Hopf Fibration

S³ → S² — every circle links every other circle exactly once

Hopf fibration η: S³ → S² maps the 3-sphere to the 2-sphere.

Each fiber η⁻¹(p) is a great circle on S³. The fibers are pairwise linked — any two Hopf circles link exactly once.

Visualized via stereographic projection S³ → ℝ³. Each S² base point (latitude, longitude) generates one colored circle fiber.

Drag to rotate. This fibration is the generator of π₃(S²) ≅ ℤ.