An artist's conception shows Voyager 1 encountering a stagnation region. To the left is interstellar space. NASA/JPL-Caltech hide caption

itoggle caption NASA/JPL-Caltech

A NASA illustration comparing the newly discovered planets to Venus and Earth. Kepler-20e is slightly smaller than both Venus and Earth. Kepler-20f is slightly larger. NASA/Ames/JPL-Caltech hide caption

itoggle caption NASA/Ames/JPL-Caltech

Artist's concept of NASA's Voyager spacecraft. For 35 years, the probes have been beaming images and information back to Earth via a 23-watt transmitter. NASA/JPL-Caltech hide caption

itoggle caption NASA/JPL-Caltech

A portion of the west rim of Endeavour crater sweeps southward in this view from NASA's Mars Exploration Rover Opportunity. NASA adjusted the colors in this image. Fans of the film Capricorn One may want to see the original orange-tinted image. NASA hide caption

itoggle caption NASA