The New 10th Planet Is Larger than Pluto - Universe Today
Astronomers have confirmed that the newly discovered 10th planet is larger than Pluto. Nicknamed 2003 UB313 for now, the new planet has a diameter of 3,000 km (1,850 miles) which is 700 km (435 miles) larger than Pluto. These new observations were made using a sensitive sensor on the IRAM 30-m telescope that measured the heat emitted by the new object, and found it had a similar reflectivity to Pluto. This allowed them to calculate its size.