– Harvard physicists have proposed that several detected deep space signals can come from an extraterrestrial probe.
As their name suggests, fast radio bursts (or FRBs) are brief yet powerful spurts of radio energy lasting only a few milliseconds. The first ones were only identified in 2007. Their source has remained a mystery and astronomers don’t know if they come from inside our galaxy or if they are extragalactic.
Scientists at the Harvard-Smithsonian Centre for Astrophysics think fast radio bursts could be coming from ‘extragalactic light sails’ powering advanced alien spacecraft.
The possibility that these mysterious deep space signals are coming from aliens is “worth contemplating”.
Last year, researchers found 16 Fast Radio Bursts all coming from the same source beyond our Milky Way.
One of the repeating FRBs has been traced to galaxy three billion light years away. The source of the burst, however, remains a mystery.
One possibility is that the signal comes from a massive, highly magnetized and rapidly rotating neutron stars called magnetas.
Another option is that FRBs originate from an unknown, natural cosmic object we still haven’t been able to identify or the are advanced probes created by extraterrestrial civilizations.
Scientists have previously suggested that a fleet of extraterrestrial probes might watch our galaxy. Alien probes can be present in other galaxies as well.
“Fast Radio Bursts are exceedingly bright, given their short duration and origin at great distances, and we haven’t identified a possible natural source with any confidence,” says theoretical physicist Avi Loeb from the Harvard-Smithsonian Centre for Astrophysics.
If scientists are picking up extraterrestrial signals, the aliens must have created a radio transmitter strong enough for it to be detectable across immense distances.
If the transmitter were solar powered, the sunlight falling on an area of a planet twice the size of the Earth would be enough to generate the needed energy. Such a vast construction project is well beyond our technology, but within the realm of possibility according to the laws of physics.
It is reasonable to ask why an advanced extraterrestrial civilization would build such an instrument in the first place.
Physicists think the most plausible use of such power is driving interstellar light sails. The amount of power involved would be sufficient to push a payload of a million tons, or about 20 times the largest cruise ships on Earth.
“That’s big enough to carry living passengers across interstellar or even intergalactic distances,” said Manasvi Lingam at Harvard University.
To power a light sail, the transmitter would need to focus a beam on it continuously. Observers on Earth would see a brief flash because the sail and its host planet, star and galaxy are all moving relative to us.
As a result, the beam sweeps across the sky and only points in our direction for a moment. Repeated appearances of the beam, which were observed but cannot be explained by cataclysmic astrophysical events, might provide important clues about its artificial origin.
Loeb admits that this work is speculative. When asked whether he really believes that any fast radio bursts are due to aliens, he replied, “Science isn’t a matter of belief, it’s a matter of evidence. Deciding what’s likely ahead of time limits the possibilities. It’s worth putting ideas out there and letting the data be the judge.”