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Broadcasting from deep space, a mysterious series of radio signals

(ESA/Hubble & NASA/NYT)

Something is happening out there, and astronomers sure wish they knew what it was.

For the past several years, they have been teased and baffled by mysterious bursts of radio waves from the distant universe: pops of low-frequency radiation, emitting more energy than the sun does in a day, that occur randomly and disappear immediately. Nobody knows when these “fast radio bursts,” or FRBs, will occur, or where exactly in the cosmos they are occurring.

More than 60 of these surprise broadcasts have been recorded so far. About the only thing astronomers agree on is that these signals probably are not extraterrestrials saying hello.

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So it was big news a year ago when scientists found a repeating radio burster and tracked it to a dwarf galaxy 3 billion light-years from Earth. Subsequent observations suggested that the burst was generated by extremely powerful magnetic fields, most likely ruling out lasers from alien spaceships.

Now a group of astronomers from Harvard and several Canadian universities have announced the discovery of a second radio repeater. The repeating bursts appeared last summer almost as soon as the team turned on and began tuning up a new telescope, the Canadian Hydrogen Intensity Mapping Experiment, or Chime, in British Columbia. The team announced the discovery in a pair of papers in Nature, and in a news conference at the American Astronomical Society meeting in Seattle on Jan. 9.

The astronomers estimated that the new repeater is about 1.5 billion light-years away, roughly half the distance to the other repeater. The existence of a second repeater suggests that there are many more to be found, said Ingrid Stairs, an astrophysicist at the University of British Columbia, in a news release.

Beyond those details, astronomers have nary a clue. The data suggest that the radio waves from the bursts were scattered by whatever surrounds the sources. Perhaps the bursts originated in some dense clump of matter or gas, such as the remains of an exploded star. Or maybe they arose near the black holes at the hearts of distant galaxies, said Cherry Ng of the University of Toronto, who added that the burst had to have come from “some special place.”

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Maybe we should thank our lucky stars once again that we do not live in such a “special place” in our own galaxy.