As a viewer of your art(and what great art it is), the brightest, largest, best detailed object in the first third of your frame causes the eye to centre on that object and then rove over the rest of the frame, to come back to the said big shiny spot, making it(to me) the main object in the image. Nothing else in the image has the attraction potential like this does.
Is it known as the rule of thirds

or something like that?