Basic Earth Science and Society - Basic Research Opportunities in Earth Science - page 22

Figure 1.3 New experiments document the appearance of the dense metallic state
of hydrogen at pressures greater than 0.6-1.0 Mbar (60-100 GPa), but with much
higher densities than had previously been expected (dotted curve; the results
shown here are for the deuterium isotope). Knowledge of the properties of
hydrogen is needed for understanding the origin and evolution of planetary
systems, with metallic hydrogen being the primary constituent of giant planets
and of stars. SOURCE: Reprinted with permission from B.A. Remington, D.
Arnett, R.P. Drake, and H. Takabe, Modeling astrophysical phenomena in the
laboratory with intense lasers, Science, v. 284, p. 1488-1493, 1999. Copyright
1999 American Association for the Advancement of Science.