On this day in 1629, Dutch physicist, mathematician, astronomer, and inventor Christiaan Huygens was born. His many accomplishments included the founding of the wave theory of light, centrifugal force, and the true shape of Saturn's rings. He also discovered the Orion Nebula AND Saturn's moon, Titan! Wow, that's quite an impressive list. Does Huygens sound familiar to you? That's because Christiaan is the namesake of the atmospheric entry probe that successfully landed on Titan back in 2005 during the Cassini-Huygens mission. Not only was this mission the first to land on Titan, it was also the farthest spacecraft probe landing ever made — almost 1 billion miles. We think that is absolutely awesome and worthy to celebrate! What are you celebrating today?