Inertia as a Manifestation of the Reality of Spacetime

Summary

The major issue discussed in this chapter is whether inertia is another manifestation of the reality of spacetime. If the worldtube of a particle is a real four-dimensional object, it follows that it should resist its deformation. As the worldtube of an accelerating particle is deformed (non-geodesic), the resistance the particle offers to its acceleration appears to originate from a four-dimensional stress that arises in the deformed worldtube of the particle. This stress, which is caused by the displacements of the constituents of the accelerated particle from their equilibrium positions, gives rise to a restoring force that tries to bring all constituents back to their non-accelerated positions.

The displacement mechanism has been examined in the case of the classical electron and it has been found that the resulting self-force acting on the classical electron when it accelerates or is supported in a gravitational field does have the form of the inertial force. The same displacement mechanism turns out to be present in the Standard Model as well. The accepted mechanism of interactions through exchange of virtual quanta in the Standard Model in conjunction with the general relativistic shift in the frequencies of the virtual quanta absorbed by a non-inertial particle lead to acceleration-dependent self-interaction effects which appear to account for the origin of inertia and mass of particles. All interactions the Standard Model deals with — electromagnetic, weak, and strong — contribute to the inertia and mass of the particles involved in these interactions.

It may be argued that the mechanism of inertia studied in this chapter can be described in the ordinary three-dimensional language as well. That is true. The real question, however, is whether inertia would exist in a three-dimensional world. We have not answered this question here. What we have shown is that, if spacetime is real, inertia must exist. One of the manifestations of the four-dimensionality of the world will be the existence of inertia through a mechanism which will be the mechanism examined here.