Comet SWAN disintegrates after close solar encounter

Comet SWAN, officially designated C/2025 F2, was discovered in March 2025 using the Solar Wind Anisotropies (SWAN) instrument aboard NASA’s Solar and Heliospheric Observatory (SOHO) spacecraft. Observations of the comet began accumulating rapidly as skygazers worldwide recorded its notable green color, attributed to diatomic carbon released during photochemical reactions involving the comet's organic material. It was anticipated that the comet would reach perihelion, its closest approach to the Sun, around May 1, 2025, sparking hopes of unaided-eye viewing. However, in recent observations, astronomers noted that the comet had not survived its final approach, leading to considerable disappointment among those hoping for a spectacular skywatching experience. Dr. Qicheng Zhang, a post-doctoral astronomer at Lowell Observatory in Arizona, reported that what remains of Comet SWAN barely resembles its original form, indicating that it has devolved into a diffuse cloud of dust. Zhang explained that the comet was a smaller type, which traditionally leads to vulnerabilities during close solar passes. As the comets approach the sun, they experience a process known as sublimation, where solid ice transitions to gas, resulting in asymmetrical outgassing. This asymmetry can torque the comet, causing it to spin rapidly and subsequently fall apart. Comet SWAN exhibited impressive visibility for observers across the globe due to its distinctive coloration, which is a result of the complex organic chemistry at play within the comet. As the comet's ice sublimated, the carbon structures emerged, giving it the striking green hue noted by many astronomers. The significance of this comet was heightened by its orbital period, estimated at 1.4 million years; thus, the current occurrence marked a unique viewing opportunity that would not recur within any individual's lifetime. Zhang's insights emphasize the fragility of smaller comets like SWAN, which can be readily disrupted by natural variances in their surrounding environments. As a result of its disintegration, this comet now exists only as a memory and serves as a reminder of the dynamic and sometimes ephemeral nature of celestial phenomena. This event has captivated both professional and amateur astronomers alike, who are left to contemplate the fleeting beauty of such astronomical occurrences.