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I thought the "reason" mars has no magnetic field is that its core solidified a long time ago. How does this new finding affect understanding of Mars magnetics?

pixl97 3y ago
Earths core spins slightly faster than its surface. If Mars core is locked with its surface speed because it is more viscous then this may kill the field generation ability.
- jpitz 3y ago
  Recently, it has come to light that the relative rotational speed of Earth's core seems to have a decades long cycle of leading and lagging the surface. https://www.space.com/earth-inner-core-slowing-study https://www.space.com/earth-inner-core-slowing-study
  - tomrod 3y ago
    Oof. Does that mean it could lock in at any time? Internal dynamics are weeeeird. Wonder if the moon affects this.
    - coderenegade 3y ago
      I mean the moon has to have some effect, right? Given the effect it has on the oceans, it must have some effect on a liquid core as well. It's actually surprising that it's not the number one suspect for causing/ generating Earth's magnetic field (whatever the mechanism) when you consider that Earth is the planet with both the relative largest magnetic field in the solar system, and the relative largest moon. Not to mention, most of the planet's surface is covered by an electrolyte. If both Mars and Venus have liquid cores and not much in the way of a magnetic field, it seems like there must be more to it, and it's likely to be one (or a combination) of factors that makes Earth unique in the solar system.
bell-cot 3y ago
My impression is that the "planet has no magnetic field <==> planet has solid core" theory was retired quite a few decades ago now. The current theory looks like, at best, a work in progress: https://en.wikipedia.org/wiki/Dynamo_theory https://en.wikipedia.org/wiki/Dynamo_theory https://en.wikipedia.org/wiki/Venus#Magnetic_field_and_core https://en.wikipedia.org/wiki/Venus#Magnetic_field_and_core

pixl97 3y ago

Earths core spins slightly faster than its surface. If Mars core is locked with its surface speed because it is more viscous then this may kill the field generation ability.

jpitz 3y ago
Recently, it has come to light that the relative rotational speed of Earth's core seems to have a decades long cycle of leading and lagging the surface. https://www.space.com/earth-inner-core-slowing-study https://www.space.com/earth-inner-core-slowing-study
- tomrod 3y ago
  Oof. Does that mean it could lock in at any time? Internal dynamics are weeeeird. Wonder if the moon affects this.
  - coderenegade 3y ago
    I mean the moon has to have some effect, right? Given the effect it has on the oceans, it must have some effect on a liquid core as well. It's actually surprising that it's not the number one suspect for causing/ generating Earth's magnetic field (whatever the mechanism) when you consider that Earth is the planet with both the relative largest magnetic field in the solar system, and the relative largest moon. Not to mention, most of the planet's surface is covered by an electrolyte. If both Mars and Venus have liquid cores and not much in the way of a magnetic field, it seems like there must be more to it, and it's likely to be one (or a combination) of factors that makes Earth unique in the solar system.

bell-cot 3y ago

My impression is that the "planet has no magnetic field <==> planet has solid core" theory was retired quite a few decades ago now. The current theory looks like, at best, a work in progress: https://en.wikipedia.org/wiki/Dynamo_theory https://en.wikipedia.org/wiki/Dynamo_theory https://en.wikipedia.org/wiki/Venus#Magnetic_field_and_core https://en.wikipedia.org/wiki/Venus#Magnetic_field_and_core