Space Telescope Science Institute
NASA's Hubble Space Telescope crossed another milestone in its 21-year space odyssey of exploration and discovery. On Monday, July 4, the Earth-orbiting observatory logged its one millionth science observation during a search for water in an exoplanet's atmosphere 1,000 light-years away. Although Hubble is best known for its stunning imagery of the cosmos, the millionth exposure is a spectroscopic measurement, where light is divided into its component colors. These color patterns can reveal the chemical composition of cosmic sources. This is an artist's concept of Hubble's millionth exposure, the extrasolar planet HAT-P-7b. It is a gas planet larger than Jupiter orbiting a star hotter than our Sun. HAT-P-7b, also known as Kepler 2b, has been studied by NASA's planet-hunting Kepler observatory after it was discovered by ground-based observations.