The James Webb Space Telescope observed thousands of galaxies that were magnified by a galaxy cluster in the foreground. Around just one of those galaxies, astronomers may have spotted some of the earliest stars yet seen.
Some of the earliest stars yet seen are now coming to light in one of the first images from the James Webb Space Telescope.
Formed roughly 800 million years after the Big Bang, the stars live in dense groups called globular clusters and surround a distant galaxy dubbed the Sparkler, astronomers report in the Oct. 1 Astrophysical Journal Letters . Globular clusters often host some of the oldest stars in contemporary galaxies such as our own, but it’s hard to tell their exact age. The new finding could help researchers pinpoint when such clusters began to form.
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Compared to a galaxy, globular clusters are tiny, which makes them hard to see from across the universe. But this time, a gargantuan natural lens in space helped. The Sparkler is one of thousands of galaxies that lie far behind a massive, much closer galaxy cluster called SMACS 0723 , which was the subject of the first publicly released science image from the James Webb Space Telescope, or JWST ( SN: 7/11/22 ). The cluster distorts spacetime such that the light from the more distant galaxies behind it is magnified.
For all those remote galaxies, that extra magnification brings out details that have never been seen before. One elongated galaxy surrounded by yellowish blobs got the attention of astronomer Lamiya Mowla and her colleagues.
“When we first saw it, we noticed all those little dots around it that we called ‘the sparkles,’” says Mowla, of the University of Toronto. The team wondered if the sparkles could be globular clusters , close-knit families of stars that are thought to have been born together and stay close to each other throughout their lives ( SN: 10/15/20 ).
“The outstanding question that there still is, is how were the globular clusters themselves born?” Mowla says. Were they born at “cosmic noon,” 10 billion years ago, when star formation throughout the universe peaked? Or did they form 13 billion years ago at “ cosmic dawn ,” when stars were first able to form at all ( SN: 3/4/22 )?
Light from the Sparkler takes about 9 billion years to reach Earth, so if the sparkles are globular clusters that shone that long ago, they might help astronomers answer that question.
Mowla and her colleagues used data from JWST to analyze the wavelengths of light coming from the sparkles. Some of them appear to be forming stars at the time when their light left the clusters. But some had formed all their stars long before.
“When we see them, the stars are already about 4 billion years old,” says astrophysicist Kartheik Iyer, also of the University of Toronto.
That means the oldest stars in the sparkles could have formed roughly 13 billion years ago. Since the universe is 13.8 billion years old, “there’s only a short amount of time after the Big Bang when these could have formed,” he says.
In other words, these clusters were born at dawn, not at noon.
Studying more globular clusters around ancient galaxies could help determine if such clusters are common or rare early on in the universe’s history. They could also help unravel galaxies’ formation histories, say Mowla and Iyer. Their team has proposed observations to be made in JWST’s first year that could do just that.
Being able to pick out tiny structures like globular clusters from so far away was almost impossible before JWST, says astronomer Adélaïde Claeyssens of Stockholm University. She was not involved in the new work but led a similar study earlier this year of multiple galaxies magnified by the SMACS 0723 cluster .
“It’s the first time we showed that, with James Webb, we will observe a lot of these type of galaxies with really tiny structures,” Claeyssens says. “James Webb will be a game changer for this field.”
This story was updated October 13, 2022, to correct the caption for the zoomed-in look at the Sparkler galaxy. The globular clusters may be stars that formed a few hundred million years after the Big Bang, not a few hundred years.
Lisa Grossman is the astronomy writer. She has a degree in astronomy from Cornell University and a graduate certificate in science writing from University of California, Santa Cruz. She lives near Boston.
Science News was founded in 1921 as an independent, nonprofit source of accurate information on the latest news of science, medicine and technology. Today, our mission remains the same: to empower people to evaluate the news and the world around them. It is published by the Society for Science, a nonprofit 501(c)(3) membership organization dedicated to public engagement in scientific research and education (EIN 53-0196483).
This image from the Hubble Space Telescope shows a split stream of dust and rock streaming off the asteroid Dimorphos nearly 12 days after the DART spacecraft smashed into it.
It worked! Humanity has, for the first time, purposely moved a celestial object.
As a test of a potential asteroid-deflection scheme, NASA’s DART spacecraft shortened the orbit of asteroid Dimorphos by 32 minutes — a far greater change than astronomers expected.
The Double Asteroid Redirection Test, or DART, rammed into the tiny asteroid at about 22,500 kilometers per hour on September 26 ( SN: 9/26/22 ). The goal was to move Dimorphos slightly closer to the larger asteroid it orbits, Didymos.
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Neither Dimorphos nor Didymos pose any threat to Earth. DART’s mission was to help scientists figure out if a similar impact could nudge a potentially hazardous asteroid out of harm’s way before it hits our planet.
The experiment was a smashing success. Before the impact, Dimorphos orbited Didymos every 11 hours and 55 minutes. After, the orbit was 11 hours and 23 minutes , NASA announced October 11 in a news briefing.
“For the first time ever, humanity has changed the orbit of a planetary body,” said NASA planetary science division director Lori Glaze.
Four telescopes in Chile and South Africa observed the asteroids every night after the impact. The telescopes can’t see the asteroids separately, but they can detect periodic changes in brightness as the asteroids eclipse each other. All four telescopes saw eclipses consistent with an 11-hour, 23-minute orbit. The result was confirmed by two planetary radar facilities, which bounced radio waves off the asteroids to measure their orbits directly, said Nancy Chabot, a planetary scientist at Johns Hopkins Applied Physics Laboratory in Laurel, Md.
The minimum change for the DART team to declare success was 73 seconds — a hurdle the mission overshot by more than 30 minutes. The team thinks the spectacular plume of debris that the impactor kicked up gave the mission extra oomph. The impact itself gave some momentum to the asteroid, but the debris flying off in the other direction pushed it even more — like a temporary rocket engine.
“This is a very exciting and promising result for planetary defense,” Chabot said. But the change in orbital period was just 4 percent. “It just gave it a small nudge,” she said. So knowing an asteroid is coming is crucial to future success. For something similar to work on an asteroid headed for Earth, “you’d want to do it years in advance,” Chabot said. An upcoming space telescope called Near-Earth Object Surveyor is one of many projects intended to give that early warning.
Lisa Grossman is the astronomy writer. She has a degree in astronomy from Cornell University and a graduate certificate in science writing from University of California, Santa Cruz. She lives near Boston.
Science News was founded in 1921 as an independent, nonprofit source of accurate information on the latest news of science, medicine and technology. Today, our mission remains the same: to empower people to evaluate the news and the world around them. It is published by the Society for Science, a nonprofit 501(c)(3) membership organization dedicated to public engagement in scientific research and education (EIN 53-0196483).
To coax human nerve cells in a laboratory to thrive, there are three magic words: location, location, location.
Many experiments grow human nerve cells in lab dishes. But a new study enlists some real estate that’s a bit more unconventional: the brain of a rat. Implanted clusters of human neurons grow bigger and more complex than their cohorts grown in dishes, researchers report online October 12 in Nature .
Not only that, but the human cells also appear functional, albeit in very limited ways. The implanted human cells can both receive signals from rat cells and influence the rats’ behavior, connections that “demonstrate more substantial integration of the transplanted neurons,” says Arnold Kriegstein, a developmental neuroscientist at the University of California, San Francisco, who wasn’t involved in the study. “This is a significant advance.”
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Over the last decade, scientists have been building increasingly complex brain organoids, 3-D clusters of cells derived from stem cells that grow and mimic the human brain ( SN: 2/20/18 ). These organoids don’t re-create the full complexity of human neurons that develop in an actual brain. But they can be windows into an otherwise inscrutable process — human brain development, and how it can go awry ( SN: 9/3/21 ). “Even if they’re not entirely perfect, [these models] are surrogates for human cells in a way that animal cells are not,” Kriegstein says. “And that’s really exciting.”
To push these cells closer to their full potential, Sergiu Pasca, a neuroscientist at the Stanford School of Medicine, and colleagues surgically implanted human cerebral organoids into the brains of newborn rat pups. Along with their hosts, the human organoids began to grow. Three months later, the organoids were about nine times their starting volume, ultimately making up about a third of one side of the rat’s cortex, the outer layer of the brain. “It pushes the rat cells aside,” Pasca says. “It grows as a unit.”
These human cells flourished because rats’ brains offer perks that lab dishes can’t, such as blood supply, a precise mix of nutrients and stimulation from nearby cells. This environmental support coaxed individual human neurons to grow bigger — six times as large by one measure — than the same sort of cells grown in dishes. Cells grown in the rat brains were also more complex, with more elaborate branching patterns and more cell connections called synapses.
The cells looked more mature, but Pasca and his colleagues wanted to know if the neurons would behave that way, too. Tests of electrical properties showed that implanted neurons behaved more similarly to cells that develop in human brains than cells grown in dishes.
Over months of growth, these human neurons made connections with their rat host cells. The human organoids were implanted in the somatosensory cortex, a part of the rat brain that handles whisker input. When researchers puffed air at the whiskers, some of the human cells responded.
What’s more, the human cells could influence the behavior of the rat. In further experiments, the researchers genetically tweaked the organoids to respond to blue light. Prompted by a flash of light, the neurons fired signals, and researchers rewarded the rats with water. Soon, the rats learned to move to the water spout when their human organoid cells sent signals.
In behavioral tests, rats with human implants didn’t show signs of higher intelligence or memory; in fact, researchers were more concerned with deficits. The human organoids were nudging out their hosts’ brains, after all. “Will there be memory deficits? Will there be motor deficits? Will there be seizures?” Pasca asked. But after extensive tests, including behavior tests, EEGs and MRIs, “we could not find differences,” Pasca says.
Other experiments included nerve cells from people with a genetic disorder called Timothy syndrome, a severe developmental disorder that affects brain growth. Growing organoids created with these patients’ cells in rats’ brains might reveal differences that other techniques would not, the researchers reasoned. Sure enough, neurons in these organoids had less complex message-receiving dendrites than those from organoids derived from people without the syndrome.
Organoids made from patient-specific cells could one day even serve as test subjects for treatments, Pasca says. “Challenging disorders will require bold approaches,” he says. “We will need to build human models that recapitulate more aspects of the human brain to study these uniquely human conditions.”
Laura Sanders is the neuroscience writer. She holds a Ph.D. in molecular biology from the University of Southern California.
Science News was founded in 1921 as an independent, nonprofit source of accurate information on the latest news of science, medicine and technology. Today, our mission remains the same: to empower people to evaluate the news and the world around them. It is published by the Society for Science, a nonprofit 501(c)(3) membership organization dedicated to public engagement in scientific research and education (EIN 53-0196483).
In life, Dakota was a 12-meter-long duck-billed dinosaur (illustrated at top). Large sections of its body, such as its right front foot, retain fossilized scaly skin (bottom) that extends down to its hooflike nail.
It might be easier for dinosaurs to “mummify” than scientists thought.
Unhealed bite marks on fossilized dinosaur skin suggest that the animal’s carcass was scavenged before being covered in sediment , researchers report October 12 in PLOS ONE . The finding challenges the traditional view that burial very soon after death is required for dinosaur “mummies” to naturally form.
The new research centers on Dakota, an Edmontosaurus fossil unearthed in North Dakota in 1999. About 67 million years ago, Dakota was a roughly 12-meter-long, duck-billed dinosaur that ate plants. Today, Dakota’s fossilized limbs and tail still contain large areas of well-preserved, fossilized scaly skin, a striking example of dinosaur “mummification.”
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The creature isn’t a true mummy because its skin has turned into rock, rather than being preserved as actual skin. Researchers have come to refer to such fossils with exquisitely preserved skin and other soft tissues as mummies.
In 2018, paleontologist Clint Boyd of the North Dakota Geological Survey in Bismarck and colleagues began a new phase of cleaning up and examining the dinosaur fossil. The team had found what looked like tears in the tail skin and puncture holes on the animal’s right front foot. To investigate what may have caused the skin marks, the researchers teamed up with Stephanie Drumheller, a paleontologist at the University of Tennessee in Knoxville, to remove extra rocky material around the marks.
The holes in the skin — particularly those on the front limb — are a close match for bite wounds from prehistoric relatives of modern-day crocodiles, the researchers say. “This is the first time that’s been seen in dinosaurian soft tissues,” Drumheller says.
Because the marks on the tail are larger than those on the front limb, the team thinks that at least two carnivores munched on the Edmontosaurus carcass, probably as scavengers because the wounds didn’t heal. But scavenging doesn’t fit into the traditional view of mummification.
“This assumption of rapid burial has been baked into the explanation for mummies for a while,” Drumheller says. That clearly wasn’t the case for Dakota. If scavengers had enough time to snack on its body, then the deceased dino had been out in the open for a while.
Observing Dakota’s deflated skin envelope, shrink-wrapped to the underlying bone with no muscle or other organs, Drumheller had an unexpected “eureka moment,” she says. “I had seen something like this before. It just wasn’t in the paleontological literature. It was in the forensics literature.”
When some smaller modern scavengers like raccoons feed on the internal organs of a larger carcass, the scavengers rip open the carcass’s body. The forensics research showed that this hole gives any gasses and fluids from further decomposition an escape route, allowing the remaining skin to dry out. Burial could happen afterward.
The researchers “make a very good point,” says Raymond Rogers, a researcher at Macalester College in Saint Paul, Minn., who studies how organisms decay and fossilize and wasn’t involved in the research. “It would be very unlikely for a carcass to achieve advanced stages of desiccation and also experience rapid burial. These two generally presumed prerequisites for mummification seem to be somewhat incompatible.”
Fossilization of soft tissues — like skin or brains or fleshy head combs — is uncommon, but not unheard of ( SN: 8/20/21 ; SN: 12/12/13 ). “If [soft tissue] requires some spectacular confluence of weird events to get it fossilized at all, it’s far more common than then you would expect if that was the case,” Drumheller says. Perhaps, then, mummies originating from common carcass fates could explain this.
But while dry, “jerkylike” skin could survive long enough to be buried, the conditions involved aren’t necessarily common, says Evan Thomas Saitta, a paleontologist at the University of Chicago who was not involved with the study.
“I still suspect that this actual process is a very precise sequence of events, where if you get the timing wrong, you end up without a mummy dinosaur,” he says.
Understanding that sequence of events, and just how common it is, requires figuring out how fossilization proceeds after a mummy’s burial. This is an area of research that Boyd says he’s interested in looking into next.
“Is it just the same fossilization process as for the bones?” he asks. “Or do we also need a different set of geochemical conditions to then fossilize the skin?”
Jake Buehler is a freelance science writer, covering natural history, wildlife conservation and Earth’s splendid biodiversity, from salamanders to sequoias. He has a master’s degree in zoology from the University of Hawaii at Manoa.
Science News was founded in 1921 as an independent, nonprofit source of accurate information on the latest news of science, medicine and technology. Today, our mission remains the same: to empower people to evaluate the news and the world around them. It is published by the Society for Science, a nonprofit 501(c)(3) membership organization dedicated to public engagement in scientific research and education (EIN 53-0196483).
New remote-sensing studies at southern Iraq’s massive Tell al-Hiba site, shown here from the air, support an emerging view that an ancient city there largely consisted of four marsh islands.
A ground-penetrating eye in the sky has helped to rehydrate an ancient southern Mesopotamian city, tagging it as what amounted to a Venice of the Fertile Crescent. Identifying the watery nature of this early metropolis has important implications for how urban life flourished nearly 5,000 years ago between the Tigris and Euphrates rivers, where modern-day Iraq lies.
Remote-sensing data, mostly gathered by a specially equipped drone, indicate that a vast urban settlement called Lagash largely consisted of four marsh islands connected by waterways, says anthropological archaeologist Emily Hammer of the University of Pennsylvania. These findings add crucial details to an emerging view that southern Mesopotamian cities did not, as traditionally thought, expand outward from temple and administrative districts into irrigated farmlands that were encircled by a single city wall, Hammer reports in the December Journal of Anthropological Archaeology .
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“There could have been multiple evolving ways for Lagash to be a city of marsh islands as human occupation and environmental change reshaped the landscape,” Hammer says.
Because Lagash had no geographical or ritual center, each city sector developed distinctive economic practices on an individual marsh island, much like the later Italian city of Venice, she suspects. For instance, waterways or canals crisscrossed one marsh island, where fishing and collection of reeds for construction may have predominated.
Two other Lagash marsh islands display evidence of having been bordered by gated walls that enclosed carefully laid out city streets and areas with large kilns, suggesting these sectors were built in stages and may have been the first to be settled. Crop growing and activities such as pottery making may have occurred there.
Drone photographs of what were probably harbors on each marsh island suggest that boat travel connected city sectors. Remains of what may have been footbridges appear in and adjacent to waterways between marsh islands, a possibility that further excavations can explore.
Lagash, which formed the core of one of the world’s earliest states, was founded between about 4,900 and 4,600 years ago. Residents abandoned the site, now known as Tell al-Hiba, around 3,600 years ago, past digs show. It was first excavated more than 40 years ago.
Drone photos taken across a massive site in southern Iraq revealed that buried structures, shown in yellow, from the ancient Mesopotamian city of Lagash clustered in four sectors that had probably been marsh islands. Walls, shown in red, surrounded two large sectors. Now-dry waterways, shown in dark blue, connected sectors and crisscrossed one sector, far right.
Previous analyses of the timing of ancient wetlands expansions in southern Iraq conducted by anthropological archaeologist Jennifer Pournelle of the University of South Carolina in Columbia indicated that Lagash and other southern Mesopotamian cities were built on raised mounds in marshes. Based on satellite images, archaeologist Elizabeth Stone of Stony Brook University in New York has proposed that Lagash consisted of around 33 marsh islands, many of them quite small.
Drone photos provided a more detailed look at Lagash’s buried structures than possible with satellite images, Hammer says. Guided by initial remote-sensing data gathered from ground level, a drone spent six weeks in 2019 taking high-resolution photographs of much of the site’s surface. Soil moisture and salt absorption from recent heavy rains helped the drone’s technology detect remnants of buildings, walls, streets, waterways and other city features buried near ground level.
Drone data enabled Hammer to narrow down densely inhabited parts of the ancient city to three islands, she says. A possibility exists that those islands were part of delta channels extending toward the Persian Gulf. A smaller, fourth island was dominated by a large temple.
Hammer’s drone probe of Lagash “confirms the idea of settled islands interconnected by watercourses,” says University of Chicago archaeologist Augusta McMahon, one of three co–field directors of ongoing excavations at the site.
Drone evidence of contrasting neighborhoods on different marsh islands, some looking planned and others more haphazardly arranged, reflect waves of immigration into Lagash between around 4,600 and 4,350 years ago, McMahon suggests. Excavated material indicates that new arrivals included residents of nearby and distant villages, mobile herders looking to settle down and slave laborers captured from neighboring city-states.
Dense clusters of residences and other buildings across much of Lagash suggest that tens of thousands of people lived there during its heyday, Hammer says. At that time, the city covered an estimated 4 to 6 square kilometers, nearly the area of Chicago.
It’s unclear whether northern Mesopotamian cities from around 6,000 years ago, which were not located in marshes, contained separate city sectors ( SN: 2/5/08 ). But Lagash and other southern Mesopotamian cities likely exploited water transport and trade among closely spaced settlements, enabling unprecedented growth, says archaeologist Guillermo Algaze of the University of California, San Diego.
Lagash stands out as an early southern Mesopotamian city frozen in time, Hammer says. Nearby cities continued to be inhabited for a thousand years or more after Lagash’s abandonment, when the region had become less watery and sectors of longer-lasting cities had expanded and merged. At Lagash, “we have a rare opportunity to see what other ancient cities in the region looked like earlier in time,” Hammer says.
Bruce Bower has written about the behavioral sciences for Science News since 1984. He writes about psychology, anthropology, archaeology and mental health issues.
Science News was founded in 1921 as an independent, nonprofit source of accurate information on the latest news of science, medicine and technology. Today, our mission remains the same: to empower people to evaluate the news and the world around them. It is published by the Society for Science, a nonprofit 501(c)(3) membership organization dedicated to public engagement in scientific research and education (EIN 53-0196483).
An ancient, armored worm may be the key to unraveling the evolutionary history of a diverse collection of marine invertebrates.
Discovered in China, a roughly 520-million-year-old fossil of the newly identified worm, dubbed Wufengella , might be the missing link between three of the phyla that constitute a cadre of sea creatures called lophophorates.
Based on a genetic analysis, Wufengella is probably the common ancestor that connects brachiopods, bryozoans and phoronid worms, paleontologist Jakob Vinther and colleagues report September 27 in Current Biology .
“We had been speculating that [the common ancestor] may have been some wormy animal that had plates on its back,” says Vinther, of the University of Bristol in England. “But we never had the animal.”
Roughly half a billion years ago, nearly all major animal groups burst onto the scene in a flurry of evolutionary diversification during what’s known as the Cambrian explosion ( SN: 4/24/19 ). During this time, lophophorates experienced a rapid growth of species, which has obscured the group’s evolutionary history.
One thing that ties together the different phyla of the group is their tentacle-like feeding tubes known as lophophores. But beyond that commonality, the phyla are all quite different. Brachiopods are shelled animals that at first glance resemble clams. Bryozoans — commonly known as moss animals — are microscopic sedentary critters that live in corallike colonies. And phoronids, or horseshoe worms, are unsegmented, soft-bodied creatures that live in stationary, tubelike structures. (More recently, some researchers have determined that hyoliths — an extinct animal known by their conical shells ( SN: 1/11/17 ) — are also lophophorates because of the tentacled organ that surrounds their mouth.)
Wufengella doesn’t belong to any of these phyla, Vinther and his colleagues found. But the critter has characteristics similar to those of brachiopods, horseshoe worms or bryozoans: a series of asymmetric, armored back plates, a wormlike body and bristles that stick out from lobes surrounding its body.
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The fossil is a “great find,” says Gonzalo Giribet, an invertebrate zoologist at Harvard University who was not involved in the research. Still, the scientists’ analysis does not confirm that Wufengella is the long-sought missing link, he cautions, but rather suggests it.
Some researchers had hypothesized that lophophorates’ common ancestor would be a stationary creature that sat on the seafloor and fed only through tubes, similar to its modern kin. The Wufengella fossil could refute this idea; the animal’s body plan suggests instead that it crawled around, the researchers say.
A fossil like Wufengella had long been high on Vinther’s bucket list of fossils that he and his colleagues hoped to find. But “we always thought, ‘Well, we probably will never see that in real life,’” he says. Typically, such a creature would have spent its life in shallow water. Organisms don’t tend to preserve well there, decaying faster due to exposure to lots of oxygen. Vinther suggests that the Wufengella that his team found probably washed out to deep water in a storm.
Now that the researchers have found one Wufengella , they hope to find more, in part to see if there are other varieties. And perhaps the team could identify even more distant ancestors further back on the tree of life that might connect lophophorates with other animal groups such as mollusks, Vinther says, further fleshing out how life on Earth is connected.
Science News was founded in 1921 as an independent, nonprofit source of accurate information on the latest news of science, medicine and technology. Today, our mission remains the same: to empower people to evaluate the news and the world around them. It is published by the Society for Science, a nonprofit 501(c)(3) membership organization dedicated to public engagement in scientific research and education (EIN 53-0196483).
