Dark Side of the Moon Tour – A Piece for Assorted Lunatics", the name under which it made its press debut in February 1972 at London's Rainbow Theatre. The title changed for the first part of the US tour to "Eclipse (A Piece for Assorted Lunatics)" during April and May before reverting to "Dark Side of the Moon – A Piece for Assorted Lunatics" in September for the second part of the US tour and finally released in 1973 under the title of "The Dark Side of the Moon". Remarkably, at its first full live performance at Guildhall, Portsmouth, England on 21 January 1972, most of
Orbit of the Moon frequencies. See also tidal acceleration for a more detailed description. The Moon is gradually receding from Earth into a higher orbit, and calculations suggest that this would continue for about 50 billion years. By that time, Earth and the Moon would be in a mutual spin–orbit resonance or tidal locking, in which the Moon will orbit Earth in about 47 days (currently 27 days), and both the Moon and Earth would rotate around their axes in the same time, always facing each other with the same side. This has already happened to the Moon—the same side always faces Earth—and is