I think the graduation of the size of circles changes periodically - they get bigger (from the centre out) and then stop, go slightly smaller, and then begin to get bigger again. With a group (mid-right) that seem to fluctuate.
I think that's what makes it 'look' messy - but perhaps it's intended?
For example - if it was representative of an object that was visible and orbiting the earth - perhaps the circles represent it's visibility, and that visibility growing and fluctuating before reaching a crescendo.
Then again, it may just be messy!