Sign up for CNN’s Wonder Theory science newsletter. Explore the universe with news on fascinating discoveries, scientific advancements and more . CNN  —  When a new comet appears in the sky, there is often excitement. But things don’t always end well for the ancient celestial objects, made of ice, frozen gases and rock, as they near the sun — and an untimely demise appears to hold true for Comet C/2025 F2 (SWAN). All signs suggest that the celestial object, which resembled a fuzzy green patch,