Common trends: researchers at the University of Tokyo have used data taken by telescopes such as the Arecibo observatory in Puerto Rico (pictured here in 2019) to uncover similarities between fast radio bursts and earthquakes (Courtesy: UCF)
Researchers in Japan have found striking similarities between the statistical behaviour of repeating fast radio bursts (FRBs) and earthquakes.
FRBs are brief, intense bursts of radio waves from outside our galaxy. Whilst these bursts typically last a few milliseconds, astronomers have also found bursts a thousand times shorter.
FRBs are broadly split into two categories: repeating FRB sources and “one-off” FRBs, which have not yet repeated. Whether all FRB sources repeat remains an open question.
In their study, astrophysicists Tomonori Totani and Yuya Tsuzuki from the University of Tokyo used a dataset of 7000 bursts from three repeating sources. The data was taken by radio astronomers using the Arecibo observatory in Puerto Rico and Five-hundred-metre Aperture Spherical Telescope in south-west China.
One of these sources – FRB20121102A – lies over three billion light-years away and was the first discovered FRB repeater.
The duo found that the arrival times of bursts from FRB20121102A showed a high degree of correlation, with many more bursts arriving within a second of each other than would be expected if the generation of bursts were completely random. This correlation faded away at longer timescales, with bursts separated by over a second arriving completely at random.
They drew similarities with this behaviour to how earthquakes produce secondary aftershocks in the hours or days following a tremor, but then become completely unpredictable once an episode of aftershocks passes.
Moreover, they found that the rate of these FRB “aftershocks” follows the same Omori-Utsu law that characterises the occurrence of earthquake aftershocks on Earth. The law states that shortly after a large earthquake, the rate of aftershocks remains constant over a brief period of minutes to hours, after which the aftershock rate drops, decaying as roughly the inverse of the time since the main shock.
They found that each burst had a 10-50% chance to produce an aftershock, depending on its source. This likelihood remained constant, even when the FRB-activity suddenly increased in a given episode. Earthquakes show similar behaviours, their aftershock rates stay constant even if the overall earthquake activity changes within a region.
There is, however, one major difference between FRBs and earthquakes. While earthquake aftershocks tend to be systematically weaker than the main shock, time-correlated FRBs have completely uncorrelated energies. This means that for FRBs there exists essentially no difference between a “preshock” and an “aftershock”, because the main shock does not stand out.
In a galaxy far, far away
Totani points out, however, that this could be due to the limited dynamic range in FRB data compared to earthquakes: most FRBs are very faint, being only slightly above the detection limit.
Out of the many theories explaining the origin of FRBs, magnetars – neutron stars with exceptionally strong magnetic fields – have become one leading option.
This is because the solid crust of neutron stars, which surrounds a superfluid core, can suddenly releases built-up stresses by starquakes that then lead to FRBs, just like tectonic plates produce earthquakes as they shift around Earth’s liquid mantle. And so, “It was rather natural to compare repeater FRBs and earthquakes,” Totani told Physics World.
The work also adds to previous findings from astronomers in China in 2018 who showed that the Gutenberg-Richter earthquake-law could be applied to the energy distribution of FRBs. The law expresses a relationship for the total number of quakes expected above a certain energy within a given time and place.
Indeed, while FRBs may seem innocuous events compared to earthquakes, they are anything but innocuous. The weakest FRB ever detected still released over a billion times more energy than the 9.5 magnitude 1960 Valdivia earthquake in Chile – the most powerful earthquake on record.
There also exist FRBs that are another 10 million times stronger, as Australian radio astronomers reported on Wednesday when they discovered a FRB that took some eight billion years to reach Earth – the furthest burst ever detected.
Totani now plans to apply mathematical models from earthquake studies to FRB data, hoping to tease out hints about the properties of nuclear matter in neutron stars.
NAIROBI, Kenya (AP) — The body of Ugandan Olympic athlete Rebecca Cheptegei — who died after being set on fire by her partner in Kenya — was received Friday by family and anti-femicide crusaders, ahead of her burial a day later.
Cheptegei’s family met with dozens of activists Friday who had marched to the Moi Teaching and Referral Hospital’s morgue in the western city of Eldoret while chanting anti-femicide slogans.
She is the fourth female athlete to have been killed by her partner in Kenya in yet another case of gender-based violence in recent years.
Viola Cheptoo, the founder of Tirop Angels – an organization that was formed in honor of athlete Agnes Tirop, who was stabbed to death in 2021, said stakeholders need to ensure this is the last death of an athlete due to gender-based violence.
“We are here to say that enough is enough, we are tired of burying our sisters due to GBV,” she said.
It was a somber mood at the morgue as athletes and family members viewed Cheptegei’s body which sustained 80% of burns after she was doused with gasoline by her partner Dickson Ndiema. Ndiema sustained 30% burns on his body and later succumbed.
Ndiema and Cheptegei were said to have quarreled over a piece of land that the athlete bought in Kenya, according to a report filed by the local chief.
Cheptegei competed in the women’s marathon at the Paris Olympics less than a month before the attack. She finished in 44th place.
Cheptegei’s father, Joseph, said that the body will make a brief stop at their home in the Endebess area before proceeding to Bukwo in eastern Uganda for a night vigil and burial on Saturday.
“We are in the final part of giving my daughter the last respect,” a visibly distraught Joseph said.
He told reporters last week that Ndiema was stalking and threatening Cheptegei and the family had informed police.
Four in 10 women or an estimated 41% of dating or married Kenyan women have experienced physical or sexual violence perpetrated by their current or most recent partner, according to the Kenya Demographic and Health Survey 2022.
TEL AVIV, Israel (AP) — A rare Bronze-Era jar accidentally smashed by a 4-year-old visiting a museum was back on display Wednesday after restoration experts were able to carefully piece the artifact back together.
Last month, a family from northern Israel was visiting the museum when their youngest son tipped over the jar, which smashed into pieces.
Alex Geller, the boy’s father, said his son — the youngest of three — is exceptionally curious, and that the moment he heard the crash, “please let that not be my child” was the first thought that raced through his head.
The jar has been on display at the Hecht Museum in Haifa for 35 years. It was one of the only containers of its size and from that period still complete when it was discovered.
The Bronze Age jar is one of many artifacts exhibited out in the open, part of the Hecht Museum’s vision of letting visitors explore history without glass barriers, said Inbal Rivlin, the director of the museum, which is associated with Haifa University in northern Israel.
It was likely used to hold wine or oil, and dates back to between 2200 and 1500 B.C.
Rivlin and the museum decided to turn the moment, which captured international attention, into a teaching moment, inviting the Geller family back for a special visit and hands-on activity to illustrate the restoration process.
Rivlin added that the incident provided a welcome distraction from the ongoing war in Gaza. “Well, he’s just a kid. So I think that somehow it touches the heart of the people in Israel and around the world,“ said Rivlin.
Roee Shafir, a restoration expert at the museum, said the repairs would be fairly simple, as the pieces were from a single, complete jar. Archaeologists often face the more daunting task of sifting through piles of shards from multiple objects and trying to piece them together.
Experts used 3D technology, hi-resolution videos, and special glue to painstakingly reconstruct the large jar.
Less than two weeks after it broke, the jar went back on display at the museum. The gluing process left small hairline cracks, and a few pieces are missing, but the jar’s impressive size remains.
The only noticeable difference in the exhibit was a new sign reading “please don’t touch.”
VICTORIA – The British Columbia government is partnering with a bear welfare group to reduce the number of bears being euthanized in the province.
Nicholas Scapillati, executive director of Grizzly Bear Foundation, said Monday that it comes after months-long discussions with the province on how to protect bears, with the goal to give the animals a “better and second chance at life in the wild.”
Scapillati said what’s exciting about the project is that the government is open to working with outside experts and the public.
“So, they’ll be working through Indigenous knowledge and scientific understanding, bringing in the latest techniques and training expertise from leading experts,” he said in an interview.
B.C. government data show conservation officers destroyed 603 black bears and 23 grizzly bears in 2023, while 154 black bears were killed by officers in the first six months of this year.
Scapillati said the group will publish a report with recommendations by next spring, while an independent oversight committee will be set up to review all bear encounters with conservation officers to provide advice to the government.
Environment Minister George Heyman said in a statement that they are looking for new ways to ensure conservation officers “have the trust of the communities they serve,” and the panel will make recommendations to enhance officer training and improve policies.
Lesley Fox, with the wildlife protection group The Fur-Bearers, said they’ve been calling for such a committee for decades.
“This move demonstrates the government is listening,” said Fox. “I suspect, because of the impending election, their listening skills are potentially a little sharper than they normally are.”
Fox said the partnership came from “a place of long frustration” as provincial conservation officers kill more than 500 black bears every year on average, and the public is “no longer tolerating this kind of approach.”
“I think that the conservation officer service and the B.C. government are aware they need to change, and certainly the public has been asking for it,” said Fox.
Fox said there’s a lot of optimism about the new partnership, but, as with any government, there will likely be a lot of red tape to get through.
“I think speed is going to be important, whether or not the committee has the ability to make change and make change relatively quickly without having to study an issue to death, ” said Fox.
This report by The Canadian Press was first published Sept. 9, 2024.
