Does it make sense for this to be a "static" function?  Everything else in this file is on the prototype.  At the very least we should provide a prototype version (and my vote would be to get rid of the static version).  Also, we usually treat `Ellipsoid` as an immutable type (obviously it can't really be one in javascript), does providing a result parameter here break that paradigm?  Don't we have a bunch of baked in assumptions that Ellipsoids don't change?