Reference Terms
from Wikipedia, the free encyclopedia
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.
Related Stories
1
2
Matter & Energy News
August 1, 2026
Aug. 1, 2026 A surprisingly simple change could make sodium-ion batteries far more powerful while opening the door to turning seawater into drinking water. Researchers at the University of Surrey found that sodium vanadium oxide performs much better when its ...
July 31, 2026 A new chemical process can transform three of the most common plastics into high-purity hydrogen without sorting them first. The technique operates at much lower temperatures than traditional ...
July 31, 2026 Scientists have built the first all-optical photonic time crystal, allowing them to reshape the behavior of terahertz light at extraordinary speeds. The breakthrough could open the door to ultrafast computing, smarter communication systems, advanced ...
July 30, 2026 Engineers have transformed a notoriously brittle cobalt-aluminum compound into a material that is both extremely strong and capable of bending without breaking. Their nanoscale design produced a ...
July 29, 2026 Rice University chemists have found a new way to make neodymium, a rare-earth metal, interact with oxygen. Using a specially designed molecular structure described as a “basket,” the team positioned the atoms so they could form a bond once ...
July 28, 2026 Scientists have created twisted laser beams that interact differently with right-handed and left-handed molecules, revealing their identity through the fragments they produce. The approach could provide a faster, simpler, and more sensitive way to ...
July 22, 2026 Researchers discovered a proton-assisted mechanism that greatly improves how triplet energy moves between quantum dots and nearby molecules. The proton briefly shifts position, helps coordinate electron movement, and then returns to where it ...
July 21, 2026 Scientists have created a programmable optical chip that can slow light on demand, giving engineers far greater control over how optical signals propagate through a circuit. The technology could provide the delays, synchronization, and buffering ...
July 19, 2026 Scientists are testing two promising ways to destroy PFAS, the stubborn “forever chemicals” that can accumulate in water and resist normal treatment. One method uses collapsing vapor bubbles to generate extreme heat and reactive molecules, while ...
July 17, 2026 A team of mathematicians used whimsical "silly sprinklers" to solve a physics mystery that has puzzled scientists for decades. Their experiments showed that the rotation of both normal and reverse ...
July 17, 2026 A new particle detector called PLATON could replace millions of tiny detector components with a single block of light-producing material. Using a light-field camera, highly sensitive photon sensors, and AI, it reconstructs particle paths in fast, ...
July 16, 2026 Researchers have created self-destructing living plastic that uses engineered bacteria to completely break itself down when activated. The material degrades in just six days without creating ...
Latest Headlines
updated 12:56 pm ET
July 31, 2026 Scientists traced a mysterious surge of low-energy gamma rays from zinc-70 to magnetic changes occurring inside its nucleus. The breakthrough could improve models of how stars, supernovae, and ...
July 30, 2026 Physicists have uncovered a surprising limit to electrical resistance caused by particles colliding. Using ultracold potassium atoms trapped in a grid of light, researchers created a highly ...
July 29, 2026 Ultrafast X-rays revealed how a molecule converts absorbed light into motion in just trillionths of a second. Individual atoms recorded different stages of the process, opening a powerful new window ...
July 24, 2026 A new analysis suggests the Sun holds far more silver than earlier estimates indicated. More advanced models of the solar atmosphere raised the calculated amount by 55 percent, bringing it into much ...
July 20, 2026 A new theoretical study offers a possible explanation for how the Universe can grow more complex without violating the second law of thermodynamics. Using a quantum gravity framework called Gravity ...
July 19, 2026 Researchers have created cosmic dust from scratch by recreating space-like conditions inside glass tubes. The dust contains complex carbon-rich molecules built from elements essential to life and ...
July 17, 2026 JWST has captured unusually detailed images of gas feeding the supermassive black hole at the center of NGC 4696. A vast filament appears to funnel material into an 800-light-year-wide spinning disk, ...
July 16, 2026 A new review highlights exciting progress in atomically thin quantum materials where light and magnetism work together in ways never before possible. In these materials, light-generated excitons can ...
July 13, 2026 Dark matter may be far more complicated than scientists once believed. A new study suggests it could consist of at least two different kinds of particles that slowly separate over time, with heavier ...
July 13, 2026 Scientists at Nanyang Technological University in Singapore have discovered a surprisingly simple way to create exotic light structures called optical skyrmions using a 200-year-old optical effect ...