Strange mystery of Phobos’ tiger stripes may finally be solved

(ORDO NEWS) — The Martian moon Phobos won’t last long for this universe.

According to astronomers’ calculations, the potato-shaped moon is slowly but inexorably approaching its host planet.

Eventually, in about 100 million years, the gravitational interaction between the two bodies will tear Phobos apart, turning the red planet into a temporary dust ring.

These gravitational interactions may already be an observed effect, according to a new study. At least some of the mysterious parallel shallow grooves that cover the entire surface of the Moon may be the result of destruction as its orbit slowly collapses and tidal forces pull harder on its bones.

“Our analysis supports the layered, heterogeneous structure of Phobos, with possible underlying failure faults, as a precursor to the possible death of a deorbiting satellite,” write a team of astronomers led by Bing Cheng of Tsinghua University in China and the University of Arizona.

The tidal forces that attract the bodies in the system are the result of their gravitational interaction, stretching their structures along the axis passing between them.

Usually, any significant effect this distortion may have on a hard surface is rather small. Where tidal forces can be easily observed in the movement of our planet’s liquid oceans, the visible effects on land masses are less obvious.

This does not mean that tidal forces between other solids cannot be more obvious. effects. Tension caused by tidal forces can in some cases cause stress cracking.

We saw this on Saturn’s moon Enceladus, whose icy shell has deep parallel cracks at the south pole caused by tidal loads.

With an orbital period of just 7 hours and 39 minutes, Phobos is quite close to Mars, approaching at a rate of about 1.8 centimeters per year.

In such proximity, it is possible that tidal forces could cause cracks in the surface of its body 27 kilometers (16.8 miles) wide.

The idea that the Phobos stripes are the result of such an interaction has also been previously considered and considered plausible.

However, it is not clear whether the current configuration and interaction of Phobos and Mars could cause the observed bands, and other explanations are also in development. For example, a 2018 study found that stripes could be the result of rolling boulders.

So Cheng and colleagues ran 3D mathematical simulations, explicitly studying the tidal expansion and contraction of a multi-layered Phobos-like body with a loose, rubble-like surface sitting above a bonding layer underneath.

The researchers ran hundreds of simulations using their model. In a significant number of these simulations, tidal forces caused the cohesive layer to split and collapse in parallel grooves, causing the top loose regolith to flow into the cracks below. The result is a striated, striated surface, very similar to the regions seen on Phobos.

Not all regions of Phobos matched the model, the team found. In particular, the grooves around the equator of the moon did not match the predictions.

But the results show that at least some of the bands could be caused by cracks as the moon spirals towards death due to tidal evisceration. This would mean that we are witnessing the beginning of the end of Phobos.

Thus, these results may have implications for studying other moons that experience significant orbital decay, such as Neptune’s moon Triton.

Withering debris could also expose pristine material on Phobos, which could make the furrows a very interesting area of ​​study for the Japan Space Agency’s upcoming lunar mission.

This mission is expected to provide strong evidence for the origin of these mysterious bands, but tidal disruption certainly seems like an intriguing possibility.

“By modeling Phobos as a pile of rubble inside, covered with a bonding layer, we find that tidal stress can create parallel cracks. at regular intervals,” the researchers write in their paper.

“Our analysis indicates that some of the grooves that line the surface of Phobos are likely early signs of the possible death of a de-orbiting satellite.”

Anybody mashed potatoes?

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