Supercomputer simulations by two Sandia researchers have significantly altered the theoretical diagram universally used by scientists to understand the characteristics of water at extreme temperatures and pressures.

The new computational model also expands the known range of water?s electrical conductivity.

The Sandia theoretical work showed that phase boundaries for ?metallic water? ? water with its electrons able to migrate like a metal?s ? should be lowered from 7,000 to 4,000 kelvin and from 250 to 100 gigapascals.

(A phase boundary describes conditions at which materials change state ? think water changing to steam or ice, or in the present instance, water ? in its pure state an electrical insulator ? becoming a conductor.)

For more:
http://www.sciencedaily.com/releases/2006/10/061004180104.htm

sweet

nice find; thanx dano

Since we're talking about neptune wouldn't we
be looking at polymorphic ice???
I remember a bit about this, (eight or more forms?),
but had trouble finding it.
Came up with this though:
http://cat.inist.fr/?aModele=afficheN&cpsidt=1096194

Depends on the pressure. And Neptune is big enough that the density will cover a large range of values.

The article mentions that the pressures found on Neptune do fall within the newly calculated phase limits. It sounds like they didn't before. ~samwik

That is my understanding.

Refined calculations changed the range of pressures believed to exist within the planet.