New Planet Discovered at Lowell TweetShareGoogle+Email A computer-generated simulation of TrES-4, with its host star on the right. Jeffrey Hall, Lowell Observatory By Geoff Norcross Listen Listening... / Flagstaff, AZ – Lowell Observatory in Flagstaff is announcing the discovery of the largest known planet in the universe. Astronomers say it's about 70 percent larger than Jupiter. Arizona Public Radio's Geoff Norcross reports. TweetShareGoogle+EmailView the discussion thread.