It seems the more we learn about black holes, the less we realize we actually know about them.
Now, astronomers have uncovered a new mystery about supermassive black holes. After studying a series of quasars at distances of billions of light-years apart, astronomers discovered that the supermassive black holes at the center of each quasar are in perfect alignment with each other.
The black holes of quasars have hot spinning discs around them that typically spit out jets as they rotate. This means that quasars appear super bright when observed from ground telescopes.
Although it's impossible to see these hot spinning discs, or axes, directly, researchers measured the polarization of light from each quasar. Astronomers used the direction of the polarization of light to figure out the angle of the axes, which also gave them the direction of the quasars' spinning.
A research team, using the Very Large Telescope in Chile, discovered 93 of these quasars, spanning distances over billions of light-years, seen when the Universe was still relatively young. The first thing they noticed was that the rotation axes of all 93 quasars were aligned with each other, in spite of the distances between them.
So what did that tell astronomers about the structure of the Universe at the time? First, we know that the Universe's galaxies aren't evenly distributed: together, they form a cosmic web of dark matter that connects them and fills in empty areas of space. The arrangement of this material is called large scale structure.
Because of this new discovery of supermassive black hole alignment, astronomers now know that if quasars exists in a long filament of a large scale structure then the black holes' spins actually aligns itself parallel along that filament.
"A correlation between the orientation of quasars and the structure they belong to is an important prediction of numerical models of evolution of our Universe," says Dominique Sluse of the Argelander Institute for Astronomy in Bonn, Germany. "Our data provide the first observational confirmation of this effect, on scales much larger that what had been observed to date for normal galaxies."
But these alignments aren't something that happens randomly. The research team estimates a less than one percent chance that these alignments are accidental. Instead, this alignment suggests that there is an order to the Universe that we're just discovering.
"The alignments in the new data, on scales even bigger than current predictions from simulations, may be a hint that there is a missing ingredient in our current models of the cosmos," says Sluse.
[Photo Credit: ESO]
