The interstellar comet 3I/Atlas is set to make a significant approach to the Sun on January 22, 2026, presenting a unique opportunity for scientists to investigate its characteristics. This rare event could potentially clarify the ongoing debate about whether the comet is an alien spacecraft, according to renowned astrophysicist Avi Loeb from Harvard University.
The comet’s alignment with the Earth-Sun axis will allow it to be illuminated from a unique angle, creating a phenomenon known as an opposition surge. This occurs when an object is brightened due to illumination from directly behind the observer, enhancing visibility. Prof. Loeb remarked, “Observations before and after the alignment offer an unprecedented opportunity, which may not repeat for decades, for characterizing the albedo, structure, and composition of interstellar matter.”
3I/Atlas, often described as Manhattan-sized, has generated considerable scientific interest and debate since its discovery. Loeb has previously suggested that it might be an artificial construct, further fueling speculation about its origins. He stated that the upcoming alignment on January 22 will see Earth positioned nearly between the Sun and the comet, with a phase angle of only 0.69 degrees.
During this period, the comet will maintain a phase angle of less than 2 degrees for approximately one week, from January 19 to 26, 2026. This extended alignment is particularly notable compared to typical cometary opposition, which often lasts just hours.
The significance of the opposition surge lies in its ability to hide shadows cast by dust particles, enhancing the object’s brightness. Loeb explained that at very small angles, light traveling through a dusty medium can interfere constructively, resulting in a pronounced brightness spike due to quantum mechanics.
Understanding the composition of 3I/Atlas could shed light on some fundamental questions. Loeb has posed inquiries about the nature of the comet’s dust: “Is the dust shed by 3I/Atlas dominated by carbonaceous material, or does it retain significant ice fragments?” He also questioned whether the grains are compact and thermally processed or if they are fluffy, fractal aggregates representing pristine material from molecular clouds.
To fully capitalize on this rare opportunity, Loeb has urged fellow scientists to observe 3I/Atlas for approximately four days before and after the alignment using high-precision relative photometry. He emphasized the need for coordinated observations from multiple locations to enhance data collection and mitigate potential weather-related disruptions.
“Even partial datasets will significantly contribute to constraining the phase-angle behavior of this rare alignment of 3I/Atlas with the Earth-Sun axis. Many observers with access to suitable telescopes should take advantage of this extraordinary alignment,” he stated.
The data gathered during this period could help decipher the nature of 3I/Atlas’s anti-tail jet and address anomalies such as its unusual polarization properties. As the world awaits this celestial event, the scientific community remains hopeful that the findings will provide clarity on the enigmatic interstellar visitor.
