When light from the early universe reaches Earth, it presents an eerie snapshot of ancient stars and galaxies that have long since died, or taken on different forms over the course of billions of years.
Though we cannot directly see the future of these objects, scientists have now figured out how to do the next best thing by “fast-forwarding” simulations of the cosmic web, a network of large-scale structures that connects the universe, over the course of 11 billion years to its present state, reports a new study.
In this way, researchers led by Metin Ata, a cosmologist at the University of Tokyo’s Kavli Institute for the Physics and Mathematics of the Universe, were able to unspool the long-term evolution of giant galaxy clusters like a “time machine,” in the words of one author.
The new technique allowed the team “to ‘fast-forward’ the simulation to our present day and study the evolution of observed cosmic structures self-consistently,” revealing that at least one of these ancient “protoclusters” likely collapsed into an enormous cosmic web filament spanning 300 million light years, according to a study published in Nature Astronomy on Thursday.
The results also provide a means to test the standard model of cosmology, alternately known as the Lambda cold dark matter (ΛCDM), which is a well-corroborated framework to explain the weird properties of the universe, including the existence of dark matter, an unexplained substance that is far more abundant than regular “baryonic” matter.
“Understanding the formation of large-scale structures in the Universe, starting from tiny fluctuations in the matter density and subsequently evolving gravitationally into the complex cosmic web seen at the present epoch, is a key ambition of cosmological science,” Ata and his colleagues said in the study.
“As gravitationally evolving objects, protoclusters are ideal observables to study early structure formation and to compare with theoretical predictions,” they continued, adding that they are “excellent laboratories to jointly study the interplay between baryonic physics and dark matter models.”
Most cosmological simulations match the general statistical distribution of matter across the universe, rather than reproducing any specific cosmic structures that we can observe from Earth. However, a subcategory of these models, known as constrained cosmological simulations, do mimic real observations, though the new study notes that they are “mainly focused on the local universe or nearby structures” rather than the distant ancient universe, which is called the “high-redshift” universe because light waves from this era become stretched into redder bands of the spectrum over time.
By merging constrained cosmological simulations with the Hubble Space Telescope’s Cosmological Evolution Survey (COSMOS), Ata’s team capitalized on what they call “a unique opportunity for studying early structure formation and matching galaxy properties” between the ancient and modern universe, according to the study.
“Observationally, the effort to find and characterize protoclusters is a lively, ongoing field,” the researchers said. “In particular, the COSMOS field is an excellent site for this, as it is covered by deep and coordinated multi-wavelength observations over a wide field” that are “suited to protocluster studies.”
“Up to this point, there has not been a uniform and self-consistent study dedicated to these structures in the COSMOS field,” the team continued. “We address this problem with constrained simulations applied towards the rich legacy of large-scale spectroscopic surveys that have been conducted on the COSMOS field over nearly a decade, achieving a cosmic volume and number density unmatched anywhere else on the sky.”
In other words, the researchers looked at real protoclusters that existed 11 billion years ago and turned the clock forward in their constrained simulations. Of particular interest was the fate of the Hyperion super-protocluster, the largest structure of its kind during cosmic dawn, which the team called “the subject of scientific and public curiosity” in the study. Whereas some scientists have speculated that this immense elongated structure would eventually collapse into a single massive galaxy cluster, Ata and his colleagues suggest that it has evolved into a giant filamentary supercluster within the cosmic web, which is embedded with multiple massive cluster cores.
“We confirm that several previously reported protoclusters will evolve into massive galaxy clusters by our present epoch, including the ‘Hyperion’ structure that we predict will collapse into a giant filamentary supercluster spanning 100 [megaparsecs],” or 300 million light years, the team said in the study. “We also discover previously unknown protoclusters with lower final masses than are typically detectable by other methods that nearly double the number of known protoclusters within this volume.”
The large-scale structures that undergird the cosmic web are mostly made of dark matter, which is only observable due to its gravitational effect on luminous objects made of regular baryonic matter. As a result, the simulations pioneered by the new study can help shed light on the nature of dark matter by charting the course of its cosmic distribution across time, providing a key test of the ΛCDM model.
“Constrained simulations of these upcoming high-redshift galaxy surveys will also allow us to probe early structure formation for consistency with the ΛCDM model with increasing sensitivity to lower-mass galaxy (proto)clusters,” the researchers said in the study.
“Each identified protocluster represents a unique environment to study the morphologies and merger rates of member galaxies in high-density environments” in the early universe, they concluded, “which is so far only possible in theoretical studies or random cosmological simulations.”
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.
