Discover the cosmosEach day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.
Explanation:Stickney Crater, the largest crater on the martian moon Phobos, is named for Chloe Angeline StickneyHall, mathematician andwife of astronomer Asaph Hall.
Asaph Hall discovered both the Red Planet’s moonsin 1877.
Over 9 kilometers across, Stickney is nearly half the diameter of Phobos itself, so large that the impact that blasted out the crater likely came close to shattering the tiny moon.
Thisenhanced-color imageof Stickney and surroundings was recorded by the HiRISE camera onboard the Mars Reconnaissance Orbiter as it passed within some six thousand kilometersof Phobosin March of 2008.
Even though the surface gravity ofasteroid-like Phobosis less than 1/1000th Earth’s gravity, streaks suggest loose material slid down inside the crater walls over time.
Light bluish regions near the crater’s rim could indicate a relatively freshly exposed surface.
The origin of the curious grooves along the surface is mysterious but may be related to tidal stresses experienced byclose-orbiting Phobos orthe crater-forming impactitself.
Tomorrow’s picture:farside