A group of U.S. scientists began observing a pair of supermassive black holes in the distant galaxy 0402+379 about 12 years ago. These black holes are quite huge. In fact, combined, they have a mass around 15 billion times that of our sun. Thus, their orbital period is extended, standing at between 20,000 and 30,000 years. Their findings were published in The Astrophysical Journal
These long orbital periods, combined with them being close together –in astronomical terms- makes measuring their movements very difficult.
The movement researchers are looking for is known as the angular motion, which is the curved motion that you would see if two objects orbit each other.
Supermassive black holes are orbiting each other at an incredibly slow pace
To measure the movements, the researchers used the Very Long Baseline Array (ten radio telescopes located across the United States) to observe different radio signals coming from the huge black holes.
“If you imagine a snail on the recently discovered Earth-like planet orbiting Proxima Centauri –a bit over four light years away- moving at one centimeter a second, that’s the angular motion we’re resolving here,” said Roger W. Romani, the study’s co-author and professor of physics at Stanford University, according to Newsweek.
The researchers found that the supermassive black holes are indeed orbiting each other. They noted that while additional observations are needed to confirm this motion and obtain a precise orbit, this appears to be the first black hole system resolved as a visual binary.
“For a long time, we’ve been looking into space to try and find a pair of these supermassive black holes orbiting as a result of two galaxies merging,” said Greg Taylor, a scientist at the University of New Mexico, according to Newsweek. “Even though we’ve theorized that this should be happening, nobody had ever seen it until now.”
The findings could help understand what happens before a black hole merger
The researchers said that the plan to continue observing the supermassive black holes over the next three to four years to confirm their orbits and the discovery. The team believes that the supermassive black holes might never collide at all. They found that they are moving at such a slow pace, that at their current speed rate they will still be orbiting one another when the universe ends, sometime around billions or trillions of years from now.
But, the researchers said the current findings should help other scientists better understand what happens before black holes merge and how galaxies evolve.
Taylor noted that supermassive black holes have a lot of influence on the stars around them and the growth and evolution of the galaxy, so understanding more about them and what happens when they merge with one another could be very important for their understanding of the universe.