Why Does Gravity Travel at the velocity of Light?
Two neutron stars collide; the resulting gravitational wave spread at the speed of light. Credit: National Science Foundation/LIGO/Sonoma State University/A. Simonne.The dead cores of 2 stars collided 130 million yrs earlier in a galaxy somewhat far away.The crash was so extreme that it originated a wrinkle in space-time-- a gravitational wave. That gravitational wave...