What happened
- A team including Zachary M. Geballe, Jing Yang and Vasilije V. Dobrosavljevic published on November 8, 2026 in Science measurements of the melting point and electrical resistivity of iron at Earth-core pressures and temperatures.
- They used a new method: microsecond pulsed Joule heating in diamond anvil cells.
- More than 300 reproducible melting measurements indicate a surprisingly shallow melting curve, at 6 K per gigapascal.
- At 200 gigapascals iron melts at 4,160 ± 80 K. The resistivity of liquid iron measured 76 microohm-centimeters. Science blocks automated reading, so this note is based on the published abstract.
Why it matters
The melting point and resistivity of iron at high pressure are essential data for understanding Earth’s core: how much heat it carries, how it cools and how it sustains the magnetic field.
If iron melts at a lower temperature than believed, the boundary between core and mantle would also be colder, and that changes models of how heat flows out of the interior.
The number
3,430 K and 9.8 TW. From their measurements, and extrapolating in pressure and alloy composition, the authors infer a relatively cold core-mantle boundary of 3,430 K and a low adiabatic outer-core heat flow of 9.8 terawatts.
Context
With those values, the authors suggest thermal convection alone could have powered the geodynamo, the dynamo that generates Earth’s magnetic field, before the inner core formed. They also conclude that today’s lowermost mantle is fully solid.
The method of heating with microsecond electrical pulses makes it possible to identify melting and measure the resistivity of solid and liquid iron under the same conditions. The figures for the real core depend on extrapolating to the alloy composition and the full core pressures, so they are inferences and not direct measurements of Earth’s interior.
At Mamífero we have followed studies of materials and other planets. Hydrogen chloride leaks over Alba Mons suggest Mars keeps internal heat, the Southern Ocean may have released CO₂ and explain half the Eocene rise, in metallic glasses local order and density appear together on crystallization and SLAC confirms altermagnetism in a MnTe crystal.
What’s next
- Other laboratories will have to reproduce the method and compare their melting curves.
- Extrapolation to alloys with other light elements will decide how cold the core-mantle boundary really is.
- Geodynamo models will have to incorporate the resistivity values.
Bottom line
The measurement puts a lower number on iron’s melting temperature under pressure and, with it, a colder picture of the interior. The effect on magnetic-field models will be seen when other groups repeat the experiment.
Sources
- Geballe, Z. M., Yang, J., Dobrosavljevic, V. V. et al., “Melting and resistivity of iron at Earth core conditions using pulsed Joule heating”, Science, November 8, 2026, DOI 10.1126/science.aeh5267, date confirmed in Crossref, link. The Science page could not be read; the note is based on the abstract supplied by Crossref.
- Cover image: National Institute of Standards and Technology, Public domain, via Wikimedia Commons
Edited by Rodrigo Cornejo. How we select and verify: who writes these notes.
