Text book for space shakers

摘要

Gravitational waves are ripples in space-time that travel through space at the speed of light. They are emitted by astrophysical sources such as binary stars or colliding black holes, or by violent phenomena such as cosmic strings or inflation in the very early Universe. Because they affect matter only weakly, gravitational waves are very hard to detect. To do so we need large instruments - interferometers several kilometres on a side - with extremely sensitive quantum-limited detectors, only recently available. The very fact that gravity couples so weakly to matter means that gravitational waves travel almost unimpeded through any material between us and the source of the gravitational waves. So they can provide a unique, direct view of some of the most dramatic cosmic events, including black-hole collisions or even the Big Bang itself.