In this video, Eliasson describes "Beauty," part of a large one-artist exhibition at the Museum of Modern Art in New York and SF MOMA in 2008, The MOMA.org Interactive Exhibitions: Take Your Time: Olafur Eliasson (2008), website, offers extensive video and photographic documentation of Eliasson's installations in the exhibition (including this video), and is highly recommended.
"As we move around on space, the degree of the rainbow changes, if we don't look the degree would also not be there, so there would be no rainbow." Olafur Eliasson
" [...] (the rainbow) it would not be here if we were not here, as anything else in a museum." OE
Quotations from the Documentary "Art Now: Olafur Eliasson" which documents the artist's major solo exhibition, Notion Motion, at the Boijmans van Beuningen museum in Rotterdam.