[ExI] physics

[Anders Sandberg]

On 2016-04-24 17:43, William Flynn Wallace wrote:
>
> Say there is a cube of space (in 'outer' space) that has not one 
> single atom of matter (violating entropy I suppose).  Does this mean 
> that it is not in some sense 'space'?  Not until some matter is there?
> That there is no 'there' there?

In the standard general relativity view there is a patch of spacetime 
there, with its own properties (curvature). And there could well be 
electromagnetic fields (like light on its way through) or more exotic 
quantum stuff. In quantum field theory "empty" space is a pretty complex 
thing and the mystery is why it is not heavy and impenetrable.


> Some say our universe is expanding.  Does this mean that some 
> 'potential space' exists beyond any matter that will become 'space' 
> when some matter gets there?

Not in the standard general relativity framework. The technical way of 
saying it is that the spacetime manifold does not require an embedding 
for the Einstein equations to work.


-- 
Anders Sandberg
Future of Humanity Institute
Oxford Martin School
Oxford University

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