An apsis (Greek ἁψίς, gen. ἁψίδος), plural apsides ( /ˈæpsɨdiːz/; Greek: ἁψίδες), is the point of greatest or least distance of a body from one of the foci of its elliptical orbit. In modern celestial mechanics this focus is also the center of attraction, which is usually the center of mass of the system. Historically, in geocentric systems, apsides were measured from the center of the Earth.

The point of closest approach (the point at which two bodies are the closest) is called the periapsis or pericentre, from Greek περί, peri, around, and κέντρον kentron. The point of farthest excursion is called the apoapsis (ἀπό, apó, "from", apocentre or apapsis [from ἀπ-, ap-, before an unaspirated, or ἀφ-, aph-, before an aspirated vowel, respectively]), (the latter term, although etymologically more correct, is much less used). A straight line drawn through the periapsis and apoapsis is the line of apsides. This is the major axis of the ellipse, the line through the longest part of the ellipse.

Derivative terms are used to identify the body being orbited. The most common are perigee  /ˈpɛrɨdʒiː/ and apogee  /ˈæpɵdʒiː/, referring to orbits around the Earth (Greek γῆ, gê, "earth"), and perihelion  /ˌpɛrɨˈhiːliən/ and aphelion  /əˈfiːliən/, referring to orbits around the Sun (Greek ἥλιος, hēlios, "sun"). During the Apollo program, the terms pericynthion and apocynthion were used when referring to the Moon.

Michael Trent Reznor (born May 17, 1965) is an American singer–songwriter, composer, and record producer. As both a vocalist and a multi-instrumentalist, Reznor has led the industrial rock project Nine Inch Nails beginning in 1988, and as of 2010 he and his wife, Mariqueen Maandig, are also members of the post-industrial band How to Destroy Angels alongside fellow composer Atticus Ross, with whom Reznor has scored two films. Reznor was previously associated with the bands Option 30, Exotic Birds, and Tapeworm, among others. Reznor left Interscope Records in 2007, and is now an independent recording artist.

Reznor began creating music early in his life, and cites his Western Pennsylvania childhood as an early influence. After being involved with a number of synthesizer-based bands in the mid-80s, Reznor gained employment at Right Track Studios in Cleveland, Ohio and began creating his own music during the studio's closing hours under the moniker Nine Inch Nails. Reznor's first release as Nine Inch Nails, Pretty Hate Machine (1989), was a commercial and critical success, and he has since released seven major studio releases. Outside of Reznor's chief project Nine Inch Nails, he has contributed to many other artists' albums, including Marilyn Manson and Saul Williams. In 1997, Reznor appeared in Time magazine's list of the year's most influential people, and in Spin magazine he was described as "the most vital artist in music."

Atticus Ross (born 16 January 1968) is an English musician, composer and producer. Ross, along with Trent Reznor, won the Academy Award for Best Original Score for The Social Network in 2010.

Atticus Ross is the son of Ian Ross, a founder of Radio Caroline, and Roxana Lampson, daughter of British diplomat Miles Lampson, 1st Baron Killearn and Jacqueline Castellani. His great-grandfather was the noted pathologist and bacteriologist Aldo Castellani, KCMG (Hon.). Liberty Ross, the model, is one of his five siblings. He was educated at Eton College, in the same house as Earl Spencer. David Cameron was also a contemporary.

Atticus Ross first came to notice in the mid-1990s as a programmer for Tim Simenon's Bomb the Bass during the period of the albums Unknown Territory and Clear. He worked on a number of production and remix projects with Simenon as well as forming a collaborative relationship with former Bad Seed Barry Adamson. He programmed The Negro Inside Me and Oedipus Schmoedipus, and produced As Above So Below before forming his own band 12 Rounds with Claudia Sarne and Adam Holden. They released two albums, Jitterjuice (Polydor Records) and My Big Hero (Nothing Records). A third full-length album was produced by Trent Reznor for Nothing Records, but ultimately never finished.^{[citation needed]} Three songs from that album have since been released at http://www.12rounds.net as of August 2011.