A decade ago, scientists first detected fast radio bursts (FRB). They’re so-called because they’re incredibly powerful bursts of radio signals, but they’re extremely short-lived: a few milliseconds in length. Last year, scientists finally managed to catch one happening in real-time. And now we’ve managed to pinpoint where a repeating signal – FRB 121102 – is coming from. What is causing it is still open to speculation.
“We now know that this particular burst comes from a dwarf galaxy more than three billion light-years from Earth,” explained Cornell University’s Shami Chatterjee.
Using the Very Large Array (VLA) telescope in New Mexico, 11 bursts from FRB 121102 were detected in 83 hours of observing time over a period of six months last year. Using the data, the team were able to pinpoint the bursts to a faint dwarf galaxy, over three billion light-years from us. To put that into perspective, it took New Horizons nine years to reach Pluto, which is 327 light-minutes away. So we’re left to pure speculation as to what is causing the signals.
“Before we knew the distance to any FRBs, several proposed explanations for their origins said they could be coming from within or near our own Milky Way Galaxy,” said Shriharsh Tendulkar, one of the team working on the project. “We now have ruled out those explanations, at least for this FRB.”
For now, the team’s working theories for the causes of the FRB include neutron stars emitting radio pulses or radio emissions from jets of material fired from the area surrounding a supermassive black hole. And of course, FRB 121102 could be different from other FRBs, for all we know. “”We do have to keep in mind that this FRB is the only one known to repeat, so it may be physically different from the others,” said Bryan Burley of the National Radio Astronomy Observatory.
One explanation conspicuous by its absence, you’ll note, is alien life – indeed, it wasn’t even mentioned by the researchers as a possibility. For a signal to travel three billion light-years, you would need a massively advanced society capable of firing off the same energy output as billions of stars. Add that to the fact that the distance involved means that the signal was first emitted three billion years ago, and this hypothetical civilisation would have reached the crazy-advanced state at a time when Earth’s smartest residents were microscopic in size.
So almost certainly not aliens then, but whatever is causing the signals, it’s a fascinating discovery, and it leaves the door open for much follow up research. “Finding the host galaxy of this FRB, and its distance, is a big step forward,” said Chatterjee, “but we still have much more to do before we fully understand what these things are.”
Images: Chuck Coker and Sweetie187 used under Creative Commons