If you’re a physicist, you’re probably beside yourself with glee.
If you’re not a physicist, you’re probably a bit confused as to what the fuss is about.
Gravitational waves are the “ripples” in spacetime that massive objects make when they accelerate. The distance between objects in space changes as gravitational waves stretch spacetime in one direction and simultaneously compress it at a 90 degree angle to that direction. Theoretically, this change can be measured. Unlike other more familiar phenomena like cosmic background radiation, gravitational waves are not on the electromagnetic spectrum, so they cannot be “seen” in the way that visible or ultraviolet radiation can be seen.
So the Laser Interferometer Gravitational-Wave Observatory (LIGO) listened.
Caltech and MIT jointly operate LIGO, which spans two locations: one in Livingston, Louisiana and one in Hanford, Washington. Each site has two 4-kilometer-long instruments arranged in an “L” shape. Together, LIGO Livingston and LIGO Hanford use meticulously aligned laser beams to detect interference that causes the beams to move infinitesimally out of alignment — about one ten-thousandth the width of a proton.
It took years to create the technology necessary to isolate the tiny movement caused by gravitational waves. Few people outside the program thought it would ever be possible to observe such small disruptions.
But when the most advanced version of LIGO was ready to test in September 2015, the experiment rewarded scientists with the sounds of something extraordinary: two black holes, each more massive than our sun, colliding a billion light-years away. To date, this is the most direct piece of evidence humanity has gathered for the existence of black holes.
If that does not put the looming threat of midterms in perspective, you may want to read it again.
The scientific impact of this discovery is far-reaching and readily apparent. Once confined to visual cues, scientists can now turn an ear to the universe.
Perhaps even more significantly, the observation is an immense step towards proving Einstein’s general theory of relativity. As astrophysics and cosmology continue their headlong rush into the abstract, a sound foundation of proven theory may soothe the current controversy over the place of empirical methodology in the theoretical sciences.
But what is the importance of this for the rest of the world? Why spend so much time trying to detect something that happened a billion years ago in a galaxy far, far away?
With so much of the earth covered with humans and our technology, it can be easy to lose sight of just how little we know of reality.
It may be hundreds of years before humankind’s understanding of dark matter climbs out of the shadows. We may not, for one reason or another, ever make contact with an extraterrestrial species we deem intelligent. Yet now, in this present, we can grasp at something beyond price: our collective wonder.
