All articles starting with R
22,461 articles
Rayan Rebbadj
Rayan Rebbadj (born 1999, Martigues) is a French rugby centre/wing for RC Toulon and a France sevens international; Olympic gold medalist in rugby sevens at Paris 2024, world champion 2024, Chevalier de la Légion d'honneur. Not to be confused with his brother Swan Rebbadj.
Rayane Belaid
Rayane Belaid Khelil (born 2005, Orihuela) is a Spanish attacking midfielder who came through Atlético Madrid's academy and joined Rayo Vallecano in September 2026 for a reported €500,000; Spain U19 and U20 international.
Rayane Messi
Rayane Messi (Rayane Messi Tanfouri), born 2007 in Sèvres, French forward; no relation to Lionel Messi. Dijon youth record scorer, Strasbourg signing (2024), loans to Pau, Neom SC, and Al-Ettifaq; France U16–U19 international.
Rayaprolu Subba Rao
Rayaprolu Subba Rao (రాయప్రోలు సుబ్బారావు; 1892–1984) was a Telugu poet regarded as a pioneer of modern Telugu literature and founder of its romantic school, Bhavakavitvam.
Rayasam
Rayasam (రాయసం) was the office of secretary and record-keeper in the Vijayanagara Empire, a secretariat attached to the king that recorded his oral orders, since sovereigns issued none in writing.
Rayasianboy
Rayasianboy, also known as Chen-Ruei Hsu, is a Taiwanese streamer whose 2023 chance meeting with Kai Cenat in Tokyo led to millions of followers and a 2025 Streamer Award.
Rayavachakamu
Rayavachakamu (రాయవాచకము, "Tidings of the King") is a Telugu historiographic text narrating the reign of Krishnadevaraya of Vijayanagara, which Phillip B. Wagoner argues was written about ninety years later at the Nayaka court of Madurai.
Raybun
Raybun, also known as Raybūn, was an ancient agricultural oasis and sanctuary complex in the lower Wadi Daw'an, Yemen, a major worship center of the kingdom of Hadramawt.
Raycast (software)
Raycast is a keyboard-driven launcher and productivity app for macOS, Windows, and iOS, founded in 2020 by former Facebook engineers Thomas Paul Mann and Petr Nikolaev.
Raychaudhuri equation
The Raychaudhuri equation, also called the Landau–Raychaudhuri equation, is an equation in general relativity that describes how a congruence of geodesics converges or expands, derived by Amal Kumar Raychaudhuri in 1955.
Raydium Semiconductor
Raydium Semiconductor (瑞鼎科技) is a Taiwanese IC design company founded in 2003 and based in Hsinchu Science Park, known for display driver, touch, and power-management chips.
Raye
Raye, real name Rachel Agatha Keen, is a British singer-songwriter from London known for My 21st Century Blues and winning six BRIT Awards in 2024.
Rayful Edmond
Rayful Edmond III (1964-2024), D.C.'s biggest crack cocaine kingpin of the late 1980s, ran a 1,700-pound-a-month trafficking operation, dealt from prison, became a federal informant, and died at 60 before his planned release.
Raygorodok Gold Mine
The Raygorodok Gold Mine is an open-pit gold mine in northern Kazakhstan's Akmola Region and one of the country's largest single gold deposits, with 194.2 tonnes of contained gold.
Rayko Daskalov
Rayko Daskalov (Райко Даскалов, 1886–1923) was a Bulgarian agrarian politician, a close associate of Aleksandar Stamboliyski, who led the 1918 soldiers' uprising and proclaimed the short-lived Radomir Republic.
Raylan Givens
Raylan Givens is Elmore Leonard's fictional Deputy U.S. Marshal, introduced in Pronto (1993) and central to the FX series Justified (2010–2015), played by Timothy Olyphant, a Stetson-wearing Harlan County, Kentucky coal miner turned quick-draw lawman.
Rayleigh (lunar crater)
Rayleigh is a large lunar impact crater on the Moon's northeastern limb, 113.77 km in diameter, centered at 29.12°N, 89.45°E and visible from Earth under favorable libration.
Rayleigh (Martian crater)
Rayleigh is an IAU-approved impact crater on Mars, Feature ID 4967, 125.66 km in diameter, centered at 75.57°S, 118.94°E (planetocentric) in the far southern hemisphere; cataloged in the USGS Gazetteer of Planetary Nomenclature.
Rayleigh (unit)
The rayleigh (R) is a photometric unit proposed in 1956 to measure the brightness of airglow and the aurora, equal to 10⁶ photons per square centimeter per second.
Rayleigh damping
Rayleigh damping is a structural dynamics damping model in which the damping matrix is a linear combination of the mass and stiffness matrices, allowing modal decoupling.
Rayleigh distribution
The Rayleigh distribution is a continuous probability distribution for the magnitude of a 2D vector with independent zero-mean Gaussian components, derived by Lord Rayleigh in 1880.
Rayleigh fading
Rayleigh fading is a statistical model of wireless signal fading that applies when many scattered multipath components arrive with no dominant line-of-sight path, causing the signal envelope to follow a Rayleigh distribution.
Rayleigh number
The Rayleigh number (Ra) is a dimensionless number measuring a fluid layer's tendency to develop convection when heated from below, defined by Lord Rayleigh in 1916.
Rayleigh scattering
Rayleigh scattering is the scattering of light by particles much smaller than its wavelength, strongest for short wavelengths. It is why the sky is blue and sunsets are red.
Rayleigh wave
A Rayleigh wave is a seismic surface wave traveling along the free surface of an elastic solid, predicted by Lord Rayleigh in 1885 and producing retrograde elliptical particle motion.
Rayleigh wave tomography
Rayleigh wave tomography is a seismological imaging method that measures Rayleigh wave dispersion along earthquake–station paths and inverts it for 3-D shear-wave velocity models of the crust and upper mantle.
Rayleigh–Bénard convection
Rayleigh–Bénard convection is the fluid motion in a horizontal layer heated from below that begins when the temperature difference exceeds a critical Rayleigh number of about 1708.
Rayleigh–Jeans law
The Rayleigh–Jeans law, derived by Lord Rayleigh in 1900 and corrected by Jeans in 1905, gives the classical blackbody spectrum and fails at high frequencies, the ultraviolet catastrophe.
Rayleigh–Plateau instability
The Rayleigh–Plateau instability is the capillary instability by which surface tension breaks a cylindrical jet of fluid into droplets, fragmenting faucet streams and limiting inkjet printing.
Rayleigh–Taylor instability
The Rayleigh–Taylor instability is the interpenetration and mixing of two fluids when a lighter fluid accelerates a heavier one, first described by Lord Rayleigh in 1880.