You're oscillating. Well, technically, not just you. We are all being stretched and squeezed by an event we can't see?"at least not with the naked eye. Imagine that throughout the day we have imperceivable fluctuations in our height, starting taller in the day, shorter at night, constantly stretching and squeezing like a spring. Our entire universe experiences something of the same, just rather than fluctuations repeating every 24 hours or so, it's every decade. Somewhere, far, far away and long, long ago, two supermassive black holes came together, forming a binary system. These black holes have gargantuan masses, at least 100 million times the mass of our sun. They were bound to each other in a seemingly perpetual orbital dance, spending tens of millions of years orbiting each other, creating ripples in the fabric of spacetime that may soon be detectable to us. As the two continue their tango, they lose energy and draw their counterparts in closer and closer. These eonic sp