Gravitational Waves Have Been Detected, a Century After Einstein Predicted Them
Listen to the sound of two black holes colliding.
Simulation of gravitational waves emerging from a black hole collision. Image: Werner Benger
The results are in, and the rumors are true. The Laser Interferometer Gravitational-Wave Observatory (LIGO), based jointly in Louisiana and Washington, has directly detected gravitational waves for the first time in history. We can now officially "hear" cosmic phenomenon such as colliding black holes, in the same way that telescopes have allowed us to see these spectacular events.
Wild applause and fervent jubilation is recommended.
"We have detected gravitational waves," said David Reitze, LIGO's laboratory executive director, during a packed press briefing this morning at 10:30 AM Eastern. "We did it."
Seriously, there is no understating the significance of this milestone for the scientific community. Gravitational waves, which are ripples in the very fabric of spacetime, are incredibly subtle and challenging to catch. Even Albert Einstein himself, who predicted the existence of these waves 100 years ago, was doubtful that such a seemingly insurmountable feat could ever be accomplished.
Well, the folks at LIGO have proved him wrong about that by proving him right about the existence of gravitational waves. The waves that the observatory picked up were emitted by two black holes, each about 30 times the mass of the Sun, that collided some 1.3 billion years ago.
Just like that, all of Einstein's major predictions from his general theory of relativity have now been borne out by direct observational evidence.
Now, cosmologists, astrophysicists, and all manner of other spacetime experts can get down to the dirty work of figuring out where this entirely new dataset fits in to our growing understanding of our own outrageously bizarre universe.
The gravitational wave that was detected by LIGO passed through the Earth on September 14, 2015 at 5:51 AM Eastern time. The tremor was created by the collision of two black holes located over one billion light years away in the general direction of the Magellanic Cloud. These objects merged at roughly half the speed of light, 1.3 billion years ago.
The full peer-reviewed paper on the historic detection was just published by the Physical Review Letters.
During her presentation on the findings, Gabriela González, a research scientist at the Louisiana LIGO center, played the chirping sound that the gravitational wave made as they swept through the detectors. You can listen to it below.
Did you hear it? Well, congratulations, because that is the first sample of the universe's never-before-heard mixtape. The presenters at today's announcement emphasized that we have now learned to record the audio of the universe, in addition to developing better visuals on it.
"This is the first time the universe has spoken to us in gravitational waves," Reitze said. "Up until now we've been deaf [...] That's just amazing to me."
One of the other major points that was stressed by several speakers was that though this historic announcement caps off 100 years of speculation about gravitational waves, it also marks a new beginning for science as a whole.
"This is the first of many to come," said González.
To that point, Reitze said that LIGO is likely to pick up on gravitational waves from predicted sources like black hole mergers, binary star systems, supernovae, and other phenomenon within the next year. What may be even more fascinating, however, is what LIGO and future gravitational wave detectors pick up that is not predicted or expected by current cosmological theories.
"What's really exciting is what comes next," Reitze said.
The detection has been compared both to Galileo's first observations through a telescope and "a scientific moonshot" on the scale of the Apollo Moon landings.
Welcome to the post-wave world, everybody. We're looking forward to listening to more of this awesome cosmic dubstep with you in the future.
This post has been updated throughout as more developments have come in.