Please view Astronomy Picture of the Day: http://apod.nasa.gov/apod/ap110503.html If we could push our way through to the core of M15, what'll we find?
The picture is that of a group of stars orbiting the Milky Way. There are more than a hundred group of stars that orbit around the Milky Way, the galaxy that our Sun is located in.
This dense group is made up of stars of all types and sizes and pulsars. There is a dramatic increase in the number of stars towards the center of the group which is the result of the presence of a Black Hole that is pulling the stars towards itself due to the infinite gravitational potential that Black Holes possess. If an astronaut in a spaceship managed to maneuver the space ship through all the stars lying around the center and reach it, there would not be more a few millionths of a second during which the Black Hole would be sensed before which the space ship would be pulled in to the Black Hole and destroyed.