In a new study, researchers consider the possibility that strange cosmic light flashes that have mystified scientists, known as fast radio bursts (FRBs), could come from alien civilizations accelerating extremely fast interstellar spacecraft.
Since the detection of the first FRB in 2007, approximately 20 have been observed. One of those, FRB 121102, repeated itself and was found to originate in a faint dwarf galaxy approximately three billion light years from Earth.
Avi Loeb of the Harvard-Smithsonian Center for Astrophysics and co-author of the study, which is scheduled for publication in The Astrophysical Journal, said that an artificial source of the bursts should be considered, as scientists have so far been unable to determine a natural source.
While the bursts last less than a second, they emit more energy than our Sun does in 10,000 years and come from galaxies billions of light years away.
Loeb and study lead author Manasvi Lingam of Harvard University explored the possibility of the radio bursts coming from a huge alien radio transmitter.
Sending signals of FRB strength such great distances would require a solar-powered transmitter capable of collecting an area of sunlight twice the size of Earth.
Water-cooling a transmitter would prevent it from melting due to heat generated by such a high level of power.
While today’s technology is not capable of building such a structure, Loeb and Lingam believe the idea is technologically feasible.
The structure could be used to accelerate interstellar spacecraft to very high speeds. Equipped with light sails, the spacecraft would use the momentum generated by the photons much like sailboats use the wind to move forward.
Light sails can be built with current technology and have already been used in space.
A structure capable of generating fast radio bursts could power a million-ton interstellar spacecraft, the researchers state.
The powerful beams, always aimed at the spacecraft’s sails, could be observed from Earth as brief flashes.
Assuming the existence of up to 10 billion habitable planets in the Milky Way alone, the researchers calculated the maximum number of advanced civilizations in the galaxy to be at most 10,000.
Nowhere in the study do the researchers argue that the fast radio bursts actually are produced by alien civilizations. Instead, they speculate about a hypothesis that merits consideration, Loeb and Lingam said.