Mercury has a complicated inside and an active geologic past
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.