The Z Accelerator at Sandia National Laboratories. Thicknesses
of the aluminum and quartz drive plates and water samples were a
few hundred microns; the rear quartz window was a few
millimeters thick. When squeezed to pressures and temperatures
like those inside giant planets, water molecules are less
squeezable than anticipated, defying a set of decades-old
equations used to describe watery behavior over a range of
conditions. Studying how molecules behave in such environments
will help scientists better understand the formation and
composition of ice giants like Uranus and Neptune, as well as
those being spotted in swarms by planet hunters. The new work,
which appears in the March 2 Physical Review Letters, also
suggests that textbooks about planetary interiors and magnetic
fields may need reworking. In the lab, scientists generated
pressures reaching 700 gigapascals—almost 7 million times the
atmospheric pressure at the Earth’s surface—using the Z machine,
an accelerator at Sandia National Laboratories in