Fast radio bursts (FRBs) are mysterious short bursts of radio waves that were first detected a decade ago. Less than a couple of dozen FRBs have been detected since their discovery in 2007. There could actually be hundreds of detectable FRBs occurring daily, but actually discovering them is made difficult by their super-short duration of only a millisecond. Astronomers are uncertain about their exact origin and some have speculated that some FRBs could be artificial in nature.
Powering Lightsail Ships
Could this be a case of aliens having some fun by racing lightsail ships that are being propelled by radio frequencies? Theorist Avi Loeb of the Harvard-Smithsonian Center for Astrophysics is currently working on a lightweight spacecraft that could be powered by light and told Inverse that he thinks it could be possible.
“We are trying to push a very lightweight spacecraft that weighs a gram or so,” Loeb said of the Breakthrough Starshot project. “A much more advanced civilization might very well develop a technology that can launch much heavier payloads. It’s the same principle. You attach the payload to the sail and you push the sail with light.”
The power of fast radio bursts could potentially propel a lightsail-based spacecraft of significant size to speeds that imply that an alien civilization could be capable of interstellar flight. The device needed to generate such a burst would theoretically be the size of Earth and could propel a mass equivalent to 20 large cruise ships.
But Would Aliens Build Such A Thing?
The obvious question here is how an extraterrestrial civilization could produce FRBs that are capable of emitting as much energy in a millisecond as our sun emits in 10,000 years, making them detectable from as far as three billion light-years away, let alone do it multiple times as in the case of FRB 121102. Perhaps by the time it becomes a necessity, they would have found more energy-efficient means to propel interstellar spacecraft and won’t need to build a device that goes way beyond the, “It’s no moon!” category. If they did build such a thing and their native star is about the same type as our G-type star, they would perhaps be able to perform one launch every ten thousand years if they capture all of the star’s energy with a device similar to a Dyson sphere and pour it into the propelling device. If this explanation is true, it may help explain why it is rare to spot an FRB in a specific location in our night sky more than once.
Other theories include the idea that FRBs like 121102 may simply naturally occur more often in active dwarf galaxies that are known for their extreme events such as powerful gamma ray bursts. They could also be caused by an exotic form of neutron star known as a magnetar, which is characterized by a powerful magnetic field that could shift in a way that causes a radio burst. Supporters of the alien hypothesis, such as Loeb, indicate that they would accept a more natural origin if new evidence comes in: “The history of science shows that it would be unwise to rule out possibilities just based on prejudice. This often leads to stagnation rather than progress.”