Image: The Copernicus Sentinel-3 mission shows us a rare, cloud-free view of Iceland captured on 17 May 2025.
The hunt for habitable worlds has become a hot topic in astronomy. For decades, the search has been focussed on planets in the "Goldilocks zone”; that narrow band around a star where water stays liquid, not too hot to boil away, not too cold to freeze solid. But habitability is far more complex and ruthless than just getting the temperature right. A world needs a protective magnetic field to shield life from radiation, a stable atmosphere thick enough to regulate climate but not so dense it crushes everything beneath it, and the right cocktail of elements forged in the nuclear furnaces of dying stars.