Quasars are among the brightest known objects in the universe, and the are defined by the massive black holes at their center. According to a report from Popular Science, astronomers working with the Hubble telescope have located a rare binary quasar system, containing two black holes on a collision course with each other.

Markarian 231, the galaxy that harbors the quasi-stellar radio source located nearly 600 million light-years away, is the closest quasar-containing galaxy to Earth. This is the very first ‘binary quasar’ ever observed, but researchers are confident that there are many more like it in the universe.

As Hubble researchers examined the quasar in Markarian 231, they noticed a peculiar gap in its accretion disk, or the circle of gas wrapping around the the black hole before it is swallowed forever. After using data gathered by the telescope to model the forces affecting the quasar’s movement, they concluded that there must be a second small black hole orbiting around the larger one.

The bigger black hole is about 150 million times heavier than our own sun, and the tinier black hole is only four times as massive. Scientists estimate that it will take hundreds of thousands of years for the larger black hole to swallow smaller one.

The team, which included scientists from the U.S. and China, believes the binary system is a product of two galaxies crashing into each other billions of years ago. Their study lays out a method for searching the skies for new binary quasars, and may help us understand how the light escaping quasars can offer clues into the origins of the universe.