Gold can remain solid even at temperatures over 14 times its melting point, defying long-held theories on the subject. A team of researchers, led by Thomas White from the University of Nevada, used high-resolution X-ray scattering to measure the temperature of gold, achieving a record-breaking 14 times its melting temperature.
Their experiment involved heating a thin film of gold using intense laser pulses and measuring the speed at which the energy was deposited into the material. By doing so, they created a state where the gold remained solid despite being incredibly hot. The team’s setup allowed them to achieve heating rates of over 1015 K s-1, far beyond the previously predicted “entropy catastrophe” limit of 3000°C.
The researchers used an ultrabright X-ray thermometer at Stanford University to accurately measure the temperature. They employed a method that relies on the Doppler shift of photons emitted by atoms or molecules in the sample, which depends on their velocity. By analyzing the width of the spectrum of light scattered by the sample, they were able to estimate its temperature.
The discovery has significant implications for fields such as planetary science and fusion energy, where precise temperature diagnostics are critical. The researchers’ method provides a direct, model-independent way to measure atom temperatures in extreme conditions, unlocking new possibilities for studying materials behavior.
The team is now applying their technique to shock-compressed materials, including iron, and plans to extend their approach to a wide range of materials and conditions. This breakthrough has the potential to revolutionize our understanding of materials science and provide new insights into the properties of solids under extreme conditions.
Source: https://physicsworld.com/a/how-hot-can-you-make-a-solid-before-it-melts