RELHICs as cosmic relic probes

Some low‑mass dark matter halos may host neutral hydrogen clouds that never formed stars (Reionization‑Limited HI Clouds, or RELHICs). Finding a genuinely starless RELHIC like 'Cloud 9' would provide a direct observable of how the ultraviolet background and halo mass set the threshold for star formation and preserve near‑pristine baryons from the early Universe. — If confirmed, RELHICs become a new empirical lever for testing galaxy‑formation models and for prioritizing follow‑up telescopes and funding, affecting astrophysics roadmaps and public investment in observatories.