To earn points you simply keep going round and round until the bar at the top of the screen fills completely, this process will give you one point and then it will reset.
The closer to the black hole you are the faster the bar will fill, so in turn, the faster you get points.
The outer most ring freezes the bars progress meaning no points will be awarded.
The second ring from the outside awards points at a rate of about two seconds per point
The third ring from the outside awards points at a rate of about one second per point
The ring closest to the black hole awards points at a rate of about half a second per point