At the planet's core sleeps an alien exploration vessel, stranded in this orbit billions of years ago when there was only a dust disk around a star that had just ignited
The government will tell you that the Earth's magnetic field is generated by a spinning core of liquid iron, but isn't it more likely that it's projected by such an alien craft? Clearly, Area 51 just has an elevator leading down to the core, and the stealth bomber stuff is decoys
Mars's magnetic field is feeble because the scout ship's batteries are depleted, we just need to find the USB port and plug it into Curiosity to charge.