Mostly everything has a nano-unit measurement including sounds. The human ear can hear things down to around 0 decibels. If you are about 100 feet from a jet as it takes off that is about 150 decibels. Your headphones can be cranked up to around 100 decibels. Scientists at the University of California in San Diego have made nano-fibers that are sensitive enough to hear things at -30 decibels. That is around 1000 times more sensitive than the human ear (decibels are measured on a log scale). They can use this device to ‘hear’ heart muscles beat. These scientists imagine that their device might be used to ‘hear’ a single bacteria (sneaking up behind you) or changes in cells that might signal their becoming cancerous. Their work was supported by the National Science Foundation
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