At the atomic level, there are no hard boundaries because atoms don't have such things as hard or rigid boundaries.
They are not solid spheres but more like fuzzy clouds with electrons going and being everywhere. At the quantum level, we can't even say that an electron is somewhere, but we talk about the probability of being somewhere. The shape and location of an atom are defined by the area of high probability.
I know I'm oversimplifying, but this is not a post about physics or quantum mechanics. You can read this page for a better explanation.
This post is a reflection on boundaries.
On how much value and attention we put on what separates us from others, from nature, from things. And yet, at the atomic level, there is no real separation. My atoms are just part of this infinite soup of atoms that is the universe.
Isn't it fascinating that if we shift our attention to infinitely small or to the incredibly big (like the astronauts looking at the Earth from up there), the boundaries that are so defining and important in our lives just disappear?
Yet, human beings are willing to do the most awful things to expand, move and protect those boundaries.