Naked Science Forum

Non Life Sciences => Geology, Palaeontology & Archaeology => Topic started by: angst on 15/06/2008 00:57:43

Title: The Earth's magnetic field and the Moon
Post by: angst on 15/06/2008 00:57:43
Why is it that there seems to be no account taken of the Moon's gravitational effect on the movement of the Earth's core (liquid outer), and the magnetic field that, it is believed, produces it?

Surely the Moon must have some effect upon the spinning of it? Is there a reason for dismissing such that I am unaware of?

Sorry if it seems a stupid question, but I don't understand why no mention of it is made.

And, futher, if it affects the movement of the liquid interior of the Earth, might that also play a part in Earth's tectonic plate activity? Is it possible that Earth's satellite, and the lack of one for either Venus or Mars (or at least one large enough) might partly explain both the lack of a magnetic field and tectonic activity on those planets?
Title: The Earth's magnetic field and the Moon
Post by: frethack on 17/06/2008 05:16:55
I dont think its been forgotten.  My understanding is that our large moon aids in our planets axial stability (both tilt and precession).  Venus has at least some sort of tectonic activity (strings of volcanos from hotspots, faults, rift lines), but not the degree of the Earths.  Ive heard this explained away as the early disappearance of water for crustal lubrication, but Im not sure that it can be explained by that alone.  Mars is a small planet, one third the size of Earth, and to my knowledge has had enough time to cool somewhat.