Computers Are Learning to Smell

You know the smell of warm, buttered popcorn. The pungent, somewhat sweet scent that precedes rain. But could you begin to describe these aromas in detail? Your nose has some 400 olfactory receptors that do the work of translating the world's estimated 40 billion odorous molecules into an even higher number of distinct scents your brain can understand. Yet although children are taught that grass is green and pigmented by chlorophyll, they rarely learn to describe the smell of a freshly cut lawn, let alone the ozone before a storm.