The brightest comet of 2025 may be disintegrating

Comet C/2024 G3 (ATLAS) flew three times closer to the Sun than Mercury (the closest planet to the Sun) on January 13 and was so bright that it could be seen with the naked eye in the days that followed. However, this comet is likely to decay, becoming a “headless” celestial body.

After taking some photos of C/2024 G3, Hungarian astronomer Lionel Majzik discovered that the comet’s head was no longer the brightest part, and a streak of light appeared in the atmosphere or gas cloud surrounding the comet. . This shows that the comet’s nucleus may be breaking into pieces, Newsweek reported on January 20.

C/2024 G3 flew to just about 13.4 million km from the Sun on January 13, the closest point to the Sun in a large orbit lasting 160,000 years through the solar system. The comet was first discovered on April 5 last year, during the Asteroid Impact Final Warning System (ATLAS) survey.

“Preliminary orbital calculations show that this is most likely a long-period comet, visits to the solar system can be separated by thousands of years,” Shyam Balaji, space researcher and physicist Astronomical particles at King’s College London, said.

C/2024 G3 reaches an apparent brightness of about -3.4 when approaching the Sun, which is only less than the brightness of Venus – the brightest celestial body in the sky except the Sun and Moon. It survived its approach to the Sun, although some experts previously feared that it would disintegrate during this period due to high temperature, gravity and solar radiation.

As a comet approaches the Sun, the heat causes the ice in its nucleus to go directly from a solid state to a gas (sublimate). This process can weaken the structure of the comet, leading to decay. The comet’s nucleus also undergoes large temperature variations during rotation, with one side facing the Sun and the other in shadow, leading to cracks and eventual decay.

The gas flow observed from the nucleus suggests that, despite surviving so far, C/2024 G3 may be succumbing to the thermal stress it experiences as it approaches the Sun. This is similar to the fate of comet C/2011 W3 (Lovejoy) in 2011. It survived the journey just 140,000 km from the Sun’s surface, but disintegrated a few days later.