On 1/6/2019 1:56 PM, agrayson2...@gmail.com wrote:
On Sunday, January 6, 2019 at 7:53:52 AM UTC, Brent wrote:
To measure small things you need comparably short wavelengths. If you
make a photon with a wavelength so short it can measure the Planck
length it will have so much mass-energy that it will fold spacetime
around it and become a black hole...so you won't be able to use it to
measure anything.
Brent
TY. That's clear enough. But there's a related question I was unable
to explain to a friend recently. Suppose we have a small spherical
cork floating on a lake, and we introduce a wave disturbance. If the
wave length is much larger than the diameter of the sphere, it will
just bob up and down as the wave passes. But if the wave length is
comparable to the diameter, the wave will be partially reflected. What
is a good *physical* argument for the existence of the reflected wave,
tantamount to a detection of the cork? I am at loss to offer a
physical explanation. TIA, AG
When the wavelength is on the order of the cork dimension or smaller the
cork can't react to the wave as if it were just part of the water.
Because of its extent it cannot move with the water at all points, so
there are pressure gradients around the cork which become the source of
scattered ripples.
Brent
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