Happy birthday, Johannes Kepler!
Kepler was born on this day in 1571. He was a German mathematician and astronomer who is most well known for his three laws of planetary motion, the first of which states that the planets orbit around the sun in ellipses. Though he was not the first to assert the heliocentric theory, he was able to determine information about the orbits mathematically based on the planet’s distance from the sun. Kepler is regarded as one of the most important astronomers of the 17th century.