|Demo by Weezer|
|Recorded||November 14, 2001|
|Rivers Cuomo song chronology|
"Cygnus X-1" was originally written, according to the Catalog O' Riffs, in early October of 2001. It is first known to have been recorded during the sessions at Cello Studios in early November of that year, though it was not finished at that time. The song was later recorded at Glenn Sound Studios on November 14 for the radio station 107.7 The End, along with the songs "Slave" and "Space Rock". The songs were never aired, and the band subsequently released them as free MP3s on their official website.
The basis for the song's title has never been commented on, but Cygnus X-1 is also the name of a galactic X-ray source in the constellation Cygnus discovered in 1964, and the first such source widely accepted to be a black hole. It is also the title of a two-part song by the band Rush from their 1977 album A Farewell to Kings.