Johannes Kepler studied the motion of planets. In 1609 and 1616 he published his three laws governing the shape of their orbits and their speed along those orbits, but did not discover why they moved that way.
d̠ʒ oʊ h æ n z WORD_BOUNDARY k ɛ p l ə ɹ WORD_BOUNDARY s t ʌ d i d WORD_BOUNDARY ð ə WORD_BOUNDARY m oʊ ʃ ə n WORD_BOUNDARY ʌ v WORD_BOUNDARY p l æ n ɪ t s WORD_BOUNDARY ɪ n WORD_BOUNDARY w ʌ n WORD_BOUNDARY θ aʊ z ə n d WORD_BOUNDARY s ɪ k s h ʌ n d ɹ ɪ d WORD_BOUNDARY n aɪ n WORD_BOUNDARY æ n d WORD_BOUNDARY w ʌ n WORD_BOUNDARY θ aʊ z ə n d WORD_BOUNDARY s ɪ k s h ʌ n d ɹ ɪ d WORD_BOUNDARY s ɪ k s t iː n WORD_BOUNDARY h iː WORD_BOUNDARY p ʌ b l ɪ ʃ t WORD_BOUNDARY h ɪ z WORD_BOUNDARY θ ɹ iː WORD_BOUNDARY l ɔ z WORD_BOUNDARY ɡ ʌ v ə ɹ n ɪ ŋ WORD_BOUNDARY ð ə WORD_BOUNDARY ʃ eɪ p WORD_BOUNDARY ʌ v WORD_BOUNDARY ð ɛ ɹ WORD_BOUNDARY ɔ ɹ b ɪ t s WORD_BOUNDARY æ n d WORD_BOUNDARY ð ɛ ɹ WORD_BOUNDARY s p iː d WORD_BOUNDARY ʌ l ɔ ŋ WORD_BOUNDARY ð oʊ z WORD_BOUNDARY ɔ ɹ b ɪ t s WORD_BOUNDARY b ʌ t WORD_BOUNDARY d ɪ d n ɑ t WORD_BOUNDARY d ɪ s k ʌ v ə ɹ WORD_BOUNDARY w aɪ WORD_BOUNDARY ð eɪ WORD_BOUNDARY m uː v d WORD_BOUNDARY ð æ t WORD_BOUNDARY w eɪ WORD_BOUNDARY