Arctic in Transition: Greenland’s Caves Preserve Ancient Climate Archive

Inside the Cove Cave, northern Greenland: A team of Innsbruck scientists studies deposits from a time when the Arctic was much warmer than today.
Photo Credit: Robbie Shone

In a remote cave in northern Greenland, a research team led by geologists Gina Moseley, Gabriella Koltai, and Jonathan Baker have discovered evidence of a significantly warmer Arctic. The cave deposits show that the region was free of permafrost millions of years ago and responded sensitively to rising temperatures. The findings, published in Nature Geoscience, provide new insights into past climate conditions and their relevance for today’s climate protection efforts.

Understanding Earth’s climate during earlier warm periods is key to predicting how it may change in the future. One particularly revealing time is the Late Miocene, which began about 11 million years ago. During this period, Earth’s distribution of land and ocean was similar to today, and both temperatures and atmospheric CO₂ levels were comparable to projections for the coming decades. Although the Arctic is known to be highly sensitive to climate change, its environmental conditions during the Late Miocene have remained poorly understood.

Increasing Heat is Super-Charging Arctic Climate and Weather Extremes

Photo Credit: Master Unknown

By evaluating historical climate records, observational and projection data, an international team of researchers found a “pushing and triggering” mechanism that has driven the Arctic climate system to a new state, which will likely see consistently increased frequency and intensity of extreme events across all system components – the atmosphere, ocean and cryosphere – this century.

“We know that mean temperatures are rising, and the Arctic is commonly considered an indicator of global changes due to its higher sensitivity to any perturbation of external and internal forcings,” says Xiangdong Zhang, research professor at North Carolina State University and senior scientist at the North Carolina Institute for Climate Studies.

“The annual mean warming rate of the Arctic is more than three times the global average – this is known as Arctic amplification,” Zhang says. “But no systematic review has been done about the interplay of warmer temperatures with the dynamics of atmosphere, ocean and sea ice in weather and climate extremes around the Arctic.” Zhang is the lead author of the study.

Tropical rivers emit less greenhouse gases than previously thought

Lowland tropical rivers emit large quantities of greenhouse gases, with rates influenced by seasonal flooding.
Photo Credit: Jenny Davis

Tropical inland waters don’t produce as many greenhouse gas emissions as previously estimated, according to the results of an international study, led by Charles Darwin University and involving researchers from Umeå University.

The study, published in Nature Water, aimed to better understand greenhouse gas emissions in tropical rivers, lakes and reservoirs by collating the growing amount of observations from across the world’s tropics – including many systems that were previously less represented in global datasets.

Researchers from Umeå University played a key role in the work, estimating the surface area of rivers and contributing to the data analysis that underpins the study’s findings.

How Hard Is It to Dim the Sun

An illustration of climate geoengineering techniques, including stratospheric aerosol injection (SAI), cirrus cloud thinning (CCT), and marine cloud brightening (MCB), and their proposed delivery systems and potential impacts. Natural stratospheric aerosol release from a volcanic eruption is also shown for context. Surface albedo geoengineering (SAG), which is based on increasing the albedo of various surfaces, is also represented with two examples: installing white roofs on urban buildings and modifying plants and shrubs surface.
Image Credit: Licensed under Creative Commons.

Once considered a fringe idea, the prospect of offsetting global warming by releasing massive quantities of sunlight-reflecting particles into Earth’s atmosphere is now a matter of serious scientific consideration. Hundreds of studies have modeled how this form of solar geoengineering, known as stratospheric aerosol injection (SAI), might work. There is a real possibility that nations or even individuals seeking a stopgap solution to climate change may try SAI—but the proponents dramatically underestimate just how difficult and complicated it will be, say researchers from Columbia University.

“Even when simulations of SAI in climate models are sophisticated, they’re necessarily going to be idealized. Researchers model the perfect particles that are the perfect size. And in the simulation, they put exactly how much of them they want, where they want them. But when you start to consider where we actually are, compared to that idealized situation, it reveals a lot of the uncertainty in those predictions,” says V. Faye McNeill, an atmospheric chemist and aerosol scientist at Columbia’s Climate School and Columbia Engineering.

Exotic roto-crystals

Spontaneous fragmentation of a rotating crystal comprised of transversely interacting particles into multiple rotating crystal fragments.
Image Credit: Wayne State University/Zhi-Feng Huang

It sounds bizarre, but they exist: crystals made of rotating objects. Physicists from Aachen, Düsseldorf, Mainz and Wayne State (Detroit, USA) have jointly studied these exotic objects and their properties. They easily break into individual fragments, have odd grain boundaries and evidence defects that can be controlled in a targeted fashion. In an article published in the Proceedings of the National Academy of Sciences, the researchers outline how several new properties of such “transverse interaction” systems can be predicted by applying a comprehensive theory.

“Transverse forces” can occur in synthetic systems, such as in certain magnetic solids. They exist in systems of living organisms too, however. In an experiment observing a host of starfish embryos conducted at American university MIT, it was found that, through their swimming movements, the embryos influence each other in a manner leading them to rotate around one another. What biological function this may have is not yet understood. The common thread in these systems is that they involve rotating objects.

Nanopore signals, machine learning unlocks new molecular analysis tool

Illustration of voltage-matrix nanopore profiling. The artistic rendering depicts proteins (colored shapes) being analyzed by solid-state nanopores under varying voltage conditions. By combining nanopore signals with machine learning, researchers can discriminate protein mixtures and detect changes in molecular populations.
Image Credit: ©2025 Sotaro Uemura, The University of Tokyo

Understanding molecular diversity is fundamental to biomedical research and diagnostics, but existing analytical tools struggle to distinguish subtle variations in the structure or composition among biomolecules, such as proteins. Researchers at the University of Tokyo have developed a new analytical approach, which helps overcome this problem. The new method, called voltage-matrix nanopore profiling, combines multivoltage solid-state nanopore recordings with machine learning for accurate classification of proteins in complex mixtures, based on the proteins’ intrinsic electrical signatures.

The study, published in Chemical Science, demonstrates how this new framework can identify and classify “molecular individuality” without the need for labels or modifications. The research holds promise of providing a foundation that could lead to more advanced and wider applications of molecular analysis in various areas, including disease diagnosis.

Canopy walkways provide a safe way for rainforest mammals to cross the forest

A canopy walkway at the Amazon Conservatory for Tropical Studies (ACTS) Field Station in the Napo-Sucusari Biological Reserve, located 40 miles outside of Iquitos, Peru.
Photo Credit: Courtesy of the researchers / Binghamton University

Look up in the woods and you may see a familiar sight: squirrels using tree limbs like a leafy highway, crossing a patch of land without putting their paws on the ground.

That’s true in the Amazon rainforest as well. A new study published by Binghamton University biologists in the journal Neotropical Biology and Conservation offers insights for the first time into how arboreal species use human-made canopy structures.

Authored by environmental studies alumnus Justin Santiago ’21, now in a master’s program at Miami University, and Binghamton University Assistant Professor of Biological Sciences Lindsey Swierk, “Arboreal mammal use of canopy walkway bridges on an Amazonian forest with continuous canopy cover” focuses on research conducted at the Amazon Conservatory for Tropical Studies (ACTS) Field Station in the Napo-Sucusari Biological Reserve, located 40 miles outside of Iquitos, Peru.

The key to why the universe exists may lie in an 1800s knot idea science once dismissed

The model suggests a brief “knot-dominated era,” when these tangled energy fields outweighed everything else, a scenario that could be probed through gravitational-wave signals.
Image Credit: Courtesy of Muneto Nitta/Hiroshima University

In 1867, Lord Kelvin imagined atoms as knots in the aether. The idea was soon disproven. Atoms turned out to be something else entirely. But his discarded vision may yet hold the key to why the universe exists.

Now, for the first time, Japanese physicists have shown that knots can arise in a realistic particle physics framework, one that also tackles deep puzzles such as neutrino masses, dark matter, and the strong CP problem. Their findings, in Physical Review Letters, suggest these “cosmic knots” could have formed and briefly dominated in the turbulent newborn universe, collapsing in ways that favored matter over antimatter and leaving behind a unique hum in spacetime that future detectors could listen for—a rarity for a physics mystery that’s notoriously hard to probe.

“This study addresses one of the most fundamental mysteries in physics: why our Universe is made of matter and not antimatter,” said study corresponding author Muneto Nitta, professor (special appointment) at Hiroshima University’s International Institute for Sustainability with Knotted Chiral Meta Matter (WPI-SKCM2) in Japan.

“This question is important because it touches directly on why stars, galaxies, and we ourselves exist at all.”

New AI Model for Drug Design Brings More Physics to Bear in Predictions

This illustration shows the mesh of anchoring points the team obtained by discretizing the manifold, an estimation of the distribution of atoms and the probable locations of electrons in the molecule. This is important because, as the authors note in the new paper, treating atoms as solid points "does not fully reflect the spatial extent that real atoms occupy in three-dimensional space."
Image Credit: Liu et al./PNAS

When machine learning is used to suggest new potential scientific insights or directions, algorithms sometimes offer solutions that are not physically sound. Take for example AlphaFold, the AI system that predicts the complex ways in which amino acid chains will fold into 3D protein structures. The system sometimes suggests "unphysical" folds—configurations that are implausible based on the laws of physics—especially when asked to predict the folds for chains that are significantly different from its training data. To limit this type of unphysical result in the realm of drug design, Anima Anandkumar, Bren Professor of Computing and Mathematical Sciences at Caltech, and her colleagues have introduced a new machine learning model called NucleusDiff, which incorporates a simple physical idea into its training, greatly improving the algorithm's performance.

X-Ray Study Reveals New Details About Betelgeuse’s Elusive Companion Star

Betelbuddy, the companion star to Betelgeuse. This image is a color composite made from exposures from the Digitized Sky Survey 2.
Image Credit: ESO/Digitized Sky Survey 2. Acknowledgment: Davide De Martin

Astronomers have long suspected that Betelgeuse — the bright red star blazing in Orion's shoulder — wasn't alone. Now, thanks to a fleeting cosmic window and swift action by Carnegie Mellon University researchers, the true nature of its elusive companion has been illuminated.

In a race against time, the CMU researchers secured director’s discretionary time on both NASA’s Chandra X-ray Observatory and the Hubble Space Telescope to investigate the long-predicted — but never detected — companion star to Betelgeuse. The timing was critical: Around Dec. 6, the companion, nicknamed “Betelbuddy,” reached its maximum separation from the massive red supergiant just before it would disappear behind it for two more years.

“It turns out that there had never been a good observation where Betelbuddy wasn't behind Betelgeuse,” said Anna O’Grady, a McWilliams Postdoctoral Fellow at Carnegie Mellon’s McWilliams Center for Cosmology and Astrophysics. “This represents the deepest X-ray observations of Betelgeuse to date.”