A team of astronomers from Yale and the University of Victoria have made an astonishing discovery – UMa3/U1 — the faintest star system ever observed orbiting our galaxy, the Milky Way.
Dubbed Ursa Major III / UNIONS 1 (UMa3/U1), it’s an incredibly dim and ancient group of stars located 30,000 light-years away in the constellation Ursa Major (which contains the Big Dipper).
UMa3/U1 hiding in plain sight
UMa3/U1 was invisible for so long because it’s incredibly faint and small. We’re talking a mere 60 stars spanning just about 10 light-years across.
For comparison, a single light-year is nearly 6 trillion miles. Even with powerful telescopes, it would be like trying to spot a handful of dust motes floating by a spotlight.
Despite its small size, this little cosmic neighbor is actually quite close, a mere 30,000 light-years from Earth. It resides in the constellation Ursa Major (which contains the Big Dipper).
Is UMa3/U1 a galaxy or a star cluster?
The key question astronomers have is this: Is UMa3/U1 a true dwarf galaxy, or is it a star cluster? The answer might come down to a mysterious, invisible substance – dark matter.
Galaxies are thought to be held together by the gravitational pull of dark matter – a type of matter we can’t see directly but that scientists know exists due to its gravitational effects.
On the other hand, gravity alone usually binds together the stars in star clusters, often without the assistance of dark matter.
Yet, the surprising spread of UMa3/U1’s stars hasn’t led to their disintegration by the Milky Way’s gravitational forces. Could the dark matter be the unseen glue holding this cosmic relic together?
“The object is so puny that its long-term survival is very surprising,” explains Will Cerny, a Yale University graduate student involved in the study. “One might have expected the harsh tidal forces from the Milky Way’s disk to have ripped the system apart by now, leaving no observable remnant.”
UMa3/U1 as a galaxy
Firstly, UMa3/U1 might be a genuine dwarf galaxy, an entity with an incredibly low amount of visible matter compared to what we typically observe in such galaxies.
This characteristic makes it an intriguing subject of study, as it suggests that UMa3/U1 could be predominantly composed of dark matter.
If UMa3/U1 is indeed a dwarf galaxy rich in dark matter, it could provide invaluable insights into the role of dark matter in galaxy formation and evolution.
It could support the theory that many such dark matter-dominated galaxies exist but remain hidden from our view, potentially revolutionizing our understanding of the universe’s structure.
Star cluster
Alternatively, UMa3/U1 could be a star cluster on the brink of disintegration. This perspective portrays UMa3/U1 as a cosmic anomaly, a cluster of stars that has stayed bound together for billions of years and is now possibly in its final stages of disintegration due to the Milky Way’s gravitational forces.
Observing such a disintegration in real-time would offer a unique opportunity to study the life cycle of star clusters and the dynamic processes involved in their evolution and dissolution.
If scenario one turns out to be true, it would be thrilling evidence supporting our current leading theory of how the universe works – the Lambda Cold Dark Matter (LCDM) model.
This model suggests that when our galaxy formed, it pulled in hundreds of smaller satellite systems that should still orbit it today.
UMa3/U1 cosmic ghost hunting
“Whether future observations confirm or reject that this system contains a large amount of dark matter, we’re very excited by the possibility that this object could be the tip of the iceberg — that it could be the first example of a new class of extremely faint stellar systems that have eluded detection until now,” says Cerny.
The team used powerful telescopes in Hawai’i, like the W. M. Keck Observatory and the Canada-France-Hawai’i Telescope (CFHT), to zero in on this celestial mystery.
Now, more observations are needed to reveal the true nature of UMa3/U1.
The fascination of the unknown
“This discovery may challenge our understanding of galaxy formation and perhaps even the definition of a ‘galaxy’,” explains Simon Smith, an astronomy graduate student at the University of Victoria and lead researcher on the study.
Whether a dwarf galaxy or a star cluster, UMa3/U1 reminds us of the vast secrets hiding in the cosmic darkness. And the excitement of discovery? Well, that shines as bright as ever.
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.
