One of the satellites of Mars – Phobos – is quite small and does not even gain 30 kilometers in diameter. On its surface, you can see the large Stickney crater, a trace of a powerful ancient collision, and a number of light, almost parallel furrows up to 30 kilometers long and a couple of hundred meters wide.
The nature of these bands is still a mystery. According to one version , they were left by debris that rolled away from the crater. According to another, the furrows are associated with tidal forces acting on the satellite from Mars.
Phobos rotates ten times closer to its planet than the Moon to the Earth, only 6,000 kilometers above its surface. Gradually, this distance is reduced, the satellite’s orbit is reduced by 1.8 centimeters per year.
Phobos is experiencing an increasingly powerful effect of tidal forces that arise when moving in the gravitational field of Mars.
Usually the influence of these forces is noticeable only in the vicinity of very massive bodies, such as Jupiter, or in liquids, such as tides in the Earth’s oceans.
However, small Phobos is already close enough to Mars to noticeably feel how the planet deforms it. Under the action of tidal forces, the satellite is slightly extended along a line directed towards the center of Mars.
This deformation can cause cracks to appear on the surface as grooves. Such a hypothesis was put forward quite a long time ago, but was considered unlikely due to the too loose structure of Phobos.
The authors of the new study suggested that only the surface of the satellite is loose, and denser layers are located deeper.
In such a case, deformation due to tidal forces could split them, creating deep cracks, where loose material from the surface fell, leaving stripes visible from afar. This idea was also confirmed by computer simulations.
Using a layered structure with different characteristics for calculations, in most of them, scientists obtained characteristic cracking in depth, as well as parallel grooves on the surface of the satellite model.
Contact us: firstname.lastname@example.org