There Was Nothing, A Great Void, Absolutely Nothing...

[sandyRoe]

Then there was a big bang and the ejecta was propelled faster than the speed of light to fill the cosmos.
And some would say that my simple faith is far fetched. Is the account of the creation in Geneses any more unlikely than the scientific alternatives?

[sandyRoe]

But wasn't it wonderfully thoughtful of Mother Church to go to the trouble of formulating a question and answer book so that the 'simple minded' wouldn't be excluded.

[LazyGun]

OK, Being dumb this morning - but I do not quite understand why this experiment - 2 mirrors placed close to each other in a vacuum and then being attracted to each other - is not simply an illustration of gravitational force?

[jomifl]

Because it only works in a vacuum... LG

[jim360]

I'd expect because you can weigh the two plates, calculate the force due to gravity between them (Newton's law would do) and then subtract any result of this off and you'd be left with an "excess" attraction. Thus, even if Gravity plays some role in bring the plates together, it doesn't play a large enough role to explain it. For that you need the Quantum Theory of ElectroDynamics that tells you there is a vacuum field that's being disrupted and adding a new force that explains the excess over gravity.

That's what I'd expect to be the case, anyway.

[jim360]

I should add that I'd be interested to find a definitive explanation of why gravity can be discounted or ignored, and it's an important question. The answer above is, I think, the correct one, and it seems like the experimenters have taken the force of gravity into account, though one or two sources would disagree. It might depends a lot on the precise experimental set-up. How heavy the plates being used are, etc.

[LazyGun]

Gravity is the attractive force between 2 masses. Does not matter if it happens in a vacuum or not, jom. The same force, gravity, that worked in a vacuum to bring together the mass that forms planets and moons should be working on 2 items of mass close together in a vacuum, it seems to me.

[LazyGun]

What does weight have to do with it? I must be really stupid this morning. Weight is surely mass x g? no? So 2 bodies with mass will tend to attract each other.

@Jim I am sure you are probably correct that they would have taken it into account - i just did not see any mention of that, but I did not read all the references.

[jomifl]

LG, the point of my remark was that if the force was due to gravity it would make no difference whether or not there was a vacuum. The apparent existence of an extra force when there is a vacuum implies the existence of some effect ther than gravity.

[LazyGun]

I misunderstood your point then, Jom .But my question still stands. I imagine that Jim is correct in that the researchers will have accounted for gravity in their study design, but I saw no specific reference to that.

I have done more reading, and it seems the equations governing the casimir effect relate more to the surface area of the plates - the attraction increases as the area increases, rather than as their mass increases, and the amount of force described is rather different than if gravity was the culprit.

I did say I was being dumb this morning :)

[jim360]

I wouldn't say that -- you had me worried for a moment that I was missing something obvious too, LG!

[mibn2cweus]

sandyRoe
Question Author
Is that a quote from a happy-clappy song?

http://www.azlyrics.com/lyrics/planetshakers/nothingisimpossible.html
07:48 Fri 21st Mar 2014

No . . . although it does however regrettably support the assertion. :o/

[modeller]

I've only just read this post but one thing strikes me is ' Can you have a void of nothing ? What sets the limits of that void. ? What's outside it ? Some talk of the emptiness of space as a void but radiation passes through it , so is that a true void . It depends on how you define a void.