from COSMOS Magazine

Sound illusions inspired Stonehenge

by Kerry Sheridan – Agence France-Presse

VANCOUVER: Ancient legends of thunder gods can be explained today with the modern science of sound waves, say scientist who believes an auditory illusion inspired the creation of Stonehenge.

The famous, 5,000 year-old stone circle in Britain is one of the best-known world heritage sites and many have guessed at the reasons for its existence, from a prehistoric observatory to sun temple to sacred healing ground.

Steven Waller, an independent scientist who has studied cave art for 20 years and cultivates a particular interest in the sounds of ancient sites, thinks that a sound wave effect was so mysterious back then that it compelled people to erect Stonehenge.

The phenomenon Waller referred to is known as acoustic interference. It happens when two sources of sound, such as two bagpipers, are playing the same note at the same time from different places in a field.

As a listener passes, the sound waves, rather than aligning to make the noise louder as one might expect, actually bounce off each other to create a wavering, muffling effect. “You hear the sound modulating between and loud and quiet,” Waller said at the American Association for the Advancement of Science conference in Vancouver.

“That would have been a very mysterious phenomenon, totally inexplicable.

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