Nuclear reactor, any of a class of devices that can initiate and control a self-sustaining series of nuclear fissions. Nuclear reactors are used as research tools, as systems for producing ... Read more »
NASA Telescope Reveals Largest Batch of Earth-Size, Habitable-Zone Planets Around Single Star
NASA's Spitzer Space Telescope has revealed the first known system of seven Earth-size planets around a single star. Three of these planets are firmly located in the habitable zone, the area around the parent star where a rocky planet is most likely to have liquid water.
