Astronomers have detected as many as 15 mysterious high-energy radio bursts in a distant galaxy.
The repeating source – FRB 121102 is the only one known to repeat: more than 150 high-energy bursts have been observed coming from the object, which was identified last year as a dwarf galaxy about 3 billion light years from Earth.
The cause of the radio bursts is unknown, but there are some theories. Possible explanations for the repeating bursts range from outbursts from rotating neutron stars with extremely strong magnetic fields – so-called magnetars – to a more speculative idea: They are directed energy sources, powerful laser bursts used by extraterrestrial civilizations to power spacecraft, akin to Breakthrough Starshot’s plan to use powerful laser pulses to propel nano-spacecraft to our solar system’s nearest star, Proxima Centauri.
“Bursts from this source have never been seen at this high a frequency,” said Andrew Siemion, director of the Berkeley SETI Research Center and of the Breakthrough Listen program.
First detected with the Parkes Telescope in Australia, fast radio bursts have now been seen by several radio telescopes around the world. FRB 121102 was discovered on Nov. 2, 2012, (hence its name) and in 2015 it was the first fast radio burst seen to repeat, ruling out theories of bursts’ origins that involved the catastrophic destruction of the progenitor, at least in this instance.
Regardless of FRB 121102’s ultimate source, when the recently detected pulses left their host galaxy, our solar system was less than 2 billion years old, noted Steve Croft, a Breakthrough Listen astronomer at UC Berkeley. Life on Earth consisted only of single-celled organisms; it would be another billion years before even the simplest multi-cellular life began to evolve.
Trouble is we still don’t know the cause of the radio bursts.