A rare celestial traveler from the depths of space, the interstellar object 3I/ATLAS, recently reached its closest point to the Sun—perihelion—on October 29, 2025. This object was initially logged by the ATLAS telescope system operating in Chile on July 1, 2025. During its closest approach, the comet passed within approximately 203 million kilometers of our star, a distance equivalent to 1.36 astronomical units. Unfortunately, this specific orbital arrangement placed the object behind the Sun relative to Earth, creating significant observational hurdles and effectively hiding 3I/ATLAS within the intense solar glare.
3I/ATLAS holds the distinction of being only the third confirmed interstellar wanderer to visit our solar system, following in the wake of 1I/'Oumuamua (detected in 2017) and 2I/Borisov (detected in 2019). The scientific opportunity presented by studying this body is invaluable, offering profound insights into the composition and fundamental nature of matter originating from distant star systems outside our own. Notably, 3I/ATLAS exhibits the highest orbital eccentricity recorded for any known interstellar body, underscoring its truly unique and hyperbolic trajectory. Furthermore, its nucleus is estimated to be quite substantial for such a visitor, spanning an impressive 10 to 20 kilometers in diameter.
The object’s passage has fueled theoretical debate among researchers. Certain figures, including Harvard astrophysicist Avi Loeb, have put forth speculations regarding a possible “Shadowing Maneuver” or Oberth maneuver, suggesting that the Sun’s gravitational pull might be exploited to intentionally alter the object's path. However, given that direct monitoring was impossible during the critical perihelion phase, verifying this specific hypothesis remains a challenge for the future. The consensus among the majority of experts, including representatives from NASA, maintains that the object's observed actions are entirely consistent with the natural physical processes expected of a typical interstellar comet.
Despite its temporary period of invisibility, the global scientific community is eagerly anticipating the resumption of close monitoring efforts. The European space probe JUICE (Jupiter Icy Moons Explorer) is scheduled to begin tracking 3I/ATLAS starting November 2, 2025, once the object has successfully moved away from the immediate vicinity of the Sun. Additionally, the American spacecraft Europe Clipper may be utilized to conduct analysis of the comet’s developing ion tail. Scientists are particularly looking forward to the beginning of December 2025, when the comet will start receding further from the Sun, finally allowing Earth-based telescopes to unlock its secrets once again.
Interest in 3I/ATLAS is further heightened by several unusual physical manifestations it has displayed. Observers previously documented a peculiar “anti-tail,” a feature pointed toward the Sun, which contradicts the standard dynamics associated with typical dust streams. Moreover, spectral analysis revealed the emission of nickel tetracarbonyl, a chemical compound previously associated with technogenic or industrial processes in some contexts. The closest approach to Earth is projected for December 19, 2025, when the object will pass at a distance of approximately 270 million kilometers (1.8 ± 0.1 a. e.).