Galileo challenges time

Philip Glass's new chamber opera begins in 1642 with the astronomer Galileo, a blind old man, musing on the events of his life. We then see him, slightly younger, recanting his theories before Pope Urban VIII. Then, younger still, he remembers a letter from his daughter. And so the plot moves on, travelling backwards in time until he is a small child attending an opera written by his father.

This chronological conceit takes a while to pay dividends but when it does, the effect is magical. The first scenes - even the recantation - seem somewhat static and dramatically unsupported. But as we move earlier in time, the dramatic ironies become more apparent. Galileo's patron, Cardinal Barberini, seems wise and supportive, for example, but we have already seen his future betrayal.

Glass's music is gorgeous, full of transparent textures, witty orchestrations and deceptively simple vocal lines. Director and librettist Mary Zimmerman does a fine job and achieves the remarkable feat of presenting Galileo's theories with both clarity and humour. And her staging of the 'opera within an opera' at the end of the piece is meltingly charming.

The standard of the singing is variable, but the tight sense of ensemble and some excellent acting (especially from Carl Halvorson as the older Galileo) more than compensates.

Galileo Galilei is showing until Sat, Barbican, Silk Street EC2,

7.45pm, Sat mat 2.30pm, £5 to £28. Tel: 020 7638 8891.

Tube: Barbican/Moorgate