The fact that time travel in the Relativistic Domain D₀ has been found to be impossible is a direct consequence of the criterion of existence in that Domain. The spatial plane of existence may therefore be considered as the only temporal location on which all physical events, past present and future can take place. Temporal separation of these events is then effected by the temporal movement of the spatial plane on the temporal axis. This will be so irrespective of the presence of a gravitational source or not. It is also a direct result of the manner in which time has been defined in this series of papers.

The inability to travel back in time is perhaps a good thing in view of the possible philosophical implications.

Sustainable energy supplies will soon become a major issue in the maintenance of our technological society. As reserves of fossil based fuels become more and more depleted, the necessity to find a permanent replacement will eventually overtake all other pressing needs. The energy contained within matter itself is clearly vast as exemplified by Einstein's classic matter/energy relationship. To be able to harness it and convert it into a useable form would solve this problem long into the future. Moreso even than the ability to generate controlled nuclear fusion.

Such energy is clearly, from the analysis presented here, inextricably associated with the temporal dimension, and the application of a suitable artificial temporal force the key to its release. The solution to such a formidable problem as generating artificial temporal forces will surely not be found in the macro fields of the gravitational or cosmological sciences, but most probably in those of the quantum mechanics of particle physics.

This is the second subject within which the application of an artificial temporal force could be put, eventually, to good use. The energy extracted from a source of matter fuel could be converted into a form useable as a propulsion drive as discussed in Section 2.3. However, because of the manner in which the matter fuel is used, all converted to kinetic energy, this application would have to be tempered in such a way that light velocity would not be achieved. However, as a source of propulsive power for a future interstellar vehicle drive, it would still provide a much superior solution than the application of simple spatial forces.

All of the subjects investigated here, would, justifiably, be classified as on the fringe of mainstream relativity research. Short term practical applications are most improbable if not non-existent. However, there is some small measure of potential in both knowledge and application in the far distant future, provided the necessary research can be funded and performed. In particular the conversion of matter to energy would be the most beneficial to society.