Final answer:
Gravitational waves are created by events such as the merging of two black holes and detected by facilities like LIGO, validating Einstein's theories on general relativity.
Step-by-step explanation:
Gravitational waves are distortions in spacetime that propagate at the speed of light and were first predicted by Einstein's general theory of relativity. An example of how a gravitational wave could be created is through the coalescence of two black holes when they spiral together and merge. This violent cosmic event distorts the surrounding spacetime, akin to dropping a pebble in a pond and creating ripples, except these ripples move at the speed of light. To detect these waves, scientists rely on highly sensitive detectors like LIGO (Laser Interferometer Gravitational-Wave Observatory), spanning across the globe with installations in the US, Italy, Germany, and Japan. The direct detection of gravitational waves by LIGO provided confirmation of general relativity's predictions and opened a new window for astronomical observations.