Astrophysicist Avi Loeb, from Harvard, identified an anomaly in the trajectory of the interstellar comet 3I/ATLAS, the third object confirmed to come from outside Sistema Solar. Descoberto on July 1, 2025 by the ATLAS telescope at Chile, the comet exhibits a non-gravitational acceleration detected during its passage through perihelion on October 29, 2025.
The closest passage will occur on March 16, 2026, 53.445 million kilometers from Júpiter, a difference of just 0.057 million kilometers. JPL’s Dados Horizons indicate that this precision is equivalent to a probability of one in 26 thousand. Loeb suggests that jets observed on the comet after perihelion may have acted as propellants for this correction.
Observations of Telescópio Espacial James Webb confirm the presence of carbon dioxide, water and carbon monoxide in the object’s coma, characteristics typical of comets. No However, the alignment with the ecliptic plane, inclined by 5 degrees, and the relative speed of 68 km/s at perihelion raise questions about origins and dynamics.
Orbital anomalies detected
The non-gravitational acceleration of 5×10^{-7} AU/day² occurred while the comet was hidden by Sol, preventing direct observations of Terra. Essa force resulted in a displacement of 0.1 million kilometers in the minimum distance to Júpiter.
Research indicates that the comet follows a hyperbolic orbit with an eccentricity of 6.5, higher than the values of ‘Oumuamua (1.2) and Borisov (3.4). Sua retrograde inclination of 175 degrees aligns it with the orbital planes of Vênus, Marte, and Júpiter.
- Minimum distance to Vênus: 0.65 AU
- Minimum distance to Marte: 0.19 AU
- Minimum distance to Júpiter: 0.36 AU
These cumulative values have a probability of 0.005% relative to random arrivals.
Initial telescopic observations
The comet was initially seen without obvious cometary features, but telescopes such as the Nordic Optical and the Canada-France-Hawaii detected a diffuse coma and 3-arcsecond tail on July 2, 2025. The reddish color of the dust suggests a carbon-rich composition.
In September 2025, the Psyche spacecraft captured images 53 million kilometers away, showing the nucleus as a bright spot with a gaseous halo. The Lucy mission recorded the object at 240 million kilometers, confirming a speed of 130 thousand miles per hour.
Telescópio Hubble revealed a dustdrop shape in July, with background stars streaked due to the hyperbolic orbit.
Maneuver hypothesis Oberth
Loeb proposes that the low perihelion of 1.35 AU allowed an Oberth maneuver, using solar gravity to assist in orbital insertion around Júpiter with ΔV of about 5 km/s. Essa strategy optimizes thrust at high speeds.
Solar occultation during perihelion facilitated any adjustment without detection. Se the comet releases objects, the relative speed of 65.9 km/s at Júpiter would require cancellation for capture, with an escape speed of 2.2 km/s at the radius of Hill.
Studies from July 2025 model deceleration scenarios for heliocentric or Jupiterian orbit.
Chemical composition revealed
Analysis of Observatório Swift on July 31 detected water vapor and OH, while Very Large Telescope identified cyanide and atomic nickel in July and August 2025. Esses elements occur in solar comets, but high CO2 suggests carbon-rich outer disk formation.
The estimated age ranges from 3 to 14 billion years, with 68% confidence in 7.6 to 14 billion, aligning it with the thick disk of Via Láctea, older than Sol.
Monitoring by probe Juno
The Juno probe, in orbit around Júpiter, equipped with UV, infrared and radio sensors, will observe the comet in March 2026 at 54 million kilometers. Qualquer new object detected could indicate release during passage.
NASA classifies 3I/ATLAS as a natural comet, with confirmed cometary activity, but Loeb emphasizes the need to verify technosignatures.
- UV sensors for atomic emissions
- Infrared for dust and gases
- Radio for potential signals
Detailed interstellar trajectory
The comet traveled billions of years through Via Láctea, with speed altered by stellar encounters. Sua high W vertical component indicates origin in the thin or thick disk, mixing it with neighboring stars.
Forecasts indicate brightness below magnitude 12 in December 2025, passing through Virgem and Leão. It poses no threat to Terra, with a minimum of 1.8 AU in mid-December.
