Phobos (left) and Deimos (right). Notice how differently colored they are! Image credit: NASA

Phobos (left) and Deimos (right). Notice how differently colored they are! Image credit: NASA

Happy Monday, Earthlings!

This segment is brought down to Earth by the two trouble-making moons of Mars- Phobos and Deimos. Don't let their names fool you- these small moons are actually not true moons, but rather captured asteroids stuck in Mars's gravitational pull. 

Here are some fascinating facts about these moons!

1-The moons were discovered in 1877 by American astronomer Asaph Hall. Phobos (fear) and Deimos (dread) were children of Ares (Roman name for Mars and God of War) to accompany in battle. 

2-Jonathan Swift's satire Gulliver's Travels (1726) describes Laputa's astronomers discovering two moons of Mars. This description refers to Keplerian laws of planetary motions and had these moons described to be at 3 and 5 Martian diameter orbits with periods of 10 and 21.5 hours. ACTUAL: Phobos and Deimos are at 1.4 and 3.5 Martian diameter orbits with 7.66 and 30.35 hour orbits, respectively. 

3-In 1752, Voltaire wrote a short story (Micromegas) that had predicted two moons of Mars. For Swift's and Voltaire's "predictions", two craters on Deimos are named after them in their honor. 

4-Although having two moons, they are too small to block out the Sun for a total eclipse. However, total lunar eclipses of Phobos are so common, they happen almost every night!

5-Just like our Moon, both Phobos and Deimos are tidally locked (the same side of the moon is always facing its planet). Phobos, however, is slowly descending its orbit into Mars. At some point in time, Phobos will be ripped apart by these extreme gravitational forces!

6-The origin of these Moons is still controversial. The compositions are still being studied and to rule out what type of asteroids (maybe?) these are. 

7-Future missions to study these moons: NASA's PADME in 2020 (flyby), NASA OSIRIS-REx II (concept mission), Russia's Fobos-Grunt (2024).

This set of three images shows views three seconds apart as the larger of Mars' two moons, Phobos, passed directly in front of the sun as seen by NASA's Mars rover Curiosity. Curiosity photographed this annular, or ring, eclipse with the telephoto-lens camera of the rover's Mast Camera pair (right Mastcam) on Aug. 20, 2013, the 369th Martian day, or sol, of Curiosity's work on Mars. Image credit: NASA/JPL-Caltech/Malin Space Science Systems/Texas A&M Univ. 

This set of three images shows views three seconds apart as the larger of Mars' two moons, Phobos, passed directly in front of the sun as seen by NASA's Mars rover Curiosity. Curiosity photographed this annular, or ring, eclipse with the telephoto-lens camera of the rover's Mast Camera pair (right Mastcam) on Aug. 20, 2013, the 369th Martian day, or sol, of Curiosity's work on Mars. Image credit: NASA/JPL-Caltech/Malin Space Science Systems/Texas A&M Univ. 

Thank you for reading and come back next week for a look at what in the world is chaos terrain?