[meteorite-list] What's that on Uranus?

From: Darren Garrison <cynapse_at_meteoritecentral.com>
Date: Mon, 18 Jan 2010 22:35:45 -0500
Message-ID: <ou9al5121mfu2pr4st20v7c235mg244gal_at_4ax.com>

Finally, the origin of carbonados!

http://news.discovery.com/space/diamond-oceans-jupiter-uranus.html

Diamond Oceans Possible on Uranus, Neptune

By melting and resolidifying diamond, scientists explain how such liquid diamond
oceans may be possible.

Oceans of liquid diamond, filled with solid diamond icebergs, could be floating
on Neptune and Uranus, according to a recent article in the journal Nature
Physics.

The research, based on first detailed measurements of the melting point of
diamond, found diamond behaves like water during freezing and melting, with
solid forms floating atop liquid forms. The surprising revelation gives
scientists a new understanding about diamonds and some of the most distant
planets in our solar system.

"Diamond is a relatively common material on Earth, but its melting point has
never been measured," said Eggert. "You can't just raise the temperature and
have it melt, you have to also go to high pressures, which makes it very
difficult to measure the temperature."

Other groups, notably scientists from Sandia National Laboratories, successfully
melted diamond years ago, but they were unable to measure the pressure and
temperature at which the diamond melted.

Diamond is an incredibly hard material. That alone makes it difficult to melt.
But diamond has another quality that makes it even more difficult to measure its
melting point. Diamond doesn't like to stay diamond when it gets hot. When
diamond is heated to extreme temperatures it physically changes, from diamond to
graphite.

The graphite, and not the diamond, then melts into a liquid. The trick for the
scientists was to heat the diamond up while simultaneously stopping it from
transforming into graphite.
Received on Mon 18 Jan 2010 10:35:45 PM PST