Two massive black holes are orbiting each other at a distance closer than scientists have ever seen, and it is likely that they will collide–in about 100,000 years.
Rhythmic Quasars
A team of astronomers at Columbia University led by Daniel D’Orazio recently published a study on the black hole duo in the journal Nature. They’ve been measuring the light from the quasar associated with the area, which has helped them to establish the relative distance and activity of the black holes.
A quasar is the term given to the flickering light sources that emanate from black holes as they burn through surrounding gas and dust. This particular quasar is called PG 1302-102, and last winter, it was determined to derive from not one, but two black holes that are rotating around one another. This discovery was the result of analyzing a rhythmic feature of the quasar’s light: once every five years, its light grows brighter by fourteen percent.
The Columbia team created models of the quasars and estimated that the black holes are about 200 billion miles apart from each other, which turns out, is extremely close in cosmic terms. 200 billion miles is not even a tenth of a light-year. Their orbit is around 3.5 billion light years away from Earth.
Their models also suggest that the black holes are moving in an orbit that spirals, rather than one that rotates evenly. The spiral appears to be bringing them closer and closer to one another, on course for collision in about 100,000 years, depending on their relative masses.
A New Theory of Gravitational Relativity?
The spiral is what’s peculiar about this particular pair of black holes. It is relatively common for black holes to orbit one another when galaxies merge, given that every galaxy “of note” contains a supermassive black hole. In order for quasars to behave in the way that PG 1302-102 is behaving, there would have to be “hundreds of millions of solar masses” accompanying the black holes and exerting gravitational forces that act on the orbits.
Further analysis of PG 1302-102 could provide insight for astrophysicists not just into these two specific black holes, but into the theories of gravity and relativity in general. As D’Orazio said, “The detection of gravitational waves lets us probe the secrets of gravity and test Einstein’s theory in the most extreme environment in our universe…Getting there is a holy grail of our field.”
