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
October 25, 2026
Oct. 24, 2026 A superconducting material studied for 40 years has turned out to be far more complex than scientists believed. Advanced 3D imaging revealed a hidden patchwork of crystal structures, with unusually ...
Oct. 23, 2026 Researchers have solved a long-standing challenge in understanding how tiny defects in materials like diamond and silicon carbide behave when exposed to light. Their new computational method revealed a surprisingly important energy-loss mechanism in ...
Oct. 22, 2026 Researchers have developed a revolutionary microscope that uses an incredibly powerful laser to make previously invisible cellular structures easier to see. The technology dramatically improves image clarity, allowing scientists to examine small ...
Oct. 19, 2026 Scientists have achieved a quantum breakthrough by creating an ultra-clean surface where individual molecules can maintain their delicate quantum properties at the fundamental limit. The discovery could unlock unprecedented control over molecules ...
Oct. 16, 2026 Scientists discovered that atomic steps just one atom high can guide quantum vortices through superconductors, making them move more than 1,000 times more easily in one direction than another. This remarkable control over quantum motion could lead ...
Oct. 13, 2026 Scientists used artificial intelligence to uncover nearly 10,000 chemical reactions involved in transforming carbon dioxide into fuels and chemicals, revealing crucial pathways that traditional models had missed. The discovery dramatically improved ...
Oct. 13, 2026 Oxford physicists have recreated a bizarre quantum effect in which a particle responds to a magnetic field without ever traveling through it. Using a hybrid quantum computer, they demonstrated how introducing a simulated magnetic flux could ...
Oct. 13, 2026 Scientists have uncovered a surprising hidden ability of light that allows it to develop spinning, twisting behavior as it travels through empty space, without special lenses, mirrors, or materials. ...
Oct. 10, 2026 Scientists in Vienna have achieved a major breakthrough in timekeeping by creating the world’s first self-stabilizing nuclear clock, a technology that could eventually surpass even the most precise atomic clocks. Instead of relying on electrons in ...
Oct. 10, 2026 Princeton Plasma Physics Laboratory may have found a dramatically more efficient route to fusion energy by reversing the traditional approach: heating plasma first, then increasing its density. Their calculations could help future reactors reach ...
Oct. 9, 2026 Scientists have developed a powerful new way to calculate the Kondo effect, a strange quantum phenomenon that appears when magnetic atoms are embedded in metals. Instead of relying on simplified models, the method uses the real atomic and electronic ...
Oct. 9, 2026 Scientists have demonstrated a remarkable new antenna that resembles a lightsaber, using a laser to create a tunable beam of plasma capable of transmitting radio waves. The technology could ...
Latest Headlines
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Oct. 22, 2026 A massive analysis of 2,884 exploding stars has uncovered new evidence that dark energy, the mysterious force accelerating the universe’s expansion, may change over time. The findings challenge a ...
Oct. 18, 2026 Physicists have discovered a strange new state of quantum matter in which ultracold atoms defy familiar organizational rules, forming a highly excited yet surprisingly orderly configuration called a ...
Oct. 18, 2026 Physicists have uncovered a hidden third form of magnetism that challenges more than 100 years of established physics. Called altermagnetism, the discovery could transform future computing and ...
Oct. 16, 2026 Scientists investigating Nazi Germany's secret nuclear program have uncovered evidence that its final experimental reactor was nowhere near as close to working as previously claimed. Analysis of ...
Oct. 13, 2026 NASA’s James Webb Space Telescope has revealed an ancient galaxy cluster with an unexpectedly dense concentration of dark matter, challenging ...
Oct. 12, 2026 Researchers discovered a hidden factor that can determine whether chemical reactions succeed or fail, and then used it to boost the proportion of the ...
Oct. 9, 2026 Scientists have uncovered a hidden world of “in-between” materials that briefly form as chemical ingredients are heated, revealing structures ...
Oct. 9, 2026 Nearly a century after physicist Hans Bethe predicted them, scientists have created and directly observed unusual quantum states known as “Bethe strings” in an ultracold gas. By cooling cesium ...
Oct. 8, 2026 Einstein Probe revealed nearly 10 minutes of soft X-ray activity following a short gamma-ray burst, exposing a phase of neutron star mergers that previous missions may have missed. The prolonged ...
Oct. 7, 2026 Physicists have found striking evidence for an unusual form of superconducting behavior in uranium ditelluride, where electron pairs organize into rippling patterns called pair density waves. Even ...