It was previously though that Mars had no significant magnetic field. However, NASA’s InSight Mars Lander has found the surface magnetic field to be 20x stronger than expected. But even more mysteriously the magnetic field tends to fluctuate in strength or direction at precisely midnight (- that is Mars Lander’s midnight on Mars, not ours). The lander has also found an unexpected electrically conductive layer about 2.5 miles thick, well below the surface.