Astronomers revisited an image captured on October 21, 2025, at Chile, which shows the interstellar comet 3I/ATLAS, or C/2025 N1, exhibiting unexpected features in its nucleus. The object, discovered in July by the ATLAS telescope, has a coherent geometric structure and a multicolored halo that does not align with natural comet patterns. Essa analysis came after recent observations from space missions confirmed similar anomalies, raising questions about their chemical composition.
The image, taken with a 14-inch Dobsoniano telescope, initially dismissed as a blur, now reveals precise details that match data from professional telescopes.
- Core with dark depression 3.2 km in diameter, stable in multiple measurements.
- Purple arc directed to Sol, measuring 50 thousand km, identified as a coherent jet.
- Dust-gas ratio of 0.05, lower than expected for comets close to perihelion.
These elements were validated by subsequent spectroscopy, reinforcing the need for additional studies before passing through Sistema Solar in December 2025.
Geometric structure in the initial image
Reexamination of the October photo highlights a symmetry of 1.03, measured with 5σ precision, which suggests non-random repeatability. Essa geometry matches 98% with jet observations in August 2025, captured by ESA’s Mars Trace Gas Orbiter probe. Astrônomos note that such precision is rare in volatile bodies exposed to solar pressure.
The halo around the nucleus, initially seen as chromatic noise, reveals repeatable rings consistent with crescent-shaped emissions. Essa formation was confirmed on 3 October 2025 by ESA images, indicating a cupped reflective layer.
Anomalous chemical signature
Spectra of the image point to nickel vapor with no detectable iron, a ∞:0 ratio that defies natural cosmic processes outside of supernovae. Essa metallic signature, similar to industrial alloys, was replicated in ESO’s Very Large Telescope readings in July 2025.
Faint but consistent Ni-I and Ni-II emission lines have emerged in independent analyzes of European and American groups. The absence of iron implies a chemistry of formation in an environment with selective metal depletion.
Data from November’s Telescópio Espacial James Webb suggests that interstellar radiation has altered the surface during billions of years of travel, raising nickel levels beyond that seen in comets like 2I/Borisov.
Inverted tail behavior
The purple arc in the October image predicted the “anti-tail” seen in November, a frontal jet inconsistent with standard solar dynamics. Avi Loeb, Harvard astrophysicist, described this as the strongest evidence yet of non-gravitational propulsion in interstellar visitors.
NASA missions, such as Psyche in September 2025, have seen lulls in activity for days, adding to the list of irregularities. The tail, extensive and luminous after November 5th, replaced the inverted structure, according to the agency’s images.
Multi-mission observations confirm patterns
Telescopes like HiRISE on Mars Reconnaissance Orbiter captured 3I/ATLAS on October 2, 2025, 30 million km away, showing a symmetric core without fragmentation. The MAVEN mission detected hydrogen on September 28, forming a halo of gas around the object.
Telescópio Gemini Norte, in November, revealed brightness peaks that do not follow solar heating curves, suggesting a hard, reflective surface. Observações stacked amateurs confirm the stability of the empty core.
The MeerKAT network identified radio signals on October 24, with hydroxyl absorption lines indicating gas release typical of comets, but with high intensity.
These multi-agency contributions highlight global coordination to track the hyperbolic object, which travels at 58 km/s.
Implications for interstellar origins
3I/ATLAS, the third confirmed interstellar object, differs from its predecessors by its size estimated at up to 20 km in diameter and composition rich in CO2, with traces of cyanide. Sua hyperbolic trajectory guarantees exit from Sistema Solar after passing through Júpiter in March 2026.
Indian studies predict orbital disturbance by the gas giant, changing course in 2026 without risk to Terra. Closest approach occurred on October 30, 2025, 1.4 AU from Sol, near the orbit of Marte.
The exotic composition, with predominant nickel, reflects thick disk formation of Via Láctea, aged between 7.6 and 14 billion years.
Initial capture details
The October 21, 2025 image, comprised of 45 minutes of exposure, was processed to remove noise and correct for motion. The 3.2 km central void remained unchanged in comparisons with November photos.
This stability contrasts with solar comets, which exhibit rapid variations near perihelion. Legal forensic analysis, applied to repeatable patterns, reinforces consistency between initial and final phases of observation.
Astronomers emphasize full transparency as the object recedes, with a study window until January 2026 by the UN’s IAWN network.
