When Kepler began to develop his laws of orbital motion, he was studying the orbit of Mars.
When Johannes Kepler first began studying the laws of planetary motion, he focused on the orbit of Mars. Mars was an intriguing choice for Kepler because its orbit appeared to be the most irregular among the planets known at that time. By meticulously observing and analyzing the data on Mars' motion provided by his predecessor, Tycho Brahe, Kepler was able to develop his groundbreaking laws of planetary motion.
