Johannes Kepler, I think, was one of my undergraduate advisor‘s favorite historical astronomers; I distinctly remember a lecture from 2003 about Kepler’s understanding of orbital motion:

If you asked Kepler, “Why do your laws work the way they do? What causes planets to move in these sorts of orbits?” Kepler would tell you that, “God is a mathematician, and so am I!”

Though Kepler’s celestial mechanics equations worked for predicting the position of Mars and other bodies, Kepler was not able to explain why planets moved the way they do around the sun without invoking a higher power.  As a geometer, Kepler tried to understand the behavior of the solar system in terms of areas, ratios, and other geometrical principles; it wasn’t until Newton came along that there was a more elegant mathematical understanding and derivation of celestial mechanics and the laws of motion: calculus and the inverse square relation for gravity.

In 2011, hundreds of years after Kepler’s life, a telescope named after this German astronomer is in orbit around Earth to look for… other Earths around other stars. Last week a bonanza of candidate Earth-like planets was announced; astronomers everywhere cannot contain their excitement at the prospect of planets like home in the habitable zones around other stars.

Kepler’s ideas were revolutionary for his time, and it’s appropriate that a revolution in Egypt occurred almost simultaneously with the release of Kepler mission results.  (I’d like to add that Jack Lissauer of the Kepler team is perhaps one of the nicest guys in astronomy; I’m really glad that someone like him is involved in this project.)

The Kepler team isn’t content to just release mountains of data on potentially habitable terrestrial planets; they also have a t-shirt available with a Carl Sagan quote:

For small creatures such as we the vastness is bearable only through love.

The shirt features a variable star light curve in the shape of a heart, which is appropriate, as asteroid light curves were my first astronomical crush.

If you’re looking for more interplanetary affection in time Valentine’s Day, NASA’s Stardust-NExT mission will be encountering comet Tempel 1 on Monday. Stardust-NExT originally sampled another comet, Wild 2, on Independence Day in 2004; Tempel 1 will be the second comet imaged by this mission. Ooh la la.

Much love to all heavenly bodies in this solar system and beyond.