The calm is deceptive. Seen from orbit, Mars presents a rust-colored disk, and Valles Marineris appears as a faint crease across its equatorial crust, an optical trick created by distance and a thin, dust-hazed atmosphere. The real scale arrives later. Valles Marineris runs roughly 4,000 kilometers along the Martian equator, reaches about 200 kilometers across in places, and drops near 7 kilometer...More