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
International Year of Planet Earth International Year of Planet Earth The United Nations General Assembly declared 2008 as the International Year of Planet Earth to increase awareness of the importance of Earth sciences for the advancement of sustainable development. UNESCO was designated as the lead agency. The Year's activities spanned the three years 2006-2009. The Year aimed to raise $20 million from industry and governments, of which half was to be spent on co-funding research, and half on "outreach" activities. It was intended to be the biggest ever international effort to promote the Earth sciences. Apart from researchers, who were expected to benefit under the