Stone of Remembrance

October 6, 2006

Metallic Water – Science, not SF

Filed under: Commentary — admin @ 13:21

DISORDER, ANYONE? The electrically conducting structure of metallic water occurs at a more accessible part of the water phase diagram than formerly thought. Here, a snapshot from a first-principles computer simulation demonstrates the atomic disorder. Red spheres are hydrogen atoms, white spheres are oxygen atoms, and the electron density from a partially occupied electron state responsible for the conductivity is shown as gold. (Image courtesy of Sandia National Laboratories)

I was pointed to this article from a post to a mailing list I regularly read. It was mentioned by the poster that James Blish talked about “metallic water” many years ago in They Shall Have Stars, the first book in Cities In Flight.

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.)

The lowered boundary is sure to revise astronomers’ calculations of the strength of the magnetic cores of gas-giant planets like Neptune. Because the planet’s temperatures and pressures lie partly in the revised sector, its electrically conducting water probably contributes to its magnetic field, formerly thought to be generated only by the planet’s core.

We science fiction writers face the inevitable drift of the future into the present. It’s pretty cool when one’s forebears come up with ideas that turn out to have some validity. Now, all I have to do is to find some way to use this in a story . . .

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