This movie begins by showing an optical image of the Rosette nebula, a turbulent star-forming region located 5,000 light-years away in the constellation Monoceros. The view then changes to show the same region as viewed by NASA's Spitzer Space Telescope.
Some of the Rosette's most massive stars, called O-stars, can be seen inside the bubble-like, red cavity as bright blue stars; however, the largest two blue stars in this picture are in the foreground, and not in the nebula itself. Radiation and winds from the super hot stars have collectively blown layers of dust (green) and gas away, revealing the cavity of cooler dust (red).
The visible light image comes courtesy of John Corban and the ESA/ESO/NASA Photoshop FITS Liberator team.
This Spitzer image shows infrared light captured by the telescope's infrared array camera. Light with wavelengths of 24 microns is red; light of 8 microns is green; and light of 4.5 microns is blue.