These clocks, which measure time by using an ultra-stable laser to monitor the resonant frequency of atoms, are now precise enough that if they ran for the age of the universe, they would lose less than one second.
Theoretical physicist Clifford Johnson answers Symmetry writer Brianna Barbu’s questions about his work in science and outreach, including advising on movies like Avengers: Endgame.
Sanford Underground Research Facility is making an effort to build bridges with Native American communities and operate with respect for the sacred land it is built on.