Fine gold sheets fired briefly with lasers have been heated up to 14 times their melting point, remaining solid, far beyond the theoretical limit. This raises the hypothesis that some solids may not have a higher melting point.
“What are the true limits of fusion?” It’s not as easy as it sounds. To further complicate the discussion, a study this Wednesday in Nature revealed that the gold can be heated up to 14 times its melting point without melting.
Overheating is a common phenomenon where a solid can heat beyond its melting point, or a liquid can heat beyond its boiling point without changing state. For example, a heated water cup in a microwave can reach temperatures above 100 ° C as long as the cup is smooth and immovable. However, as soon as the cup is shaken, the water will boil violently.
For the solids, Many physicists proposed a higher limit for overheatingat a temperature about three times higher than the standard melting point in Kelvin.
This point is designated by entropy catastrophewhich is when entropy, often defined as the amount of disorder in a system, for the solid state would become larger than if the substance was liquid.
As it refers, if the substance remained solid above this temperature, it would violate the second law of thermodynamics, which says entropy cannot decrease over time for most systems.
Gold surprises physical
The new study revealed that the gold can warm up to 14 times its melting point, keeping solid, far above your entropy catastrophe point.
After confirming that they had not fooled in measurements, the team again analyzed the theory and realized that the extremely fast warming of gold meant that solid gold entropy could remain lower than the potential liquid form, allowing it to allow it exceed the predicted temperature limit.
“It is important to say that we did not break the Second Law of Thermodynamics“The investigation leader warned, Thomas Whitefrom the University of Nevada, to New Scientist.
The true limit of overheating remains a differentityrefers to physics. “We may have thought that we had resolved it in the 1980s with this overheating limit, but now I think it is an open question again. To what extent can one warm up before it melted?” He reflected.
“Now it would also be interesting to see if this applies to solids beyond gold and if there is a maximum limit for heating before merger,” says Vinko.
