NEOWISE Watches Comet Catalina
Comet C/2013 UQ4 (Catalina) looked like an asteroid when NASA's NEOWISE team first observed it on Dec. 31, 2013. By the time of this image, on July 7, 2014, the target appeared to be a highly active comet one day past perihelion.
Credits: NASA/JPL-Caltech