The collision took place 7.5 billion light-years from Earth and the black holes were about the size of Long Island.

This illustration shows a stage in the merger of two galaxies that forms a single galaxy with two centrally located supermassive black holes surrounded by disks of hot gas. The black holes orbit each other for hundreds of millions of years before they merge to form a single supermassive black hole that sends out intense gravitational waves. Image credit: NASA/CXC/A.Hobart

The collision between two black holes is known to send ripples in space and time but is not known to emit light – till now. Astronomers have now revealed that they saw a flare of light coming out when two black holes rapidly spun around each other before making a violent union.

The astronomers claim that this is the first time they have seen a merger of black holes giving off light.

A new study published in the journal Physical Review Letters says that the black holes may have just been in the right place at the right time because of which the researchers observed a flare of light.

The research has been conducted by a team of scientists from Graduate Center, CUNY, Caltech’s Zwicky Transient Facility (ZTF), Borough of Manhattan Community College (BMCC) and the American Museum of Natural History (AMNH), reported SciTech Daily.

When the celestial dance took place, the black holes were located inside a giant disc of gas and dust. What happened was that their merger created something like a shock wave that crashed into the surrounding dirt and gas. As a result of this, the nearby material got heated, causing the light to emerge.

The collision took place 7.5 billion light-years from Earth and the black holes were about the size of Long Island.

“If it’s two black holes merging, you don’t expect to see anything. But because the black holes are surrounded by this stuff, by this accretion disc, that’s different," reported The Verge quoting Matt Graham, a research professor of astronomy at Caltech and lead author of the study.

The light was observed using the LIGO-Virgo collaboration, an international scientific partnership that’s become increasingly skilled at detecting cataclysmic events like black holes merging.