"I never thought I'd see it in my lifetime." Scientists announced today they detected gravitational waves from two colliding neutron stars, which sent ripples through the fabric of spacetime--and gave off a bright flash of light, long enough for telescopes around the world to point in that direction of the sky. #UChicago physicist Daniel Holz, part of the international #LIGO-Virgo collaboration, used the discovery to make a new calculation of the size of the universe and how fast it's expanding.