The Spitzer infrared space telescope took this incredible image of the Andromeda galaxy:
This is a three channel image of the galaxy. That means it is a composite of 24 microns (blue), 70 microns (green), and 160 microns (red). The colors are "fake" (we can't really see infrared light, but the telescope detects it, assigns colors to it, and creates its own "image" of it). Just thought I'd stop whining about cosmetics and show some real natural beauty!
The Andromeda Galaxy is visible with the naked eye. It looks like a smudge near the constellation Andromeda, which is a northern hemisphere Fall constellation, so get out there if you live in the northern hemisphere! Wait 'till spring if you live south of the equator Here's help in finding it. It's even better if you have some binoculars or a small telescope!
For a long time, it was thought to be a nebula. That is until Henrietta Leavitt determined that the period and luminosity of Cepheid variable stars can be used to determine their distance. A Harvard "computer," she is not often given much credit in the textbooks (check out "Miss Leavitt's Stars," a new book by George Johnson). Edwin Hubble found a Cepheid variable in Andromeda and determined that it was VERY far away. Seeing as how it is still visible dispite its distance from us, it must be ginormous! Of course, it has since been confimed that this smudge is, in fact, a galaxy- a collection of billions of stars!