Astronomers have discovered previously hidden supermassive black holes and speculate that there could be millions of others hidden in space. An international team led by astronomers from Durham University, U.K., said on Sunday that it had detected five such black holes, which were obscured by dust and gas.

The team used NASA’s Nuclear Spectroscopic Telescope Array (NuSTAR) satellite observatory. Their findings were presented at the Royal Astronomical Society's National Astronomy Meeting in Wales on Monday.

Supermassive black holes differ from other black holes, as their names might imply, by being significantly larger than their regular-sized cousins. One supermassive black hole located outside the Milky Way was found to be 12 billion times larger than the Earth’s sun. They consume all matter, including light, and therefore can’t be seen with conventional methods. Instead, scientists need to look for distortions in the area around a black hole.

The five supermassive black holes discovered by the team were much brighter and more active than previously thought, as they had consumed large amounts of nearby material and emitted significant amounts of high energy X-rays into space.

The team found them by pointing NuSTAR at nine potential supermassive black holes. This sort of observation was impossible before NuSTAR was launched in 2012 -- the high-fidelity telescope eschews conventional mirrors and lenses in favor of a novel X-ray based optics system that allows it to see black holes and other obscured stellar bodies with unprecedented clarity.

George Lansbury, of the Durham University Centre for Extragalactic Astronomy and the study’s lead author, said that there were many more potential supermassive black holes that were obscured from human view.

"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." Lansbury said in a press release. "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."