Colwell, Joshua: - Dr. Joshua Colwell is a Planetary Scientist and Pegasus Professor of Physics at the University of Central Florida. His research interests are in the origin and evolution of the solar system, planet formation, planetary rings, asteroids and comets. He worked on the Cassini mission from 1990 until 2017, and continues to analyze data from it. His experiments have flown on the Space Shuttle, the International Space Station, suborbital rockets, and parabolic airplane flights. He produces and hosts the astronomy podcast Walkabout the Galaxy.