Across the long arc of human curiosity, few ambitions reach as far as the desire to touch another star. Breakthrough Starshot, conceived in 2016, proposes to send gram-scale nanocraft to Alpha Centauri at one-fifth the speed of light — compressing a 165,000-year journey into roughly 20 years by trading mass for velocity and chemical fuel for laser light. The concept obeys known physics, yet no propulsion system, no sail, and no launch date exist; what endures is the question itself, older than any spacecraft, of whether the distance between stars is a wall or merely a threshold.