Physicists Blast Gold to Astonishing Temperatures, Overturning 40 Years of Physics
Overheated gold defies the limit of entropy disaster, overthrowing 40 -year -old physics
Physicists have overheated gold at 14 times its melting point, refuting a long -standing prediction on the temperature limits of solids
Greg Stewart / Slac National Accelerator Laboratory
Gold generally melts at 1,300 kelvin – a temperature warmer than the fresh lava of a volcano. But scientists recently sent a gold sample to nanometers thick with a laser and heated it to an amazing 19,000 kelvin (33,740 degrees Fahrenheit) – all without melting the material. The feat was completely unexpected and overthrew 40 years of physics accepted on the temperature limits of solid materials, report the researchers in an article published in the journal Nature. “It was extremely surprising,” said Thomas White, a member of the study team, of the University of Nevada, Reno. “We were totally shocked when we saw how hot it was.”
The measured temperature is far beyond the “entropy disaster” proposed by Gold, the point to which entropy or disorder, in the material, should force it to melt. Beyond this limit, the theorists had predicted solid gold would have higher entropy than liquid gold – a clear violation of the laws of thermodynamics. By measuring such blistering temperature in a solid in the new study, the researchers refuted the prediction. They realized that their solid gold was capable of becoming so overheated because it was warmed incredibly quickly: their laser castigated the gold for only 45 femtoseconds, or 45 quadrillions of a second – a “flash heating” which was far too fast to allow the time of the material to develop and therefore kept entropy within the limits of known physics.
“I would like to congratulate the authors for this interesting experience,” said Sheng-Nian Luo, a physicist at the Southwest Jiaotong University in China, who studied overheated overheating and was not involved in the new research. “However, fusion in ultra-narrow, Ultrasmall and UltraClex conditions could be too interpreted.” The gold of the experience was a solid ionized ionized in a way that could have caused high internal pressure, he says, so that the results may not apply to normal solids under regular pressures. Researchers, however, doubt that ionization and pressure can explain their measures. The extreme temperature of gold “cannot reasonably be explained by these effects alone”, explains White. “The observed overheating scale suggests a truly new diet.”
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The Chandra Curry project scientist works at the Linac coherent light source at the Slac National Accelerator Laboratory.
Jacqueline Ramseyer Orrell / SLAC National Accelerator Laboratory
To take the gold temperature, the team used another laser – in this case, the most powerful X -ray laser in the world, which is three kilometers (1.9 thousand) long. The machine, the Linac coherent light source at the Slac National Accelerator Laboratory in California, accelerates electrons with more than 99% of the speed of light, then pulls them through wavy magnetic fields to create a very brilliant beam of a Billion (1012) X -ray photons.
When this laser shot the overheated sample, X -ray photons dispersed the atoms inside the material, allowing researchers to measure the speeds of atoms to effectively take gold temperature.
“The biggest sustainable contribution will be that we now have a method to really measure these temperatures with precision,” explains Bob Nagler, member of the study team, scientist of the SLAC. Researchers hope to use the technique on other types of “hot dense matter”, such as materials intended to imitate the interior of stars and planets. Until now, they had no good way to take the temperature of the material in such grilled states, which generally last just a second fractions. After the gold test, the team turned its laser thermometer on a piece of iron sheet which had been heated with a laser shock wave to simulate the conditions in the center of our planet. “With this method, we can determine what is the melting temperature,” explains Nagler. “These questions are super important if you want to model the earth.”
The temperature technique should also be useful to predict how the materials used in fusion experiments will behave. The national ignition installation of the Lawrence Livermore National Laboratory, for example, draws lasers to a small target to heat it and compress it quickly to light the thermonuclear merger. Physicists can now determine the melting point for different targets – which means that the whole field could warm up in the near future.
