A galaxy and a tree have something in common.

Zoom in on a branch… or zoom out on a spiral arm—and structure persists. Branches split into smaller branches, just as galaxies form spiraling arms upon arms. The same organizing principles appear across vastly different scales—this is known as scale invariance.

Limited

But the scale invariance observed in nature is not the infinite recursion of mathematical fractals. The self-similarity we observe is a limited phenomenon. Just as a tree's branches eventually taper to leaves, revealing its cells and molecules, so too do galactic spirals resolve into individual stars, planets, and nebulae upon closer inspection.

As above, so below

In fact, the adage 'as above, so below' describes a real tendency in the universe. However, it remains true only within certain limits, beyond which patterns diverge, and each scale reveals its governing principles.