We knew our universe had black holes, but we didn’t know it had this many.
NASA’s Wide-field Infrared Survey (WISE) telescope has just completed a broad scan of our universe and found more black holes than scientists estimated.
The all-sky survey, taken in February 2011, created so much data that it took NASA scientists a long time to sift through it all. Among the discoveries is that there are 2.5 million black holes out there.
That’s three times more black holes than originally thought.
The black holes are described as “supermassive” cosmic entities known as quasars that devour nearby matter and release light as a byproduct. It’s this light from the quasars, some of the brightest objects in the universe despite what you think of when you hear the term “black hole,” that WISE was able to detect.
“We expected that there should be this large population of hidden quasars in the universe, but WISE can now identify them across the sky,” NASA’s astronomer Daniel Stern said. “We think these quasars are really important for shaping how galaxies look today.”
The survey also revealed some other interesting discoveries. They’ve also picked up on about 1,000 rare galaxies dubbed “hot DOGs,” for “hot, dust-obscured galaxies.” Astronomers believe these galaxies would appear much brighter, but they are obscured by dust.
Based on their location, it’s also believed that they existed in the earliest days of the universe because of how long (billions of years, most likely) it took for their light to make it to Earth. Though hot DOGs could be a new type of galaxy, astronomers think it’s more likely that they represent a transitional phase between spiral and elliptical galaxies, and they even suspect that our Milky Way galaxy could become a hot DOG when it collides with the Andromeda galaxy in about 2 billion years.