Laser-powered nanocraft could reach a nearby black hole within a century to test gravity

A speculative concept by Cosimo Bambi envisions gram‑scale, laser‑driven nanocrafts accelerated by Earth‑based lasers to roughly one‑third light speed, potentially reaching a nearby black hole 20–25 light‑years away in 60–75 years, with data returning 20–25 years later. The mission could involve two probes to test Einstein’s general relativity near the Kerr metric, investigate the event horizon, and probe fundamental constants in strong gravity. However, no suitable nearby black hole is known (Gaia BH1 is too distant), the approach requires a massive, costly laser system (on the order of a trillion euros with current tech), and significant navigation and propulsion challenges remain, so the concept is a roadmap, not a ready-to-build mission.