Physicists have superheated gold to an astonishing 19,000 Kelvin (33,740 degrees Fahrenheit), 14 times its melting point, without causing it to melt. This groundbreaking experiment has overturned four decades of accepted physics related to the behavior of solid materials under extreme temperatures.
Why it matters: The findings challenge the long-standing prediction about the temperature limits of solids, known as the “entropy catastrophe” limit, and suggest a potentially much higher or even no limit for superheating solids. This discovery opens new frontiers in material science and planetary physics.
The details:
- Researchers at SLAC’s Matter in Extreme Conditions (MEC) instrument used a laser to heat a 50-nm-thick polycrystalline gold sample for just 45 femtoseconds.
- The ultrafast heating prevented the gold from expanding, allowing it to maintain its solid structure at temperatures far beyond the predicted limit.
- The team utilized the world’s most powerful x-ray laser at SLAC to measure the gold’s temperature by analyzing the scattering of x-ray photons off atoms inside the sample.
The researchers hope to apply this technique to other types of “warm dense matter” and to accurately measure the melting points of materials used in fusion experiments.
What they’re saying:
- “This was extremely surprising,” said Thomas White, a study team member from the University of Nevada, Reno. “We were totally shocked when we saw how hot it actually got.”
- Sheng-Nian Luo, a physicist at Southwest Jiaotong University in China, who was not involved in the research, offered cautious praise: “I would like to congratulate the authors on this interesting experiment.” However, he also suggested that the ultrafast, ultrasmall nature of the experiment could lead to overinterpretation.
The bottomline: This breakthrough not only challenges long-held scientific theories but also opens new frontiers in material science and planetary physics, underscoring the profound impact of innovative experimental techniques on our understanding of the natural world.
