The Arditti String Quartet is one of the most formidable new-music ensembles on the planet, and its appearance at the Library of Congress on Tuesday night was something of an event: a marathon, three-hour concert that ranged from an early modernist quartet by Alban Berg to a dazzling new piece by the 40-something British composer Thomas Ades. And given that the evening was part of this year’s John Cage Centennial (watch for a major festival of his work here in September), it made sense that violinist Irvine Arditti and pianist Stephen Drury would open with a spare, stunning and quintessentially “Cageian” work by the late American master.

Little actually happens, in the usual sense, in Cage’s “Two4.” Thin, sustained notes on the violin float quietly over distant chords on the piano, like cirrus clouds high over a vast and unending desert. But out of these slight materials Cage builds music of nearly unfathomable beauty; there’s a wonder-inducing sense of immensity to it, a sense of music that exists as part of the universe, infinitely serene and utterly indifferent to our little human dramas. The impact was unsettling, as if our minds had been scraped clean of everything nonessential. Arditti and Drury had to break for an intermission at the end, to let us all return to earth and resume our usual chatter.

Cage famously declared that “Beethoven was wrong,” so the Arditti’s members may have been winking a bit as they launched into Beethoven’s Grosse Fuge, Op. 133, a piece as passionate as the Cage is serene. The quartet played it skillfully enough, but for a work that usually explodes out of the gate and thunders into the heavens, it came off with all the fire of a nice cup of tea. Alban Berg’s String Quartet, Op. 3, which followed, was a rich and ravishing thing, however, unfolding in a heady sweep of always-surprising ideas; a memorable and deeply satisfying performance in every way.

Bela Bartok’s Quartet No. 4 in C made a powerful close to the evening, but it was Ades’s less familiar “Four Quarters” that really made the ears stand up and jump around. A fascinating, virtuosic and spectacularly colorful journey through the course of a day, it’s a real gem — and proof, if any were needed, that the string quartet genre is still alive, well and inspiring brilliant new work.

Brookes is a freelance writer.

The Arditti String Quartet. (Astrid Karger)