A New Galaxy Gallery
NASA's Spitzer Space Telescope is now in the second act of its observing life. Launched in 2003, it operated well beyond its initial 2.5 year mission, until its liquid hydrogen was exhausted in 2009. Some of its instruments can still function without the cryogen, so Spitzer keeps on observing in its "warm mission" phase. Meanwhile, scientists are still processing the data collected during its primary mission, and recently released infrared images of over 200 galaxies. These images, like the one of M91 above, were taken in the mid-infrared, and can now be used to compare with images taken by ESA's Herschel Space Observatory, which observes in the far-infrared. The bright red and orange colors indicate heat emitted from interstellar dust. The new Spitzer images are all available for viewing and download.
Photo: NASA / Spitzer