London: Planetary scientists have claimed
that oceans of liquid diamond, topped with solid "icebergs" of
the precious gems, could be on Uranus and Neptune.
According to them, as much as 10 per cent of both
the two giant gas planets is carbon and a liquid diamond ocean
could deflect the angle of the magnetic field out of alignment
with the planets` rotation.
The two planets, unlike Earth, do not have magnetic
poles which match up with their geographical poles.
In laboratory conditions which simulated pressure
levels on the gas planets, the scientists found that little
crystals of solid diamond formed like icebergs in the liquid
carbon they created.
Jon Eggert of Lawrence Livermore National Laboratory
in California was quoted by `The Daily Telegraph` as saying,
"The idea of significant quantities of pure carbon existing
in giant planets such as Uranus and Neptune has gained both
experimental and theoretical support.
"It is now accepted that the high-pressure, high-
temperature behaviour of carbon is essential to predicting the
evolution and structure of such planets. An ocean of diamond
could help explain the orientation of Uranus` and Neptune`s
For their research, the planetary scientists took a
half-millimetre wide diamond a tenth of a carat in weight and
blasted it with lasers at high pressure, similar to that which
could be found on Uranus and Neptune.
The diamond was liquefied at pressures 40 million-
times greater than at sea-level on Earth, and from there the
scientists slowly reduced the temperature and pressure. When
the pressure fell to only 11 million-times Earth sea level and
temperatures dipped to 50,000 degrees Celsius, solid chunks of
diamond began to appear in the liquid.
As the pressure continued to drop more and more
chunks formed in the liquid diamond and did not sink. With
most materials the solid state is more dense than the liquid
state -- with water one of the few exceptions.
"Diamond is relatively common material on Earth,
but its melting point has never been measured. You can`t just
raise the temperature and have it melt, you also have to go to
very high pressures, which makes it very difficult to measure
the temperatures," Eggert wrote in `Nature Physics` journal.