So just how much of a magnetic field would be needed to protect Mars and the humans that might someday live on it? Surprisingly, the team writes that the force needed to deflect say, solar wind, is about the same as a regular fridge magnet. But they’d need to generate it over the entire planet, a substantial challenge. The scientists suggested a few ways to pull it off. These include restarting and circulating Mars’ iron core, creating a continuous solid loop or loop of solid-state magnets, or using a chain of coupled sources with a controlled beam or a plasma...