In the “simple model pdf” embedded below to read and/or download it, we consider a simple possible model for the earth at an early stage in the history of its formation, in which the earth was a nearly homogeneous fluid sphere with convective motions generated by an uniform distribution of heat sources under the influence of gravitation. From the model we can infer the existence of a stationary convection pattern at marginal stability which divides the sphere into two equal cells with oppositely directed current systems. The point on the surface of the sphere where the material ascending from the centre emerges is antipodal to the point where the material, having traversed half a great circle, starts descending to the centre, as we can see in the streamlines and velocities representation figure (Fig.1), belonging to the considered axisymmetric motion mode which generates the convection pattern.
Moreover, of the two hemispheres centred on these antipodal points, the one in which the current system converges towards the centre will be cooler than the one in which diverges from the centre, as we can see in the temperature field representation figure (Fig.2).
The division of the earth’s surface into a land and an ocean hemisphere, which reflects a higher deposition of sial in one hemisphere than in the other, confirms this temperature difference between hemispheres predicted by the model.
Also, the “Python code 1 pdf” and “Python code 2 pdf” below, present Python programming for the calculation and plotting of the velocity field and streamlines, respective the temperature field, according to the model.
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