Heat Seeker

Spitzer Space Telescope stares into the infrared sky in this illustration. The telescope, which was launched in 2003, is the last of NASA's Great Observatories, a series that includes Hubble Space Telescope. Spitzer studies infrared wavelengths, which reveal details about gas clouds, stellar nurseries, distant galaxies, newly forming planetary systems, the comets and asteroids in our own solar system, and much more. Infrared is an object's heat energy, although some of the brightest infrared objects are extremely cold. [NASA/JPL/Caltech/R. Hurt (SSC)]