space

[azafran]

A 60 year old mechanical engineer speaking (MSc etc etc). If space is expanding what is the opposite? You get nothing for nothing therefore a 'force' must be created for every cubic metre of space that is being created as the universe expands. Fair enough, but this means each cubic metre of space in the universe contains some sort of force that was required to create it during the original expansion?

 

Answers in less than 1000 words please.

[granpa]

yes it takes energy to create space

[PerpetuallyConfused]

wait wait wait... isnt space the absence of stuff?

 

why would you need energy for an absence of anything?

[granpa]

if space is 'simply' the absence of anything then why do you suppose that there are only 3 dimensions?

why not 1000 dimensions?

why not 10^1000 dimensions?

 

why do you suppose that c^2 = a^2 + b^2?

why not c^3 = a^3 + b^3?

why not c^1000000 = a^1000000 + b^1000000?

why not simply c = a + b?

 

space is clearly not nothing.

for one thing it has a very complex metric.

for another, its full of virtual particles.

 

http://en.wikipedia.org/wiki/Dirac_sea

 

The Dirac sea is a theoretical model of the vacuum as an infinite sea of particles with negative energy. It was first postulated by the British physicist Paul Dirac in 1930 to explain the anomalous negative-energy quantum states predicted by the Dirac equation for relativistic electrons. The positron, the antimatter counterpart of the electron, was originally conceived of as a hole in the Dirac sea, well before its experimental discovery in 1932

Edited March 31, 2012 by granpa

[JohnStu]

Velocity is not a force, but result of force. So only when space is accelerating (as oppose to moving at a constant speed) do we ask is there another force as its counterpart.

Edited April 9, 2012 by JohnStu

[elfmotat]

Velocity is not a force, but result of force. So only when space is accelerating (as oppose to moving at a constant speed) do we ask is there another force as its counterpart.

 

Velocity certainly isn't necesarily the result of a force, and I don't know if it's at all meaninful/useful to think of expansion as a result of a force.

[AChillyDog]

I don't think there is such thing as space, because space is where matter or energy is absent. Therefore, how must space exist?