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
January 9, 2026
Jan. 9, 2026 Scientists in South Korea have discovered a way to make all-solid-state batteries safer and more powerful using inexpensive materials. Instead of adding costly metals, they redesigned the battery’s internal structure to help lithium ions move ...
Jan. 8, 2026 A team of physicists has discovered a surprisingly simple way to build nuclear clocks using tiny amounts of rare thorium. By electroplating thorium onto steel, they achieved the same results as years of work with delicate crystals — but far more ...
Jan. 8, 2026 Nearly everything in the universe is made of mysterious dark matter and dark energy, yet we can’t see either of them directly. Scientists are developing detectors so sensitive they can spot particle interactions that might occur once in years or ...
Jan. 7, 2026 Researchers have built a new platform that produces ultrashort UV-C laser pulses and detects them at room temperature using atom-thin materials. The light flashes last just femtoseconds and can be ...
Jan. 6, 2026 Scientists are learning to engineer light in rich, multidimensional ways that dramatically increase how much information a single photon can carry. This leap could make quantum communication more secure, quantum computers more efficient, and sensors ...
Jan. 6, 2026 A new chip-based quantum memory uses nanoprinted “light cages” to trap light inside atomic vapor, enabling fast, reliable storage of quantum information. The structures can be fabricated with extreme precision and filled with atoms in days ...
Jan. 5, 2026 Scientists have found a way to see ultrafast molecular interactions inside liquids using an extreme laser technique once thought impossible for fluids. When they mixed nearly identical chemicals, one combination behaved strangely—producing less ...
Jan. 4, 2026 Seeing plastic trash while hiking inspired a Rutgers chemist to rethink why synthetic plastics last forever while natural polymers don’t. By mimicking tiny structural features used in DNA and proteins, researchers designed plastics that remain ...
Jan. 3, 2026 Scientists have developed molecular devices that can switch roles, behaving as memory, logic, or learning elements within the same structure. The breakthrough comes from precise chemical design that ...
Jan. 2, 2026 A physicist has proposed a bold experiment that could allow gravitational waves to be manipulated using laser light. By transferring minute amounts of energy between light and gravity, the ...
Jan. 1, 2026 A new advance in bromine-based flow batteries could remove one of the biggest obstacles to long-lasting, affordable energy storage. Scientists developed a way to chemically capture corrosive bromine during battery operation, keeping its ...
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 ...
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Jan. 8, 2026 Einstein’s claim that the speed of light is constant has survived more than a century of scrutiny—but scientists are still daring to test it. Some theories of quantum gravity suggest light might ...
Jan. 8, 2026 When scientists repeatedly drove a strongly interacting quantum system with laser “kicks,” they expected it to heat up and grow chaotic. Instead, the atoms abruptly stopped absorbing energy and ...
Jan. 7, 2026 Researchers at TU Wien have discovered a quantum system where energy and mass move with perfect efficiency. In an ultracold gas of atoms confined to a single line, countless collisions occur—but ...
Jan. 5, 2026 Inside high-energy proton collisions, quarks and gluons briefly form a dense, boiling state before cooling into ordinary particles. Researchers expected this transition to change how disordered the ...
Jan. 4, 2026 Researchers using China’s “artificial sun” fusion reactor have broken through a long-standing density barrier in fusion plasma. The experiment ...
Jan. 3, 2026 Scientists have precisely measured two unstable atomic nuclei that play a crucial role in explosive X-ray bursts on neutron stars. The results reveal faster nuclear reactions than previously thought, ...
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. 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 ...
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 ...
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 ...