A comet dubbed the “comet of the century” has been captivating stargazers as it passed by Earth, seemingly developing a physics-defying second tail. Known as Tsuchinshan-ATLAS or A3, the comet made its closest approach to Earth in over 80,000 years, becoming visible to observers around the world in late September.
Discovered in 2023, A3 originates from the Oort debris cloud at the edge of the Solar System and has an orbital period of approximately 80,660 years. The comet’s recent flyby brought it within 70 million km of Earth on 12 October, drawing attention for its bright and clear appearance, with some astronomers hailing it as the “comet of the century”.
Austrian photographer Michael Jäger captured striking images of the comet, revealing not only its bright tail but also a faint structure in the opposite direction known as an “anti-tail”. This anti-tail phenomenon, observed by NASA last year, is considered unusual and has puzzled scientists.
The formation of a comet tail typically results from dust and ions being emitted from the comet due to solar wind, reflecting sunlight and glowing faintly as the ions cool down. However, A3’s anti-tail appears to defy conventional physics, appearing in the opposite direction of the comet’s actual tail as Earth intersects the comet’s orbital plane.
Nasa explained that as Earth crosses the comet’s orbital plane, the cooled dust and ions are re-illuminated by sunlight, creating the appearance of an anti-tail shooting in the opposite direction. This unique phenomenon has intrigued experts and sparked further study into the comet’s behaviour.
While the comet may decrease in brightness in the coming days, experts suggest it could again be visible to the naked eye in late January next year. Stargazers are encouraged to continue observing this rare celestial event, using binoculars for optimal viewing until 30 October.
The comet’s unusual characteristics and captivating display serve as a reminder of the wonders of the cosmos and the ongoing discoveries in the field of astronomy, inspiring both scientists and enthusiasts alike to delve deeper into the mysteries of the universe.