A rotation is a circular movement of an object around a center of rotation. A three-dimensional object can always be rotated around an infinite number of imaginary lines called rotation axes. If the axis passes through the body's center of mass, the body is said to rotate upon itself, or spin. A rotation about an external point, e.g. the Earth about the Sun, is called a revolution or orbital revolution when it is produced by gravity. The axis is called a pole. Mathematically, a rotation is a rigid body movement which, unlike a translation, keeps a point fixed; this definition applies to rotations within both two and three dimensions All rigid body movements are rotations, translations, or combinations of the two. A rotation is a progressive radial orientation to a common point; that common point lies within the axis of that motion. The axis is 90 degrees perpendicular to the plane of the motion. If the axis of the rotation lies external of the body in question the body is said to orbit. There is no fundamental difference between a “rotation” and an “orbit” and or "spin".

The key distinction is where the axis of the rotation lies, either within or outside of a body in question. This distinction can be demonstrated for "non rigid" bodies. If a rotation around a point or axis is followed by a second rotation around the same point/axis, a third rotation results; the reverse of a rotation is a rotation. Thus, the rotations around a point/axis form a group. However, a rotation around a point or axis and a rotation around a different point/axis may result in something other than a rotation, e.g. a translation. Rotations around the x, y and z axes are called principal rotations. Rotation around any axis can be performed by taking a rotation around the x axis, followed by a rotation around the y axis, followed by a rotation around the z axis; that is to say, any spatial rotation can be decomposed into a combination of principal rotations. In flight dynamics, the principal rotations are known as yaw and roll; this terminology is used in computer graphics. In astronomy, rotation is a observed phenomenon.

Stars and similar bodies all spin around on their axes. The rotation rate of planets in the solar system was first measured by tracking visual features. Stellar rotation is measured by tracking active surface features; this rotation induces a centrifugal acceleration in the reference frame of the Earth which counteracts the effect of gravity the closer one is to the equator. One effect is that an object weighs less at the equator. Another is that the Earth is deformed into an oblate spheroid. Another consequence of the rotation of a planet is the phenomenon of precession. Like a gyroscope, the overall effect is a slight "wobble" in the movement of the axis of a planet; the tilt of the Earth's axis to its orbital plane is 23.44 degrees, but this angle changes slowly. While revolution is used as a synonym for rotation, in many fields astronomy and related fields, revolution referred to as orbital revolution for clarity, is used when one body moves around another while rotation is used to mean the movement around an axis.

Moons revolve around their planet, planets revolve about their star. The motion of the components of galaxies is complex, but it includes a rotation component. Most planets in our solar system, including Earth, spin in the same direction; the exceptions are Uranus. Uranus rotates nearly on its side relative to its orbit. Current speculation is that Uranus started off with a typical prograde orientation and was knocked on its side by a large impact early in its history. Venus may be thought of as rotating backward; the dwarf planet Pluto is anomalous in other ways. The speed of rotation is given by period; the time-rate of change of angular frequency is angular acceleration, caused by torque. The ratio of the two is given by the moment of inertia; the angular velocity vector describes the direction of the axis of rotation. The torque is an axial vector; the physics of the rotation around a fixed axis is mathematically described with the axis–angle representation of rotations. According to the right-hand rule, the direction away from the observer is associated with clockwise rotation and the direction towards the observer with counterclockwise rotation, like a screw.

The laws of physics are believed to be invariant under any fixed rotation. In modern physical cosmology, the cosmological principle is the notion that the distribution of matter in the universe is homogeneous and isotropic when viewed on a large enough scale, since the forces are expected to act uniformly throughout the universe and have no preferred direction, should, produce no observable irregularities in the large scale structuring over the course of evolution of the matter field, laid down by the Big Bang. In particular, for a system which behaves the same regardless of how it is oriented in space, its Lagrangian is rotationally invariant. According to Noether's theorem, if the action (the integral over tim

List of members of the 3rd House of Commons of Northern Ireland

This is a list of Members of Parliament elected in the 1929 Northern Ireland general election. Elections to the 3rd Northern Ireland House of Commons were held on 22 May 1929. All members of the Northern Ireland House of Commons elected at the 1929 Northern Ireland general election are listed. Sir James Craig, continued as Prime Minister. 10 November 1930: James Fulton Gamble elected for the Unionists in North Tyrone, following the death of William Thomas Miller. 31 January 1933: Death of James Lenox-Conyngham Chichester-Clark. This vacancy remained unfilled at the time of the next general election. Biographies of Members of the Northern Ireland House of Commons

Grammy Award for Song of the Year

The Grammy Award for Song of the Year is an honor presented at the Grammy Awards, a ceremony, established in 1958 and called the Gramophone Awards. The Song of the Year award is one of the four most prestigious categories at the awards presented annually since the 1st Grammy Awards in 1959. According to the 54th Grammy Awards description guide, the award is presented: to honor artistic achievement, technical proficiency and overall excellence in the recording industry, without regard to album sales or chart position. Song of the Year is related to but is conceptually different from Record of the Year or Album of the Year: Song of the Year is awarded for a single or for one track from an album; this award goes to the songwriter who wrote the lyrics and/or melodies to the song. "Song" in this context means the song as composed, not its recording. Record of the Year is awarded for a single or individual track, but the recipient of this award is the performing artist, the producer, recording engineer and/or mixer for that song.

In this sense, "record" means a particular recorded song, not an album of songs. Album of the Year is awarded for a whole album, the award is presented to the artist, producer, recording engineer, mastering engineer for that album. In this context, "album" means a recorded collection of songs, not the individual songs or their compositions; the Song of the Year awards have been awarded since 1959. It is one of the four most prestigious Grammy Awards. Despite both the Record of the Year award and Song of the Year being awarded for a single or for one track from an album, this award goes only to the composer of the song whereas the Record of the Year award goes to the performer and production team of the song. According to the 54th Grammy Awards description guide, the award is given to the songwriter of a song that "must contain melody and lyrics and must be either a new song or a song first achieving prominence during the eligibility year. Songs containing prominent samples or interpolations are not eligible".

Since the late 1960s other songwriter's awards have been presented for genre-specific categories including Grammy Award for Best Country Song, Grammy Award for Best R&B Song, Grammy Award for Best Song Written for Visual Media, Grammy Award for Best Rock Song, most Grammy Award for Best Rap Song, Grammy Award for Best Gospel Song, Grammy Award for Best Contemporary Christian Music Song, Grammy Award for Best American Roots Song, Grammy Award for Best Gospel Performance/Song, Grammy Award for Best Contemporary Christian Music Performance/Song. Thirty-one of the winning songs have won the award for Record of the Year; the category was expanded to include eight nominees in 2019. In many cases, the songwriters were the performers. Multiple winners in this category include Henry Mancini, Johnny Mercer, James Horner, Will Jennings, U2, Adele, winning two times each. However, songs written for Andy Williams, Barbra Streisand, Bette Midler, Roberta Flack have received this award twice. Christopher Cross and Billie Eilish are the only artists to receive the Grammys for Song of the Year as well as for Record of the Year, Album of the Year, Best New Artist in one ceremony.

Adele is the first artist to receive the award for Song of the Year, Record of the Year, Best New Artist, Album of the Year and first woman to accomplish this feat. Only six artists have won the Song of the Year and Best New Artist awards the same year: Christopher Cross, Alicia Keys, Amy Winehouse, Sam Smith and Billie Eilish. With four nominations, Marilyn Bergman and Taylor Swift are the most nominated female songwriters in the history of the award; the first woman to win the award was Carole King in 1972, for "You've Got a Friend". Adele was the first female artist to win the award twice, winning for "Rolling in the Deep" and "Hello"; the song "Volare", winner in 1959 by Domenico Modugno and performed in Italian, is the only foreign-language song to win this award, although the 1967 winner "Michelle" by The Beatles has a critical part of its lyrics in French. The song "Theme of Exodus", winner in 1961 by Ernest Gold is the only instrumental song to receive this award. Since creation of this category, no songwriter has won Song of the Year twice in a row.

Members of the National Academy of Recording Arts and Sciences nominate their choices for song of the year. A list of the top twenty records is given to the Nominations Review Committee, a specially selected group of anonymous members, who select the top eight records to gain a nomination in the category in a special ballot; the rest of the members vote a winner from the five nominees. In 2018, it was announced the number of nominated tracks will be increased to eight An asterisk indicates this recording won