Five monster black holes that were previously hidden by dust and gas have been uncovered by astronomers.
The British-led discovery suggests there may be millions more "supermassive" black holes in the universe than were previously thought.
Supermassive black holes are powerful cosmic "drains" sucking material into a point of infinite density formed from the compressed mass of hundreds of thousands to billions of suns.
High energy X-rays emitted from around the newly identified black holes revealed their presence at the centre of five galaxies.
They were detected by the American space agency Nasa's Nuclear Spectroscopic Telescope Array (NuSTAR) orbiting observatory which was launched in 2012.
The space telescope is designed to pick up extremely high energy X-rays from distant objects.
Lead scientist George Lansbury, from the Centre for Extragalactic Astronomy at the University of Durham, said: "For a long time we have known about supermassive black holes that are not obscured by dust and gas, but we suspected that many more were hidden from our view.
"Thanks to NuSTAR for the first time we have been able to clearly see these hidden monsters that are predicted to be there, but have previously been elusive because of their 'buried' state.
"Although we have only detected five of these hidden supermassive black holes, when we extrapolate our results across the whole universe then the predicted numbers are huge and in agreement with what we would expect to see."
The scientists presented their findings at the Royal Astronomical Society's National Astronomy Meeting, in Llandudno, Wales.
Dr Daniel Stern, NuSTAR project scientist at the American space agency Nasa's Jet Propulsion Laboratory in Pasadena, US, said: "High-energy X-rays are more penetrating than low-energy X-rays, so we can see deeper into the gas burying the black holes. NuSTAR allows us to see how big the hidden monsters are and is helping us learn why only some black holes appear obscured."
The research, funded by the Science and Technology Facilities Council (STFC), has been accepted for publication in The Astrophysical Journal.
Meanwhile, Comet lander Philae may be sitting on an object teeming with alien microbial life, according to two leading astronomers.
Distinct features of the comet 67P/Churyumov-Gerasimenko, such as its organic-rich black crust, are best explained by the presence of living organisms beneath an icy surface, they claim.
Rosetta, the European space craft orbiting the comet, is also said to have picked up strange "clusters" of organic material that look suspiciously like viral particles.
But neither Rosetta nor its lander are equipped to search for direct evidence of life after a proposal to include this in the mission was allegedly laughed out of court.
Astronomer and astrobiologist Professor Chandra Wickramasinghe, who was involved in the mission planning 15 years ago, said: "I wanted to include a very inexpensive life-detection experiment. At the time it was thought this was a bizarre proposition."
He and colleague Dr Max Wallis, from the University of Cardiff, believe 67P and other comets like it could provide homes for living microbes similar to the "extremophiles" that inhabit the most inhospitable regions of the Earth.
Why are you making commenting on The Herald only available to subscribers?
It should have been a safe space for informed debate, somewhere for readers to discuss issues around the biggest stories of the day, but all too often the below the line comments on most websites have become bogged down by off-topic discussions and abuse.
heraldscotland.com is tackling this problem by allowing only subscribers to comment.
We are doing this to improve the experience for our loyal readers and we believe it will reduce the ability of trolls and troublemakers, who occasionally find their way onto our site, to abuse our journalists and readers. We also hope it will help the comments section fulfil its promise as a part of Scotland's conversation with itself.
We are lucky at The Herald. We are read by an informed, educated readership who can add their knowledge and insights to our stories.
That is invaluable.
We are making the subscriber-only change to support our valued readers, who tell us they don't want the site cluttered up with irrelevant comments, untruths and abuse.
In the past, the journalist’s job was to collect and distribute information to the audience. Technology means that readers can shape a discussion. We look forward to hearing from you on heraldscotland.com
Comments & Moderation
Readers’ comments: You are personally liable for the content of any comments you upload to this website, so please act responsibly. We do not pre-moderate or monitor readers’ comments appearing on our websites, but we do post-moderate in response to complaints we receive or otherwise when a potential problem comes to our attention. You can make a complaint by using the ‘report this post’ link . We may then apply our discretion under the user terms to amend or delete comments.
Post moderation is undertaken full-time 9am-6pm on weekdays, and on a part-time basis outwith those hours.
Read the rules hereComments are closed on this article