Mars’s Liquid Center Cooling in Unusual Manner, Study Suggests National Geographic News

The planet Mars may well have a liquid center, scientists say.
That’s a surprise because Earth’s core, which contains similar elements as Mars, has a solid, metal interior surrounded by a layer of molten metal. The discovery was made by a team of European scientists using a device called a high-pressure anvil, which is capable of producing pressures of up to 6 million pounds per square inch (40 Gigapascals).
In experiments, the authors squeezed together high-temperature mixtures of iron, nickel, and sulfur to replicate conditions found on Mars. The researchers were able to determine that the Martian core is still mostly, if not entirely, liquid.