2001: A Space Odyssey (soundtrack) used is Ligeti's "Lux Aeterna" and an electronically altered form of his "Aventures", the last of which was so used without Ligeti's permission and is not listed in the film's credits. Since the film, "Also sprach Zarathustra" has been used in many other contexts. It was used by the BBC and by CTV in Canada as the introductory theme music for their television coverage of the Apollo space missions, as well as stage entrance music for multiple acts including Elvis Presley late in his career. Jazz and rock variants of the theme have also been composed, the most well known
2001: A Space Odyssey (film) essay "Odyssey of Stanley Kubrick" wrote, "Kubrick has conceived a film which in one stroke has made the whole science fiction cinema obsolete." Others credit "2001" with opening up a market for films such as "Close Encounters of the Third Kind", "Alien", "Blade Runner", "Contact", and "Interstellar", proving that big-budget "serious" science-fiction films can be commercially successful, and establishing the "sci-fi blockbuster" as a Hollywood staple. Science magazine "Discover"s blogger Stephen Cass, discussing the film's considerable impact on subsequent science fiction, writes that "the balletic spacecraft scenes set to sweeping classical music, the tarantula-soft tones of HAL 9000, and the