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
Gliese 687 40% of the Sun's mass and nearly 50% of the Sun's radius. Compared to the Sun, it has a slightly higher proportion of elements with higher atomic numbers than helium. It appears to have a rotation of 60 days and to be somewhat chromospherically active. It displays no excess of infrared radiation that would indicate orbiting dust. It is known to have a planet, Gliese 687 b, with a mass of 18.394 Earth masses (which makes it comparable to Neptune), an orbital period of 38.14 days, and a low orbital eccentricity. Gliese 687 is a solitary red dwarf that emits