The

The nature of such a **SC **coordinate may be defined as;

- A first order spacetime curvature resulting from a gravitational field.
- A second order - larger localized spacetime curvature.
- A third order general spacetime curvature that applies to large areas of galactic scale.

In the second case, there is, to date, no evidence of localized spacetime curvature. It is therefore impossible at this time to state if such theorized second order curvatures would be sufficiently large enough to need inclusion in a galactic coordinate system.

In the third case, it is generally accepted that there may be
a large black hole in the center of the galaxy. The black hole plus the
combined mass of the galactic central area would certainly alter galactic
distances in a subtle way, growing weaker, the further one is distanced
from the center of the galaxy. Such a third order curvature of spacetime
would affect the distances in a long galactic trip and may need to be factored
in using the fifth
**SC **coordinate, much in a similar way to the north
pole magnetic deviation experienced on Earth.

In conclusion, all of the above deviations are well below the
accuracy range of our current knowledge of interstellar distances. In other
words, before it becomes necessary to use a fifth **SC** coordinate,
one must first vastly improve the accuracy of current measurements. A **SC**
coordinate may have it's place in an improved
**SGC** map that has been
surveyed for accuracy in the future.