But for astrobiologists, the $64,000 question remains: How rare is Earth’s own robust global magnetic field? And how well do such magnetic fields hold up, particular when on close orbits around active Red dwarf stars? Credits: NASA/GSFCUp until some 4 billion years ago, Mars apparently had a robust global magnetic field that coincided with the presence of water on its surface. But even the science surrounding how magnetic fields begin and evolve and sometimes completely turn off is still not completely understood. That is, as opposed to being directed along Earth’s magnetic field lines and ultimately crashing back into the atmosphere.

Source: Forbes April 10, 2017 09:56 UTC