It's harder and harder to find peace and, especially, quiet.Even -in the most remote parts of Alaska the sound of a jet crossing overhead is all too common.Scientists set off across the U.S. to study the audio ecology. They recorded more than a million hours of sound from various sources.

They found that noise pollution is not good for people and it's even worse for animals with more sensitive ears. And the problem is not confined to land but echoes across the seas as well, where human-produced noise interferes with the live of various ocean dwellers.These days on Earth it's rare to hear “silence”.