Apparently it originates from J. Robert Oppenheimer. It's his own interpretation of a line from the Bhagavad Gita, which he says came to mind as he was watching the Trinity test (the first test of nuclear weapon technology).
It is especially appropriate when one considers the rest of the verse to which that line belongs (as interpreted by Robert Jungk):
- If the radiance of a thousand suns
- were to burst into the sky,
- that would be like
- the splendor of the Mighty One—
- I am become Death, the shatterer of Worlds.