Kuiper runs with a new friend at the dog park.

Kepler and Tycho Brahe

Kuiper orbits a new friend at Thousand Acres.

On this day in 1571, German astronomer Johannes Kepler was born. Kepler didn’t have the best start in life; his mom was convicted of being a witch and nearly burned at the stake, and his dad disappeared when he was 5. When Kepler’s plan to become a Lutheran minister fell through, he ended up working for the truly eccentric astronomer Tycho Brahe.

Tycho, his metal nose, and his drunk pet moose warrant their own post (or 4.) However, the important part today is that Kepler ended up with a ton of Tycho’s data after he died suddenly and somewhat suspiciously (btw Kepler was exonerated for murder in 2010.) Using Tycho’s data, Kepler came up with 3 basic principles of planetary motion:

☀️ Planets move in elliptical orbits (stretched out circles with more than one “center”) around the sun.
☀️ Planets go faster when they’re closer to the sun and slower when they’re further away. (For us here on Earth, we’ll hit our fastest speed on January 3rd. Wheeee!)
☀️ The “year” of a planet is proportional to its average distance to the sun, i.e. Mercury and Venus have shorter “years” than Earth (88 & 225 days.) Mars, Jupiter, Saturn, Uranus and Neptune have longer years than Earth (687 days and 12, 29, 84 and 165 years, respectively.) For those of us who graduated high school before 2006 😂, a year on Pluto is 248 years on Earth.

Kepler described what was going on more or less correctly, but no one really knew *why* planets acted this way (or how to account for things like the Moon) until Newton came along and invented calculus.

Through his laws of motion and law of universal gravitation, Newton was able to distill Kepler’s ideas into math formulas that could account for the motion of any object (or any number of objects) rather than just planets orbiting around the sun.

Original post: https://www.instagram.com/p/Br680hbjnNX/

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