Stellar Orbits Around Milky Way's Central Black Hole (1995 - 2195)
I remember seeing something like this a while back, and I just came across it again on Starts with a Bang! It's just the coolest thing ever. The video is speeded up by a factor of two hundred million, but as I recall there are some planets that are so close to the center that they have an orbital period measured in days. How they managed to collect the data in order to produce this video borders on witchcraft. YouTube blurb:
This demo shows the observed and predicted orbits of thirteen stars that were used by astronomers at the Keck/UCLA Galactic Center Group to predict the position of a huge black hole at the center of the Milky Way. This data was provided by Andrea Ghez and Jessica Lu. The animation spans 200 years between 1995 and 2195.