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Originally Posted by Sticks
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Thanks for bringing this up,
Sticks. Interesting.
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One astronomer who has studied "shadow bands" was sceptical of the new idea, however. Professor Barrie Jones, from the Open University in Milton Keynes, said that sound travelled too fast to be responsible for the phenomenon.
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I wondered about that when I read it. Wouldn't the speed of sound at the surface be slower than the earth's rotation, for a lot of the earth? Up to about latitude 45. I know the geometry is not that simple, but still. Then I read the following quote:
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Dr Eves says the speed of the Moon's shadow is generally supersonic and likens the phenomenon to the sonic boom of a jet breaking the sound barrier.
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So, I'd like to understand Barrie Jones' argument a little more. Oops, here it is:
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Barrie Jones, who is director of the physics and astronomy department of the Open University, told BBC News: "I'm not sure how infrasound could generate the bands - it's too fast.
He added: "Infrasonic waves in the atmosphere would move at the speed of sound, which would be something like 400m/s. Shadow bands move at wind speed, so they can be anything from stationary to a few metres per second."
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I'm confused.
O no:
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Stuart Eves thinks that demonstrating a role for infrasound might explain some other puzzling phenomena associated with eclipses.
For example, long period Foucault pendulums - designed to demonstrate the rotation of the Earth - have been known to swing wildly during eclipses.
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Whew, that would explain
everything 