Before the Spitzer space telescope launched on 25 August 2003, a lot lay hidden in the dark corners of the Universe. One of Nasa's four Great Observatories (other siblings were Compton Gamma Ray Observatory, the Chandra X-ray Observatory, and the Hubble space telescope), Spitzer was different in that it was designed to detect the Universe's infrared radiation, in which cooler things like planets appear relatively brighter, and hot things like stars relatively dimmer. This allows it to peer into interstellar dust clouds and stretches of deep space that appeared unexciting to ordinary telescopes.
The telescope has studied comets and asteroids, it has helped to detect far-flung galaxies, and it even discovered soccer-ball-shaped carbon spheres called buckyballs. It was the first to detect light coming from a planet outside our solar system, and discovered the largest of Saturn's many rings. Even though it ran out of the helium coolant needed to use its far-infrared detectors in 2009, two detectors have continued to provide striking images of the Universe.
Nasa says that Spitzer will continue to explore the cosmos in its second decade of operation. For instance, it will attempt to examine a small near-Earth asteroid named 2009 DB to better determine its size, which the space agency says will help them understand potential candidates for its asteroid capture and redirection mission.
But for now, we at BBC Future want to wish Spitzer a very happy anniversary, and celebrate this by showing some of its most memorable images over the decade.