Mystery Low-Frequency Space Signal Spotted for First Time

Strange and mysterious radio signals are bleeping throughout space. Fast radio bursts (FRBs)—elusive twinkles discovered just over a decade ago—travel billions of light-years to reach our telescopes. But nobody knows where they come from.

Now, a new telescope combing the skies for hydrogen has spotted another of the bizarre radio blips: FRB 180725A. And this FRB is the lowest-frequency burst ever discovered, scientists reported in The Astronomer's Telegram.

CHIME looks between 400 - 800 MHz and most FRBs have been found between 1,000 - 1,500 MHz. Before this the lowest frequency an FRB was detected at was 700 MHz with the GBT (Masui et al. 2015). But FRB 180725 was seen down to ~580 MHz. (8/10)

— Dr. Emily Petroff (@ebpetroff) August 1, 2018

Although their origin is a mystery, astronomers think the weird blips might come from neutron stars in extreme space environments like interstellar clouds, nebulae or the region around a hungry black hole. Some scientists even think FRBs might be a sign of alien life.

Astronomers used a new telescope called the Canadian Hydrogen Intensity Mapping Experiment (CHIME) to spy the latest weird signal. It lasted for just a couple of milliseconds and was detected at about 580 MHz. FRBs are normally found between 1,000 and 1,500 MHz, so that's a pretty big deal for scientists.

In fact, the CHIME astronomers reported they've spotted even more low frequency space bleeps since FRB 180725, but they haven't published their findings yet.

This image of galaxy cluster Abell 2744, also called Pandora's Cluster, was taken by the Spitzer Space Telescope. Astronomers think FRBs originate far beyond our own Milky Way galaxy. JPL-Caltech/NASA

FRBs appear all over the sky, but it's hard to log them in real time as telescopes usually focus on small slivers of our starry canopy. Imagine trying to catch shooting stars through binoculars and you'll get an idea of the problem.

So far, astronomers have discovered less than 40 of these strange flashes in over ten years, so every new FRB has been pretty big news. But scientists think they'll be spotting FRBs on a daily basis with CHIME.

Back in 2016, scientists reported a repeating FRB to much fanfare. Since then, public interest in the strange signals has boomed. Earlier this year, astronomers spotted their brightest-ever FRB using the Parkes Observatory in Australia. But even this telescope only finds five or six FRBs per year.

CHIME is watching 200 square degrees at a time, which is far more than most telescopes. "CHIME is…a really sensitive, large field of view telescope which means it's perfect for searching for FRBs," Emily Petroff, an astrophysicist and FRB-hunter at ASTRON, the Netherlands Institute for Radio Astronomy, tweeted. But the telescope still watches less than one percent of the sky, she wrote.

Every new FRB is another clue to the origin of the strange extragalactic signals so, even if it's spotting just a fraction of all FRBs, CHIME is still incredibly exciting for astronomers. You can find a list of all known FRBs on Petroff and team's log,