Fast radio bursts: Are these mysterious signals from deep space getting even stranger?

New discoveries are shaking up what little we thought we knew about fast radio bursts

- by TOM HOWARTH

Fast radio bursts (FRBs) are among the greatest cosmic enigmas of our time. First discovered in 2007, these fleeting flashes of radio waves have been puzzling astronomers ever since. Despite detecting thousands of them, we still don't know exactly what causes them, where they come from or why they behave so unpredictably.

Just when scientists thought they were beginning to piece together the puzzle, two new studies, published in January this year, threw a spanner in the works, challenging previous theories and adding new layers of intrigue to the FRB mystery.

"FRBs are one of these mysteries of the Universe that deserves to be solved," says Dr Tarraneh Eftekhari, a radio astronomer at Northwestern University, in the US, and lead author of first of the new papers published in The Astrophysical Journal Letters. A solution may well be long overdue, but the Universe, it seems, isn't giving up its secrets just yet.

WHAT'S SO MYSTERIOUS ABOUT FRBS?

While it wouldn't be quite right to say that FRBs were discovered by accident, it's true that when first spotted, they were buried within data collected for an entirely different purpose: tracking down pulsars.

Pulsars, or 'pulsating radio sources', are a far better understood cosmic phenomenon. They were discovered in 1967 by Prof Jocelyn Bell Burnell and are known to originate from neutron stars – the incredibly dense remnants of massive stars that boast magnetic fields trillions of times stronger than Earth's. These fast-spinning stellar corpses emit regular pulses of radio waves, acting like cosmic lighthouses.

The regularity of the pulses Bell spotted, and the fact they were being emitted at a very specific frequency, hinted that they might be artificially, rather than naturally, generated and led her to nickname that first pulsar “Little Green Man 1”. But while pulsars quickly found their place in the astrophysical playbook, FRBs are a different story.