In a paper published in the Astronomy & Astrophysics Journal, an international team of astronomers reports the discovery of a group of objects that appear to be an emerging accumulation of galaxies in the making — known as a protocluster.

“This discovery is an important step toward reaching our ultimate goal: understanding the assembly of galaxy clusters, the most massive structures that exist in the universe,” said Brenda Frye, an associate professor of astronomy at the University of Arizona’s Steward Observatory and a co-author of the study.

The Milky Way, home to our solar system, belongs to a galaxy cluster known as the Local Group, which in turn is a part of the Virgo supercluster. But what did a supercluster such as Virgo look like 11 billion years ago?

“We still know very little about protoclusters, in part because they are so faint, too faint to be detected by optical light,” Frye said. “At the same time, they are known to radiate brightly in other wavelengths such as the sub-millimeter.”

Initially discovered by the European Space Agency’s Planck telescope as part of an all-sky survey, the protocluster described in the new paper showed up prominently in the far-infrared region of the electromagnetic spectrum. Sifting through a sample of more than 2,000 structures that could be in the process of becoming clusters, researchers came across a protocluster designated as PHz G237.01+42.50, or G237 for short. The observations looked promising, but to confirm its identity required follow-up observations with other telescopes.

Led by Mari Polletta at the National Institute for Astrophysics in Milan, Italy, the team conducted observations using the combined power of the Large Binocular Telescope in Arizona, which is managed by UArizona, and the Subaru Telescope in Japan. The team identified 63 galaxies belonging to the G237 protocluster. The original discovery was published in a previous paper, and follow-up observations were also obtained using archival data, the Herschel Space Observatory and the Spitzer Space Telescope.

“You can think of galaxy protoclusters such as G237 as a galaxy shipyard in which massive galaxies are being assembled, only this structure existed at a time when the universe was 3 billion years old,” Frye said. “At the same time, the genealogy may be closer than you think. Because the universe is homogeneous and the same in all directions, we think that the Milky Way may have docked at a protocluster node similar to G237 when it was very young.”

At first, observations of G237 implied a total star formation rate that was unrealistically high, and the team struggled to make sense of the data. The G237 protocluster seemed to be forming stars at a rate of 10,000 times that of the Milky Way. At that rate, the protocluster would be expected to rapidly use up its stellar fuel and subsequently settle down into a complex system similar to the Virgo supercluster.

“Each of the 63 galaxies discovered so far in G237 was like a star factory in overdrive,” Frye said. “It’s as if the galaxies were working on overtime to the assemble stars. The rate of production was unsustainable. At such a pace, the supply chains are expected to break in the near future, and in a way that permanently shuts down the galaxy shipyard.”

Such high yields could only be maintained by a continuous injection of fuel, which for stars is hydrogen gas. Frye said that would require an efficient and unbroken supply chain that drew in unreasonably large amounts of fresh gas to fuel the star-forming factories.

“We don’t know where that gas was coming from,” she said.

Later, the team discovered that some of what it was seeing came from galaxies unrelated to the protocluster, but even after the irrelevant observations were removed, the total star formation rate remained high, at least 1,000 solar masses per year, according to Poletta. In comparison, the Milky Way produces about one solar mass each year.

“The picture we have pieced together now is that of a successful galaxy shipyard, which is working at high efficiency to assemble galaxies and the stars within them and has an energy supply that is more sustainable,” Frye said.

All galaxies in the universe are part of a giant structure that resembles a three-dimensional spider web shape called the cosmic web. The filaments of the cosmic web intersect at the nodes, which equate to the galaxy shipyards in the analogy.

“We believe that the filaments mediate the transfer of hydrogen gas from the diffuse medium of intergalactic space onto these hungry, newly forming protocluster structures in the nodes,” Frye said.

Pointing to future research, Polletta said: “We are in the process of analyzing more observations on this and other Planck protoclusters with the goal of tracing the gas that gives birth to these newly forming stars and feeds the supermassive black holes, to determine its origin and explain the observed extraordinary activity.”

Frye said she is looking forward to combining data from the Large Binocular Telescope with observations from NASA’s the James Webb Space Telescope, to be launched in December.

“Protoclusters offer an opportunity to investigate key questions in astronomy that only this new observatory can answer,” she said, “such as what mechanisms drive the prodigious star formation, and when will the hydrogen supply run out, forcing this galaxy shipyard to close its doors and turn into a supercluster similar to the one our Milky Way is in?”

Please see the paper for a full list of authors and funding information.

The confirmation was made possible using a new method to analyse family lineages using ancient DNA fragments, developed by a team of scientists led by Professor Eske Willerslev of the University of Cambridge and Lundbeck Foundation GeoGenetics Centre. The results are published today in the journal Science Advances.

The technique searches for ‘autosomal DNA’ in the genetic fragments extracted from a body sample. Since we inherit half of our autosomal DNA from our father and half from our mother, this means genetic matches can be checked irrespective of whether an ancestor is on the father or mother’s side of the family.

Autosomal DNA from Lakota Sioux leader Sitting Bull’s scalp lock was compared to DNA samples from Ernie Lapointe and other Lakota Sioux. The resulting match confirms that Lapointe is Sitting Bull’s great-grandson, and his closest living descendant.

“Autosomal DNA is our non-gender-specific DNA. We managed to locate sufficient amounts of autosomal DNA in Sitting Bull’s hair sample, and compare it to the DNA sample from Ernie Lapointe and other Lakota Sioux — and were delighted to find that it matched,” said Professor Eske Willerslev in the University of Cambridge’s Department of Zoology and Lundbeck Foundation GeoGenetics Centre, senior author of the report.

Lapointe said: “over the years, many people have tried to question the relationship that I and my sisters have to Sitting Bull.”

Lapointe believes that Sitting Bull’s bones currently lie at a site in Mobridge, South Dakota, in a place that has no significant connection to Sitting Bull and the culture he represented. He also has concerns about the care of the gravesite. There are two official burial sites for Sitting Bull — at Fort Yates, North Dakota and Mobridge — and both receive visitors.

With DNA evidence to back up his claim of a bloodline, Lapointe now hopes to rebury the great Native American leader’s bones in a more appropriate location.

The new technique can be used when very limited genetic data are available, as was the case in this study. The work paves the way for similar DNA testing of the relationship between many other long-dead historical figures and their possible living descendants.

The technique could also be used to answer important questions based on old human DNA that might previously have been considered too degraded to analyse — for example in forensic investigations.

“In principle, you could investigate whoever you want — from outlaws like Jesse James to the Russian tsar’s family, the Romanovs. If there is access to old DNA — typically extracted from bones, hair or teeth, they can be examined in the same way,” said Willerslev, who is a Fellow of St John’s College, Cambridge.

It took the scientists 14 years to find a way of extracting useable DNA from the 5-6cm piece of Sitting Bull’s hair. The hair was extremely degraded, having been stored for over a century at room temperature in Washington’s Smithsonian Museum before it was returned to Lapointe and his sisters in 2007.

The technique differs from traditional approaches to DNA analysis, which look for a genetic match between specific DNA in the Y chromosome passed down the male line, or, if the long-dead person was female, specific DNA in the mitochondria passed from a mother to her offspring. Neither are particularly reliable, and in this case neither could be used as Lapointe claimed to be related to Sitting Bull on his mother’s side.

Tatanka-Iyotanka, better known as the Native American leader and military leader Sitting Bull (1831-1890), led 1,500 Lakota warriors at the Battle of the Little Bighorn in 1876 and wiped out US General Custer and five companies of soldiers. The blood-soaked feat — also known as ‘the Battle of the Greasy Grass’ — will forever symbolise the resistance of Native Americans to the white man’s insatiable appetite for empire-building. Sitting Bull was assassinated in 1890 by the ‘Indian Police’, acting on behalf of the US government.

“Sitting Bull has always been my hero, ever since I was a boy. I admire his courage and his drive. That’s why I almost choked on my coffee when I read in a magazine in 2007 that the Smithsonian Museum had decided to return Sitting Bull’s hair to Ernie Lapointe and his three sisters, in accordance with new US legislation on the repatriation of museum objects,” said Willerslev.

He added: “I wrote to Lapointe and explained that I specialised in the analysis of ancient DNA, and that I was an admirer of Sitting Bull, and I would consider it a great honour if I could be allowed to compare the DNA of Ernie and his sisters with the DNA of the Native American leader’s hair when it was returned to them.”

Until this study, the familial relationship between LaPointe and Sitting Bull was based on birth and death certificates, a family tree, and a review of historical records. This new genetic analysis provides an additional line of evidence to strengthen his claim.

Before the remains from the Mobridge burial site can be reburied elsewhere, they will have to be analysed in a similar way to the hair sample to ensure a genetic match to Sitting Bull. Under US law, Lapointe owns the legal rights to Sitting Bull’s genetic data so can decide who should do the analysis.

This research was funded by the Danish National Research Foundation.

Kit Hamley, National Science Foundation graduate research fellow with the UMaine Climate Change Institute, spearheaded the first-ever scientific investigation into prehistoric human presence on the Southern Atlantic archipelago. She and her team collected animal bones, charcoal records and other evidence from across the islands over multiple expeditions and examined them for indications of human activity using radiocarbon dating and other laboratory techniques.

One notable sign of pre-European human activity derived from a 8,000-year-old charcoal record collected from a column of peat on New Island, located in the southwestern edge of the territory. According to researchers, the record showed signs of a marked increase in fire activity in 150 C.E., then abrupt and significant spikes in 1410 C.E., and 1770 C.E., the latter of which corresponds with initial European settlement.

Researchers also gathered sea lion and penguin samples on New Island near the site where a landowner discovered a stone projectile point that is consistent with the technology Indigenous South Americans have used for the past 1,000 years. The bones were heaped in discrete piles at one site. Hamley says the location, volume and type of bones indicated that the mounds were likely assembled by humans.

Most of the evidence Hamley and her colleagues collected indicated that Indigenous South Americans likely travelled to the Falkland Islands between 1275 C.E. and 1420 C.E. Arrival dates prior to 1275 C.E., however, cannot be ruled out because some evidence dates back even earlier, according to researchers. For example, the team found a tooth from an extinct Falkland Islands fox called the warrah with a radiocarbon date of 3450 B.C.E., the oldest for the species. Regardless, all of the team’s findings indicate that people landed in the archipelago before British navigator John Strong in 1690, the first European to set foot on the archipelago.

Indigenous people likely visited the islands for multiple short-term stays, as opposed to long-term occupation, according to the UMaine researchers. As a result, they left few cultural materials there, but enough for Hamley and her colleagues to find a discernible anthropogenic and paleoecological footprint and conduct their study.

“These findings broaden our understanding of Indigenous movement and activity in the remote and harsh South Atlantic Ocean,” says Hamley, a UMaine Ph.D. student of ecology and environmental sciences. “This is really exciting because it opens up new doors for collaborating with descendant Indigenous communities to increase our understanding of past ecological changes throughout the region. People have long speculated that it was likely that Indigenous South Americans had reached the Falkland Islands, so it is really rewarding to get to play a role in helping bring that part of the past to life of the islands.”

UMaine researchers who participated in the study with Hamley include her adviser, Jacquelyn Gill, an associate professor of paleoecology and plant ecology; Daniel Sandweiss, a professor of anthropology; and Brenda Hall, a professor of glacial geology.

Other investigators involved in the research include Dulcinea Groff, a postdoctoral research scientist at the University of Wyoming and former UMaine Ph.D. student; Kathryn Krasinski, an assistant professor of anthropology at Adelphi University; John Southon; a researcher with the Department of Earth System Science at the University of California-Irvine; Paul Brickle, executive director of the South Atlantic Environmental Research Institute; and Thomas Lowell, a geology professor with the University of Cincinnati.

Science Advances published a report of their findings.

Hamley’s most recent study builds on her research into the warrah (Dusicyon australis), an extinct species of fox. The warrah was the only native and terrestrial mammal to reside on the Falkland Islands at the time of European arrival. Subsequent hunting wiped the species out in 1856, making it the first extinct canid in the historic record, Hamley says.

For years, various scholars, including Charles Darwin, have debated the warrah’s origins and how it came to the islands. Hamley hypothesizes that humans may have introduced the species to the archipelago prior to European settlement. Many previously rejected the theory based on a prior lack of scientific evidence, but the latest findings from Hamley’s team reopens that possibility, she says. Indigenous South Americans may have domesticated warrah as they have with other foxes and canids, and brought them to the islands during their voyages and short-term stays.

During a 2018 expedition to the islands, Hamely and her colleagues found three warrah bone samples at Spring Point Farm in West Falkland. Carbon dating and isotopic analysis revealed the warrah whose bones were analyzed “had a marine-based diet consisting primarily of apex marine predators” like sea lions and fur seals, a similar diet to seafaring Indigenious South Americans in prehistoric times, according to researchers. While these findings could reflect coastal scavenging, it may exemplify the food their potential human counterparts were procuring and eating, researchers say.

“This study has the potential to change the trajectory of future ecological research in The Falklands,” says Hamley. “The introduction of a top predator, like the warrah, could have had profound implications for the biodiversity of the islands, which are home to ground nesting seabirds such as penguins, albatross and cormorants. It also changes the ever-captivating story of past human-canine relationships. We know that Indigenous South Americans domesticated foxes, but this study helps show how potentially important these animals were to those communities extending back thousands of years.”

Hamley conducted her research during three expeditions to the Falkland Islands in 2014, 2016 and 2018. During the 2016 journey, she participated in UMaine’s Follow a Researcher program, through which scientists give K-12 students a glimpse of their work through live expedition updates, Twitter chats and videos.

The study led by Hamley contributes to the growing body of scientific investigations into the ecological, anthropological and climate history of the Falklands Islands conducted by UMaine researchers. A 2020 UMaine-led study discovered that the establishment of seabird colonies on the islands in response to an abrupt regional cooling period 5,000 years ago changed its ecosystems.

“As the world warms, we hope our growing understanding of the pre-colonial history of the Falklands will help decision-makers balance the needs of wildlife and people, who rely on ecotourism, fisheries and other industries,” says Gill, an NSF CAREER researcher who was named a 2020 Friend of the Planet by the National Center for Science Education. “We’re only just beginning to piece together the role people played in the Falklands before European settlement. Because of centuries of colonialism on the mainland, a lot of the oral knowledge about this period was lost. Western science needs updating, and we hope future work will be done in collaboration with the modern-day Indigenous people in the region; their ancestors were the first experts here.”