Astronomers at the European Southern Observatory have produced this stunning panorama of the heart of the Milky Way galaxy, creating a mosaic out of nine billion pixels. The photo was taken using the VISTA survey telescope that, despite its European name and heritage, is actually located in the mountains of Chile. The VISTA's special infrared cameras allow it to see through space dust, allowing a much clearer picture of the universe than astronomers are used to.
The number of stars that are visible in the photo is somewhere around 84 million, give or take a few red dwarfs. The image is being used by researchers to plot a "census" of the galaxy, marking each star's relative size and location.
The photo is actually a composite of many different shots, and at full resolution is 108,500 by 81,500 pixels—far to large to display on your puny computer monitor, but hopefully this gives you some idea. If you were to print it out as a standard book photo, it would be nine meters wide and seven meters tall. A more manageable (and zoomable) version of the image is posted on the ESO website.