Supermassive black holes lie at the very hearts of distant galaxies. Sucking in material at a prodigious rate, these huge structures have long remained a mystery to scientists. Now, NASA's black-hole-hunter spacecraft, the Nuclear Spectroscopic Telescope Array (NuSTAR) has bagged is first 10 supermassive black holes, giving researchers the data they need to learn a bit more about black holes.

The black holes that the spacecraft sighted are between .3 and 11.4 billion light-years from Earth. Before now, it was impossible to properly view these black holes. NuSTAR, though, has the ability the focus the highest-energy X-ray light into detailed pictures--a useful skill when it comes to viewing black holes.

Yet spying these black holes wasn't the main mission for NuSTAR. In fact, the researchers spotted these black holes serendipitously as they glanced over the pictures that the spacecraft took. The black holes were located in the background of the images. Even so, they provide a wealth of data for scientists.

In order to learn more about these 10 black holes, the researchers then combed through previous data taken by NASA's Chandra X-ray Observatory and the ESA's XMM-Newton satellite. That's when they realized that the objects had been detected before, but that they weren't prominent enough to warrant further study.

"We are getting closer to solving a mystery that began in 1962," said David Alexander, one of the researchers, in a news release. "Back then, astronomers had noted a diffuse X-ray glow in the background of our sky but were unsure of its origin. Now, we know that distant supermassive black holes are sources of this light, but we need NuSTAR to help further detect and understand the black hole populations."

In fact, NuSTAR is particularly suited for this mission. The comic X-ray background peaks at the high-energy frequency that the spacecraft is designed to see. This allows it to identify exactly what's producing the light.

"Our early results show that the more distant supermassive black holes are encased in bigger galaxies," said Daniel Stern, one of the researchers, in a news release. "This is to be expected. Back when the universe was younger, there was a lot more action with bigger galaxies colliding, merging and growing."

The researchers plan to continue exploring the galaxy with NuSTAR as it hunts for other exotic objects.

The findings are published in The Astrophysical Journal.