Gravitational Waves: Hearing Space for the First Time

Predicted model of a black hole and it's accretion disk based on the 'Gargantua' seen in Interstellar. Photo courtesy of Gizmodo, 2015.

On February 11th the Laser Interferometer Gravitational-Wave Observatory (LIGO) detected the presence of gravitational waves (that was it's job after all) and confirmed a theory that Einstein predicted roughly a century ago. Part of the development of this theory was the notion that space and time are stretched like a giant blanket. We still don't understand how this works (like, the core of what makes gravity gravity) but when you add things with mass to this blanket their gravity bends the web and pulls smaller objects toward them. This explains the moon's orbit around the Earth, the Earth around the Sun, the Sun around the center of the universe, the universe around the... you get it. When large, or dense, objects with a lot of gravity (say, black holes) collide or accelerate at high speeds it was predicted that they would release a gravitational burst that would distort the fabric of space time. Last week we confirmed that this is, in fact, real. 

So, how did they do it? The lab itself used to test this is constructed of two giant arms extending out from each other at a 90 degree angle. At each end are mirrors that face opposite each other and fire a small laser back and forth 400 times. These gravity waves have virtually no bearing on us, but light is a sensitive thing and can pick up on these small variations. To detect the presence of these waves there needs to be some difference in the time it takes for the beams to reach their source. This difference was recorded at two sperate LIGO facilities on the same day, the source that generated it? A pair of black holes merging. Yeah.

The significance of this discovery is layered and perhaps not readily apparent (at least not for me). We didn't discover gravitational waves, we confirmed them. In essence, this guy was able to reason a profound fundamental truth about the nature of the universe using only his mind and the logic derived from within. Since he first put forth his theory of relativity, we've confirmed that gravity distorts light, time, and can distort the space around an object across the universe. And he reasoned all this was likely before we had the internet. 

But there's more to what this news means for all of us. On the one hand, it reveals another layer of uniform intricacy within our universe. We've been studying for years the nature of waves and what consistency might remain across the different forms (light, sound, magnetic, quantum, etc) and this allows for another form of this phenomenon to be studied. What's more, we've spent the majority of human history studying space through light and light alone. This opens up a completely new way to detect the goings on all around us. The metaphor being tossed around is that it's like suddenly being able to listen to the universe. We of course won't know what all we're listening to, but imagine yourself walking through the rain forest with your ears covered. There's a deeper (maybe even scarier) world that is revealed once you can hear your surroundings as well. 

There's no limit to what these new ears can give us but one thing is certain: there's going to be a lot we just had no clue about. On a personal note, one of my favorite things about space exploration, and particularly the folks who study this stuff, is that you have to have certain willingness to be dumbfounded, to be surprised. To be completely wrong. For me, there's something wildly profound about leaping off into the unknown, into this great void around us and daring to come back with something new, some greater triumph. Like some Theseus shit or something. When I write, this sort of exploration is always present in my mind. To have the courage to dig up some deep (and often dark) inner truths about yourself, and to know that sometimes they won't necessarily be explained or reasoned away. Sometimes all you can do is take a step back, see it for what it is and say "wow."