For most of my adult life, the scientific consensus seemed to be that convection cells in the Earth's core, circulating molten metallic material, induced electric currents and created the earth's magnetic field. There has never been any proof for this consensus theory, however – nor has there been any good alternative theory.
But now a scientist has shown, through calculations, that variations in the observed magnetic field could, theortetically, be explained by electric currents flowing in our salt oceans (which are conductive). Fascinating stuff, and an interesting view of science being made...
Everything I've ever read about the rings of Saturn says that they are remarkably thin and sparse collections of dust and pebbles, swirling around Saturn in the same plane as the Saturn's satellites. Now I learn that there are mile-high “bumps” in the rings that were predicted by computer models of the rings, but never seen.