Researchers Detect 157-Day Pattern In Mysterious Radio Bursts From Space

For the second time, scientists detected a pattern in the mysterious signals coming from space, a discovery which highlights how much there still is to learn about Fast Radio Bursts (FRB).

FRBs are some of the most mysterious events in astronomy. Having been discovered as recently as 2007, FRBs are bursts of extragalactic radio waves that pop up for mere milliseconds.

Some FRBs were found to be one-off events, but others, known as repeating FRBs, tend to flash multiple times. FRB 121102, for instance, was first detected using the Arecibo radio telescope in 2012 and was found to repeat in 2016. However, a new study found that FRB 121102 is not only repeating but is doing so in a consistent pattern.

For the new study published in Monthly Notices of the Royal Astronomical Society, the researchers used the long-term monitoring capabilities of the Lovell Telescope to observe FRB 121102 for four years.

During that time, the international team observed 32 bursts in a cyclic pattern wherein the bursts would be observed within a 90-day period followed by a 60-day silence. The observed pattern repeats every 157 days.

According to the researchers, repeating FRBs could be a result of the orbital motion either from a massive star, a black hole or a dense neutron star. For instance, it could be the result of the wobbling motion of a neutron star's axis.

However, this explanation is more suited for FRBs that repeat over a span of a few weeks. The explanation is not quite a good fit for the longer pattern of FRB 121102.

So what really causes FRBs and repeating FRBs? The answer, so far, is unclear. To date, out of hundreds of recorded FRBs, scientists have only pinpointed the origin of a handful, including FRB 121102 and FRB 180916.J0158+65, the only other another repeating FRB known to have a pattern.

Finding out what really causes them will take more time and research, but the current study provides a significant clue regarding the mysterious bursts' actual origin.

"This exciting discovery highlights how little we know about the origin of FRBs," study co-author and Associate Dean for Research at West Virginia University, Duncan Lorimer, said in a news release from the University of Manchester. "Further observations of a larger number of FRBs will be needed in order to obtain a clearer picture about these periodic sources and elucidate their origin."