... Venus' Once Molten Surface . ... Magellan orbited Venus and used radar to map our neighboring planet's surface between 1990 and 1994. ... Majestic on a truly cosmic scale, M100 is appropriately known as a Grand Design spiral galaxy. ... Like cosmic snowballs, fluffy comet-like objects the size of houses and composed mostly of water-ice, may be pummeling planet Earth 5 to 30 times a minute. ... Neptune, the Solar System's outermost gas giant planet, is 30 times farther from the Sun than Earth. ...