Harvard researchers have proposed a theory about the possibility of mysterious celestial phenomena known as fast radio bursts (FRB) being caused by alien space travel or advanced alien technology.
"Specifically, these bursts might be leakage from planet-sized transmitters powering interstellar probes in distant galaxies," suggested astronomers from the Harvard-Smithsonian Center for Astrophysics.
Theoretical physicist Avi Loeb who works at the centre believes because science has so far failed to identify a natural source of FRBs, "an artificial origin is worth contemplating and checking."
Powerful fast radio bursts are one of astronomy's most enigmatic phenomena and have intrigued scientists for years.
They are pulses of radio energy that originate from an unknown cosmic address and last just milliseconds before seemingly disappearing forever. They can emit as much energy in a millisecond as the sun does in 10,000 years.
Since first discovering the phenomena in 2007, fewer than two dozen have been recorded. Their existence has been attributed to all sorts of conspiracies and theories including alien broadcasting, stars collapsing into black holes and the explosion of a super-luminous supernovas.
Now, Professor Loeb, along with fellow Harvard scientist Manasvi Lingam, have theorised about the possibility they could be the result of a massive power plant system used by an alien species for cosmic travel.
The theory, as crazy as it sounds, explores how an immensely powerful solar radio transmitter could use photonic propulsion to power ships across the galaxy.
They examined the feasibility of creating such a radio transmitter and found that if you doubled the amount of sunlight to hit Earth, then that would be enough energy to theoretically power such a device, according to a statement released by the Harvard-Smithsonian Center for Astrophysics.
"That's big enough to carry living passengers across interstellar or even intergalactic distances," Lingam said.
A powerful enough beam of light can propel a reflective surface in the vacuum of space, which is the basis for light sail technology that underpins the theory - something which astronomers have been experimenting with.
Such a capability theorised by the Harvard scientists is well beyond our technology, but within the realm of possibility according to the laws of physics.
It may all sound far-fetched (and is really an exercise in the power of imagination), but the theory is at least technically robust enough to have been accepted by the Astrophysical Journal Letters and is currently published online.
"The optimal frequency for powering the light sail is shown to be similar to the detected FRB frequencies. These 'coincidences' lend some credence to the possibility that FRBs might be artificial in origin," the researchers wrote.
Of course, it remains a mystery what causes these brief barrages of radio waves but earlier in the year researchers published an article in the prestigious journal Nature which, for the first time, pinpointed the location of the first known FRB to repeat itself.
FRB 121102, the only repeating fast radio burst know to science, emanates from a dwarf galaxy some three billion light years from Earth, scientists wrote.