Beneath the explosions, collisions and other intermittent bangs in the cosmos, scientists suspect a nonstop soundtrack plays, created by ripples in spacetime continually washing through the universe. After more than a decade of searching, scientists may have finally heard that background hum.
Several teams of researchers from around the world reported on June 28 the first clear evidence of these gravitational waves. Unlike previously detected gravitational waves, these new ones have ripples that are staggeringly long — on the scale of light-years. Their likely source: innumerable pairs of gargantuan black holes, which churn the spacetime cauldron as they orbit one another.