A newly discovered black hole is believed to be closer to Earth than any others previously found.
It is thought to be just 1,011 light years away in the star system HR 6819, a distance scientists say is close enough to be seen by the naked eye.
The discovery was unveiled on Wednesday in the journal Astronomy and Astrophysics.
The cosmic object is understood to be four times the mass of the sun, but squeezed into the space of just a few kilometres, National Geographic reports.
According to the magazine, if in a model of the Milky Way the Earth was only a hair's distance away from the sun, HR 6819 would be four miles away.
In astronomy terms, this is so close that scientists believe the galaxy could be home to millions of other black holes, some of which may be even closer.
"This source is actually close enough to see with the naked eye. That's what really stunned me about this discovery," Alan Duffy, an astronomer at Swinburne University in Melbourne, Australia explains.
He told 9news.com.au : "It means we had this monster hiding in plain sight for years. For some reason we didn't detect it earlier.
"For us to have a found a black hole so close to us means there must be hundreds of millions of these black holes in our galaxy. Indeed there must be one or two that are even closer."
Black holes are regions of space with a gravitational field so strong that not even light can escape.
Because most are invisible, the only way to detect them is through their gravitational effects on nearby objects.
Professor Duffy added that the "extraordinary" discovery will allow scientists to learn more about gravity.
Thankfully, despite its proximity, experts do not believe the new black hole is a threat to Earth.
