What did plato propose about all heavenly motion? it is in circular paths. it is incomprehensible from earth. only its shadow can be seen on earth. it is in elliptical paths. (b) why did plato propose what he did about heavenly motion and the shape of heavenly objects? because of the shape of the sun and the moon because of his telescopic observations because he believed the sphere to be the most perfect geometrical form because earth seems to be a disk around us, and the sky appears to be a spherical shell above us (c) what effect did plato's proposal have on future astronomers? none at all; being a philosopher and not an astronomer, what he said was ignored. none, at least outside of his homeland, greece. his idea of a sphere being the most perfect geometric form influenced astronomical theories for literally hundreds of years. his idea of elliptical orbits was "rediscovered" by kepler.