One unproved prediction is that an accelerating mass should create gravitational waves, like the ripples from a boat sailing across the surface of a lake. In July, the hunt for those waves will heat up with the launch of a detector called Lisa Pathfinder, which will test technology for a new gravitational wave observatory in space. Starting in 2015, two earthbound experiments, Advanced Ligo and Advanced Virgo, will be brought online. They should be able to pick up gravitational disturbances from exploding stars. Another test will examine the motions of a triple-star system called PSR J0337+1715 to check if gravity behaves the same toward all kinds of matter, as Einstein believed.