The mystery of how an exhausted Martian moon got its stripes may have been solved

there Many things are mysterious around Mars’ moon Phobos. we do not know where are you fromWhat is inside it, what are the strange straight lines on its surface, and it is likely that it is in the process of being torn apart by Mars. In fact, according to a new research paper, this is the reason for Phobos’ strange tiger stripes.

We know he’s going to die someday, probably in about 50 million years – the question is how? Astronomers have discovered that the unusual parallel grooves covering the surface, thought likely to be the result of some ancient impact, are actually dust-filled grooves that are expanding wider as intense gravitational forces tear the moon and planet apart.

Both of Mars’ moons are named ominously after twin sons of Mars, the Roman god of war: Phobos, the larger of the two, to the god of fear and panic; And the DeimosThe younger brother of the god of terror and terror. However, the reason Phobos is called Mars’ “doomed” moon is because the satellite is caught in a death spiral around it. Marsslowly falling toward the Red Planet at 1.8 cm (0.7 in) each year (which is faster than Venetian sinking) until they finally collide.

Both moons of Mars are progressively conjunct the planet, which means that they always present the same face towards Mars. The tidal forces that pull objects in space are due to gravitational interactions and can have remarkable effects, such as the influence of the moon’s gravitational pull on Earth’s water in the form of tides.

However, the effects visible on the solid surface of objects in space are usually very small. This does not mean that it did not happen – the icy shell of Saturn’s moon Enceladus is covered with stress fractures caused by the tidal pull of its giant planet.

Phobos orbits Mars in just 7 hours, 39 minutes, and is so close to Mars that it makes sense that tidal forces would cause surface rifting on the young moon. This idea was even put up before. Spinning so close brings Phobos closer and closer to the Roche limit, the place where gravitational forces will attract any object orbiting it. This happens because the gravity on the side facing the planet is much greater than the gravity on the other side and it cannot stay in one piece. Eventually, Phobos will be destroyed, forming a smaller version of Saturn’s rings around Mars.

Alternative hypotheses have also been put forward. In 2018 it was proposed rock bouncing Grooves are carved on the surface of Phobos.

In the new study, the team ran hundreds of simulations using a 3D mathematical model of a Phobos-like object, investigating the expansion and compression that occur from tidal forces within a Phobos-like orbit. They found that by modeling Phobos as an “internal rubble pile covered by a cohesive layer,” many simulations created parallel cracks evenly spaced like those seen on the Martian moon.

“The opening of the fracture leads to the discharge of overhead bulk material into these deep valleys, which we show can naturally lead to the formation of gully-like structures,” they wrote.

Not all regions of Phobos matched the simulations — for example, the gullies around the equator were not explained by their predictions. However, the results indicate that some (or even most) of the streaks are caused by tidal rifting as the Moon continues on its doomed course to collide with Mars.

All of this makes an intriguing goal for the Japan Space Agency’s Mars Moon Exploration (MMX) mission of 2024 to land spacecraft on both Phobos and Deimos, returning samples in 2029. We might even be able to see the beginning of the end for Phobos.

The study has been published in Planetary Science Journal.

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