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Mars has two of the ugliest moons in the solar system, namely Phobos, a strange and hallmark shaped moon with a distinctive set of stripes. Astronomers have debated the origin of these furrows for decades, but a new computer simulation suggests that Phobos streaks were created by rolling and bouncing dislodged rocks with a cataclysmic asteroid strike.
The peculiarity of this moon, apart from its grooves, is a gigantic impact crater known as the Stickley Crater. Phobos only measures 27 kilometers at its widest point, but this crater extends for nine kilometers.
A new study published this week in the scientific journal Planetary and Space Science provides evidence linking the impact event that created the Stickley Crater and the visible furrows of Phobos. A new computer model developed by scientists at Brown University suggests the ancient impact of the rocks, which bounced, rolled and slid, forming the bands we see today.
The theory is certainly intuitive, but these grooves are not alike.
For example, not all grooves are divergent from Stickney's crater, as would be expected if they were created by the crater event. In addition, some grooves overlap, suggesting that they were formed at different times. Some bands pass through the Stickney crater itself, which seems to imply that the crater was already in place when the grooves were formed. Finally, there is Dead Spot of Phobos, an area of the moon in which no furrow exists; if the furrows were caused by bouncing rocks, it seems odd that they all managed to avoid this particular area.
The bouncing block theory was first proposed in 1989, but because of these anomalous observations, other theories have managed to stay in place. Some argued that the massive asteroid strikes on Mars covered Phobos with debris carving grooves, while others assumed that Mars' gravity was tearing Phobos apart, the grooves showing signs of structural failure.
Brown University planetary scientists Kenneth Ramsley and James Head decided to test the theory of bouncing blocks, which they did by launching a computer simulation of the ancient asteroid strike. Their model took into account the ridiculous gravity of Phobos, as well as its twisted topography, rotation, and orbital relationship with Mars. Ramsley and Head had no preconceived idea of what the simulation could show.
"The model is really just an experience we run on a laptop," Ramsley said in a statement. "We put all the basic ingredients, then we pressed the button and we saw what was happening."
Looking at the simulation unfolding, the researchers saw how the debris moved from the site of the impact to the outside, the rocks aligned in sets of parallel paths, observation consistent with the sets of grooves parallels observed on Phobos.
Due to the low gravity of the moon, however, some rocks kept rolling and bouncing. In fact, some rocks have rolled so long that they have traveled Phobos …and then always kept going. The breathtaking observation of circumnavigator blocks could explain why some grooves are not aligned radially with the crater and why some are superimposed. The simulations also showed that some rocks were returning to their original point, which could explain why grooves can be seen inside the Stickney Crater.
The models also provided an explanation of the breakeven point. This low-lying region is surrounded by higher elevation areas. Looking at the simulation, the researchers saw the rocks clashing at the lip and literally jumping over the Dead Spot, taking off in the air for a long time and resulting in a landing of the plane. other side.
"It's like a ski jump," Ramsley said. "The rocks continue, but suddenly there is no more land under them. They end up doing this suborbital flight over this area. "
Ramsley and Head say their new model "is a pretty solid argument" to explain the origin of most, if not all, Phobos furrows. Of course, this is a computer model, so it would be good to corroborate these results with other forms of data, such as geological analysis. It would also be good to see other researchers duplicate these results with their own computer simulations, as some of the variables used in the simulations may have been biased or somehow inaccurate.
Be that as it may, the theory of bouncing blocks is becoming the most plausible explanation for the distinctive furrows of Phobos. It's a cool theory, but Phobos, along with his mate Deimos, are still ugly.
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