Daily Weird News Report
Scientists have recreated a tiny piece of the extreme environment believed to exist deep inside ice giants, using lasers to melt a diamond and track what happened inside it.
The experiment was carried out by physicists from Lawrence Livermore National Laboratory at the University of Rochester’s Omega Laser Facility. A laser vaporized the outside of a diamond sample, sending a powerful shock wave through the remaining material. For roughly a billionth of a second, the diamond experienced pressure more than three times that at Earth’s core and temperatures comparable to the Sun’s surface.
Researchers monitored the brief event with several sensors, including ultrafast X-ray diffraction. Their measurements addressed a long-standing disagreement between laboratory observations and computer models of diamond’s melting point. Earlier measurements and quantum-mechanics-based calculations had differed by as much as 20 percent—more than 1,000 kelvins under the conditions involved.
The new data, reported in Nature Physics, were consistent with modern quantum-physics models. The researchers also found that solid diamond can be less dense than liquid metallic carbon under the right conditions. That means diamond could float in a sea of liquid carbon rather than immediately sinking through it.
This finding is relevant to the proposed phenomenon known as diamond rain. Scientists have suggested that the intense pressure and heat inside Neptune and Uranus could break carbon-rich material into diamonds, which might then descend toward the planets’ cores. The LLNL experiment did not observe diamond rain inside either planet, but it provided experimental information about the pressure and temperature conditions under which the process could occur.
The work may also affect efforts to improve nuclear fusion experiments. The diamond capsule used in the study resembles the type of target used at Lawrence Livermore’s National Ignition Facility. Based on their calculations, the researchers said a slower initial shock could melt such a capsule while using less power, potentially producing about three times more fusion energy from its fuel.
That projected increase would still fall short of the level required for a practical fusion power plant. Even so, the same experiment has linked a decades-old question about diamond’s behavior under extreme conditions with possible clues about the interiors of distant planets.
