This trinity is variously explained in the texts but for our purpose here we consider Ishvara as the creative equanimity ; Shiva as the chaotic destroyer and Vishnu as the one that preserves order. In the galaxies above us the supernovas are bursting with tremendous energies and the black holes are coalescing these under crushing gravitational forces. These are the two extremes of the visible universe and beyond these all scientific explanations seize. The expanding supernovas is Vishnu that is always depicted with agni or fire emanating from it. The root verb ‘ag’ means ‘a tortuous movement’ and the suffix ‘ni’ means in this context ‘to throw out’. So, agni is ‘the flickering of the flame’ that shines and spews forth energy. The opposite is n-agni or nāgini that means a snake, literally ‘a black tortuous movement’ that absorbs energy.
Thus Shiva is portrayed with snakes around his neck. The river Ganges entangled in Shiva’s flowing mane, at another level, stands for ‘Aakash-Ganga’ – the Sanskrit name for our galaxy ‘the Milky-way’.