Gravitational waves are fluctuations in the fabric of spacetime; as they pass, they distort distances between objects. For example, a gravitational wave passing through this page would alter it so that it became wider, then taller, then wider, and so forth. Predicted by Einstein’s theory of general relativity, gravitational waves are analogous to the electromagnetic waves predicted by Maxwell’s equations. Unlike electromagnetic radiation, which is caused by accelerated charge, gravitational radiation is caused by accelerated mass.
Astronomers have already seen compelling, indirect evidence of gravitational waves in the energy loss and orbital decay of PSR B1913+16, the binary neutron star system whose discovery earned Russell Hulse and Joseph Taylor the 1993 Nobel Prize in Physics. Now, in the 21st century, the hope is to detect gravitational waves directly and to exploit them as a tool for learning about the cosmos.
As with electromagnetic waves, one can specify a gravitational wave...
