In a groundbreaking discovery, astronomers using the James Webb Space Telescope (JWST) have detected the most distant merger between supermassive black holes ever observed. The colliding black holes, located at the centers of merging galaxies, provide a glimpse into the early universe only 740 million years after the Big Bang.

The presence of supermassive black holes, with masses millions or even billions of times that of the sun, has long been suspected to play a crucial role in the cosmic evolution of galaxies. The new findings from the JWST suggest that these massive black holes have been shaping the universe since its inception.

The JWST, with its powerful infrared capabilities, has consistently unearthed supermassive black holes in the infant universe. However, this posed a challenge as the merger process that drives their growth typically takes over a billion years. This discovery could shed light on the perplexing question of how supermassive black holes attained tremendous masses so early in the history of the universe.

Hannah Übler, a scientist from the University of Cambridge and the research leader of the study, stated, "Our findings suggest that merging is an important route through which black holes can rapidly grow, even at cosmic dawn. Together with other Webb findings of active, massive black holes in the distant universe, our results also show that massive black holes have been shaping the evolution of galaxies from the very beginning."

Supermassive black holes reside at the core of active galactic nuclei (AGN) and are responsible for powering bright emissions called quasars. These quasars can outshine the combined light of all the stars in their surrounding galaxies. Their distinctive characteristics, observable only by telescopes in Earth's orbit, help astronomers identify them as feeding supermassive black holes.

To investigate the merging quasars in the early universe, Übler and her team focused on a galactic system known as ZS7, located approximately 12 billion light-years away. Utilizing the JWST's Near-InfraRed Spectrograph (NIRSpec), they discovered dense gas with fast motions surrounding one of the supermassive black holes, as well as hot, highly ionized gas illuminated by the energetic radiation emitted during accretion episodes.

While the research team estimated that one of the merging black holes had a mass equivalent to around 50 million suns, conclusive confirmation of the second black hole's mass was hindered by dense surrounding gas.

Pablo G. Pérez-González, a scientist from the Centro de Astrobiología (CAB) and a member of the team, remarked, "The stellar mass of the system we studied is similar to that of our neighbor, the Large Magellanic Cloud. We can try to imagine how the evolution of merging galaxies could be affected if each galaxy had one supermassive black hole as large or larger than the one we have in the Milky Way."

Once these two supermassive black holes merge, they would produce gravitational waves that ripple through space. These tiny ripples could be detected by future gravitational wave detectors, including the Laser Interferometer Space Antenna (LISA), a space-based system being developed jointly by NASA and the European Space Agency (ESA), set to launch in 2035.

Nora Luetzgendorf, the ESA's Lead Project Scientist for LISA, emphasized, "The JWST's results are telling us that lighter systems detectable by LISA should be far more frequent than previously assumed. It will most likely make us adjust our models for LISA rates in this mass range. This is just the tip of the iceberg."

The discovery of this distant merger of supermassive black holes not only offers insights into the cosmic evolution of galaxies but also presents exciting prospects for future astronomical investigations. With each new finding, scientists come closer to unraveling the mysteries of the universe's early days.