Grok explains why light travels ~40% faster in vacuum than in fiber, key to Starlink laser links

MickeySteamboat · x · 2026-09-25

Grok explains that light travels 40% faster in vacuum than in typical terrestrial fiber: fiber's refractive index of 1.44–1.5 limits speed to 67–70% of c (≈200,000 km/s vs 300,000 km/s). Elon Musk has cited this exact advantage for Starlink's laser links.

Original post →

More from Fun

Fun channel →