Scientists have been slowly extending the periodic table one element at a time, pushing to higher and higher masses, and have discovered some incredibly useful materials along the way. But the elements at the current end of the table are so unstable that they decay almost as soon as they’re created in our particle accelerators. Have we reached the end of the line of discoverable elements? There are new rows of the periodic table to unlock, and more stable versions of known heavy elements to synthesize—and while our accelerators are coming up short, astronomers have found a strange cosmic phenomenon that may populate the periodic table beyond our wildest dreams.