The Indivisible Atom...

The word atom comes from the Greek "atomos", meaning "indivisible". It was once thought to be the indestructible building block of material things. Before that, it was "fire", "water", "earth", and "air". After it came the quantum, the "indivisible" unit of energy. Some day that too will likely fall.

The atom is roughly associated with where the micro world ends and the macro world begins. It's where the properties of the modern chemical elements, such as carbon, hydrogen, oxygen, and iron take form.

In time, the atom was penetrated when it became apparent that it was comprised of a proton-neutron nucleus surrounded by an accompaniment of electrons. Its form revolves around electromagnetic attraction which draws the negatively charged electron to the positively charged nucleus. But the electron reacts to this confinement by whirling, the tighter, the faster. It is estimated to achieve speeds of 600 miles per second. The great centrifugal forces created tend to pull it away from the nucleus. The nuclear force, which is strongly attractive at a distance, becomes strongly repulsive with proximity.

The atom, once considered a solid structure, is mostly "empty" space. If an atom where the size of a stadium, the nucleus would be the size of a pea on pitcher's mound, with electrons the size of dust buzzing the outside edge. It's the propeller effect that gives it its rigid appearance.

Thus, the macro world of mass, of form, once had its beginning.

But things change.