For the first time in the history of astronomical exploration, a direct radio image has been captured, revealing the gravitational ballet of two supermassive black holes orbiting within the core of the distant quasar OJ 287. Situated approximately five billion light-years from Earth, this remarkable phenomenon provides tangible confirmation of theoretical concepts that have long suggested the existence of such binary systems. The discovery, which marks a pivotal shift from speculative models to concrete visual evidence, was recently published in the esteemed journal, The Astrophysical Journal.
Quasar OJ 287 is renowned for its extraordinary luminosity, so bright it is observable even by amateur astronomers using private telescopes. For decades, however, it presented a profound enigma due to a consistent 12-year cycle in its brightness variation. This periodicity, which scientists have been tracking since the 19th century, served as the crucial indicator, leading researchers to hypothesize the presence of a second, less massive black hole revolving around the dominant primary object. The dual system hypothesis, initially put forth in the 1980s, has now been visually substantiated through a collaborative effort.
The successful observation crucially involved the Russian space radio telescope “RadioAstron” onboard the “Spektr-R” spacecraft. The resulting image achieved an unprecedented level of detail, boasting a resolution roughly 100,000 times superior to that of standard optical telescopes. This clarity allowed scientists to pinpoint not only the objects themselves but also their complex dynamics.
The central, more massive component of the system possesses an estimated mass of about 18 billion solar masses. Its companion, significantly smaller, weighs in at approximately 150 million solar masses. While the black holes themselves remain invisible, their presence is betrayed by powerful, radio-emitting streams known as jets. A particularly fascinating aspect is the jet emanating from the smaller black hole. It appears distinctly curved, described by researchers as a “wagging tail,” which is a direct consequence of its rapid orbital motion around its much larger partner.
This specific effect allows investigators, such as Mauri Valtonen from the University of Turku, to move beyond merely confirming the pair's existence and instead refine the detailed dynamic model of the system. Furthermore, analyzing archival data proved fruitful: a retrospective examination of older “RadioAstron” measurements from 2014 successfully detected the signal produced by the smaller black hole—an achievement likened to trying to spot a coin lying on the surface of the Moon. This breakthrough inaugurates a new era in understanding the evolution of galactic nuclei, where the eventual merger of such colossal entities is a fundamental process driving growth. Scientists anticipate that the orbital path will once again align the smaller black hole's jet with our line of sight sometime in the 2030s, offering fresh opportunities to study this monumental cosmic interaction in greater depth.