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Kepler's Second Law of Planetary Motion
"A radius vector joining and planet to the sun sweeps out equal areas in equal lengths of time."- Published in Astronomia nova, 1609. Due to the planet's changing rate of speed during its orbit, the areas from the sun to its orbit is proportional during all parts of the orbit. This law illustrates two planets move faster when they are closer to the sun and slower when they are further away in their orbits. https://www.youtube.com/watch?v=qd3dIGJqRDU -
Kepler's First Law of Planetary Motion
"All planets move around the sun in elliptical orbits, having the sun as one of the foci."- Published in Astronomia nova, 1609. In simpler terms, each planet travels in an orbit, and that orbit is not circular. The planet's orbits are more oval or egg shaped. He also noted that at the sun was the center of one focal point of the ellipse or oval. https://www.youtube.com/watch?v=qDHnWptz5Jo -
Astronomia Nova
Astronomia Nova was a book published in 1609 written by Johannes Kepler. Astronomia nova is a Latin word, and when translated in english means New Astronomy. This book introduces Kepler's first two laws; the law of ellipses and the law of planetary motion. This book is one of the most important pieces of literature when it comes to the Scientific Revolution. -
Kepler's Third Law of Planetary Motion
"The squares of the sidereal periods (of revolution) of the planets are directly proportional to the cubes of their mean distances from the sun."- Published in Harmonices Mundi, 1619. This law has a lot to do with the gravitational pull from the sun. Just like satellites orbiting Earth, the faster they travel the closer they will be to the gravitation pull which is keeping them in orbit. Since Mercury is closer to the sun, it will travel faster in its orbit than Neptune with is further away. -
Harmonices Mundi
Harmonices Mundi was another famous book written by Johannes Kepler which was published in 1619. Like his other book, Astronomia Nova, this too was written in Latin and the title translates in English to The Harmony of the World. In this book Kepler introduces his third law of planetary motion, which discusses he orbit cycles of the planets.
