Although he remains best known for the works he wrote for his own ensemble, orchestral music has been at the forefront of Philip Glass� activities for much of the last two decades. Having achieved success in 1993 with his Low Symphony, a reworking of David Bowie and Brian Eno�s classic rock album Low, three years later Glass repeated the experiment with another Bowie/Eno collaboration, Heroes, an album that drew its inspiration from the then-divided city of Berlin. The six movements of Heroes Symphony function as independent pieces that between them build into a self-sufficient musical work. The Light has its inspiration in a very different source: the Michelson-Morley experiment confirming the uniform speed of light. Seeking a musical corollary, Glass� piece has an expressive introduction followed by an energetic main movement: a �before� and �after� mirroring the onset of modern scientific research.