What is the equation that gives 19.5 degrees based on a tetrahedral within a sphere?
It is arcsin(1/3). The center of a tetrahedron is 1/4 of the way along any of its altitudes. Therefore, the radius of the circumscribing sphere is the remaining 3/4. Since the base of the tetrahedron extends 1/4 of the altitude below the center, the sine of the latitude must be 1/4 divided by 3/4, or 1/3. That gives about 19.5 degrees. Incidentally, the Great Red Spot is at 22 degrees south latitude, not 19.5. It’s probably just coincidence, since there are not two other similar storms separated by 120 degrees of longitude from the GRS.
