from here : http://cfa-www.harvard.edu/press/pr0325image.html

Caption: The spiral galaxy Messier 81 (M81), located 12 million light-years away in the constellation Ursa Major, is a near-twin to our own Milky Way galaxy. In this visible light image, it displays an unremarkable disk and central bulge of stars. Dust lanes wind throughout the disk, hiding details of the galaxy's structure and composition. Credit: N.A. Sharp/NOAO/AURA/NSF

Caption: IRAC uncovered areas in M81 where star formation is taking place, visible in this image as reddish, infrared-bright clumpy knots within the well-defined spiral arms. The huge amounts of hot dust revealed by IRAC, and the associated hydrogen gas, will provide raw materials for future star formation. Credit: NASA/JPL-Caltech/S. Willner (Harvard-Smithsonian Center for Astrophysics)

Caption: Herbig-Haro 46 (HH 46) and its partner, HH 47, show where twin jets of material spew out in opposite directions from a previously hidden source, generating huge shock waves as they plow through anything in their way. The sharp infrared eyes of IRAC exposed the source of these jets - a young protostar embedded in an obscuring cloud of matter. Credit: NASA/JPL-Caltech/A. Noriega-Crespo (SSC/Caltech), Digital Sky Survey