Scientists have sought experimental evidence for gravitational waves for more than 40 years.
Einstein himself actually thought a detection might be beyond the reach of technology.
His theory of General Relativity suggests that objects such as stars and planets can warp space around them - in the same way that a billiard ball creates a dip when placed on a thin, stretched, rubber sheet.
Gravity is a consequence of that distortion - objects will be attracted to the warped space in the same way that a pea will fall in to the dip created by the billiard ball.
Inspirational moment
Einstein predicted that if the gravity in an area was changed suddenly - by an exploding star, say - waves of gravitational energy would ripple across the Universe at light-speed, stretching and squeezing space as they travelled.
Although a fantastically small effect, modern technology has now risen to the challenge.
Much of the R&D work for the Washington and Louisiana machines was done at Europe's smaller GEO600 interferometer in Hannover.
"I think it's phenomenal to be able to build an instrument capable of measuring [gravitational waves]," said Prof Rowan.
"It is hugely exciting for a whole generation of young people coming along, because these kinds of observations and this real pushing back of the frontiers is really what inspires a lot of young people to get into science and engineering.