Watch LIGO's Dazzling Simulations of Merging Black Holes and Gravitational Waves

Thursday, 11 February 2016 - 2:15PM
Astrophysics
Thursday, 11 February 2016 - 2:15PM
Watch LIGO's Dazzling Simulations of Merging Black Holes and Gravitational Waves
Today, scientists from the Laser Interferometer Gravitational Wave Observatory (LIGO) made the historic announcement that they have detected gravitational waves, confirming a key prediction of Einstein's theory of relativity, and by extension providing compelling evidence for the Big Bang theory and inflationary theory. 
Opening quote
"These gravitational waves were produced by two colliding black holes, which came together and formed a single black hole by 1.3 billion years ago," LIGO laboratory executive director David Reitze said during the announcement. "The signal is exactly what Einstein's theory of general relativity would predict for two massive objects like black holes spiraling and merging together."
Closing quote


During the announcement, LIGO showed two amazing videos of the merger of binary black holes and gravitational waves traveling to Earth, respectively. Both videos are actual computer simulations that solve Einstein's equations for the merger of black holes and resultant gravitational waves. As Reitze put it, "This is really what it would look like if you were in a spaceship close-up."

According to the new study, LIGO detected an event in which two black holes merged 1.3 billion years ago, each of which was 30 times the mass of the sun and 150 km in diameter To put that in perspective, it's like stuffing 30 suns into an area that's a little larger than the DC metropolitan area, accelerating it to half the speed of light, and then colliding two of those together. 

As the black holes spin around each other, the strong gravitational fields bend the light around them, warping the stars that lie behind the black holes. The orbit speeds up as they become closer and closer together, and eventually it decays altogether and they merge.

Gravitational Waves 

Gravitational Waves      

The event horizons join together, two smaller black holes die, and one large one is born. The resultant black hole is comparatively static, although there is a "hint of vibration" around the edges:

Gravitational Waves

Opening quote
"This is the first time this type of system has ever been seen--a binary black hole merger--and it's proof that binary black holes exist in the universe," said Reitze.
Closing quote


In another simulation, LIGO shows the same event, but this time visually representing the gravitational waves, or the ripples in spacetime that are created when the orbit decays and the black holes merge together. Some waves are created as the black holes spin around each other, followed by a burst of gravitational waves from the force of the merger:

Gravitational Waves

Gravitational Waves

That burst of gravitational waves travels for 1.3 billion years, passing through all matter it encounters, including stars, planets, and entire galaxies, before finally reaching Earth:

Gravitational Waves

When the gravitational waves reach Earth, they warp spacetime, stretching and compressing space:

Gravitational Waves

Gravitational Waves

The effect in the video is, of course, exaggerated greatly, as Reitze assures us that the Earth does not actually "jiggle like Jell-o." Rather, the warping of spacetime can only be detected at the tiniest levels by LIGO, namely at a scale of 1/1000 of the size of a proton. It's so sensitive, in fact, it can actually record the sound of the universe, including the sound of two black holes colliding with each other:

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Astrophysics

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