Extraterrestrial skies Mars appears to be the angular diameter as seen from Earth (0.35°), and sends 40% of the light, approximately the brightness of a slightly cloudy afternoon on Earth. On June 3, 2014, the "Curiosity" rover on Mars observed the planet Mercury transiting the Sun, marking the first time a planetary transit has been observed from a celestial body besides Earth. Mars has two small moons: Phobos and Deimos. From the Martian surface, Phobos has one-third to one-half the angular diameter of the Sun while Deimos is barely more than a dot (only 2′ angular diameter). The orbital period of Phobos
Curiosity (rover) California, where she signed her name directly onto the rover as it was being assembled. Ma wrote in her winning essay: "Curiosity" landed in Quad 51 (nicknamed Yellowknife) of Aeolis Palus in Gale Crater. The landing site coordinates are: . The location has been named Bradbury Landing in honor of science fiction author Ray Bradbury. Gale crater, an estimated 3.5 to 3.8 billion-year-old impact crater, is hypothesized to have first been gradually filled in by sediments; first water-deposited, and then wind-deposited, possibly until it was completely covered. Wind erosion then scoured out the sediments, leaving an isolated mountain, Aeolis Mons