By Nadia Drake
THE WOODLANDS, Texas — Mercury is even weirder than expected, NASA’s MESSENGER probe is showing.
For starters, the planet’s interior is built differently than anything else scientists have blueprints for. Unlike Earth’s, Mercury’s core — which gobbles up 85 percent of the planet’s radius — consists of three layers instead of two. At the planet’s heart lies a probable solid layer, surrounded by a swirling liquid iron layer, all encapsulated by a third, solid iron-sulfur layer.
The new MESSENGER results were presented on March 21 at the Lunar and Planetary Science Conference, as well as in two papers appearing online in Science. One paper discusses the gravity measurements leading to the new model of the planet’s interior, and the other describes surface features in the northern hemisphere.