Free Astronomy Magazine May-June 2021

51 ASTRO PUBLISHING It was first spotted in January 2018 by the Subaru Telescope, located on Maunakea in Hawai’i. Its discoverers could tell it was very far away, but they weren’t sure exactly how far. They needed more observations. “At that time we did not know the object’s orbit as we only had the Subaru discovery observations over 24 hours, but it takes years of obser- vations to get an object’s orbit around the Sun,” explained co-dis- coverer Scott Sheppard of the Carnegie Institution for Science. “All we knew was that the object ap- peared to be very distant at the time of discovery.” Sheppard and his colleagues, David Tholen of the University of Hawai’i and Chad Trujillo of Northern Ari- zona University, spent the next few years tracking the object with the Gemini North telescope (also on Maunakea in Hawai’i) and the T his illustration depicts the most distant object yet found in our Solar System, nicknamed “Farfar- out,” in the lower right. In the lower left, a graph shows the dis- tances of the planets, dwarf plan- ets, candidate dwarf planets, and Farfarout from the Sun in astro- nomical units (au). One au is equal to Earth’s average distance from the Sun. Farfarout is 132 au from the Sun. [NOIRLab/NSF/AURA/J. da Silva]