Without the outer core, life on Earth would be very different. Convection of liquid metals in the outer core creates the Earth's magnetic field. This magnetic field extends outward from the Earth for several thousand kilometers, and creates a protective magnetosphere around the Earth that deflects the Sun's solar wind. Without this field, the solar wind would directly strike the Earth's atmosphere. This might have removed the Earth's atmosphere, making the planet nearly lifeless. It may have happened to Mars.