The moons of Mars could be fragments of a large asteroid

A new study published in Space suggests that the mysterious moons Phobos and Deimos of Mars could have originated from debris left over when a big asteroid passed dangerously near the Red Planet. According to this new theory, Phobos and Deimos were formed from the remains of a bigger asteroid that had traveled too near to Mars and passed its Roche limit, which is the point at which the asteroid was torn apart by the gravitational tidal forces coming from the planet.

It is difficult to explain the moons of Mars. Both appear to be captured asteroids because they are tiny, with Phobos measuring 16 miles (26 km) across at its widest point and Deimos about 10 miles (16 km). They are also lumpy. Saturn’s moon Phoebe and Neptune’s moon Triton are two excellent examples of objects caught in orbit that often have extended, tilted, and occasionally retrograde orbits around their new home planet. But the orbits of Phobos and Deimos are neatly spherical and line up with the equatorial plane of Mars, which suggests that they originated in orbit around the planet.

ALSO READ: The United Kingdom approved the emergency use of a bee-harming neonicotinoid pesticide

Another theory is that Phobos and Deimos developed similarly to Earth’s moon, with debris from an impact on Mars’ surface sending it into orbit and later combining to create the two moons. However, models that simulate an impact on the surface struggle to explain Phobos and Deimos’ stark differences in elevation above the surface of Mars, which are around 6,000 km (3,700 miles) and 23,000 km (14,577 miles), respectively.

Since Phobos and Deimos have been left without a third choice, this new model created by Kegerreis and his colleagues may have provided it. In addition to explaining how Deimos may have developed so distant from Mars, this new model also explains why Phobos and Deimos are found in round, equatorial orbits around the planet. Kegerreis and Lissauer admit that their concept is still only a theory at this time. That will soon be tested, though.

Read the full article here.