0 c speed Sound / modons / GWs c = ℏ/(m₁ξ) ≈ 3×10⁸ m/s — BEC quasiparticle spectrum Outer rotation (ω₀ξ) ~800 km/s (0.003c) — lattice-scale vorticity Tkachenko modes ~9 km/s (3×10⁻⁵c) — vortex lattice elasticity SC2 (4π) governs the lattice configuration, not this speed