Things would have been pretty chaotic if there were more than one, but the symbolism of that one star is fundamental to good metaphysics because what it is essentially saying is that there is only one fundamental driving life , the fundamental of perfect oneness without any other essence or influence around.
It is spiritually very liberating to realise that there is only one guiding light in our lives because then we realise that we don’t have to be concerned about other influences and orbits. In divine Science there is only the one guiding light , there is no other and sensing the hegemony of the unique star and shining light we are not then distracted by illusory counterfeits.
God has stuck one sun in the sky to symbolize just this point and we might as well learn the lesson and drop the idea that there are other guiding lights.
Error and mortal mind would have it that darkness and evil (black holes) have some role to play in experience but these things have never succeeded in dragging things in our universe out of their orbit because the immensity and power of the sun dwarfs their efforts. So it is with spiritual life. Love , purity and everlasting life shine brightly to the dispersal of any shadows and doubts to the contrary.
And just in case you forget the lesson , the sun will come up every morning to remind you. And Mary Baker Eddy's words will do the same:
Science reveals only one Mind, and this one shining by its own light and governing the universe, including man, in perfect harmony.