This artist's concept animation shows a brown dwarf with bands of clouds, thought to resemble those seen on Neptune and the other outer planets in the solar system.

By using NASA's Spitzer Space Telescope, astronomers have found that the varying glow of brown dwarfs over time can be explained by bands of patchy clouds rotating at different speeds.

NASA's Jet Propulsion Laboratory manages the Spitzer Space Telescope mission for NASA's Science Mission Directorate, Washington. Science operations are conducted at the Spitzer Science Center at Caltech in Pasadena, California. Spacecraft operations are based at Lockheed Martin Space Systems Company, Littleton, Colorado. Data are archived at the Infrared Science Archive housed at the Infrared Processing and Analysis Center at Caltech. Caltech manages JPL for NASA.