A nuclear bomb in the Barbican

How do you set an atomic bomb to music? To attempt it, you have to think big. Over the centuries, the greatest composers have arguably stood or fallen by their willingness to tackle the giant topics of their time, sometimes those of all time. Bach set the Crucifixion. Beethoven tackled liberty and fraternity. Wagner portrayed the end of the world and its rebirth. In Dr Atomic, John Adams has depicted a night that changed history forever, building up to the test of a nuclear bomb at Los Alamos and, at the last moment, fusing this event with the use of the "gadget" (as some of the characters call it) a few weeks later on Hiroshima and Nagasaki.

Adams, currently circumnavigating the world for his 70th birthday celebrations, has been in London this week recording the opera with the BBC Symphony Orchestra, finishing with a sort-of-semi-staged concert last night at the Barbican. Although the work was done at ENO when brand new, it isn't performed live often and the chance to be fully immersed in its terrifying world and boundary-crunching approach is not to be missed.

It's a dark, desperate piece that, in exploring an incident that changed humankind into a species capable of destroying its own world, plunges deep into the impulses of the soul - and manipulates our sense of time while doing so. We become intensely aware of the beauty and wonder of the world, the sensuality of it heightened by the poetry selected by Peter Sellars for the libretto, while intensifying the consciousness of horrifying imminent destruction.

John Adams. Photo: Vern Evans

The drama is in many ways inward, as Oppenheimer - at first seemingly transfixed by scientific data and the prospect of a "brilliant luminescence" - then becomes increasingly tortured and implicitly terrified by what he has created. In concert, the effect is in some ways more that of an oratorio than an opera: the settings of poems by John Donne, Charles Baudelaire, Muriel Rukeyser and others offer moments of reflection on love, death, sensuality and beauty, set to music that ebbs and flows in waves of shimmering, multifaceted, orchestral gorgeousness, the voices often soaring across the top in widespread extended phrases that reach both stratospheres and profundities of range, often in quick succession.

The personal interactions could be seen as the equivalent of recitatives and are mostly discussions between the men: General Groves bullies Frank Hubbard to predict good weather for the test even though dangerous storms are taking place, and engages in a lighter-hearted exchange with Oppenheimer about diet [dang! I thought Roxanna and I were the first team to put chocolate brownies into an opera, but no...]. Ensembles are few, though mesmerising when they occur - Wilson's dream of falling from the bomb tower is a case in point. Choruses are illustrative, sometimes devastating - the vision of Vishnu in particular - and the chorus's role is to contextualise, comment and evoke, but not especially to be a human presence.

The overarching time-drama of the whole edifice, though, is not so much Bachian as Wagnerian. The entire three-or-so hours of music is a build-up of tension to the final event. In short, we are waiting for a nuclear bomb to explode. At the end, it does.

Along the way, we sense the shifting of history's tectonic plates - keening violins, shuddering double-basses, the inimitable threat from the bass clarinet, visionary swirls of harp, flashes of lightening from piccolo or trumpet, an extraordinary episode early in act II, brass-led, that builds upwards and outwards, transforming its harmonies continually like a passage Wagner forgot to write. And like the fall of Valhalla, like the death of Stravinsky's Chosen Maiden, the release of tension in the final cataclysm is a form of catharsis. In music, after all, these violent ends sometimes presage a renewal of hope. (Having so said, this opera is probably the scariest musical experience I've encountered since first hearing The Rite of Spring.)

Conducted by the composer himself, the BBC Symphony Orchestra played like people possessed, fully matched by the BBC Singers, sounding like an ensemble twice the actual size (they also put believable American twists into their diction). The soloists were pure gold: Gerald Finley, Adams's original, the powerful and vocally luminous Oppenheimer; Julia Bullock radiant and expressive as Kitty, relishing the sensual poetry of "fierce peace"; Jennifer Johnston a dark, aching Pasqualita. The subsidiary male roles were all characterful and persuasive: Brindley Sherratt a fine Teller, Andrew Staples touching as Wilson, Aubrey Allicock a General Groves one wouldn't want to come up against if one was a weather-forecaster, Marcus Farnsworth and Samuel Sakker excellent as Hubbard and Captain James Nolan.

Staging, handled sensitively by Kenneth Richardson, was necessarily limited as the orchestra is absolutely vast, with a heavy-duty, space-eating plethora of percussion; there's not much room to move, so most of the effect was achieved by costumes and lighting. But there's much that can be done with that: a blaze of red light as the explosion begins, the ensemble cover their eyes - then darkness. As the final recorded voice intones Japanese pleas for help, for water for the children, the orchestra switch off their lights one by one until nothing is left but a ground zero in the pitch-black soul of humanity itself.

One might have expected the standing ovation to continue for longer, but the impression was that much of the audience was seriously shaken up by the experience and probably wanted air, which was in short supply. But one overriding image? The bomb explodes; and the composer stands, measuring out the bars with his baton. Humanity can create the horrors of the atomic bomb. Humanity can also create the wonder of great music about giant topics. Adams has done so.