Orion's masterpiece

Two of NASA's "Great Observatories" have teamed up to produce a painterly masterpiece showing our galaxy's nearest stellar nursery, the Orion Nebula.

In reality, no human eye could see this scene in such multicolored hues - because the palette reflects wavelengths in the infrared as well as the visible-light spectrum. But like most images from the Hubble and Spitzer space telescopes, the picture's "false color" is meant to highlight true science.

This view of the nebula is centered on the Trapezium - a knot of four massive stars wrapped in interstellar dust. At first glance, the scene looks like nothing so much as a Turner seascape (spacescape?), but Tuesday's image advisory from the Spitzer science team explains the cosmic color coding:

• The swirls of green represent hydrogen and sulfur gas that has been heated and ionized by the Trapezium stars' intense emissions, as seen in ultraviolet and visible light by Hubble.
• The wisps of red and orange are actually traces of polycyclic aromatic hydrocarbons, or PAHs, illuminated in the infrared by the Trapezium's stars and detected by Spitzer's infrared camera. PAHs are carbon-rich organic chemicals that arise on Earth from such humble sources as burnt toast and car exhaust.
• The orange-yellow dots are infant stars, deeply embedded in clouds of dust and gas but easily seen by Spitzer's infrared eye.
• The blue and green dots are stars that are more out in the open, and detectable by Hubble's visible-light camera.

Taken together, this composite image serves as a more comprehensive map of Orion's star-forming region, 1,500 light-years from Earth. The nebula, in the constellation Orion, is thought to contain more than 1,000 young stars.

If you think this image is cool, you should check out the video clips from the Spitzer Web site, which show how the imagery morphs from the Hubble view, to the Spitzer view, to the final composite. While you're at it, be sure to check out our roundups of the "greatest hits" from Hubble and Spitzer.