Mars’ two moons were probably once a single object, a new study reveals

Researchers have long been confused about the origin of the two Martian moons, confused by their recognizable shapes that are inconsistent with other celestial bodies. New research, however, offers insight into the potentially violent origins of some of the smallest planetary satellites in the solar system.

The two Martian moons – Phobos and Deimos – could be fragments of a larger satellite that once orbited the Red Planet, split in two by a massive collision.

According to a study by astronomers from ETH Zurich published in the journal Nature Astronomy on Tuesday, Phobos and Deimos probably originated from a larger single celestial body.

The object – thought to be a disk of rock and dust – could have been hit by another body, such as an asteroid, some 2.7 billion years ago, causing a powerful explosion. The two remnants of the explosion were then trapped in the orbit of Mars – becoming Phobos and Deimos.

Seismic data from NASA’s InSight mission was transmitted through a computer simulation based on two-month property approximations to observe the historical orbits of both Martian satellites.

“The idea was to return the orbits and their changes to the past,” said Dr. Amir Khan from the University of Zurich and the Institute of Geophysics at ETH Zurich.

According to the data, Phobos and Deimos would cross at some historical moment – suggesting that they were probably in the same place and therefore share a starting point.

The two months are known to be “very irregular in shape – like potatoes”, as described by Amirhossein Bagheri, a doctoral student at the Institute of Geophysics at ETH Zurich.

“Phobos and Deimos look more like asteroids than natural moons,” he added.

Strange shapes of the moon are irregular in space and have confused astronomers for decades. Planets and moons usually become round over time due to condensing gravitational forces.

Traditional orbit theories are inconsistent with their asteroid-like appearance. Once trapped surrounding a larger planet, asteroids tend to fall at a certain angle to the surrounding object, with unique planetary cycles extended at one end.

However, Phobos and Deimos have a circular orbit around Mars and are almost in line with the equator of the Red Planet.

Zurich astronomers have accumulated data on the properties of rocks that make up moons via InSight and combined this with measurements from other Mars explorations.

Researchers were then able to create a model of ‘tidal forces’, a cosmic phenomenon that assumes that every existing celestial body exerts some force against others nearby, including the way the Moon and Earth are in constant gravitational tension.

The range of tides is influenced by a number of factors such as the composition of the objects, their mass and the distance between them.

Observation of Mars, Phobos, and Deimos becomes difficult because, although mass and proximity can be calculated, their composition is largely unknown because no samples were taken from the Martian months. Current estimates claim that the moons are composed of highly porous material of very low density.

As part of its Martian Moon Exploration project, Japan hopes to reach Phobos in 2025 and become the first country to extract surface samples and return them to Earth for observation.

InSight and other projects estimate that the lunar density is about two grams per cubic centimeter – less significant than chalk (2.5 g / cm ^ 3) and limestone (2.7 g / cm ^ 3).

Using this assumption, researchers can create a picture of the history of two months, their potential origins, and even predict their future.

The unique space cluster that later became Phobos and Deimos was more distant from Mars than Phobos is today and probably in the position of Deimos. Phobos is observed to be receding toward Mars and is expected to collide with Mars in just under 40 million years.

Deimos, similar to the predicted end of the Earth’s own moon, will slowly move away from its planet in orbit until it is completely free.

The largest of the two – Phobos, is only 21 km wide, while Deimos has a diameter of only 7.5 kilometers. Phobos is closer to Mars than its counterpart. In parallel, the Earth’s moon has a diameter of 2158 miles – 155 times larger than Phobos and 288 times larger than Deimos.

Phobos is closer to Mars than its smaller celestial brother and sister.

Their names are the names of two divine twins of Greek mythology, after they were discovered by the American astronomer Asaph Hall in August 1877. They are named after the children of Ares (Mars) and Aphrodite (Venus) with Phobos as the deity of fear and panic and Deimos is attributed to fear and terror.