One summer season night in 1877, American astronomer Asaph Hall was browsing his telescope in Washington, D.C. Mars was at its closest indicate Earth in its orbit, and Hall had one concern on his mind: Does the Red Planet have a moon

After several nights of browsing in heavy fog, Hall found not simply one however 2 moons, which he called Phobos and Deimos, the “terror” and “panic” twins in Greek folklore whose moms and dads were Ares and Aphrodite(Mars and Venus in Roman folklore). These moons, nevertheless, look really various from our own– and researchers still have a great deal of concerns about their origins.

“Phobos and Deimos are some of the smallest moons in our solar system,” Christopher S. Edwardsa teacher of astronomy and planetary science at Northern Arizona University, informed Live Science in an e-mail.

Compared to our moon, which determines 2,159 miles (3,475 kilometers) throughout, Phobos and Deimos are simply small specks in the sky. Usually, Phobos determines simply 14 miles (22 km) throughout, and Deimos is even smaller sized, about 7 miles (12 km) throughout usually. Their width is not constant due to the fact that these 2 small moons aren’t completely round.

“They are sort of bumpy, potato shaped, and are really, really dark, like the brightness of new asphalt,” Edwards discussed.

A moon is specified as any naturally-formed body that completely orbits a world. Since of their irregular shape and mini size, lots of researchers state that Phobos and Deimos look more like asteroids than moons.

It’s possible that Mars’ moons were initially asteroids that were recorded by the world’s gravitational pull. There’s likewise a theory that the 2 moons were developed after a big things hit Mars, developing particles that formed the 2 lunar bodies, comparable to how Earth’s moon most likely formed. Both of these hypotheses are still up for dispute.

Related: The number of moons remain in the planetary system?

“How the moons of Mars formed is a major open question for science,” Nancy Chabotprimary researcher for the Space Exploration Sector at the Johns Hopkins Applied Physics Laboratory, informed Live Science in an e-mail.

In the meantime, there’s proof on both sides. Noticeable and shortwave infrared spectral analyses of the moons point towards a structure constant with asteroids, however it’s likewise hard to discuss the physics behind Mars nabbing up 2 asteroids, Edwards stated. That’s due to the fact that Mars has a reasonably weak gravitational pull, and the shape and area of the 2 moons’ orbits would be challenging to accomplish through asteroid capture. Edwards included that information from the Hope Emirates Mars Mission recommends the 2 moons have a little various structures, even more making complex things.

An approaching objective to Mars might quickly offer more responses. The Martian Moons Exploration (MMX) objective by the Japan Aerospace Exploration Agency (JAXA), prepared to introduce in 2026, will take a trip to Mars and explore its 2 moons, and even bring a sample from Phobos back to Earth.

“JAXA’s MMX mission is very exciting and is set to be the first to unravel the mysteries of the Martian moons, including answering how they formed,” Chabot stated.

Evaluating the structure of this sample will assist clarify Phobos’ and Deimos’ origin, due to the fact that a moon that was when an asteroid would have an extremely various chemical structure to a moon that formed from pieces of early Mars.

If the Phobos sample suggests that the moons formed from a crash with Mars, it might unlock to a lot more amazing discoveries. Because case, the sample might clarify whether the early Red Planet had the capacity for extraterrestrial life.

“These could in fact be samples of early Mars,” which might have as soon as been congenial for life, Edwards stated.

Mars test: Is your understanding of the Red Planet out of this world?