A new study led by a researcher from the School of Zoology and the Steinhardt Museum of Natural History at Tel Aviv University analyzed rare fossils with intact feathers and found evidence that these dinosaurs were not capable of flight. This unusual discovery offers a rare look at how animals lived 160 million years ago and sheds new light on how flight evolved in both dinosaurs and modern birds. The researchers note, “This finding has broad significance, as it suggests that the development of flight throughout the evolution of dinosaurs and birds was far more complex than previously believed. In fact, certain species may have developed basic flight abilities — and then lost them later in their evolution.”

The research was led by Dr. Yosef Kiat, alongside collaborators from China and the United States, and published in the journal Communications Biology by Nature Portfolio.

How Feathers Evolved in Dinosaurs

Dr. Kiat, an ornithologist who studies feathers, explains that dinosaurs split from other reptiles about 240 million years ago. Not long after (on an evolutionary timescale), many species developed feathers, which are lightweight, protein-based structures used for flight and temperature regulation. Around 175 million years ago, a group of feathered dinosaurs known as Pennaraptora appeared. These animals are considered distant ancestors of modern birds and were the only dinosaur lineage to survive the mass extinction at the end of the Mesozoic era 66 million years ago.

Scientists believe Pennaraptora evolved feathers for flight, but environmental changes may have led some species to lose that ability over time, similar to flightless birds today such as ostriches and penguins.

Rare Fossils Preserve Feather Color and Structure

The study focused on nine fossils from eastern China belonging to Anchiornis, a feathered Pennaraptoran dinosaur. These fossils are exceptionally rare because they preserved not only the feathers but also their original coloration, thanks to unique fossilization conditions in the region. Each specimen showed wing feathers that were white with a distinct black spot at the tip.

This preserved coloration allowed researchers to closely examine the structure and growth of the feathers in ways that are usually impossible with fossils.

Molting Patterns Reveal Flight Ability

Dr. Kiat explains that feathers grow over two to three weeks before detaching from the blood supply and becoming nonliving material. Over time, they wear out and are replaced in a process known as molting. This process can reveal whether an animal could fly.

“Feathers grow for two to three weeks. Reaching their final size, they detach from the blood vessels that fed them during growth and become dead material. Worn over time, they are shed and replaced by new feathers — in a process called molting, which tells an important story: birds that depend on flight, and thus on the feathers enabling them to fly, molt in an orderly, gradual process that maintains symmetry between the wings and allows them to keep flying during molting. In birds without flight ability, on the other hand, molting is more random and irregular. Consequently, the molting pattern tells us whether a certain winged creature was capable of flight.”

By examining the fossilized feathers, researchers identified a continuous line of black spots along the wing edges. They also spotted developing feathers whose black spots were out of alignment, showing they were still growing. A detailed analysis revealed that the molting pattern was irregular rather than orderly.

Evidence That Anchiornis Could Not Fly

Dr. Kiat concluded, “Based on my familiarity with modern birds, I identified a molting pattern indicating that these dinosaurs were probably flightless. This is a rare and especially exciting finding: the preserved coloration of the feathers gave us a unique opportunity to identify a functional trait of these ancient creatures — not only the body structure preserved in fossils of skeletons and bones.”

He adds, “Feather molting seems like a small technical detail — but when examined in fossils, it can change everything we thought about the origins of flight. Anchiornis now joins the list of dinosaurs that were covered in feathers but not capable of flight, highlighting how complex and diverse wing evolution truly was.”

In total, the team evaluated more than 700 hypotheses and asked the same question 10 times for each one to measure consistency.

Accuracy Results and Limits of AI Performance

When the experiment was first conducted in 2024, ChatGPT answered correctly 76.5% of the time. In a follow-up test in 2025, accuracy rose slightly to 80%. However, once the researchers adjusted for random guessing, the results looked far less impressive. The AI performed only about 60% better than chance, a level closer to a low D than to strong reliability.

The system had the most difficulty identifying false statements, correctly labeling them only 16.4% of the time. It also showed notable inconsistency. Even when given the exact same prompt 10 times, ChatGPT produced consistent answers only about 73% of the time.

Inconsistent Answers Raise Concerns

“We’re not just talking about accuracy, we’re talking about inconsistency, because if you ask the same question again and again, you come up with different answers,” said Cicek, an associate professor in the Department of Marketing and International Business in WSU’s Carson College of Business and lead author of the new publication.

“We used 10 prompts with the same exact question. Everything was identical. It would answer true. Next, it says it’s false. It’s true, it’s false, false, true. There were several cases where there were five true, five false.”

AI Fluency vs. Real Understanding

The findings, published in the Rutgers Business Review, highlight the importance of using caution when relying on AI for important decisions, especially those that require nuanced or complex reasoning. While generative AI can produce smooth, convincing language, it does not yet demonstrate the same level of conceptual understanding.

According to Cicek, these results suggest that artificial general intelligence capable of truly “thinking” may still be further away than many expect.

“Current AI tools don’t understand the world the way we do — they don’t have a ‘brain,'” Cicek said. “They just memorize, and they can give you some insight, but they don’t understand what they’re talking about.”

Study Design and Methods

Cicek worked with co-authors Sevincgul Ulu of Southern Illinois University, Can Uslay of Rutgers University, and Kate Karniouchina of Northeastern University.

The team used 719 hypotheses from scientific studies published in business journals since 2021. These types of questions often involve nuance, with multiple factors influencing whether a hypothesis is supported. Reducing such complexity to a simple true or false judgment requires careful reasoning.

The researchers tested the free version of ChatGPT-3.5 in 2024 and the updated ChatGPT-5 mini in 2025. Overall, performance remained similar across both versions. After adjusting for random chance, which gives a 50% probability of a correct answer, the AI’s effectiveness was only about 60% above chance in both years.

Key Weakness in AI Reasoning

The results point to a fundamental limitation of large language model AI systems. Although they can generate fluent and persuasive responses, they often struggle to reason through complicated questions. This can lead to answers that sound convincing but are actually incorrect, Cicek said.

Why Experts Urge Caution With AI

Based on these findings, the researchers recommend that business leaders verify AI-generated information and approach it with skepticism. They also emphasize the need for training to better understand what AI systems can and cannot do effectively.

Although this study focused specifically on ChatGPT, Cicek noted that similar experiments with other AI tools have produced comparable outcomes. The work also builds on earlier research pointing to caution around AI hype. A 2024 national survey found that consumers were less likely to purchase products when they were marketed with a focus on AI.

“Always be skeptical,” he said. “I’m not against AI. I’m using it. But you need to be very careful.”

The world, called L 98-59 d (an exoplanet, meaning it orbits a star outside our Solar System), circles a small red star about 35 light-years from Earth. Data from the James Webb Space Telescope (JWST) and ground based observatories revealed something unusual. For a planet about 1.6 times the size of Earth, it has a surprisingly low density and an atmosphere rich in hydrogen sulfide.

A Planet That Defies Classification

Until now, scientists would have grouped a planet like L 98-59 d into one of two categories. It could be a rocky “gas-dwarf” with a hydrogen dominated atmosphere, or a water rich world covered by deep oceans and ice.

New evidence shows it fits neither category. Instead, L 98-59 d appears to belong to a completely different class of planet dominated by heavy sulfur compounds.

A Global Magma Ocean Beneath the Surface

To understand this unusual world, researchers from the University of Oxford, the University of Groningen, the University of Leeds and ETH Zurich used advanced computer simulations to trace its evolution from shortly after formation to today, spanning nearly five billion years. By combining telescope observations with detailed models of planetary interiors and atmospheres, they were able to infer what is happening deep inside the planet.

Their findings suggest that L 98-59 d has a mantle made of molten silicate, similar to lava on Earth. Beneath its surface lies a vast magma ocean extending thousands of kilometers deep. This enormous reservoir allows the planet to trap large amounts of sulfur within its interior over long periods of time.

The magma ocean also helps maintain a thick hydrogen rich atmosphere that contains sulfur bearing gases such as hydrogen sulfide (H2S). Normally, radiation from the host star would gradually strip these gases away into space through X-ray driven processes.

Sulfur Cycling Between Interior and Atmosphere

Over billions of years, ongoing chemical exchanges between the molten interior and the atmosphere have shaped the planet’s current appearance. These interactions explain the unusual signals detected by telescopes.

Researchers suggest that L 98-59 d may be the first identified example of a broader population of gas rich sulfur dominated planets that sustain long lived magma oceans. If that is the case, it points to a much wider variety of planetary types across the galaxy than previously recognized.

Lead author Dr. Harrison Nicholls (Department of Physics, University of Oxford) said: “This discovery suggests that the categories astronomers currently use to describe small planets may be too simple. While this molten planet is unlikely to support life, it reflects the wide diversity of the worlds which exist beyond the Solar System. We may then ask: what other types of planet are waiting to be uncovered?”

How Sulfur Shapes the Atmosphere

JWST observations from 2024 detected sulfur dioxide along with other sulfur gases high in the upper atmosphere of L 98-59 d. According to the team’s models, these gases form when ultraviolet radiation from the host star, the red dwarf L 98-59, drives chemical reactions.

At the same time, the magma ocean below acts as a massive storage system for volatile materials, absorbing and releasing gases over billions of years after the planet formed. This combination of deep interior storage and ultraviolet driven chemistry explains the planet’s distinctive properties.

Simulations indicate that L 98-59 d likely formed with a large supply of volatile material and may once have resembled a larger sub-Neptune type planet. Over time, it cooled, lost part of its atmosphere, and became smaller.

Scientists note that magma oceans are thought to be the initial state of all rocky planets (including the Earth and Mars). Studying these environments on distant worlds can provide insight into the earliest stages of our own planet’s history.

Reconstructing Alien Worlds With Models

Co-author Professor Raymond Pierrehumbert (Department of Physics, University of Oxford) said: “What’s exciting is that we can use computer models to uncover the hidden interior of a planet we will never visit. Although astronomers can only measure a planet’s size, mass and atmospheric composition from afar, this research shows that it is possible to reconstruct the deep past of these alien worlds — and discover types of planets with no equivalent in our own Solar System.”

JWST is already delivering a growing stream of data, and future missions such as Ariel and PLATO are expected to expand that dataset even further. The research team plans to apply their models to these observations using machine learning to map the diversity of planets beyond our Solar System and link them to their early development.

By doing so, scientists hope to better understand how planets form and evolve, and to identify which types of worlds might be capable of supporting life.

Dr. Richard Chatterjee (University of Leeds/ University of Oxford) said: “Our computer models simulate various planetary processes, effectively enabling us to turn back the clock and understand how this unusual rocky exoplanet, L 98-59 d, evolved. Hydrogen sulfide gas, responsible for the smell of rotten eggs, appears to play a starring role there. But, as always, more observations are needed to understand this planet and others like it. Further investigation may yet show that rather pungent planets are surprisingly common.”

“Our study is the first to clearly demonstrate how this anti-amyloid antibody therapy works in Alzheimer’s disease. We show that the therapy’s efficacy relies on the antibody’s Fc fragment, which activates microglia to effectively clear amyloid plaques,” says Dr. Giulia Albertini, co-first author of the study. “The Fc fragment works as an anchor that microglia latch onto when they are near plaques, as a consequence of which these cells are reprogrammed to clear plaques more efficiently.”

Alzheimer’s Disease and the Role of Microglia

More than 55 million people worldwide live with Alzheimer’s disease, which is driven by the buildup of amyloid plaques in the brain. These toxic protein clusters damage neurons and eventually lead to dementia. Although microglia naturally gather around these plaques, they are typically unable to remove them effectively. In response, researchers have been developing treatments aimed at restoring this essential immune function.

Antibody Therapy and the Fc Fragment

Lecanemab is one of the therapies designed to target amyloid-beta plaques and slow disease progression, and it has already received FDA approval. However, side effects have limited its overall benefit, and until now, its exact mode of action remained unclear.

Antibodies are made up of two main parts. One part binds to a specific target such as amyloid plaques, while the other part, the Fc fragment, signals the immune system. Earlier research suggested that microglia play a role in clearing plaques, but direct proof linking their activity to lecanemab’s effectiveness was missing. Some scientists had also proposed that plaque removal could occur without involvement of the Fc fragment. The team led by Prof. Bart De Strooper demonstrated that this fragment is essential, as microglia only responded when it was intact and functional.

To investigate this, researchers used a specially designed Alzheimer’s mouse model that included human microglial cells. This allowed them to closely observe how lecanemab interacts with human immune cells and promotes plaque clearance. When the Fc fragment was removed, the antibody no longer had any effect.

“The fact that we used human microglia within a controlled experimental model was a major strength of our study. This allowed us to test the very antibodies used in patients and observe human-specific responses with unprecedented resolution,” adds Magdalena Zielonka, co-first author.

Inside the Brain’s Plaque-Clearing Process

The team then examined how activated microglia actually remove amyloid plaques in this hybrid model. They identified key cellular processes involved in this cleanup, including phagocytosis and lysosomal activity. These processes were only triggered when the Fc fragment was present. Without it, the microglia remained inactive.

Using advanced techniques such as single-cell and spatial transcriptomics, the researchers also identified a specific gene activity pattern in microglia associated with effective plaque removal. This pattern included strong expression of the gene SPP1 and was uncovered using NOVA-ST, a method developed by the Stein Aerts lab (VIB-KU Leuven).

Toward Safer and More Effective Alzheimer’s Treatments

By defining the exact microglial program responsible for clearing plaques, the findings point toward new strategies for treating Alzheimer’s disease. Future therapies may be able to activate microglia directly, without relying on antibodies.

“This opens doors to future therapies that may activate microglia without requiring antibodies. Understanding the importance of the Fc fragment helps guide the design of next-generation Alzheimer’s drugs,” concludes Prof. Bart De Strooper.

The research conducted at the VIB-KU Leuven Center for Brain & Disease Research was supported by the European Research Council (ERC), Alzheimer’s Association USA, Research Foundation Flanders (FWO), Queen Elisabeth Medical Foundation for Neurosciences, Stichting Alzheimer Onderzoek — Fondation Recherche Alzheimer (STOPALZHEIMER.BE), KU Leuven, VIB, and UK Dementia Research Institute University College London.

The study is the first to quantitatively examine uncertainty in the birefringence angle. This measurement is important because it may provide clues about unknown physical theories that violate the universe’s left right symmetry. It could also help scientists better understand dark matter and dark energy.

A Subtle Twist in the Universe’s Oldest Light

The cosmic microwave background, which is the faint afterglow left behind by the Big Bang, contains valuable information about the early universe. Recent observations suggest that the polarization of this ancient light may undergo a slight rotation. This effect is known as cosmic birefringence.

Scientists suspect that this subtle rotation could be linked to hypothetical elementary particles called axions. Precisely determining the amount of rotation, known as the birefringence angle, is therefore essential for testing possible new physics. Researchers measure this angle by analyzing the strength of a signal called the CMB EB correlation. Earlier studies estimated the rotation angle to be around 0.3 degrees.

Investigating the Measurement Uncertainty

The research team was led by University of Tokyo Graduate School of Science PhD candidate Fumihiro Naokawa, working with Kavli Institute for the Physics and Mathematics of the Universe (Kavli IPMU, WPI) Project Associate Professor Toshiya Namikawa. Their analysis carefully examined the uncertainties that affect measurements of cosmic birefringence.

Their results suggest that the rotation angle may actually be larger than the previously reported value of about 0.3 degrees.

“Can you tell what day it is, just by looking at a clock? No, you cannot. To determine the date from the clock hands, you need to know how many times the hands have rotated since a specific reference date and time. In scientific terms, a situation like this clock’s hands — where observing only the current state does not reveal how many rotations occurred in the past — is described as having 360-degree phase ambiguity.

“Like a clock, the CMB we can observe is only in its current state. Therefore, rotation angles such as 0.3 degrees, 180.3 degrees, and 360.3 degrees should be indistinguishable. This means the birefringence angle has a phase ambiguity of 180 degrees,” said Naokawa.

Solving the Phase Ambiguity Problem

To address this issue, the researchers developed a technique to resolve the ambiguity. They discovered that the detailed shape of the EB correlation signal contains clues about how many times the polarization direction may have rotated.

By analyzing these subtle features within the EB correlation signal, scientists may be able to determine the true rotation angle and eliminate the ambiguity.

Improving Future Cosmology Experiments

The new method provides a tool for analyzing future high precision observations of cosmic birefringence. Upcoming experiments, including the Simons Observatory and LiteBIRD, could use this technique to test new theoretical models of fundamental physics.

The team also discovered that when this phase uncertainty is considered, cosmic birefringence influences another signal in the cosmic microwave background known as the EE correlation. Scientists use the EE correlation to estimate the Universe’s “optical depth,” an important quantity for studying cosmic reionization. Because of this connection, the new findings may require researchers to revisit previously reported optical depth measurements.

A New Way to Confirm Cosmic Birefringence

In a separate study also published in Physical Review Letters, Naokawa examined ways to reduce errors introduced by telescopes when measuring cosmic birefringence. He proposed a method to confirm the effect by observing particular astronomical sources, including radio galaxies powered by supermassive black holes.

These observations could provide another way to verify cosmic birefringence and may help scientists uncover deeper insights into the nature of dark energy.

A study led by chemists at the University of Bristol found that the smell associated with mummies is not simply the result of aging or decay. Instead, it reflects a complex blend of substances used during embalming, along with preserved fabrics and materials wrapped around the body. Together, these lingering chemical traces reveal how mummification methods changed and became more sophisticated over hundreds of years.

Lead author Dr. Wanyue Zhao, Research Associate in Organic Geochemistry at the University of Bristol, said: “The findings mark a significant step forward in improving our understanding of Egyptian history and the fascinating ritual of mummification. Our analysis of the associated scents has uncovered new insights into how the practice developed through the ages and became increasingly sophisticated.”

Analyzing the Air Around Ancient Remains

To investigate the source of mummy scents, researchers examined the air surrounding extremely small mummy fragments about the size of a peppercorn. This approach differs from traditional techniques, which often require dissolving samples in solvents and can damage delicate artifacts.

The team used a combination of advanced analytical tools including solid phase microextraction, gas chromatography, and high resolution mass spectrometry. These methods allowed them to capture gases inside small sealed containers and separate the different scent components known as Volatile Organic Compounds (VOCs) so they could be studied in detail.

The research, published in the Journal of Archaeological Science, analyzed 35 samples of balms and bandages from 19 mummies. These remains spanned more than 2,000 years of Egyptian history between 3200 BC and 395 AD. Across all samples, scientists identified 81 distinct VOCs that offer clues about the materials used during the embalming process and the time periods in which the mummies were prepared.

Chemical Clues Reveal Embalming Ingredients

Even when present in extremely small quantities, these chemical compounds helped researchers identify the substances used in preservation. They grouped the compounds into four main categories connected to specific embalming ingredients.

Fats and oils generated aromatic compounds and short chain fatty acids. Beeswax produced mono-carboxylic fatty acids and cinnamic compounds. Plant resins released aromatic compounds and sesquiterpenoids, while bitumen produced naphthenic compounds.

Dr. Zhao said: “Our findings showed the chemical patterns varied across historical periods. Earlier mummies had simpler profiles dominated by fats and oils, while later mummies displayed more complex mixtures incorporating imported resins and bitumen. Such materials were more costly and required more specialized preparation, as the practice became more advanced.”

Different Body Parts Used Different Embalming Recipes

The chemical signatures also varied depending on which part of the body was sampled.

“For instance, samples from heads often contained different patterns than those from torsos, suggesting embalmers applied distinct recipes to separate parts of the body to possibly aid preservation. This is an area which needs further analysis and research to better understand what techniques were used and why,” Dr. Zhao added.

The findings provide a more detailed understanding of known embalming mixtures and offer deeper insight into how these preservation techniques developed over time.

A New Way to Study Mummies Without Damaging Them

Study co-author Richard Evershed, Professor of Chemistry at the University of Bristol, said: “Our volatile analysis proved sensitive enough to detect residues at extremely low concentrations. For example, bitumen biomarkers were previously difficult to detect with earlier soluble residue methods.

“This approach expands the study of ancient Egyptian funerary practices, presenting a clearer, fuller picture of mummification recipes, material choices, and preservation strategies.”

The technique could also be valuable for museums and research collections. Sampling the air around mummies provides a fast, non destructive method for examining fragile remains while preserving their physical condition.

Study co-author Ian Bull, Professor of Analytical Chemistry at the University of Bristol, added: “Physical sampling still plays a role for detailed work, yet volatile analysis provides an effective and enlightening first step for studying embalmed remains across collections and time periods.”