Spin is linear motion with curvature. Both are similar in many ways, beyond the difference in geometry. Both spin and linear motion carry momentum. Spin has angular momentum, while linear motion has just momentum. Angular simply tells us the velocity has high curvature. If we had a rock on a string, and rotated this in a circle and let the string break, there is conservation of momentum.

In terms of electrons in atoms, opposite spin electrons will attract, while same spin electrons will repel in terms of their magnetic fields. This is essentially the same as opposite direction currents in linear wires will attract, while same direction currents in linear wires will repel. The affect is consistent for both.

Spin is both a velocity and an acceleration, while linear motion is just a velocity. What that means is spin contains extra time potential beyond the velocity of linear motion. This is inferred from acceleration having the units of d/t/t, while velocity is d/t. Spin has extra units of time. The acceleration implicit of spin contains extra time potential.

If you look at gravity and GR, GR curves space-time. GR can cause linear motion to curve by means of the mass following the curvature of space-time. Spin is essentially paralleling an affect analogous to paths confined by the curvature of space-time. If we had a collapsing cloud of space gas and debris, as it collapses, linear motion will begin to curve until rotation appears in the bulk mass, where all the linear paths of all the particles, take on circular paths; orbit.

The question becomes, where is the extra time potential, associated with spin; d/t/t versus the original d/t, coming from? When gravity lowers potential, if gravity is a force, then there should be an exothermic output as the gravitational potential between two particles of mass lower. This exothermic output does not appear to be in the form of photon type energy, since we don't see such an energy signal, per se. Rather the exothermic output appears to be connected to potential in time. This would need to be seen in an indirect way or inferred from affect.

Much of the original linear momentum of the particles that make up the earth; originally moving toward center of gravity, are perpetuated in time as angular momentum; rotation of the earth. If we did not have the earth spinning, the original linear velocity and momentum of its atoms would have already stopped in time. The spin conserves the original momentum in time, with the extra time conserve in the acceleration implicit of spin.

One possible way to explain this in terms of the intrinsic spin of an electron, is to consider an electron. In larger atoms, like Gold, electrons move close enough to the speed of light to induce relativistic affects; relativistic quantum chemistry. These show up as anomalies in the Schrödinger equations used to model the wave functions of atomic orbitals. These anomalies can be explain with accuracy using relativity. The yellow color of the metal Gold is connected to a time shift in the reflected light; all the reflected light gains a yellow cast. This is not due to excited electrons since even red reflected light will get a yellow cast, with yellow higher energy than red.

If we assume these gold electrons are moving at relativistic speeds, there will define a reference that is different from the bulk earth reference of the lab. Their time clocks will run slightly slower due to SR. This time difference has a connection to the Heisenberg uncertainty principle, since it is not easy to synchronize two clocks that run at different rates. One can synchronized time for an instant; position. Or one has to anticipate when the second hands from both clocks coincide; momentum.

That aside, since the electron clock is running slower, than the lab clock, they will linger slightly longer in time; the electron twin ages slower. The extra potential in time is expressed, at elates in part, as the extra time in spin. Nuclei and the nucleons of atoms also have spin; time potential. Nuclei orbitals are less based on energy levels, as there are on time potential levels; spin based magnetic addition.