Gamma

This article is about the letter. For the electromagnetic ray, see Gamma ray

Greek alphabet
Α α Alpha	Β β Beta
Γ γ Gamma	Δ δ Delta
Ε ε Epsilon	Ζ ζ Zeta
Η η Eta	Θ θ Theta
Ι ι Iota	Κ κ Kappa
Λ λ Lambda	Μ μ Mu
Ν ν Nu	Ξ ξ Xi
Ο ο Omicron	Π π Pi
Ρ ρ Rho	Σ σ ς Sigma
Τ τ Tau	Υ υ Upsilon
Φ φ Phi	Χ χ Chi
Ψ ψ Psi	Ω ω Omega
obsolete letters
Digamma	San
Qoppa	Sampi
Ϛ ϛ Stigma	Sho

Gamma (upper case Γ, lower case γ) is the third letter of the Greek alphabet. It derives from the Phoenician Gimel . In Modern Greek, it is pronounced [ɣ] or [ʝ], and in Ancient Greek, it was pronounced [ɡ] or ŋ before plosives. In the system of Greek numerals it has a value of 3.

Letters that arose from Gamma are the Roman C and G and the Cyrillic letters Ge Г and Ghe Ґ.

Contents 1 Use in science 1.1 Upper-case 1.2 Lower-case 2 Fictional names 3 Trivia

Use in science

Gamma is often used to denote a variable in mathematics and physics. In certain areas it has specific meaning.

• Gamma correction in photography, television and computer display systems. Gamma is the exponent in a power-law relationship between video or pixel values and the displayed brightness. In photography it is the slope of the curve of (density or log(opacity)) of the film image versus log(exposure) (the Hurter-Driffield curve), in the straight line region.
• 1 gamma is a unit of magnetic flux density, 1 gamma = 10⁻⁹ tesla or 1 nanotesla.
• Gamma waves are a type of brain waves around 40 hertz.
• Gamma rays are the highest point on the electromagnetic spectrum.

Upper-case

The upper-case letter Γ is used as the symbol for:

• The gamma function (related to factorials) in mathematics.
• The Gamma distribution in probability theory and statistics.
• The Christoffel symbol in General Relativity.
• The reflection coefficient in electrical engineering.
• The linewidth relating to uncertainty of mass energy in short-lived particles.
• The symbol on the hat of Nintendo character Waluigi.

Lower-case

The lower-case letter γ is used as the symbol for:

• The Euler-Mascheroni constant in mathematics.
• A risk management measure in mathematical finance.
• The photon, seen as an elementary particle in physics.
• Gamma rays in physics and astronomy.
• The gamma factor in relativity theory and astronomy.
• The adiabatic index of a gas in physics. Often the letter kappa κ is used.
• The propagation constant of an electromagnetic wave (in electrical engineering and electromagnetic theory).
• The third brightest (usually) star in a constellation. See Bayer designation.

Fictional names

• In the game of Tetris, gamma is another name for the J tetromino.
• E-102 Gamma is a fictional robotic character in the Sonic the Hedgehog universe.
• Gamma is a giant peace-keeping robot stolen by Dr. Wily which is the final boss of Capcom's Nintendo game Megaman 3.
• Gamma is the third caste in Aldous Huxley's dystopic satire Brave New World.

Trivia

• Tropical Storm Gamma is the third Atlantic tropical storm to be named using the Greek alphabet.

The content of this page is retrieved from http://en.wikipedia.org/wiki/Gamma under GFDL