You can have differential rotation among concentric shells over geological times only if the space between the shell is vacuum.

Any fluid contained between them would, via shear stress, nullify the differential rotation over the above mentioned geological times.

A shear stress, often denoted by $\tau$, is the component of stress coplanar with a material cross section. Shear stress arises from the force vector component parallel to the cross section of the material. Normal stress, on the other hand, arises from the force vector component perpendicular to the material cross section on which it acts.

 

Shear stress arises from shear forces, which are pairs of equal and opposing forces acting on opposite sides of an object.

Unless you have an external source of energy that keeps adding energy to the system to maintain the differential.

You can have differential rotation among concentric shells over geological times only if the space between the shell is vacuum.

Any fluid contained between them would, via shear stress, nullify the differential rotation over the above mentioned geological times.

A shear stress, often denoted by $\tau$, is the component of stress coplanar with a material cross section. Shear stress arises from the force vector component parallel to the cross section of the material. Normal stress, on the other hand, arises from the force vector component perpendicular to the material cross section on which it acts.

Shear stress arises from shear forces, which are pairs of equal and opposing forces acting on opposite sides of an object.

Unless you have an external source of energy that keeps adding energy to the system to maintain the differential.

You can have differential rotation among concentric shells over geological times only if the space between the shell is vacuum.

Any fluid contained between them would, via shear stress, nullify the differential rotation over the above mentioned geological times.

Unless you have an external source of energy that keeps adding energy to the system to maintain the differential.

You can have differential rotation among concentric shells over geological times only if the space between the shell is vacuum.

Any fluid contained between them would, via shear stress, nullify the differential rotation over the above mentioned geological times.

A shear stress, often denoted by $\tau$, is the component of stress coplanar with a material cross section. Shear stress arises from the force vector component parallel to the cross section of the material. Normal stress, on the other hand, arises from the force vector component perpendicular to the material cross section on which it acts.

Shear stress arises from shear forces, which are pairs of equal and opposing forces acting on opposite sides of an object.

Unless you have an external source of energy that keeps adding energy to the system to maintain the differential.