Mars once had a magnetic field strong enough to deflect solar wind, just as Earth’s does now — when it collapsed, the planet lost its atmosphere and its oceans within a geologically brief period, transforming from a world that may have held life into the frozen desert it is today

Mars once had a global magnetic field, generated deep inside the planet, strong enough to deflect the solar wind much as Earth’s does today. When that field faded, Mars lost its thick atmosphere and its surface water, and over time it changed from a world that may once have been habitable into the frozen desert [...] The post Mars once had a magnetic field strong enough to deflect solar wind, just as Earth’s does now — when it collapsed, the planet lost its atmosphere and its oceans within a geo