Making LIGO Possible: A Technical History*

The first detection of gravitational waves by LIGO was remarkable not only because of its impact on the Theory of General Relativity and on the astrophysics of neutron stars and black holes, but also because of the sensitivity of the detectors required.  The LIGO interferometers had to be capable of discerning changes as small as 1E-18 m in the length of its 4-km long arms, certainly one of the most precise physical measurements ever made.  To achieve this incredible sensitivity, LIGO scientists spent over 30 years understanding and overcoming a plethora of competing noise sources. In this talk, I will describe a diverse handful of these technical challenges, selected because of their importance to the project or their broader general interest, and trace the sometimes circuitous path that led to each one being brought under control.