Hello,
I recently heard about Mars lacking magnetosphere, and I’m curious why it is not present even though it’s core is made of molten metals?
Does it’s lack of magnetosphere is related to tectonic activity on Mars? If so please explain how, or why not.
Thank You for Your knowledge!
In: 3
A planet’s magnetic field is generated by convection in the outer core – the liquid metal is heating up near the inner core and then rising up towards the mantle, where it cools off and sinks back down.
This mass-scale circulation of conductive liquid generates a planet-sized magnetic field.
Mars doesn’t have this anymore because the core has cooled significantly since formation. It’s still warm enough to generate a small layer of molten metal, but not the vast planetary ocean that Earth has beneath the mantle.
With lower heat, less liquid, and a largely solid mantle there’s just not enough of a circulating dynamo to generate a field.
Venus is a more interesting comparison – it also lacks a magnetic field due to negligible convection in the outer core, but it’s not really clear why. The planet seems to just boil over and totally resurface itself once every billion years instead a more orderly convective release of heat.
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