Astronomers capture historic image of two black holes orbiting each other

In a discovery that would provide a glimpse into the future of the universes, a global team of astronomers that included scientists from two Indian research institutes have for the first time spotted two black holes circling each other in distant space.

Black holes are regions in space where gravity is so strong that nothing, not even light, can escape. This intense gravity is caused by a massive amount of matter being squeezed into a very small area, which can happen when a massive star collapses at the end of its life. Because no light can escape, they are invisible, but they can be detected by their effects on nearby matter and stars.

“Seeing two black holes in orbit is more than a stunning image,” according to the Ministry of Science and Technology. “It is a window into the future of our universe. When black holes eventually collide, they release titanic ripples in ‘space-time’ called gravitational waves, the very ripples that some observatories have detected. Studying this gives scientists a natural laboratory for understanding how such cataclysmic events unfold,” the ministry said.

Black holes are usually invisible, but their surroundings glow brightly as matter falls in. Astronomers have previously imaged just two of them directly — the supermassive black hole in the galaxy Messier 87 and in the heart of the Milky Way. Both revealed a shadowy silhouette surrounded by a ring of light, according to information shared by the ministry.

Using an extraordinary network of telescopes — including one orbiting halfway to the Moon, scientists from Aryabhatta Research Institute of Observational Sciences (ARIES), Nainital and Tata Institute of Fundamental Research, Mumbai, along with experts from Finland, USA, Japan, Spain, Czech and Poland, found something different.

They spotted radio image of quasar known as OJ287, a distant galaxy powered by not one, but two black holes orbiting each other every 12 years. For decades, astronomers suspected this cosmic duo existed because of the quasar’s rhythmic flickering, a pattern first traced back to 19th-century photographs, but this remained to be proved. The question was whether both black holes were bright enough to be seen and if there was an image of high enough resolution that they can be separated spatially.

The breakthrough, published in The Astrophysical Journal, came when the team used the RadioAstron space telescope — an antenna orbiting Earth at vast distances — together with ground-based observatories. This setup provided resolution sharper than any telescope on Earth alone could achieve.

The image revealed not one, but two distinct points of radio emission. Just as predicted, these were the two black holes of OJ287. Even more striking, the smaller black hole was seen launching a jet of high-energy particles. Because it whirls around its massive partner, the jet twists like a “wagging tail” or a spinning garden hose, changing direction as the black hole speeds along its orbit.

In 2021, Indian and American experts in the team had monitored OJ287 with NASA’s TESS satellite. They discovered a huge brightening in just 12 hours, corresponding to the extra brightness of some hundred galaxies. OJ287 faded away equally fast and it was confirmed by ground-based observations by a number of telescopes. A case was made for having seen the second black hole of the OJ287 system in action.

In the meantime, a radio image of OJ287 was produced which had the unprecedented resolution, resolving even higher detail than the images of the two black holes in the Milky Way and Messier.