Just a thought...re the giant impact theory of formation of the moon...[theory says we hit a Mars-sized body called Theia, which fragmented, shared some with us, and reaggregated as Luna.] I just had this odd thought re the aggregation of rocky planets. Factoid: Mercury has a very thin crust, and is kind of a large metal ball bearing orbiting close to the sun. Its core is larger than ours, far larger, proportionately. Venus core...they dont know. It lacks a magnetic field, so its not rotating, they think, or has no convection currents...which would be kind of weird, since shes our twin in so many aspects except having a large moon. Venus is overall a volcanic hell, but has no field, and we dont know the size of the core. Then theres us, the Goldilocks planet, with a nice convection, and rotation, of an iron core the size of our moon...which has no prospect of cooling down and locking the plates. This, however, happened to Mars: its smaller, and at a certain stage, its core seized up, chilled down, and its magnetic field doesnt exist as ours does, though theres some magnetism at the surface. Massive volcano that represents a mantle plume that locked in place, unlike Hawaii, because its plates didnt move. Im just wondering if the iron core, during accretion, kind of determines a planets fate...if it gets enough iron, it becomes a planet of a certain size, and may then differentiate into a core/crust/plate/magnetic field planet, and if not enough, it becomes Mars....we dont know about Venus. If too much, it becomes Mercury. Just idle thoughts of the sort I have at 3 am...
Posted on: Sun, 13 Oct 2013 18:31:06 +0000