Expanding Universe and Conservation of Energy
Or lack thereof.
I’ve been getting lots of questions about my post on how conservation of energy isn’t conserved in an expanding universe. Happily, I just ran across this excellent post from Sean that may clarify things a bit more.
Does Einstein’s general relativity really say that energy is not conserved? You will be unsurprised to hear that the answer depends on what you mean by “energy.” and what you mean by “conserved.” (Full post)
Read that and see if it helps. Spacetime is the field upon which the laws of physics play themselves out, and that field is not static and unchanging…
Technorati Tags: cosmic variance, cosmology, expanding universe
Sean Carroll’s comment “… there is generally, once again, no such thing as the conserved total energy. (In a closed universe there is — and it’s always exactly zero, for all the good it does us.)”
is interesting to me, because I suspect that the total energy of the Universe is indeed zero (see my comment to the original article here).
If it can be demonstrated that the global energy is zero then it would support the argument for a closed Universe and vice versa. If, on the other hand, one or the other is conclusively demonstrated otherwise, then it might mean that our quaint notions of “energy” and what-not are just simple-minded.
But, wait, we already know that, don’t we?