A new study suggests more supermassive black holes may be lurking in the universe than previously thought.

Astronomers from the University of Southampton have discovered that 35 per cent of these enormous entities—some of which are billions of times heavier than the sun—remain undetected.

This is because they are concealed by dense clouds of gas and dust, a significant increase from the previous estimate of 15 per cent.

Professor Poshak Gandhi, co-author of the study published in the Astrophysical Journal, said: "Black holes are the most mysterious objects in the universe and are present everywhere – yet we still don’t fully know how they evolve.

"We’ve found that many more are lurking in plain sight – hiding behind dust and gas rendering them invisible to normal telescopes.

"This is the first time we have a highly refined census of black holes growing by consuming interstellar material surrounding them.

"If we didn’t have a supermassive black hole in our Milky Way galaxy, there might be many more stars in the sky.

"That’s just one example of how black holes can influence a galaxy’s evolution."

The research team utilised data from NASA's InfraRed Astronomy Satellite and the X-ray space telescope NuSTAR to examine infrared emissions from these obscuring clouds.

Prof Gandhi added: "Though black holes are dark, surrounding gas heats up and glows intensely, making them some of the brightest objects in the universe.

"Even when hidden, the surrounding dust absorbs and re-emits this light as infrared radiation, revealing their presence.

"X-rays provide a complementary view peering through the veiling gas, much like a medical X-ray scan allows a doctor to peer through to our insides."

Lead author Dr Peter Boorman, formerly of the University of Southampton and now at Caltech, in Pasadena, California, said: "Black holes also influence the galaxies they live in – this happens because they are surrounded by massive clouds of gas and dust and can consume vast amounts of material."

The team believe that understanding the proportion of hidden to known black holes could provide insights into how these cosmic giants grow to their immense sizes.