How in the world can we 'hear' gravitational waves traveling from 1.3 billion light-years away?
The Laser Interferometer Gravitational-Wave Observatory (LIGO) detected these gravitational waves coming from the collision and merging of two black holes 1.3 billion years ago. And it turns out that when those waves reach us, they sound like a high-pitch chirp.
Gravitational waves are incredibly faint and difficult to detect. They move the Earth by less than the width of an atom's nucleus. But you can "hear" them if you have the right equipment and data.
"We can hear these gravitational waves, we can hear the universe," LIGO spokesperson Gaby Gonzalez said during a press conference on February 11.
Here's what the waves sound like:
We can hear them because LIGO's two detector systems of lasers and mirrors actually act more like a pair of ears than a pair of eyes.
Here's LIGO's explanation for why we can hear the gravitational waves coming from a pair of merging black holes:
Another way to think about it is to consider speech patterns. In the same way that tone of voice and pitch can help you make sense of what's happening in a room full of people talking, changes in the amplitude and frequency of the gravitational waves can tell scientists the kind of sound it's making.
"I like to think of it in a linguistic way," MIT physicist Scott Hughes told The Atlantic. "The vocabulary of the [black hole merger] is imprinted on the wave."
We're excited to hear more chirps, but for now we've got our new text message tone picked out.