The interstellar object 3I/ATLAS has developed a distinct greenish glow as it makes its final high-speed passage through the inner Solar System, a phenomenon that has captivated astronomers and reignited the debate over its composition.
While the National Aeronautics and Space Administration (Nasa) attributes the colour change to standard cometary chemistry, the visual transformation has fuelled further speculation from observers who argue the object's behaviour is anomalous.
