Andromeda’s glow masks an Earth twin: why direct imaging there is off the table
The article explains that Andromeda is visible because the light from hundreds of billions of stars blends into a single patch, not because individual stars are resolved. A hypothetical Earth-like planet orbiting a star in Andromeda would be about 10 billion times fainter than its star and separated by only about 1.3 microarcseconds, a scale far beyond current or planned direct-imaging capabilities. Even advanced future telescopes (like Webb or Roman) would struggle, requiring an unrealistically large aperture or space interferometry; indirect methods such as microlensing could, in principle, detect such planets, but imaging a world in another galaxy remains out of reach.