Gravitational Wave Might Have Come From 'Twin' Black Holes Born In The Same Star

The original baby boomers

a black hole against a starry sky

Simulation Of Two Merging Black Holes In Front Of Milky Way

Andy Bohn, François Hébert, William Throwe, Darius Bunandar, Katherine Henriksson, Mark A. Scheel, and Nicholas W. Taylor

Earlier this month, scientists announced the first official discovery of the gravitational waves that Einstein predicted 100 years ago. The ripples in space-time emanated from the massive collision of two black holes 1.3 billion light-years away from us. Now, observations from the Fermi Space Telescope could tell us more about the nature of those black holes.

Fermi detected a gamma ray burst just 0.4 seconds after the gravitational waves were detected. And although the European INTEGRAL gamma-ray satellite could not confirm the signal, the researchers think the signal could mean that the two black holes that collided were actually born in the same, massive star.

Ordinarily, at the end of its life, a massive star would collapse into one black hole. But sometimes if the star is spinning rapidly, it can stretch out into a dumbbell shape that separates into two black holes.

"It's the cosmic equivalent of a pregnant woman carrying twins," said astrophysicist Avi Loeb of the Harvard-Smithsonian Center for Astrophysics.

After their birth, the two baby black holes, which weighed about 29 and 36 times the mass of the Sun, may have begun feeding on the remains of their mother star, consuming huge amounts of matter and burping out those gamma rays that Fermi detected. Says a press release:

In order to power both the gravitational wave event and the gamma-ray burst, the twin black holes must have been born close together, with an initial separation of order the size of the Earth, and merged within minutes.

We're glad that the human process of giving birth to twins is not quote as violent as all that.

Still, it's important to note that Fermi's signal could certainly be a false alarm, since the other telescope couldn't confirm it. It's possible the binary black holes formed in the 'usual' way, during the merger of two galaxies.