Measuring cosmic distances with standard sirens

Daniel Holz, Scott Hughes, and Bernard Schutz in Physics Today:

The chirp of GW150914, the first gravitational-wave event to be detected.

Decades of experimental effort paid off spectacularly on 14 September 2015, when the two detectors of the Laser Interferometer Gravitational-Wave Observatory (LIGO) spotted the gravitational waves generated by a pair of coalescing black holes.1 To get a sense of the effort leading to that breakthrough, consider that the gravitational waves caused the mirrors at the ends of each interferometer’s 4 km arms to oscillate with an amplitude of about 10−18 m, roughly a factor of a thousand smaller than the classical proton radius. The detection was also a triumph for theory. The frequency and amplitude evolution of the measured waves precisely matched general relativity’s predictions for the signal produced by a binary black hole merger, even though the system’s gravity was orders of magnitude stronger than that of any system that had been precisely probed before that detection. As figure 1 shows, gravitational-wave astronomy began not with a bang but with a chirp.

More here.  [Thanks to Sean Carroll.]

Like what you're reading? Don't keep it to yourself!
Share on Facebook
Facebook
Tweet about this on Twitter
Twitter
Share on Reddit
Reddit
Share on LinkedIn
Linkedin
Email this to someone
email