In 2 billion years, the 2200 km outer core will completely solidify, with the magnetic dynamo halting sometime before then. The solid core is growing/solidifyin

In 2 billion years, the 2200 km outer core will completely solidify, with the magnetic dynamo halting sometime before then. The solid core is growing/solidifying a millimeter a year. With no magnetic field there will be more harsh radiation at the surface. Plus the solar wind may erode away the atmosphere as has on field-less Mars.