<p>&nbsp; Using the theory of Interference can prove
this.Scientists emitted a laser in a laboratory of two L shapes to beam
splitter into two; one went straight while the other went left. The light will
reflect when encountering the mirror at the end of 4-kilometer-long way. In
normal situation, at the moment the two lights encounter each other, there will
be a counteraction because of the interference effects. However, if there are
gravity waves passing through the lab, the space-time will be twisted, the
length of the two tunnels will be changed. Since the light waves weren’t
completely countered, the lights still existed. That’s how the scientists verified the gravity
waves.<br></p>