Gravity

Gravity or gravitation is a natural phenomenon by which all things with energy are brought toward (or gravitate toward) one another, including stars, planets, galaxies and even light and sub-atomic particles. Gravity is responsible for many of the structures in the Universe, by creating spheres of hydrogen — where hydrogen fuses under pressure to form stars — and grouping them into galaxies. On Earth, gravity gives weight to physical objects and causes the tides. Gravity has an infinite range, although its effects become increasingly weaker on farther objects.

Gravity is most accurately described by the general theory of relativity (proposed by Albert Einstein in 1915) which describes gravity not as a force but as a consequence of the curvature of spacetime caused by the uneven distribution of mass/energy; and resulting in gravitational time dilation, where time lapses more slowly in lower (stronger) gravitational potential. However, for most applications, gravity is well approximated by Newton's law of universal gravitation, which postulates that gravity is a force where two bodies of mass are directly drawn (or 'attracted') to each other according to a mathematical relationship, where the attractive force is proportional to the product of their masses and inversely proportional to the square of the distance between them. This is considered to occur over an infinite range, such that all bodies (with mass) in the universe are drawn to each other no matter how far they are apart.

Gravitation (disambiguation)

Gravitation is the mass-proportionate force of attraction among matter.

Gravitation may also refer to:

See also

Gravitation (book)

In physics, Gravitation is a well-known compendium on Einstein's theory of gravity by Charles W. Misner, Kip S. Thorne, and John Archibald Wheeler, originally published by W. H. Freeman and Company in 1973. It is often considered the early "bible" of general relativity by researchers for its prominence and is frequently called MTW after its authors' initials.

The book, whose size and shape at over 1200 pages is similar to that of a large telephone book, covers many aspects of general relativity and also considers some extensions of it as well as experimental confirmations. The book is divided into two "tracks", the second of which covers more advanced topics. MTW uses the −+++ metric convention. A substantial fraction of the book consists of boxes which add supplementary substance to the already thorough main text.

Here is an example of how it can be cited:

Song

A song is a single (and often standalone) work of music intended to be sung by the human voice with distinct and fixed pitches and patterns using sound and silence and a variety of forms that often include the repetition of sections. Written words created specifically for music or for which music is specifically created, are called lyrics. If a pre-existing poem is set to composed music in classical music it is an art song. Songs that are sung on repeated pitches without distinct contours and patterns that rise and fall are called chants. Songs in a simple style that are learned informally are often referred to as folk songs. Songs that are composed for professional singers are called popular songs. These songs, which have broad appeal, are often composed by professional songwriters, composers and lyricists. Art songs are composed by trained classical composers for concert performances. Songs are performed live and recorded. Songs may also appear in plays, musical theatre, stage shows of any form, and within operas.

Song (disambiguation)

A song is a musical composition for voice or voices.

Song or songs or The Song may also refer to:

Music

Albums

Songs

Song (airline)

Song, LLC was a low-cost air service within an airline brand owned and operated by Delta Air Lines from 2003 to 2006.

Song's main focus was on leisure traffic between the northeastern United States and Florida, a market where it competed with JetBlue Airways. It also operated flights between Florida and the West Coast, and from the Northeast to the west coast.

Song's aircraft were fitted with leather seats and free personal entertainment systems at every seat, with audio MP3 programmable selections, trivia games that could be played against other passengers, a flight tracker, and satellite television (provided by the DISH Network). Song offered free beverages, but charged for meals and liquor. Both brand-name snack boxes and healthy organic meals were offered. The flight safety instructions were sung or otherwise artistically interpreted, depending on the cabin crew. In addition to crew uniforms designed by Kate Spade, customized cocktails created by nightlife impresario Rande Gerber and an in-flight exercise program designed by New York City fitness guru David Barton, the airline created its own distinct mark in the industry. The Song brand was placed on more than 200 flights a day which carried over ten million passengers.