A mysterious dead star that releases a giant burst of energy three times an hour has been detected 4,000 light years from Earth.
Astronomers say that the celestial object is unlike anything they have seen before.
It's believed to be a 'magnetar' - which have the most powerful known magnetic fields in the universe.
If it was located a sixth of the way to the Moon - about 40,000 miles - it would wipe the data from all of the credit cards on Earth.
The strange object sends out a beam of radiation that crosses our line of sight.
For a minute in every twenty, it's one of the brightest radio sources in the sky.
Observations match a predicted astrophysical object called an 'ultra-long period magnetar'.
Lead author Dr Natasha Hurley-Walker, of Curtin University in Australia, said: "It’s a type of slowly spinning neutron star that has been predicted to exist theoretically.
"But nobody expected to directly detect one like this because we didn't expect them to be so bright.
"Somehow it's converting magnetic energy to radio waves much more effectively than anything we've seen before."
Magnetars are a type of neutron star that form after a supernova - and suffer violent eruptions that last just a fraction of a second.
They can contain up to half a million times the mass of Earth - in a diameter of just 12.4 miles.
Dr Hurley-Walker said: "This object was appearing and disappearing over a few hours during our observations.
"That was completely unexpected. It was kind of spooky for an astronomer because there's nothing known in the sky that does that.
"And it's really quite close to us - about 4,000 light years away. It's in our galactic backyard."
Honours student Tyrone O'Doherty made the discovery using the MWA (Murchison Widefield Array) telescope in the Australian outback.
Mr O’Doherty, who is now studying for a PhD at Curtin, said: "It's exciting the source I identified last year has turned out to be such a peculiar object.
"The MWA's wide field of view and extreme sensitivity are perfect for surveying the entire sky and detecting the unexpected."
Objects that turn on and off in the universe are known as 'transients' - dying stars or the remnants they leave behind.
Co-author Dr Gemma Anderson, also from Curtin, said: "Slow transients - like supernovae - might appear over the course of a few days and disappear after a few months.
"Fast transients - like a type of neutron star called a pulsar - flash on and off within milliseconds or seconds."
But finding something that turned on for a minute was really weird, she said.
It was incredibly bright and smaller than the Sun - emitting highly-polarised radio waves.
Dr Hurley-Walker is monitoring it with the MWA to see if it switches back on.
She said: "If it does, there are telescopes across the Southern Hemisphere and even in orbit that can point straight to it."
Dr Hurley-Walker plans to search for evidence of more in the vast archives of the MWA.
She said: “More detections will tell astronomers whether this was a rare one-off event or a vast new population we'd never noticed before."
The MWA is a precursor instrument for the Square Kilometre Array (SKA) - a global initiative to build the world’s largest radio telescopes in Western Australia and South Africa.
Director Professor Steven Tingay added: "There are, no doubt, many more gems to be discovered by the MWA and the SKA in coming years."
The Murchison Widefield Array is located on the Murchison Radio-astronomy Observatory in Western Australia. The study was published in the journal Nature.
