Once again, Albert Einstein has proven to be quite the genius we all know him to be. Einstein actually predicted that gravitational waves existed way back in 1916. To find these ripples in space, scientists have constructed LIGO. Together, the Massachusetts Institute of Technology (MIT) and the California Institute of Technology (Caltech) are working towards the mysterious discoveries of these gravitational waves.
The key component of LIGO is the laser interferometer. This is the instrument that will be used to find the existing gravitational waves. Below is a diagram of a laser interferometer:
(image from http://www.space.com/5221-scientists-expect-find-gravitational-waves.html)
This experiment needs high levels of precision and steady ground in order to not get excess noise in the data. For precision, a laser light is shot at the mirrors. The laser is shot through a beam splitter to divide the light. Each part of the beam travels separately down the two perpendicular arms of the system. Each arm consists of two mirrors in which the light can bounce between them. The two arms have the same length causing the beams to interfere and not be read by the photodetector. For the photodetector to read any light, there would have to be some sort of change in the light beams. Well there is something that does just that, gravitational waves! The ripples of the gravitational waves causes the beams of light not to interfere and the photodetector is able to read light going through it. These ripples in space are caused by massive events such as collisions of the stars.
The LIGO team has sought out to find the gravitational waves for many years. When the beam of light of the interferometer is altered and after data analysis, the team will know that they have found gravitational waves.
To get an idea of what the observatory looks like (the long arms are quite noticeable):
Livingstone, Louisiana
(picture from http://www.universetoday.com/46847/ligo/)
Richland, Washington
(picture from http://www.ligo.caltech.edu/LIGO_web/0405news/0405liv.html)
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