We live in an era of noise. Beginning with the first industrial revolution, and moving with a ceaseless trajectory since, noise has become an omnipresent bedfellow for all who live in or near cities. Cities are great gathering-sites of sound. They do not discriminate but proclaim the clamour within. In every house, devices hum and buzz. Fridges whir and mine occasionally shudders as if shaking off the cold. When reversing my car I get an emphatic beep.

This morning I went shopping at a large supermarket in Katoomba. Whilst waiting in the queue, I tried tuning in and out to the different layers of noise that surrounded all of us there. Stratas of white sound - refrigerators and air-conditioning were a soup of loud hushing - formed an almost benign background to the chirrup of cash registers, exclamations of customers and clatter of trolleys. It was impossible to imagine a place beneath all this racket where there might be a kind of silence.

Back home, cockatoos swooped loudly on some bread I put outside. I suspect their shrieks could shatter glass under the right conditions. I don't know of a noisier bird, and en masse they might even wake the dead.

One day the universe will end in silent darkness, but for now, we have an interminable light and sound show.