, who led the study.
Phobos’ grooves, which are visible across most of the moon’s surface, were first glimpsed in the 1970s by NASA’s Mariner and Viking missions. Over the years, there has been no shortage of explanations put forward for how they formed. Some scientists have posited that large impacts on Mars have showered the nearby moon with groove-carving debris. Others think that Mars’ gravity is slowly tearing Phobos apart, and the grooves are signs of structural failure.
In the late 1970s, planetary scientists Lionel Wilson and Jim Head proposed the idea that ejecta – bouncing, sliding and rolling boulders – from Stickney may have carved the grooves. For a moon the size of the diminutive Phobos – 27 kilometers across at its widest point – Stickney is a huge crater at nine kilometres across. The impact that formed it would have blown free tonnes of giant rocks, making the rolling boulder idea entirely plausible, Ramsley said.