Reference Terms
from Wikipedia, the free encyclopedia
Atom
In chemistry and physics, an atom is the smallest particle of a chemical element that retains its chemical properties. An atom consists of a dense nucleus of positively-charged protons and electrically-neutral neutrons, surrounded by a much larger electron cloud consisting of negatively-charged electrons. An atom is electrically neutral if it has the same number of protons as electrons. The number of protons in an atom defines the chemical element to which it belongs, while the number of neutrons determines the isotope of the element.
The first nuclei, including most of the helium and all of the deuterium in the universe, were theoretically created during big bang nucleosynthesis, about 3 minutes after the big bang. The first atoms were theoretically created 380,000 years after the big bang, an epoch called recombination, when the universe cooled to allow electrons to become attached to nuclei. Since then, atoms have been combined in stars through the process of nuclear fusion to generate atoms up to Iron.
A human hair is about 1 million carbon atoms wide.
Related Stories
1
2
Matter & Energy News
August 7, 2026
Aug. 7, 2026 Scientists have demonstrated that heat can move through a crystal in focused, wave-like rays at room temperature instead of spreading randomly. The breakthrough could make it possible to route heat around sensitive parts of next-generation chips and ...
Aug. 6, 2026 A new hollow nanoreactor mimics living cells to make hydrogen peroxide more efficiently using visible light. Its light-trapping cavity and proton-shuttling shell could open new possibilities for cleaner chemical manufacturing and artificial ...
Aug. 4, 2026 Scientists have successfully generated electricity with a hydrogen turbine that produces its own pressure through detonation waves instead of relying on a mechanical compressor. The breakthrough could unlock dramatically more efficient power systems ...
Aug. 4, 2026 A new 3D printing technique can produce exceptionally hard tungsten carbide cobalt while using less of its expensive raw materials. By softening rather than fully melting the material, researchers created defect-free samples with industrial-grade ...
Aug. 3, 2026 Researchers have found a way to build much larger “twisted” oxide materials while precisely controlling how their atomic layers line up. Because these materials can be made over large areas and transferred onto different surfaces, the technique ...
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 ...
Latest Headlines
updated 12:56 pm ET
Aug. 5, 2026 A massive magma reservoir has been detected deep beneath Tuscany, despite showing no obvious signs at the surface. Scientists mapped the roughly 6,000-cubic-kilometer body using natural ground ...
Aug. 3, 2026 When atomic nuclei smash together at nearly the speed of light, they create the hottest fluid in the universe, but scientists may have overlooked one of its most important forces. New simulations ...
Aug. 1, 2026 Scientists have identified LHAASO J1912+1014u as a cosmic accelerator that can push protons beyond one quadrillion electron volts. The finding may ...
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 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 ...
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 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 ...