To understand galaxies, you really need to see their pieces. And that's not easy, since galaxies emit light in many different wavelengths of the electromagnetic spectrum, each slice telling a different story. And some of that light gets blocked by dust.
The Spitzer Space Telescope was designed with this in mind. It sees through dust, using an infrared camera to detect heat. And by taking multiple pictures with different filters, astronomers can isolate telling features in a combined image.
This false-color view of a galaxy called NGC 300, released this week, illustrates what astronomers are doing with Spitzer. NGC 300 is a spiral galaxy 7.5 million light-years away in the southern constellation Sculptor. It is seen face-on.
The densest region of stars, near the center of the galaxy, shows up as blue. This is where mostly older stars reside. Dusty spiral arms are red. The dust includes organic compounds called polycyclic aromatic hydrocarbons, which are produced by the knots of star formation -- packed with hot, young stars -- in the arms.
