Simplified operation of a gravitational wave observatory
<p><b>Figure 1</b>: A beamsplitter (green line) splits coherent light (from the white box) into two beams which reflect off the mirrors (cyan oblongs); only one outgoing and reflected beam in each arm is shown, and separated for clarity. The reflected beams recombine and an interference pattern is detected (purple circle).
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<b>Figure 2</b>: A gravitational wave (yellow) passing over the left arm changes its length and, thus, the interference pattern.
<a href="//commons.wikimedia.org/wiki/User:Cmglee" title="User:Cmglee">Cmglee</a>
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<span class="int-own-work" lang="en">Own work</span>