The resulting pressure estimations in the paper are ‘strange, if not incorrect’, according to Mikhail Eremets from the Max Planck Institute for
Chemistry in Mainz, Germany. Dias and Silvera find that pressure changes in direct proportion to the force applied by turning the screws that crush
the anvils together. That’s not what Eremets has observed in his own high pressure hydrogen research. The Harvard scientists extrapolate this
relationship to get the 495GPa measurement, he explains, whereas if they’d used the more conventional pressure–force relationship they would get
590GPa. That stretches plausibility, he underlines. ‘They might be lucky,’ Eremets says. ‘They used good diamonds, maybe it helped. But we’ve
done the same for three years at least. In our experience it’s impossible to reach such high pressures.’ He’s therefore ‘very surprised’ the
paper was published. |