Overheated gold crushing restrictions once considered unbreakable

In dazzling experiments involving ultrafast lasers and X-rays, scientists measured the atomic temperature of overheated gold for the first time, and in doing so, they overturned decades of theories.

Their discovery was published in natureproving that solid gold can withstand more than 14 times its melting point without decomposing, against what physicists once called the “entropy disaster.”

Take almost untouchable temperatures

Extreme materials like internal stars, fusion reactors or planetary cores belong to a class of substances called warmth, where heat and pressure are so intense that a standard thermometer is useless. So far, scientists have relied on indirect models to estimate how hot these systems are – models often with large uncertainties.

“We have good technology to measure the density and pressure of these systems, but no temperature,” said Bob Nagler, a scientist at the SLAC National Accelerator Laboratory in the Ministry of Energy. “It’s a decades-long problem.”

To solve it, Nagler and colleagues turned to this problem in an extreme condition (MEC) instrument of SLAC, where they used lasers to explode nano-thin gold foil with intense pulses, and then photographed it with Ultrabirt X-rays from Linac Cooherent Light Source (LCLS). As atoms vibrate from heat, their movement slightly shifts the energy of the scattered X-rays, a shift that directly reveals the temperature.

Beyond no reward

At first, the researchers just wanted to prove that their new approach worked. But the numbers coming back were unexpected. They found that pure gold survived without melting temperatures up to 19,000 kelvins (33,000 degrees Fahrenheit).

“We were surprised to find that these superheated solids were much higher than we originally expected, which was contrary to the long-term theory of the 1980s,” said Tom White, co-leader at the University of Nevada, Reno. “This wasn’t our original goal, but that’s what science means – discovering new things you don’t know exist.”

What is an entropy disaster?

Most materials melt or boil at well-defined temperatures. However, under special conditions, if there is no time to decompose the solid, the solid can be “superheated” beyond its melting point. For decades, theorists have suggested that there are limits to how far this can go: the so-called entropy disaster. If the entropy or disease of the solid is equal to its liquid state, the law of thermodynamics indicates that it must melt immediately.

The entropy disaster point of gold is considered to be about three times its melting temperature. But in this study, gold was overheated to nearly 14 times without violating thermodynamics. The trick? speed.

“What we prove is that if the material heats very quickly, in our case, these disasters can be avoided.”

Key Discovery

• The team heats the gold to 19,000 K, more than 14 times the melting point
• Direct temperature measurements Doppler widening using X-rays
• Gold remains solid far beyond predicted entropy disaster limits
• Rapid heating prevents the expansion of the lattice, thus disregarding the material from conventional melting behavior
• The heating rate used in this experiment is up to 6×10¹⁵ k/s

Impact on Fusion and Planetary Science

The discovery has a great impact on astrophysics and energy research. Warm dense matter is the core of inertial fusion energy, where tiny fuel particles are compressed and heated to generate power. So far, scientists have no reliable way to measure the heat of these materials before the phase of change.

“To design useful goals, we need to know that they will experience significant state changes in temperatures. Now, we finally have a way to do these measurements.”

The team has used their method to study impact compression materials that mimic the conditions deep inside the planet, which they hope to apply widely to fusion and materials research.

Why it matters

This study not only breaks theoretical limitations, but also introduces a new, reliable way to track temperatures under the most extreme conditions. It raises the basic question: If you have fast enough heat, can you not limit overheating? Now, what other assumptions in high-energy physics need to be reexamined?

“If our first experiment using this technique presents a significant challenge to established science, I can’t wait to see where other discoveries lie,” Nagler said.

Journal Reference

White, TG, etc. “The golden color exceeds the predicted entropy disaster threshold.” nature,roll. 643, pp. 950–954 (2025).
doi:10.1038/s41586-025-09253-y

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