Helium is the second-most common element in the cosmos, but it's far rarer on planet Earth. As part of our celebration of the periodic table's 150th birthday, reporter Geoff Brumfiel shares a brief history of helium's ascent, to become a crucial part of rocket ships, MRI machines, and birthday parties. Follow host Maddie Sofia on Twitter @maddie_sofia. Email the show at shortwave@npr.org.