Page 13, The Milky Way: [Previous Page] [Next Section] [Class Home Page] Text Pages 366-370

At the center of the circum-nuclear disk we see a LOT of stars. A million stars, packed into an area smaller than the distance between the Sun and its nearest Stellar neighbor. Very careful monitoring of the exact position of the bright, radio source, Sgr A* has been kept, relative to very distant objects for more than two decades. Sgr A*'s position NEVER varies. Everything around it varies, but the radio position of the unresolved source, Sgr A*, (shown as a red cross) does not. What is Sgr A*? By looking at the motions of the stars nearby (shown to the right), Astronomers have measured the mass of this unseen object. It appears to have a mass of: MSgrA* = 106 MSun (a million Suns) Yet, it lies in an area no bigger than our Solar System. Most astronomers believe it is a million solar mass Black Hole, that sits at the exact center of our Galaxy.

For a movie, click here
For a slide show on the galactic center go here
More on the blackhole here and here.