Reference Terms
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Mass
Mass is a property of a physical object that quantifies the amount of matter it contains. Unlike weight, the mass of something stays the same regardless of location. Mass is a central concept of classical mechanics and related subjects, and there are several forms of mass within the framework of relativistic kinematics. In the theory of relativity, the quantity invariant mass, which in concept is close to the classical idea of mass, does not vary between single observers in different reference frames. In classical mechanics, there are three types of mass or properties called mass: Inertial mass; passive gravitational mass; and active gravitational mass. Although inertial mass, passive gravitational mass and active gravitational mass are conceptually distinct, no experiment has ever unambiguously demonstrated any difference between them.
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Matter & Energy News
December 31, 2025
Dec. 29, 2025 A new catalyst design could transform how acetaldehyde is made from renewable bioethanol. Researchers found that a carefully balanced mix of gold, manganese, and copper creates a powerful synergy that boosts efficiency while lowering operating ...
Dec. 29, 2025 MIT researchers have designed a printable aluminum alloy that’s five times stronger than cast aluminum and holds up at extreme temperatures. Machine learning helped them zero in on the ideal recipe in a fraction of the time traditional methods ...
Dec. 29, 2025 A major breakthrough in battery science reveals why promising single-crystal lithium-ion batteries haven’t lived up to expectations. Researchers found that these batteries crack due to uneven internal reactions, not the grain-boundary damage seen ...
Dec. 28, 2025 Researchers found that U.S. metal mines already contain large amounts of critical minerals that are mostly going unused. Recovering even a small fraction of these byproducts could sharply reduce dependence on imports for materials essential to clean ...
Dec. 26, 2025 A shiny gray crystal called platinum-bismuth-two hides an electronic world unlike anything scientists have seen before. Researchers discovered that only the crystal’s outer surfaces become superconducting—allowing electrons to flow with zero ...
Dec. 25, 2025 Scientists are digging into the hidden makeup of carbon-rich asteroids to see whether they could one day fuel space exploration—or even be mined for valuable resources. By analyzing rare meteorites ...
Dec. 23, 2025 A new discovery shows that messy, stray light can be used to clean up quantum systems instead of disrupting them. University of Iowa researchers found that unwanted photons produced by lasers can be canceled out by carefully tuning the light itself. ...
Dec. 21, 2025 Superconductors promise loss-free electricity, but most only work at extreme cold. Hydrogen-rich materials changed that—yet their inner workings remained hidden because they only exist under enormous pressure. Now, researchers have directly ...
Dec. 19, 2025 Gravitational waves from black holes may soon reveal where dark matter is hiding. A new model shows how dark matter surrounding massive black holes leaves detectable fingerprints in the waves recorded by future space ...
Dec. 15, 2025 Researchers in Sweden have unveiled a way to create high-performance electronic electrodes using nothing more than visible light and specially designed water-soluble monomers. This gentle, chemical-free approach lets conductive plastics form ...
Dec. 13, 2025 Researchers at the University of Warsaw have unveiled a breakthrough method for detecting and precisely calibrating terahertz frequency combs using a quantum antenna made from Rydberg atoms. By combining atomic electrometry with a powerful ...
Dec. 13, 2025 MOCHI uses microscopic, air-filled channels to stop heat in its tracks while remaining nearly crystal clear. If scaled up, it could transform windows into powerful energy savers and solar ...
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Dec. 30, 2025 Neutrinos may be nearly invisible, but they play a starring role in the Universe. Long-standing anomalies had hinted at a mysterious fourth “sterile” neutrino, potentially rewriting the laws of ...
Dec. 28, 2025 Researchers say fusion reactors might do more than generate clean energy—they could also create particles linked to dark matter. A new theoretical study shows how neutrons inside future fusion ...
Dec. 27, 2025 In collisions at CERN’s Large Hadron Collider, hotter than the Sun’s core by a staggering margin, scientists have finally solved a long-standing mystery: how delicate particles like deuterons and ...
Dec. 23, 2025 More than 200 years ago, Count Rumford showed that heat isn’t a mysterious substance but something you can generate endlessly through motion. That insight laid the foundation for thermodynamics, ...
Dec. 23, 2025 Using ultracold atoms and laser light, researchers recreated the behavior of a Josephson junction—an essential component of quantum computers and voltage standards. The appearance of Shapiro steps ...
Dec. 22, 2025 Black holes are among the most extreme objects in the universe, and now scientists can model them more accurately than ever before. By combining Einstein’s gravity with realistic behavior of light ...
Dec. 18, 2025 After a decade of painstaking measurements, scientists have delivered a major plot twist in particle physics: a long-hypothesized “mystery particle” likely doesn’t exist. Using the MicroBooNE ...
Dec. 17, 2025 A long-standing physics mystery has been solved with the discovery of emergent photon-like behavior inside a strange quantum material. The finding confirms a true 3D quantum spin liquid and unlocks a ...
Dec. 16, 2025 Physicists have found a clever way to detect the elusive Unruh effect without extreme accelerations. By using atoms that emit light cooperatively between mirrors, acceleration subtly shifts when a ...
Dec. 15, 2025 A new theory proposes that the universe’s fundamental forces and particle properties may arise from the geometry of hidden extra dimensions. These dimensions could twist and evolve over time, ...