Cosmic Planes: Why Our Solar System and Galaxy Are Flat
The Sun and planets all orbit in a single, flat disk aligned to the ecliptic because the solar nebula collapsed with rotation; similarly, the Milky Way and Local Group lie in near-planes (galactic and supergalactic), though these planes tilt relative to one another. “Down” isn’t universal in space—it depends on the reference plane—demonstrating how initial angular momentum during formation shapes the cosmos’s familiar flat structure from the solar system outward.
