Author Topic: Casimir Tractor  (Read 1455 times)

Offline Akya2120

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Casimir Tractor
« on: 03/19/2018 08:20 PM »
The casimir effect is generally know, and regarded as a real phenomena created by essentially selecting the set of wavelengths that fit between two parallel plates. This in turn creates a force on the two plates. Now, what happens when we spatially translate the two plates together? Does this set of plates now in turn push on the set of free roving wavelengths in it's local region of space? If so,  theoretically we could make an assembly of plates on two rotating tracks (similar to two tractor treds facing each other but rather than treds we have casimir plates,) on one side the plates intermesh with each other and cause the casimir effect to take place, everywhere else there is no interference allowing the assembly to push only in one direction. Is this a theoretically viable mechanism for generating directional force?


Keep in mind this is a thought experiment, and not something that will likely ever be built since the mechanical difficulties of creating such an assembly would be quite troubling.

Offline meberbs

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Re: Casimir Tractor
« Reply #1 on: 03/19/2018 09:26 PM »
No, this wouldn't work.

First, an alternative equivalent description of the Casimir effect is simply that Van der Waals forces between very closely placed pieces of metal attract them to each other. This is always equal and opposite between the plates.

Nothing is different if the plates are both moving together with the same velocity, there isn't something external they are pushing on. This is also the basis of the principle of relativity, there isn't a background frame that you can measure things moving relative to, so a system moving at constant speed behaves the same as one standing still.

Offline QuantumG

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Re: Casimir Tractor
« Reply #2 on: 03/19/2018 09:53 PM »
Sounds like you're trying to describe optical tweezers.
Jeff Bezos has billions to spend on rockets and can go at whatever pace he likes! Wow! What pace is he going at? Well... have you heard of Zeno's paradox?

Offline Akya2120

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Re: Casimir Tractor
« Reply #3 on: 03/19/2018 10:35 PM »
As I understand though, casimir force on two plates is caused by the radiation surrounding them. While I realize radiation pressure is different than for example fluid pressure, usually we get reaction force from pushing against a pressure.

Offline meberbs

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Re: Casimir Tractor
« Reply #4 on: 03/19/2018 10:51 PM »
As I understand though, casimir force on two plates is caused by the radiation surrounding them. While I realize radiation pressure is different than for example fluid pressure, usually we get reaction force from pushing against a pressure.
No, it is not created by real radiation pressure. If that was the case it wouldn't depend on the distance between the plates and would depend on if the outer surfaces of the plates were painted white or black and the strength and position of the radiation sources.

It can be described with virtual particles, but virtual particles are not the same thing, and, again, there simply isn't a velocity they have that you can move relative to.

Offline sanman

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Re: Casimir Tractor
« Reply #5 on: 04/05/2018 06:23 PM »
Sounds like you're trying to describe optical tweezers.

Btw, here's something on optical nano-tweezers that's just come out:

https://www.nature.com/articles/s41566-018-0134-3

Can't see the spaceflight applications, though - unless you could have tiny mote-sized probes

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