This is information that matters because we can now determine melt
points for other elements at similar pressures. All molecules
disassociate down there and proper modeling needs accurate transition
points.
Recall that the key element at the final point of disassociation will
be elemental carbon and I suspect that we actually have a working
layer of it. Thus our diamond pipes are really carbon pipes rapidly
burning their way upward. This also establishes a natural slip plane
for the crust itself and allows the crust itself to remain in
permanent balance.
It is also good to eliminate a problem with thermal flows although I
disagree that it is the cause of our magnetic field. That
conjectured carbon layer is much more convincing.
We can now start piecing it all together with some accuracy.
Earth's Core 1,000
Degrees Hotter Than Expected
By Elizabeth
Howell,
Earth's internal
engine is running about 1,000 degrees Celsius (about 1,800 degrees
Fahrenheit) hotter than previously measured, providing a better
explanation for how the planet generates a magnetic field, a new
study has found.
A team of scientists
has measured the melting point of iron at high precision in a
laboratory, and then drew from that result to calculate the
temperature at the boundary of Earth's inner and outer core —
now estimated at 6,000 C (about 10,800 F). That's as hot as the
surface of the sun.
The difference in
temperature matters, because this explains how the Earth generates
its magnetic field. The Earth has a solid inner core surrounded by a
liquid outer core, which, in turn, has the solid, but flowing, mantle
above it. There needs to be a 2,700-degree F (1,500 C) difference
between the inner core and the mantle to spur "thermal
movements" that — along with Earth's spin — create the
magnetic field.
The previously
measured core temperature didn't demonstrate enough of a
differential, puzzling researchers for two decades. The new results
are detailed in the April 26 issue of the journal Science.
The centerpiece of the
experiment was a new X-ray technique that takes measurements faster
than before. Iron samples compressed in the laboratory
typically last for only a few seconds, making it difficult to
determine in previous experiments if the iron is still a solid, or if
it is starting to melt.
The technique makes
use of diffraction that occurs when X-rays, or other forms of light,
hit an obstacle and bend around it. Scientists sent X-ray bursts at
the sample and observed the "signature" of heating, which
is a diffuse ring, that pinpointed the temperature.
These experiments
pegged the melting point of iron at 4,800 C (about 8,700 F) at a
pressure of 2.2 million times that is found on Earth's surface at sea
level.
Extrapolating from
that measurement, scientists estimated the boundary between Earth's
inner and outer core is a searing 10,832 F, give or take about 930
degrees, at a pressure of 3.3 million atmospheres (or 3.3 million
times the atmospheric pressure at sea level).
Participating
organizations in the experiment include CEA (a French national
technological research organization), the French National Center for
Scientific Research (CNRS) and the European Synchrotron Radiation
Facility (ESRF).
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