SPACE/COSMOS

Why some objects in space look like snowmen

Gravitational collapse may explain the origin of contact binaries in the Kuiper Belt, MSU simulation finds

Michigan State University

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This image was taken by NASA's New Horizons spacecraft on Jan. 1, 2019 during a flyby of Kuiper Belt object 2014 MU69, informally known as Ultima Thule. It is the clearest view yet of this remarkable, ancient object in the far reaches of the solar system – and the first small "KBO" ever explored by a spacecraft.

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Credit: NASA

Astronomers have long debated why so many icy objects in the outer solar system look like snowmen. Michigan State University researchers now have evidence of the surprisingly simple process that could be responsible for their creation.

Far beyond the violent, chaotic asteroid belt between Mars and Jupiter lies what’s known as the Kuiper Belt. There, past Neptune, you’ll find icy, untouched building blocks from the dawn of the solar system, known as planetesimals. About one in 10 of these objects are contact binaries, planetesimals that are shaped like two connected spheres, much like Frosty the Snowman. But just how these objects came to be without the help of a magic silk hat was an open question.

Jackson Barnes, an MSU graduate student, has created the first simulation that reproduces the two-lobed shape naturally with gravitational collapse. His work is published in the Monthly Notices of the Royal Astronomical Society.

Earlier computational models treated colliding objects as fluid blobs that merged into spheres, making it impossible to form these unique shapes. Thanks to MSU’s Institute for Cyber-Enabled Research, or ICER, and its high-performance computing cluster, Barnes’ simulations produce a more realistic environment that allows objects to retain their strength and rest against one another.

Other formation theories involve special events or exotic phenomena that, while possible, aren’t likely to happen on a regular basis.

“If we think 10 percent of planetesimal objects are contact binaries, the process that forms them can’t be rare,” said Earth and Environmental Science Professor Seth Jacobson, senior author on the paper. “Gravitational collapse fits nicely with what we’ve observed.”

Contact binaries were first imaged up close by NASA’s New Horizons spacecraft in January 2019. These images prompted scientists to take another look at other objects in the Kuiper belt, and it turned out that contact binaries accounted for about 10 percent of all planetesimals. These distant objects float mostly undisturbed and safe from collisions in the sparsely populated Kuiper belt.

In the early days of the Milky Way, the galaxy was a disc of dust and gas. Remnants of the galaxy’s formation are found in the Kuiper Belt, including dwarf planets like Pluto, comets and planetesimals.

Planetesimals are the first large planetary objects to form from the disc of dust and pebbles. Much like individual snowflakes that are packed into a snowball, these first planetesimals are aggregates of pebble-sized objects pulled together by gravity from a cloud of tiny materials.

Occasionally as the cloud rotates, it falls inward on itself, ripping the object apart and forming two separate planetesimals that orbit one another. Astronomers observe many binary planetesimals in the Kuiper belt. In Barnes’ simulation, the orbits of these objects spiral inward until the two gently make contact and fuse together while still maintaining their round shapes.

How do these two objects stay together throughout the history of the solar system? Barnes explains they’re simply unlikely to crash into another object. Without a collision, there’s nothing to break them apart. Most binaries aren’t even pocked with craters.

Scientists long suspected that gravitational collapse was responsible for forming these objects, but they couldn’t fully test the idea. Barnes’ model is the first to include the physics needed to reproduce contact binaries.

“We’re able to test this hypothesis for the first time in a legitimate way,” Barnes said. “That’s what’s so exciting about this paper.”

Barnes expects his model will help scientists understand binary systems of three or more objects. The team is also working to create a new simulation that better models the collapse process.

As more NASA missions explore uncharted realms of the solar system, Jacobson and Barnes suspect Frosty may have more distant cousins yet to be found.

Simulation of gravitational collapse [VIDEO] |

Jackson Barnes created this computer simulation showing how a contact binary’s two-lobed shape could be formed by gravitational collapse.

 

Jackson Barnes created this contact binary in a computer simulation showing how the two-lobed shape could be formed by gravitational collapse.

Credit

Michigan State University Jacobson Lab

New Horizons video [VIDEO] 

This short movie shows the view of Kuiper Belt object 2014 MU69 (nicknamed Ultima Thule) as seen by NASA's New Horizons spacecraft from Dec. 7, 2018 to Jan. 1, 2019. During the approach, Ultima Thule transforms from a faint dot 20 million miles (31 million kilometers) away, indistinguishable from thousands of background stars, to a newly revealed world unlike any seen before, from a range of 5,000 miles (8,000 kilometers). The sequence consists of actual New Horizons images, taken at discrete intervals during the approach, supplemented with computer-generated intermediate frames in order to make a smooth movie. Time slows down during the movie to show clearly both the slow initial phases of the approach and the very rapid final stages. The final image is a parting crescent view of Ultima Thule, taken 10 minutes after closest approach occurred at 12:33 a.m. EST on Jan. 1.

Credit

NASA

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Journal

Monthly Notices of the Royal Astronomical Society

DOI

10.1093/mnras/stag002 

Article Title

Direct contact binary planetesimal formation from gravitational collapse

Article Publication Date

19-Feb-2026

STEM IS DEI

PhD student maps mysterious upper atmosphere of Uranus for the first time

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Northumbria University

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Paola Tiranti of Northumbria University

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Credit: Northumbria University/Barry Pells

A Northumbria University PhD student has led an international team of astronomers in creating the first-ever three-dimensional map of Uranus's upper atmosphere, revealing how the ice giant's unusual magnetic field shapes spectacular auroras high above the planet's clouds.

 

Using the James Webb Space Telescope, led by NASA with its partners, ESA (European Space Agency) and CSA (Canadian Space Agency), Paola Tiranti and her colleagues observed Uranus for nearly a full rotation, detecting the faint glow from molecules up to 5,000 kilometres above the cloud tops.

 

The observations provide the most detailed picture yet of where the planet's auroras form and how energy moves through its atmosphere.

 

The study, published today (19 Feb) in Geophysical Research Letters, also confirms that Uranus's upper atmosphere has continued to cool over the past thirty years – a trend that has been surprising scientists for over three decades.

 

Auroras occur when energetic particles become trapped in a planet's magnetic field and strike the upper atmosphere, releasing energy that creates a signature glow.

 

Using Webb's Near-Infrared Spectrograph, the team mapped out the temperature and density of ions in Uranus's ionosphere, a region where the atmosphere becomes ionised and interacts strongly with the planet's magnetic field.

 

The measurements revealed that temperatures peak between 3,000 and 4,000 kilometres above the cloud tops, whilst ion densities reach their maximum around 1,000 kilometres.

 

Speaking about the findings, lead author Paola Tiranti said: “This is the first time we've been able to see Uranus's upper atmosphere in three dimensions. With Webb's sensitivity, we can trace how energy moves upward through the planet's atmosphere and even see the influence of its lopsided magnetic field.”

 

Uranus's magnetosphere is one of the strangest in the Solar System. Unlike Earth, where the magnetic field is relatively aligned with the planet's rotation axis, Uranus's magnetic field is tilted by nearly 60 degrees and offset from the planet's centre. This means its auroras sweep across the surface in complex ways.

 

The Webb observations detected two bright auroral bands near Uranus's magnetic poles, together with a distinct depletion in emission and ion density between them – a feature likely linked to how magnetic field lines guide charged particles through the atmosphere. Similar darkened regions have been seen at Jupiter, where magnetic field geometry controls particle flow.

 

Webb's data also confirmed that Uranus's upper atmosphere is still cooling, extending a trend that began in the early 1990s. The team measured an average temperature of around 426 kelvins (about 150 degrees Celsius), lower than values recorded by ground-based telescopes or previous spacecraft observations.

 

Understanding why Uranus is cooling, despite being so far from the Sun, could provide crucial insights into how ice giant planets regulate their atmospheric temperature.

 

Paola Tiranti said: “By revealing Uranus's vertical structure in such detail, Webb is helping us understand the energy balance of the ice giants. This is a crucial step towards characterising giant planets beyond our Solar System.”

 

The study is based on data from JWST General Observer programme 5073, led by Dr Henrik Melin of Northumbria University, which used the telescope's Integral Field Unit on 19 January 2025 to observe Uranus for 15 hours.

 

Planetary scientists from Northumbria University's Solar and Space Physics peak of research excellence have been involved in a number of research projects using data from Webb, specifically exploring the upper atmospheres of our solar system's giant gas planets – Jupiter, Saturn, Uranus and Neptune.

 

• Deep space telescope captures Neptune's auroras for the first time
• Unveiling Jupiter's upper atmosphere
• Uranus aurora discovery promises new riches from James Webb Space Telescope
• Telescope to provide insight into Solar System light shows
• Telescope reveals unexpected activity above Jupiter's Great Red Spot

 

The James Webb Space Telescope is the world's premier space science observatory. Webb is solving mysteries in our solar system, looking beyond to distant worlds around other stars, and probing the mysterious structures and origins of our universe and our place in it. Webb is an international program led by NASA with its partners, ESA (European Space Agency) and CSA (Canadian Space Agency).

  

Uranus (January 2025)

Credit

ESA/Webb, NASA, CSA, STScI, P. Tiranti, H. Melin, M. Zamani (ESA/Webb)

Paola Tiranti of Northumbria University

Credit

Northumbria University/Barry Pells

Journal

Geophysical Research Letters

DOI

10.1029/2025GL119304 

Method of Research

Imaging analysis

Subject of Research

Not applicable

Article Title

JWST Discovers the Vertical Structure of Uranus' Ionosphere

Article Publication Date

19-Feb-2026

NASA delivers harsh assessment of botched Boeing Starliner test flight

By AFP
February 19, 2026


NASA duo Butch Wilmore and Suni Williams were stuck on the ISS for nine months - Copyright AFP/File TED ALJIBE

Charlotte Causit and Maggy Donaldson in New York

NASA on Thursday blamed what it called engineering vulnerabilities in Boeing’s Starliner spacecraft along with internal agency mistakes in a sharply critical report assessing a botched mission that left two astronauts stranded in space.

The US space agency labeled the 2024 test flight of the Starliner capsule a “Type A” mishap — the same classification as the deadly Challenger and Columbia shuttle disasters — a category that reflects the “potential for a significant mishap,” it said.

The failures left a pair of NASA astronauts stranded aboard the International Space Station for nine months in a mission that captured global attention and became a political flashpoint.

“Starliner has design and engineering deficiencies that must be corrected, but the most troubling failure revealed by this investigation is not hardware. It’s decision-making and leadership,” said NASA administrator Jared Isaacman in a briefing.

“If left unchecked,” he said, this mismanagement “could create a culture incompatible with human spaceflight.”

The top space official said the investigation found that a concern for the reputation of Boeing’s Starliner clouded an earlier internal probe into the incident.

“Programmatic advocacy exceeded reasonable bounds and place the mission, the crew and America’s space program at risk in ways that were not fully understood at the time,” Isaacman said.

He said Starliner currently “is less reliable for crew survival than other crewed vehicles” and that “NASA will not fly another crew on Starliner until technical causes are understood and corrected” and a problematic propulsion system is fixed.

But the administrator insisted that “NASA will continue to work with Boeing, as we do all of our partners that are undertaking test flights.”

In a statement, Boeing said it has “made substantial progress on corrective actions for technical challenges we encountered and driven significant cultural changes across the team that directly align with the findings in the report.”



– ‘We failed them’ –



Isaacman also had harsh words for internal conduct at NASA.

“We managed the contract. We accepted the vehicle, we launched the crew to space. We made decisions from docking through post-mission actions,” he told journalists.

“A considerable portion of the responsibility and accountability rests here.”

In June 2024 Butch Wilmore and Suni Williams embarked on what was meant to be an eight-to-14-day mission. But this turned into nine months after propulsion problems emerged in orbit and the Starliner spacecraft was deemed unfit to fly them back.

The ex-Navy pilots were reassigned to the NASA-SpaceX Crew-9 mission. A Dragon spacecraft flew to the ISS that September with a team of two, rather than the usual four, to make room for the stranded pair.

The duo, both now retired, were finally able to arrive home safely in March 2025.

“They have so much grace, and they’re so competent, the two of them, and we failed them,” NASA associate administrator Amit Kshatriya told Thursday’s briefing.

“The agency failed them.”

Kshatriya said the details of the report were “hard to hear” but that “transparency” was the only path forward.

“This is not about pointing fingers,” he said. “It’s about making sure that we are holding each other accountable.”

Both Boeing and SpaceX were commissioned to handle missions to the ISS more than a decade ago.

 

New ‘scimitar-crested’ Spinosaurus species discovered in the central Sahara

The first indisputable evidence of a new species of Spinosaurus in over a century belongs to S. mirabilis, named for its scimitar-shaped crest and found at a locality far from the ocean’s edge

University of Chicago Medical Center

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Paleoartist rendering of Spinosaurus mirabilis eating a coelacanth. Art by Dani Navarro.

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Credit: Art by Dani Navarro

A new paper published in Science describes the discovery of Spinosaurus mirabilis, a new spinosaurid species found in Niger. A 20-person team led by Paul Sereno, PhD, Professor of Organismal Biology and Anatomy at the University of Chicago, unearthed the find at a remote locale in the central Sahara, adding important new fossil finds to the closing chapter of spinosaurid evolution.

Eye-catching anatomy

The scimitar-shaped crest of S. mirabilis was so large and unexpected that the paleontologists initially didn’t recognize it for what it was when they plucked it and some jaw fragments from the desert surface in November 2019. Returning with a larger team in 2022 and finding two additional crests, they realized the novelty of the new species they had unearthed. Based on the crest’s surface texture and interior vascular canals, the experts believe the crest was sheathed in keratin. They reckon that this display feature was brightly colored in life, curving toward the sky as a blade-shaped beacon.

Another striking feature of the skull is its interdigitating upper and lower tooth rows, which make a deadly trap for slippery fish. Interdigitating teeth, where those of the lower jaw protrude outward and between those of the uppers, is a time-honored adaptation among fish-eaters in the fossil record — including aquatic ichthyosaurs, semi-aquatic crocodile and airborne pterosaurs. Among dinosaurs, it sets Spinosaurus and closest kin apart.

“This find was so sudden and amazing, it was really emotional for our team,” Sereno said. “I’ll forever cherish the moment in camp when we crowded around a laptop to look at the new species for the first time, after one member of our team generated 3D digital models of the bones we found to assemble the skull — on solar power in the middle of the Sahara. That’s when the significance of the discovery really registered.”

Far from shore

Previously, spinosaurid bones and teeth had only been found principally in coastal deposits not far from the shoreline, leading some experts to hypothesize recently that these fish-eating theropods may have been fully aquatic, pursuing prey underwater.

However, the new fossil area in Niger documents animals that were living inland, some 500-1000 km from the nearest marine shoreline. Their proximity to intact partial skeletons of long-necked dinosaurs, all buried in river sediments, suggest they lived in a forested inland habitat dissected by rivers.

“I envision this dinosaur as a kind of ‘hell heron’ that had no problem wading on its sturdy legs into two meters of water but probably spent most of its time stalking shallower traps for the many large fish of the day,” Sereno said.

A remarkable expedition to Niger

The journey that culminated in this remarkable discovery started with a single sentence in a monograph from the 1950s, where a French geologist mentioned finding a single sabre-shaped fossilized tooth resembling those of the giant predator Carcharodontosaurus found in Egypt’s Western Desert at the turn of the last century.

“No one had been back to that tooth site in over 70 years,” Sereno mused. “It was an adventure and a half wandering into the sand seas to search for this locale and then find an even more remote fossil area with the new species. Now all of the young scholars who joined me are co-authors on the report gracing the cover of Science.”

The team ended up meeting a local Tuareg man who led them on his motorbike deep into the center of the Sahara, where he had seen huge fossil bones. After nearly a full day of travel with no shortage of doubts regarding the success of the effort, he led them to a fossil field. There, with little time to spare before returning to camp, the team found teeth and jaw bones of the new species of Spinosaurus.

“I was attracted to the Sahara like a magnet once I set foot there 30 years ago,” Sereno said. “There’s nowhere else like it. It’s as beautiful as it is daunting.” After excavating more than 100 tons of fossil finds, he says of the Sahara, “If you can brave the elements and are willing to go after the unknown, you might just uncover a lost world.”

This latest discovery adds to Niger’s rich legacy in paleontology and archaeology, both of which Sereno has engaged. He has led an international award-winning effort to build the world’s first zero-energy museum, the Museum of the River, on an island in the center of Niger’s capital city of Niamey. It will showcase their world class patrimony that documents Africa’s lost world of dinosaurs, now including an astonishing spinosaur species, as well as stone-age cultures that once lived in a Green Sahara.

“The local people we work with are my lifelong friends, now including the man who led us to Jenguebi and the astonishing spinosaur. They understand the importance of what we’re doing together — for science and for their country,” Sereno said.

Envisioning Spinosaurus mirabilis with multimedia science and paleoart

Back home in Chicago, Sereno’s team at his South Side Fossil Lab in Washington Park cleaned and then CT scanned the teeth and bones, assembling a digital skull rendering for the research report. Using that rendering, Sereno worked with paleoartist Dani Navarro in Madrid to create an action scene involving flesh reconstructions of the new species tussling over a coelacanth carcass. Navarro went farther, creating a detailed 3D physical model of S. mirabilis by adding flesh over a skeletal reconstruction.

Other paleoartists in Chicago (Jonathan Metzger) and Italy (Davide la Torre) animated Nararro’s model, bringing back to life the action behind the scene chosen for the cover of Science. More adept programs, cameras and drones have revolutionized visualization in paleontology as practiced today in the field and lab.

Inspiring young minds

As part of these reconstruction efforts, the team also prepared a replica of the newly discovered skull and a touchable, colorful model of the scimitar crest.

On March 1, in the wake of the Science paper, both replicas will join Sereno’s previous Dinosaur Expedition exhibit at the Chicago Children’s Museum, where kids will be among the first to get up close and personal  with this latest dinosaur find.

“Letting kids feel the excitement of new discoveries — that’s key to ensuring the next generation of scientists who will discover many more things about our precious planet worth preserving,” Sereno said.

 

“New scimitar-crested Spinosaurus species from the Sahara caps stepwise spinosaurid radiation” was published in Science in February 2026. Co-authors are Paul C. Sereno, Daniel Vidal, Nathan P. Myhrvold, Evan Johnson-Ransom, María Ciudad Real, Stephanie L. Baumgart, Noelia Sánchez Fontela, Todd L. Green, Evan T. Saitta, Boubé Adamou, Lauren L. Bop, Tyler M. Keillor, Erin C. Fitzgerald, Didier B. Dutheil, Robert A. S. Laroche, Alexandre V. Demers-Potvin, Álvaro Simarro, Francesc Gascó-Lluna, Ana Lázaro, Arturo Gamonal, Charles V. Beightol, Vincent Reneleau, Rachel Vautrin, Filippo Bertozzo, Alejandro Granados, Grace Kinney-Broderick, Jordan C. Mallon, Rafael M. Lindoso and Jahandar Ramezani.

Fossilized head crests of S. mirabilis were among the researchers’ first finds in the remote fossil area they call Jenguebi. Photo by Daniel Vidal.

Credit

Photo by Daniel Vidal

 

With only a few hours to spend after discovering the remote fossil area Jenguebi in November of 2019, Spanish paleontologist

Dan Vidal hovers over a quickly gathered collection of fossils, which included the crest and jaw pieces of a new scimitar-
crested spinosaurid Spinosaurus mirabilis (photograph by Paul Sereno)

Credit

`Photograph by Paul Sereno

Paul Sereno poses with reconstructed skull of Spinosaurus mirabilis. Photograph by Keith Ladzinski.

Credit

Photograph by Keith Ladzinski

A single Spinosaurus mirabilis rears over a carcass of the coelacanth Mawsonia on the forested bank of a river some 95 million years ago in what is now the Sahara Desert in Niger. A scimitar-shaped head crest and interdigitating teeth characterize this wading giant, one of the last-surviving species of a spinosaurid radiation some 50 million years in the making (artwork by Dani Navarro)

Credit

Artwork by Dani Navarro

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Journal

Science

DOI

10.1126/science.adx5486 

Article Title

New scimitar-crested Spinosaurus species from the Sahara caps stepwise spinosaurid radiation

Article Publication Date

19-Feb-2026