Galaxy NGC 5866 lies 44 million light-years from Earth and has a diameter of roughly 60,000 light-years — a little more than half the diameter of our own Milky Way galaxy. From our viewpoint, NGC 5866 is oriented almost exactly edge-on, yielding most of its structural features invisible.
Spitzer detects infrared light, and the red color here corresponds to a wavelength typically emitted by dust. The clean edges of the dust emission from NGC 5866 indicate that there is a very flat ring or disk of dust circling the outer region of the galaxy.
Spitzer took this image during its "cold" mission, which ended in 2009. The colors represent three infrared wavelengths captured by the Infrared Array Camera instrument. Blue light corresponds to a wavelength of 3.6 microns, produced mainly by stars; green corresponds to 4.5 microns, and red corresponds to 8 microns.
The Jet Propulsion Laboratory in Pasadena, California, manages the Spitzer Space Telescope mission for NASA's Science Mission Directorate in Washington. Science operations are conducted at the Spitzer Science Center at Caltech in Pasadena. Space operations are based at Lockheed Martin Space Systems in Littleton, Colorado. Data are archived at the Infrared Science Archive housed at IPAC at Caltech. Caltech manages JPL for NASA.
For more information on Spitzer, visit: