Final answer:
Mars does not currently have a global magnetic field from its core, but there were indications of a global field billions of years ago. Earth's magnetic field is generated by moving material in its liquid metallic core.
Step-by-step explanation:
Mars does not currently have a global magnetic field from its core. However, there are areas of strong surface magnetization on the planet, indicating that there was a global magnetic field in the past. Mars has a small metal core and its overall density suggests a composition primarily consisting of silicates.
Earth's magnetic field is generated by moving material in its liquid metallic core. This liquid metal circulates, setting up a circulating electric current, which produces a magnetic field. Mars, on the other hand, does not have liquid material in its core today that would conduct electricity, leading to the absence of a global magnetic field.
Scientists have made observations near Mars in 1998-2000 that suggest the planet may have had a molten metallic core in its ancient era, similar to how the Moon's surface became weakly magnetized in some patches. This indicates that in the past, Mars, like Earth now, may have had a molten metallic core in which electric currents generated a magnetic field.