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Categories: Paleontology: Climate, Physics: General

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Societies and political structures, like the humans they serve, appear to become more fragile as they age, according to an analysis of hundreds of pre-modern societies. A new study, which holds implications for the modern world, provides the first quantitative support for the theory that the resilience of political states decreases over time. 

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Hydrogen is a building block for the energy transition. To obtain it with the help of solar energy, researchers have developed new high-performance nanostructures. The material holds a world record for green hydrogen production with sunlight.

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Friction is hard to predict and control, especially since surfaces that come in contact are rarely perfectly flat. New experiments demonstrate that the amount of friction between two silicon surfaces, even at large scales, is determined by the forming and rupturing of microscopic chemical bonds between them. This makes it possible to control the amount of friction using surface chemistry techniques.

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Identifying how and why Antarctica's major ice sheets behaved the way they did in the early Miocene could help inform understanding of the sheets' behavior under a warming climate. Together, the ice sheets lock a volume of water equivalent to more than 50 meters of sea level rise and influence ocean currents that affect marine food webs and regional climates. Their fate has profound consequences for life nearly everywhere on Earth.  

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Long before researchers discovered the electron and its role in generating electrical current, they knew about electricity and were exploring its potential. One thing they learned early on was that metals were great conductors of both electricity and heat. And in 1853, two scientists showed that those two admirable properties of metals were somehow related: At any given temperature, the ratio of electronic conductivity to thermal conductivity was roughly the same in any metal they tested. This so-called Wiedemann-Franz law has held ever since -- except in quantum materials. Now, a theoretical argument put forth by physicists suggests that the law should, in fact, approximately hold for one type of quantum material, the cuprate superconductors.

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A recent study demonstrates how dripstones can be crucial for reconstructing past climates. The new approach can provide a detailed picture of the climate around early human occupations in South Africa.

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The San Joaquin Valley in California has experienced vast variability in climate extremes, with droughts and floods that were more severe and lasted longer than what has been seen in the modern record, according to a new study of 600 years of tree rings from the valley.

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Researchers discover a new type of ultrafast magnetic switching by investigating fluctuations that normally tend to interfere with experiments as noise.

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A landmark study into the geological timescale distribution of sediment and nutrients over 500 million years shows that species biodiversity on Earth is driven by landscape dynamics.

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Scientists have revealed how lattice vibrations and spins talk to each other in a hybrid excitation known as an electromagnon. To achieve this, they used a unique combination of experiments on an X-ray free electron laser. Understanding this fundamental process at the atomic level opens the door to ultrafast control of magnetism with light.

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A new kind of 'wire' for moving excitons could help enable a new class of devices, perhaps including room temperature quantum computers.

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Researchers have demonstrated a compact particle accelerator less than 20 meters long that produces an electron beam with an energy of 10 billion electron volts (10 GeV). There are only two other accelerators currently operating in the U.S. that can reach such high electron energies, but both are approximately 3 kilometers long. This type of accelerator is called a wakefield laser accelerator.

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Scientists have made a surprising discovery that sheds new light on the role that oceanic deoxygenation (anoxia) played in one of the most devastating extinction events in Earth's history. Their finding has implications for current day ecosystems -- and serves as a warning that marine environments are likely more fragile than apparent. New research, published today in leading international journal Nature Geosciences, suggests that oceanic anoxia played an important role in ecosystem disruption and extinctions in marine environments during the Triassic--Jurassic mass extinction, a major extinction event that occurred around 200 million years ago.  Surprisingly however, the study shows that the global extent of euxinia (an extreme form of de-oxygenated conditions) was similar to the present day.

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Wondering whether whether Dark Matter particles actually are produced inside a jet of standard model particles, led researchers to explore a new detector signature known as semi-visible jets, which scientists never looked at before.

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Experiments have provided the first direct evidence that electricity seems to flow through 'strange metals' in an unusual liquid-like form.

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Hopfions, magnetic spin structures predicted decades ago, have become a hot and challenging research topic in recent years. New findings open up new fields in experimental physics: identifying other crystals in which hopfions are stable, studying how hopfions interact with electric and spin currents, hopfion dynamics, and more.

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Quantum scientists have discovered a rare phenomenon that could hold the key to creating a 'perfect switch' in quantum devices which flips between being an insulator and superconductor.

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Biological materials are made of individual components, including tiny motors that convert fuel into motion. This creates patterns of movement, and the material shapes itself with coherent flows by constant consumption of energy. Such continuously driven materials are called 'active matter'. The mechanics of cells and tissues can be described by active matter theory, a scientific framework to understand shape, flows, and form of living materials. The active matter theory consists of many challenging mathematical equations. Scientists have now developed an algorithm, implemented in an open-source supercomputer code, that can for the first time solve the equations of active matter theory in realistic scenarios. These solutions bring us a big step closer to solving the century-old riddle of how cells and tissues attain their shape and to designing artificial biological machines.

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Using historical records from around Australia, an international team of researchers have put forward the most accurate prediction to date of past Antarctic ice sheet melt, providing a more realistic forecast of future sea level rise.   The Antarctic ice sheet is the largest block of ice on earth, containing over 30 million cubic kilometers of water.   Hence, its melting could have a devasting impact on future sea levels. To find out just how big that impact might be, the research team turned to the past.  

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In 1973, physicist Phil Anderson hypothesized that the quantum spin liquid, or QSL, state existed on some triangular lattices, but he lacked the tools to delve deeper. Fifty years later, a team has confirmed the presence of QSL behavior in a new material with this structure, KYbSe2.