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Researchers heated an ultra-thin sheet of gold to 14 times its melting point using a laser pulse lasting just 45 quadrillionths of a second, yet the gold remained solid. This defies the previously accepted "entropy catastrophe" limit, which predicts that solids can't be heated beyond about 3 times their melting point without melting. The team used a new X-ray method to confirm the extreme temperatures.
Because the heating was so fast, the atoms didn’t have time to reorganize into a liquid, meaning thermodynamic laws like entropy increase didn’t apply in the usual way. This finding suggests that the true upper temperature limit before melting may not exist or may depend on the speed of heating, potentially redefining how we understand melting and phase transitions in solids.