Re: The of "hard" SF

Wayne Throop wrote:
: Erik Max Francis <max@xxxxxxxxxxx>
: Worse than that: Global conservation of energy is Right Out as well in : our current theories. Energy is only locally conserved, not globally in : general relativity. In expanding (or contracting) spacetime there's a : pretty obvious example of this: cosmological redshift (or blueshift).

It's not quite as obvious as all that, is it... that is, not just
from redshift/blueshift; those could represent energy going into or
out of some form of potential form... um... couldn't it?

Not in general relativity; the redshifting/blueshifting of photon is caused by spacetime expansion/contraction, but it doesn't go "into the potential" of the spacetime that's expanding/contracting. After all, things completely unrelated to photons can be causing/encouraging/countering/reinforcing the expansion, such as vacuum energy.

Well anyways, yes, "problematic" is an understatement.
I'd not say "right out", since the problem is, it becomes difficult
to even *define* what the global energy of the universe is, let
alone assert that it is or is not conserved.

Well, you if are looking for a conservation law of X, and you can't even define what X is, then that conservation law is about as Right Out as it gets.

--
Erik Max Francis && max@xxxxxxxxxxx && http://www.alcyone.com/max/
San Jose, CA, USA && 37 18 N 121 57 W && AIM, Y!M, Skype erikmaxfrancis
Trying to mend our hearts in vain
-- Sandra St. Victor
.

Relevant Pages

  • Re: Nova / Einsteins 100th anniversary show
    ... >> and frequency, energy actually means the observed mass, and the observed ... >> describing an object with this mass traped in the curvature of spacetime. ... it is mistakenly identified as the proper ... >> law of the conservation of energy is a fundamental phenomenon applying to ...
    (sci.physics.relativity)
  • Re: Nova / Einsteins 100th anniversary show
    ... mathematical expression that equates observed energy and the observed mass. ... describing an object with this mass traped in the curvature of spacetime. ... One is the conservation of angular momentum where it ... it is mistakenly identified as the proper spacetime ...
    (sci.physics.relativity)
  • Re: .Re: Why all the fascination with E = mc^2 ??
    ... >> Conservation of Momentum, which, in Newtonian mechanics, is a direct ... >> consequence of Newton's Third Law of Motion. ... >> and the kinetic energy of a body is given by ...
    (sci.physics)
  • Re: The theoretical problem of action at a distance
    ... "Just what does it mean to say that the total energy and momentum ... In this region particle B has ... we know that conservation laws are simply tautological statements about the ...
    (sci.physics.relativity)
  • Re: NDC-Al Gore invented being a hypocrite
    ... The bottomline is that whether Al practices what he preaches is ... but did you see how much energy his family uses up? ... I am not a Gore fan, I haven't seen his movie (I will probably rent the DVD ... IMO environmental conservation is probably the most important ...
    (rec.music.gdead)
Loading