Who discovered the moons of Mars and when did Asaph Hall III find Deimos?
Asaph Hall III discovered the moons of Mars while working at the US Naval Observatory in Washington, D.C. He spotted Deimos on the 12th of August 1877 using a 26-inch refractor telescope.
What are the physical dimensions and orbital characteristics of Phobos compared to Deimos?
Phobos measures 22.2 km across with an orbital period of 7.66 hours while Deimos spans only 12.6 km and takes 2.7 days to set below the horizon. The inner moon orbits closer with a semi-major axis of roughly 9,377 km whereas the outer moon orbits far enough away that its path is being boosted instead.
How did Henry Madan name the moons of Mars after Homer's Iliad?
Henry Madan proposed the final spellings for Phobus and Deimus from Book XV of the Iliad where Ares summoned Fear and Fright to battle. These twin characters accompanied their father into war alongside Mars which later inspired Venetia Burney to name Pluto as his granddaughter.
When will JAXA launch the Martian Moons eXploration mission to collect samples from Phobos?
JAXA plans to launch the Martian Moons eXploration mission in 2026 to gather sand-like regolith particles using a pneumatic system. Return Module flights to Earth are scheduled for July 2029 with a requirement to collect at least 10 grams from Phobos's surface.
What theories explain whether the moons of Mars formed from Mars itself or arrived as captured asteroids?
Scientists debate whether these moons formed from Mars itself via a giant impact event or arrived later as captured carbonaceous C-type asteroids. Seismic data from the InSight Mission supports fragmentation theory suggesting disruption of a common parent body around 1 to 2.7 billion years ago.