This is the title track from Vangelis's 1977 album, "Spiral." This particular piece is notable for featuring an unusual sound effect that creates a spiralling sensation around the listener. It is also notable for being the artist's first piece created using a Yamaha CS80 synthesizer, which he used on his best work - from 1977 to 1988.
The video itself consists of various images of galaxies, in particular the titular spiral variety.