Alternative R & B

Today the NASA Dawn spacecraft went into orbit around Ceres, a 600-mile-wide, roughly spherical world. The mission, en route since 2007 driven by a revolutionary ion propulsion system, is managed by the Jet Propulsion Laboratory on behalf of NASA’s Science Mission Directorate. 

Designed to orbit the dwarf planet as it had previously orbited the asteroid Vesta, the mission’s eyes include a camera sensitive to visible light, a spectrometer for observing aspects of visible and infrared light, and another sensitive to gamma rays and neutrons. In addition, information gleaned from navigational data is expected to provide insights into the mass and internal structure of the dwarf planet. Unlike Vesta, Ceres appears more akin to icy moons orbiting Jovian worlds than it is to terrestrial planets such as Earth. Comparisons between Vesta and Ceres are expected to reveal fundamental insights into how a vast nascent protosolar nebula of gas and dust contracted four and a half billion years ago and evolved into today’s Solar System. Other important questions relating to the mission include the quest for specifics about a significant mass of water believed to exist beneath Ceres’ surface. Before we knew much about other worlds, Earth was sometimes described as a unique “water planet.” Space age studies show that water is not uncommon in the universe, with substantial amounts in comets, certain asteroids, a number of Jovian planet moons, and interstellar space.