Researchers simulated the rocks from the Rocks emitted from Stickney, taking into account Phobos form and topography, as well as…
Researchers simulated the rocks from the Rocks emitted from Stickney, taking into account Phobos form and topography, as well as its gravity environment , rotation and orbit around March. (Image Source: NASA)
Strict traces crossing the surface of Marshmallow Phobos was likely made of rolling stone blocks blasted free from an old asteroid effect, a study has found. The research, published in the magazine Planetary and Space Science, used computer models to simulate the movement of debris from Stickney crater, a big gash at one end of Phobo’s oblong body.
The models show that stone blocks roll over the surface in the aftermath of the Stickney support could have created the puzzling patterns of tracks seen on Phobos today. “These traces are a hallmark of Phobos, and how they were formed have been discussed by planet scientists for 40 years,” said Ken Ramsley, a planet science researcher at Brown University in the United States. “We think this study is another step towards nullifying an explanation,” said Ramsley, who led the study.
Phobos tracks, visible over most of the moon’s surface, first glimpsed in the 1970s by NASA’s Marines and Viking missions. Over the years, there have been no shortages of explanations as to how they were formed. Some researchers have suggested that major effects on Mars have showered the nearby moon with grout cutting products. Others believe that Mars gravity slowly breaks down Phobos, and the traces are indicative of a structural failure.
In the late 1970s, the planet sciences Lionel Wilson and Jim Head presented the idea that ejecting bouncing, sliding and rolling stone blocks – from Stickney may have slipped the tracks. For a moon, the size of the diminutive Phobos – 27 miles across at its widest point – Stickney is a great crater of nine kilometers. The consequences that formed it would have blown free tons of giant rocks, making the scrolling idea totally credible, said Ramsley.
Researchers designed computer models to see if the “Rolling Stone Model” could recreate these confrontational patterns. The models simulate the stones thrown out of Stickney, taking into account Phobo’s form and topography, as well as its gravitational environment, rotation and orbit around Mars. The models showed that the stone blocks tended to align in sets of parallel roads, which are jibes with the sets of parallel tracks seen on Phobos. The models also provide a potential explanation for some of the other more confusing track patterns.
The simulations show that because of Phobo’s small size and relatively weak gravity, the Stickney stones only continue to roll, rather than stopping after a mile or so as they might on a larger body. Some stone blocks would have rolled and bordered all the way around the little moon. The circumvention can explain why some traces are not radically aligned with the crater. Boulders that begin rolling over Phobo’s east hemisphere produce traces that appear to be inaccurate from the crater when they reach the western hemisphere.
-globe rolling also explains how some tracks are superimposed on top of others. The models show that the tracks lie shortly after the support was crossed minutes to hours later by rocks that completed their global travels. In some cases, the globe-rocks rolled their entire back to where they started – Stickney Crater. That explains why Stickney himself has a track, scientists said. “We think this is a rather strong case that this rolling rock model accounts for most if not all of the tracks on Phobos,” says Ramsley.