The paths of four of the new moons as they orbit Saturn (black circle at center) during the period 2019-2021. The colored dots mark the observed position for each moon; the dashed curve shows the orbit that connects them. Credit: University of British Columbia
The work of an international team of astronomers has resulted in the announcement of 62 new moons of Saturn, catapulting it back into first place of the “moon race” around the giant planets of our solar system.
The team is led by Edward Ashton (currently a postdoctoral fellow at Taiwan’s Academia Sinica Institute of Astronomy and Astrophysics) and includes professor Brett Gladman (Department of Physics & Astronomy at the University of British Columbia), Mike Alexandersen (Harvard Smithsonian Center for Astrophysics), Jean-Marc Petit (Observatoire de Besancon), and Matthew Beaudoin (University of British Columbia).
Over the past two decades, Saturn’s surroundings have been repeatedly examined for moons with increasing sensitivity. In this latest study, Dr. Ashton’s team used a technique known as “shift and stack” in order to find fainter (and thus smaller) saturnian moons. This method has been used for moon searches around Neptune and Uranus, but never for Saturn.
Shifting a set of sequential images at the rate that the moon is moving across the sky results in enhancement of the moon’s signal when all the data is combined, allowing moons that were too faint to be seen in individual images to become visible in the “stacked” image. The team used data taken using the Canada-France-Hawaii Telescope (CFHT) on top of Mauna Kea, Hawaii between 2019 and 2021. By shifting and stacking many sequential images taken during 3 hour spans, they were able to detect moons of Saturn down to about 2.5 kilometers in diameter.
The original discovery search was done in 2019 when Ashton and Beaudoin were students at the University of British Columbia, uncovering the moons in a meticulous search of the deep CFHT imaging acquired that year. But just finding an object close to Saturn on the sky is insufficient to say for certain that it is a moon; it could in principle be an asteroid that just happened to be passing close to the planet (although this is unlikely).
To be absolutely sure, the object must be tracked for several years before one can establish that it is certainly orbiting the planet. After painstakingly matching objects detected on different nights over two years, the team has managed to track 63 objects, thus confirming them as new moons. One of the new moons, designated S/2019 S 1, was announced back in 2021, with the rest being announced over the last couple of weeks. Some of the team’s linked orbits were identified with past observations from many years ago that briefly glimpsed some of these moons (but were not tracked long enough to establish their orbit around Saturn).
“Tracking these moons makes me recall playing the kid’s game Dot-to-Dot, because we have to connect the various appearances of these moons in our data with a viable orbit,” explains Edward Ashton, “but with about 100 different games on the same page and you don’t know which dot belongs to which puzzle.”
All of the new moons are in the class of irregular moons, which are thought to be initially captured by their host planet long ago. Irregular moons are characterized by their large, elliptical, and inclined orbits compared to regular moons. The number of known saturnian irregular moons has more than doubled to 121, with 58 previously known before the search began.
Including the 24 regular moons, there is now a total of 145 recognized (by the International Astronomical Union) moons orbiting Saturn. The new discoveries have resulted in multiple milestones for the ringed planet. Saturn has not only regained its crown for having the most known moons (overtaking Jupiter with 95 recognized moons), it is also the first planet to have over 100 discovered moons in total.
The irregular moons tend to clump together into orbital groups based on the tilt of their orbits. In the saturnian system there are 3 such groups whose names are drawn from different mythologies: there is the Inuit group, the Gallic group, and the much more populated Norse group. For example, three new discoveries fall in the Inuit group: S/2019 S 1, S/2020 S 1 and S/2005 S 4 have very small orbits tilted similarly to that of the previously known larger irregulars Kiviuq and Ijiraq. All of the new moons fall into one of the three known groups, with the Norse group again being the most populated among the new moons. The groups are thought to be the result of collisions, where the current moons in a group are remnants of one or more collisions on the originally-captured moons.
A better understanding of the orbital distribution thus provides insight into the collisional history of the irregular moon system of Saturn. Based on their past studies of these moons, this team has suggested that the large number of small moons on retrograde orbits is the result of a relatively recent (in astronomical terms, being in the last 100 million years) disruption of a moderately sized irregular moon that is now broken into the many fragments that are being catalogued in the Norse group.
As professor Gladman explains, “as one pushes to the limit of modern telescopes, we are finding increasing evidence that a moderate-sized moon orbiting backwards around Saturn was blown apart something like 100 million years ago.”
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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.
