Blue asteroids are rare, and blue comets are almost unheard of. An international team led by Teddy Kareta, a graduate student at the University of Arizona's Lunar and Planetary Laboratory, investigated (3200) Phaethon, a bizarre asteroid that sometimes behaves like a comet, and found it even more enigmatic than previously thought. Phaethon sets itself apart for two reasons: it appears to be one of the "bluest" of similarly colored asteroids or comets in the solar system; and its orbit takes it so close to the Sun that its surface heats up to about 800 degrees Celsius (1,500 degrees Fahrenheit), hot...