42,772 articles
Omanago Group
Omanago Group (大真名子山) is a cluster of closely spaced dacitic lava domes in Nikko National Park, Tochigi Prefecture, Japan, built north of Nantai volcano, with a last known eruption around 3050 BCE.
Omar Azzaroni
Omar Azzaroni, born in 1974, is an Argentine chemist at the Universidad Nacional de La Plata known for supramolecular materials, polymer thin films, and solid-state nanopores.
Omar K. Farha
Omar K. Farha is a Palestinian-born chemist at Northwestern University, chair of its chemistry department since 2024, known for record-setting metal–organic frameworks for gas storage and destroying chemical warfare agents.
Omar Yaghi
Omar M. Yaghi (عمر ياغي), born 1965 in Amman, Jordan, is a chemist at UC Berkeley who founded reticular chemistry and won the 2025 Nobel Prize in Chemistry for metal-organic frameworks.
OMat24
OMat24 (Open Materials 2024) is an open dataset of over 110 million density functional theory calculations on inorganic materials, released by Meta's FAIR group in October 2024.
Omayra Sánchez
Omayra Sánchez Garzón was a 13-year-old girl from Armero, Colombia, who died in November 1985 after roughly 60 hours trapped in debris from the Nevado del Ruiz lahar.
Ombrotrophic
Ombrotrophic describes a peatland, typically a bog, that receives all its water and dissolved nutrients from rain and snow, with no groundwater or runoff from mineral soil.
Omega Canis Majoris
Omega Canis Majoris (ω CMa) is a bright Be star of type B2 in Canis Major, about 923 light-years away and a standard reference object for Be-star studies.
Omega Centauri
Omega Centauri (ω Cen) is the brightest, most massive globular cluster of the Milky Way, about 10 million stars 17,700 light-years away, likely a stripped dwarf galaxy nucleus.
Omega equation
The omega equation is a diagnostic equation of quasi-geostrophic theory that determines vertical velocity in synoptic-scale atmospheric flow from geostrophic wind, pressure, and temperature fields, without time derivatives.
Omega Orionis
Omega Orionis is a rapidly rotating classical Be star in Orion about 1,382 light-years away, known for its circumstellar disk and for a suggested magnetic field never directly detected.
Omega Scorpii
Omega Scorpii is a pair of naked-eye stars in Scorpius, a hot blue-white star and a yellow giant that appear close but lie 470 and 290 light-years away.
Omega-3-enriched structured triglycerides from fish oil
Omega-3-enriched structured triglycerides from fish oil are interesterified fish-oil fats enriched in EPA and DHA; exemplified by GRN 200 N3-TG-3020, FDA no-questions 2006, 3 g/day EPA+DHA ceiling.
Omicron Andromedae
Omicron Andromedae, approved as Alfarasalkamil by the IAU in 2025, is a quadruple star system in Andromeda whose brightest component is a Be shell star about 690 light-years away.
Omicron Aquilae
Omicron Aquilae is an F-type main-sequence star in the constellation Aquila, about 62.6 light-years from Earth and one of nine solar-type stars known to have produced a superflare.
Omicron Persei
Omicron Persei, also known as Atik, is a blue giant star of spectral type B1 III in Perseus, about 1,121 light-years from Earth. It is a spectroscopic binary with an orbital period of about 4.4 days.
Omnibus test
An omnibus test is a statistical test of whether a set of effects or parameters is jointly significant, without identifying which individual component drives the result.
OMol25
OMol25 (Open Molecules 2025) is an open dataset of more than 100 million DFT calculations released by Meta's FAIR team in May 2025 to train machine learning interatomic potentials.
On Physical Lines of Force
On Physical Lines of Force is an 1861–1862 paper by James Clerk Maxwell modeling electromagnetic phenomena and first proposing that light is an electromagnetic wave.
On the Origin of Species
On the Origin of Species is an 1859 scientific book by the English naturalist Charles Darwin arguing that species descend from common ancestors and change over time by natural selection.
On-chip Brillouin scattering
On-chip Brillouin scattering is the scattering of light by acoustic phonons in waveguides and resonators on photonic chips, first demonstrated in 2011 and used for lasers, filters, and gyroscopes.
On-Line Encyclopedia of Integer Sequences
The On-Line Encyclopedia of Integer Sequences (OEIS), also called Sloane's OEIS, is a free online database of integer sequences, online since 1996 and holding over 400,000 entries.
On-site electrochemical H2O2 synthesis
On-site electrochemical H2O2 synthesis produces hydrogen peroxide at the point of use, typically via the two-electron oxygen reduction of oxygen and water with renewable electricity, avoiding hazardous transport of centralized peroxide.
On-surface synthesis
On-surface synthesis is a method that carries out organic chemical reactions on solid surfaces, typically under ultra-high vacuum, to build atomically precise nanostructures like graphene nanoribbons.
On-the-fly probability enhanced sampling
OPES (On-the-fly Probability Enhanced Sampling) is an enhanced sampling method for molecular dynamics simulations that builds a bias potential on the fly, introduced by Michele Invernizzi and Michele Parrinello in 2021.
On-water reaction
An on-water reaction is an organic reaction run as an aqueous suspension that proceeds far faster than in organic solvents, a term coined by Barry Sharpless in 2005.
Ondrej Krivanek
Ondrej Krivanek (Ondřej Křivánek) is a Czech-British physicist who designed the first practical aberration corrector for electron microscopes, co-founded Nion, and won the 2020 Kavli Prize.
One Clean Qubit
One Clean Qubit is a restricted model of quantum computation, formalized as complexity class DQC1, proposed by Knill and Laflamme in 1998 to explore computing with highly mixed states.
One- and two-tailed tests
A one-tailed (one-sided) test places its entire rejection region in one tail, testing a directional effect, while a two-tailed (two-sided) test splits it between both tails.
One-electron universe
The one-electron universe, proposed by John Wheeler to Richard Feynman in 1940, holds that all electrons are the same electron moving back and forth through spacetime; it is now discounted.