In a recent study which has been approved for publication Astrophysical Journal Letters, Harvard researchers, Manasvi Lingam and Abraham Loeb suggest that aliens may actually co-exist with Fast Radio Bursts(FRBs), whose origin has been a cause of speculation since their discovery in 2007. FRBs are actually leakages from planet-sized transmitters, which are used to power interstellar spaceships in distant galaxies.
The study explores this possibility with a detailed synopsis, "We examine the possibility that Fast Radio Bursts (FRBs) originate from the activity of extragalactic civilizations. Our analysis shows that beams used for powering large light sails could yield parameters that are consistent with FRBs." FRBs have been recorded to be giving out millisecond-long flashes of radio emission with energy potential of the brief moment being equal to what the sun can produce in 10,000 years.
This may sound a tad bit far-fetched but as theories go, this is among the several possibilities that is open for exploration, "'[C]oincidences' lend some credence to the possibility that FRBs might be artificial in origin.....The first, and most immediate, possibility is that they serve the purpose of 'beacons', and are thus meant to broadcast the presence of alien civilizations," read the report.
We are on the brink of scientific exploration and making headway in a intergalactic exploration in the very near future and as the study says. "Although the possibility that FRBs are produced by extragalactic civilizations is more speculative than an astrophysical origin, quantifying the requirements necessary for an artificial origin serves, at the very least, the important purpose of enabling astronomers to rule it out with future data."