And, to make matters even more alarming, researchers have now realised that the signals have been arriving at our planet since 1988 – but no-one understands what object might be sending them.
Every 22 minutes for the last 35 years, blasts of energy in varying levels of brightness have been picked up, sometimes lasting for five minute intervals.
Scientists previously believed it was impossible to send such a signal with such frequency and kind of brightness for so long – until this object seemed to prove otherwise.
A new paper called ‘A long-period radio transient active for three decades,’ published in the journal Nature last week, explained that researchers are calling the signal-emitting object GPMJ1839-10.
And, by going back through old records, they suddenly realised this signal had been reaching Earth since 1988 – and could be 15,000 light-years away.
There’s a theory that the flashing could come from pulsars – these are neutron stars which spin quickly and throw out radio blasts in the process.
Usually, when one of these emissions reaches Earth, they can be picked up very briefly and brightly, comparable to the flash from a rotating lighthouse.
Our planet can only pick these signals up if the object is rotating fast enough and its magnetic field is very strong – otherwise we wouldn’t be able to see it.
But pulsars’ signals usually trail off as they die (that’s known as the death line), a few months or years after they start emitting the signals. That’s when their magnetic field gets too weak to generate more high-energy radiation.
But this signal, having been picked up on Earth for more than 30 years, seems to be the exception.
If it’s not a pulsar, it could be a magnetar – another neutron star which has a larger magnetic field than a pulsar but spins much more slowly.
However, in a statement, radio astronomer at Australia’s International Centre for Radio Astronomy Research and lead author of a study on the object, Natasha Hurley-Walker, said in a statement: “The object we’ve discovered is spinning way too slowly to produce radio waves – it’s below the death line.
“Assuming it’s a magnetar, it shouldn’t be possible for this object to produce radio waves. But we’re seeing them.”
This object was first discovered in September 2022, using the Murchison Widefiled Array, a radio telescope array in the Australian outback.
Hurley-Walker also explained previous scientists had “missed” the radio waves “because they hadn’t expected to find anything like it.”
The object’s a slow rotation, long pulse period and lengthy period of emission defies all models which could explain it.
She added: “This remarkable object challenges our understanding of neutron stars and magnetars, which are some of the most exotic and extreme objects in the universe.
“Whatever mechanism is behind this is extraordinary.”