/// <summary>
        /// This asteroid was destroyed, see if it is big enough for child asteroids to spawn, and if so spawn them.
        /// </summary>
        /// <param name="Asteroid"></param>
        internal static void SpawnSubAsteroids(Entity Asteroid, DateTime atDateTime)
        {
            Game         game = Asteroid.Manager.Game;
            MassVolumeDB ADB  = Asteroid.GetDataBlob <MassVolumeDB>();

            //const double massDefault = 1.5e+12; //150 B tonnes?
            const double massThreshold = 1.5e+9; //150 M tonnes?

            if (ADB.Mass > massThreshold)
            {
                //spawn new asteroids. call the asteroid factory?

                double newMass = ADB.Mass * 0.4; //add a random factor into this? do we care? will mass be printed to the player?

                OrbitDB    origOrbit = Asteroid.GetDataBlob <OrbitDB>();
                PositionDB pDB       = Asteroid.GetDataBlob <PositionDB>();

                EntityManager mySystem = Asteroid.Manager;


                var origVel = OrbitProcessor.AbsoluteOrbitalVector(origOrbit, atDateTime);

                //public static Entity CreateAsteroid(StarSystem starSys, Entity target, DateTime collisionDate, double asteroidMass = -1.0)
                //I need the target entity, the collisionDate, and the starSystem. I may have starsystem from guid.
                //Ok so this should create the asteroid without having to add the new asteroids to a list. as that is done in the factory.
                Entity newAsteroid1 = AsteroidFactory.CreateAsteroid4(pDB.AbsolutePosition_AU, origOrbit, atDateTime, newMass);
                //var newOrbit = OrbitDB.FromVector(origOrbit.Parent, )
                Entity newAsteroid2 = AsteroidFactory.CreateAsteroid4(pDB.AbsolutePosition_AU, origOrbit, atDateTime, newMass);

                mySystem.RemoveEntity(Asteroid);

                //Randomize the number of created asteroids?
            }
            else
            {
                //delete the existing asteroid.
                PositionDB pDB = Asteroid.GetDataBlob <PositionDB>();

                StarSystem mySystem;
                if (!game.Systems.TryGetValue(pDB.SystemGuid, out mySystem))
                {
                    throw new GuidNotFoundException(pDB.SystemGuid);
                }

                mySystem.RemoveEntity(Asteroid);
            }
        }