Saturday, February 13, 2016

Gravitational Waves

Idealized spacetime curvature
caused by Earth's mass
Gravitational waves are wave-like ripples in the curvature of spacetime.

One precept of Einstein's General Relativity is that spacetime is perturbed by the presence of matter.
Generally, the more mass that is contained within a given volume of space, the greater the curvature of spacetime will be at the boundary of this volume.
Gravitational Waves, Wikipedia
More than a century following Einstein's proposition of gravitational waves, physicists at the Laser Interferometer Gravitational-Wave Observatory (LIGO) have detected the presences of gravitational waves. These waves are believed to be emanating from the collision of two massive black holes that merged some 1.3 billion years ago.
The Universe has spoken and we have understood.
― David Blair, LIGO collaboration member

Idealized depiction of gravitational waves
by Frank Glowna - Own work, CC BY-SA 3.0

LIGO's discovery appears to be empirical confirmation of the gravitational waves predicted by Einstein's 1918 paper Über Gravitationswellen where he calculated the effect of gravitational waves.

The LIGO system consists of identical detectors in Livingston, Louisiana and Hanford, Washington, that discern tiny vibrations from passing gravitational waves.
It will give us ears to the Universe where before we’ve only had eyes.
― Karsten Danzmann, LIGO collaboration member
Ironically Einstein considered gravitational waves a theoretical construct, perhaps too small to be detected.
Imagination is more important than knowledge. For knowledge is limited to all we now know and understand, while imagination embraces the entire world, and all there ever will be to know and understand.
Albert Einstein