Heat at the Limit: Measuring 3000-Degree Temperatures express

Original: "Closing the ultrahigh temperature metrology gap: non-contact thermal conductivity ($$\mathrm{k}$$) and spectral emittance ($$\mathrm{\varepsilon_{\lambda}}$$) of molybdenum up to 3200 K"

· Hunter B. Schonfeld, Elizabeth Golightly, Milena Milich, Scott Bender, Konstantinos Boboridis, Davide Robba, Luka Vlahovic, Rudy Konings, Ethan Scott, Patrick E. Hopkins

arXiv:2604.09873 · 2026-04-10 · CC BY 4.0 · 1 min

Materials

Scientists have learned to accurately measure how metals conduct heat at temperatures near melting.

A red-hot piece of metal in a furnace is like a frying pan on the stove: the hotter it gets, the faster heat travels to your hand if you touch it. But at temperatures where the metal is close to melting, measuring that speed is very tricky: sensors don't make good contact, heat escapes into the air, and the glowing sample confuses the instruments.

This new method sidesteps those obstacles. A laser hits a tiny spot on the surface, and an infrared camera tracks how heat spreads from that spot. By comparing the temperature difference between the heated point and the rest of the metal, you can calculate how well the material conducts heat. It's like estimating the force of a thrown stone by watching the ripples on water.

Molybdenum passed the test: its thermal conductivity was measured from 1500 to 3000 K — nearly its melting point. The uncertainty was only 7.9–11%.

The method also made it possible to measure how molybdenum emits light in both solid and liquid states. This data is needed for creating components that work in extreme heat: in hypersonic aircraft, nuclear reactors, and laser 3D printing with metal.

So a red-hot piece of metal is no longer a mystery: now its thermal properties can be determined precisely, without even touching it.

Whole graph →

Molybdenum melts at 2623 °C — hotter than the surface of Venus, the hottest planet in the solar system.

Scientists

Ludwig Boltzmann Rudolf Clausius Christian Doppler D. B. McLaughlin Didier Queloz Michel Mayor

Concepts

room temperature superconductivity high temperature superconductor thermal conductivity thermal property measurement molybdenum quantum thermometer thermoelectric device kelvin thermometer tungsten niobium nitride millikelvin liquid helium non destructive testing rubidium vapor absolute zero superconductivity enhancement mechanisms aluminum nitride heat transport joule per kelvin

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Heat at the Limit: Measuring 3000-Degree Temperatures express