Re: NANO: Casimir force a source of energy/propulsion?

From: Anders Sandberg (
Date: Fri Jan 25 2002 - 00:24:27 MST

On Thu, Jan 24, 2002 at 01:36:52PM -0800, Robert J. Bradbury wrote:
> We need harder numbers here on the amount of force/atom the Casimir
> force can produce.

The Casimir force is F=- pi^2 hbar c A / 240 r^4 where A is the area of
the plates and r their distance.

So for nanometer distances, r=1e-9 m and A=1e-18 m^2, I get F= - 1.29e-9
N, which sounds awfully large. Here obviously edge effects play a big
role though - while a MEMS may be a good imitation of an infinite
conducting plane, an atom isn't. My guess is that the force decreases
quite a bit due to a softening when matter becomes spread out objects
rather than infinite chunks.

Anders Sandberg                                      Towards Ascension!                  
GCS/M/S/O d++ -p+ c++++ !l u+ e++ m++ s+/+ n--- h+/* f+ g+ w++ t+ r+ !y

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