PhysicsUltracold clocks could reveal how quantum physics alters time The world’s best clocks may be sensitive to an odd mix of quantum and relativistic effects that would stretch time and test the boundaries of physics News
SpaceWhy it's taking a century to pin down the speed of the universe The Hubble constant, a set number that connects a galaxy’s speed to its distance from Earth and tells us how fast the universe is expanding, was first described more than a hundred years ago – but astronomers have debated it ever since News