Terry Riley: Written in the stars

When the American composer Terry Riley began to write Sun Rings, a piece for the innovative Kronos Quartet that was inspired by the sounds emanating from space, little did he know how the meaning and very nature of the piece would come to be influenced by subsequent events here on Earth.

That was two years ago. Riley's creative juices had hardly started to flow when the cataclysmic tragedy of September 11 occurred. It made him radically rethink his approach. The result of that rethink, which was first performed in Iowa last October, has its European premiere at the Barbican, in London, tomorrow night.

En route, it has acquired new resonances. For some, it has become a kind of requiem for those who died in last month's Columbia space-shuttle disaster, and now, with the Iraq crisis, its profoundly anti-war message seems even more relevant.

Riley was profoundly affected by September 11. As David Harrington, leader of the Kronos Quartet, recalls, the project was nearly derailed. "Suddenly, all parties questioned the relevance of Sun Rings in the wake of the terrorist attacks and the impending war on Afghanistan," he says. But Riley found new inspiration from the poet Alice Walker, whom he heard talking on radio about her new September 11 mantra, "One Earth, One People, One Love". Suddenly, he realised that contemplating outer space could be a way to put the problems of Earth into perspective. He used not only the Walker mantra as the title of the concluding movement of Sun Rings, but also the voice of the poet herself intoning those words.

By an eerie coincidence, the quartet were playing this concluding movement on the very night of the space-shuttle accident on 1 February. They were performing it in Monterey, California, not as part of Sun Rings but as the closing sequence of their Visual Music programme (which they perform tonight at the Barbican).

"People asked us if we wanted to dedicate it to the astronauts, but we chose not to say anything," says Harrington. "I am not interested in turning our concerts into anything other than a musical experience. I feel that music is so personal and private, and so public at the same time, that it will be able to do what it needs to do."

Harrington knows better than most the dangers faced by astronauts, having witnessed the launch of the Columbia in September 2000. "It is an amazing experience," he recalls. "One of the things you are left with is how terrifying it is, and how dangerous it is for these human beings who are, in effect, sitting on top of a bomb."

The Barbican performance of Sun Rings will be the third. Again by chance, it has coincided with another momentous event, the Iraq crisis, and, inevitably in this context, the concert will be seen as an impassioned anti- war statement.

Riley, of West Coast hippie extraction, has already written in protest at his government's stance to President Bush, and the Kronos Quartet are among the numerous signatories from the American artistic establishment to the recent full-page advertisement in The New York Times advocating peace. The relevance of the piece is explained by Willie Williams, rock'n'roll designer for groups such as the Rolling Stones and U2, who was recruited by Kronos to provide the visual accompaniment to Sun Rings.

"There is nothing overtly political about it, but it does have quite a sombre quality," Williams says. "It is about our position in the cosmos, and it is about our humanity, which is in stark contrast to the petty tribalism afflicting us here on Earth. It gives us a context."

None of this was in anyone's mind when Nasa originally commissioned the piece to mark the 25th anniversary of the Voyager space missions. Harrington, Riley and Williams were put in touch with Don Gurnett, a physicist at the University of Iowa, who has a cardboard box full of tapes of sounds that he has collected from space over the past 40 years. Both Harrington and Riley were enthused by Gurnett, who loves to play sounds like the so-called "whistlers", caused by deep-space lightning, to anyone who wants to listen. He even played the "dawn chorus" from Jupiter over the telephone to me. It is indeed reminiscent of the sounds made by birds in a tropical forest, though, in fact, as Gurnett explains, the sound of "Jupiter singing to us" actually originates from electrons in the radiation belt "getting together spontaneously".

To Harrington, the sounds from space seemed to be "part of nature but a part I had not heard before". To Riley, they were the raw material of composition. He even discerned fragments of melody. When he listened carefully to the crackles and squeals of the magnetic field surrounding Jupiter's largest moon, Ganymede, it sounded to him like a voice saying "beebopterismo", which became the starting point for one of the movements.

Some sounds Riley incorporated into the live performance, using the strings of the quartet to imitate and build upon them. In two of the movements, he introduces an 80-strong choir "to emphasise that this work is largely about humans as they reach out from Earth to gain an awareness of their solar-system neighbourhood". Altogether, Sun Rings has 10 movements and lasts about 90 minutes.

In illustrating the piece, Williams was sorely tempted by the thousands and thousands of slides provided by Nasa. "I was completely blown away by everything", he says, "but some of the pictures you see a lot, and I wanted to find things that were not so familiar."

He opted for some moving early footage of Jupiter taken in the Seventies. Even though it was of relatively poor quality, it had a reality denied audiences fed on computerised images. He was also taken with material on the gold disc carried by Voyager, which was designed to show aliens, should they find it, who we are. "It is actually very beautiful and oddly moving," says Williams.

Whether Sun Rings will have the same resonance here as it did in the United States remains to be seen. According to Harrington, the response to the premiere in Iowa was "amazing, unparalleled. It truly felt as though we were part of this completely enveloping experience".

And that is what Riley was seeking. "If only we will let the stars mirror back to us the big picture of the universe and the tiny, precious speck of it we inhabit that we call Earth," he says, "maybe we will be given the humility and insight to love and appreciate all life and living forms wherever our journeys take us."

The Kronos Quartet perform 'Visual Music' at the Barbican Hall, London EC2 (020-7638 8891) tonight at 7.30pm, and 'Sun Rings' at the same venue tomorrow at 7.30pm