According to Hindu mythology, the universe was created with a sound: “Om.” It is a syllable that contains within it everything that ever was and everything that will be.

When the Arecibo telescope is pointed at the space between stars, it hears a faint hum. Astronomers call that the “cosmic microwave background.” It’s the residual radiation of the Big Bang, the explosion that created the universe fourteen billion years ago.

But you can also think of it as a barely audible reverberation of that original “Om.” That syllable was so resonant that the night sky will keep vibrating for as long as the universe exists.

When Arecibo is not listening to anything else, it hears the voice of creation.
—  The Great Silence, Ted Chiang