There is so much mystery to be understood in the material world, that inventing other realities is not necessary. We, as a species have perceived the atom, peered inside it and realised its ethereal nature.
The Buddha defined the tiniest specks of matter (paramanu) [synonymous with ‘atoms’] to be occupying (and moving about within) time and space, whilst flickering in and out of existence. This is how the Buddha redefines matter (rupa) as being both ‘existant’, and ‘insubstantial’ (or non-existant).
Although the different Buddhist schools argued over the existence or nature of the atom, the Theravada thinkers conceived of an atom comprised of ‘space’ and ‘sub-particles’ (dravya-paramanu) which is physically complex (rupa-kalapa), whilst its constituent parts exist in a state on constant flux (kalapanga).