Despite his workload, he continued his study of the stars and planets, gathering evidence to support a revolutionary theory ​ — that the earth was not the stationary center of the universe but, in fact, moved around the sun.
Hoolimata töökoormusest, jätkas ta tähtede ja planeetide uurimist, et koguda tõendusmaterjali oma pöördelise teooria tarbeks, mille kohaselt Maa ei ole Universumi liikumatu kese, vaid hoopis tiirleb ümber Päikese.