What Does One Trillion Stars Look Like? Here is an image from the Spitzer Space Telescope of our magnificent neighbor, M31, Andromeda. Recent estimates put Andromedas star count at one trillion. Two and one-half times greater in diameter than our own Milky Way Galaxy, Andromeda is 260,000 light-years across. She is our closest galactic companion, 2.5 million light-years distant, and is part of the Local Group, which consists of the Andromeda, Milky Way, and Triangulum galaxies. Our Miliky Way is approaching Andromeda at more than 100km per second. We can put off worrying about impact, since it will not occur for about 3 billion years. The red swaths in the image are new star formation regions of Andromeda. If only one in one billion star systems support life, then the image you are looking at here would contain 1000 alien ecosystems. http://gallery.spitzer.caltech.edu/Imagegallery/image.php?image_name=sig06-024 This second image is a Hubble Space Telescope photo of Andromedas nucleus. You can see from the photo that there are two concentrations of mass near the center. P2, the dimmer of the two concentrations, lies at the true galactic center. It is about 1.5 parsecs, or 5000 light-years, from P1. There is a black hole at the true galactic center equal to about 100 million solar masses.