Astronomers say the object, which is about 4,000 light-years from Earth, is pulsing every 18.18 minutes, a frequency that has never been observed before.
Australian researchers have discovered a strange spinning object in the Milky Way they say is unlike anything astronomers have ever seen.
The object, first spotted by a university student working on his undergraduate thesis, releases a huge burst of radio energy three times every hour.
The pulse comes "every 18.18 minutes, like clockwork," said astrophysicist Natasha Hurley-Walker, who led the investigation after the student's discovery.
While there are other objects in the universe that switch on and off, such as pulsars, Hurley-Walker said 18.18 minutes is a frequency that has never been observed before - "nothing known in the sky that does that."
The research team is now working to understand what they have found, and there are still many mysteries to untangle.
'It could be some entirely new type of object'
Trawling back through years of data, researchers have been able to establish a few facts: the object is about 4,000 light-years from Earth, is incredibly bright and has an extremely strong magnetic field.
"If you do all of the mathematics, you find that they shouldn't have enough power to produce these kind of radio waves every 20 minutes," Hurley-Walker said. "It just shouldn't be possible."
The object may be something researchers have theorised could exist but have never seen called an "ultra-long period magnetar" or a white dwarf, a remnant of a collapsed star.
"But that's quite unusual as well. We only know of one white dwarf pulsar, and nothing as great as this," Hurley-Walker said.
"Of course, it could be something that we've never even thought of - it could be some entirely new type of object."
'Not an artificial signal'
On the question of whether the powerful, consistent radio signal from space could have been sent by some other life form, Hurley-Walker conceded: "I was concerned that it was aliens."
But the research team was able to observe the signal across a wide range of frequencies. "That means it must be a natural process, this is not an artificial signal," Hurley-Walker said. The next step for the researchers is to look for more of these strange objects across the universe.
"More detections will tell astronomers whether this was a rare one-off event or a vast new population we'd never noticed before," Hurley-Walker said.
The team's paper on the object has been published in the latest edition of the journal Nature.