The sort of clocks we use on Earth move at a different pace on the moon. That’s in part because of gravitational pull. Even slight variations in timing can be problematic, since missions to space rely on exacting precision. So, the White House has instructed NASA to come up with a new standard that it’s calling “coordinated lunar time.” Priyamvada Natarajan, an astrophysicist at Yale University, explains what that means to The World’s Carolyn Beeler.