NASA confirmed this week the occurrence of an additional slowdown in the interstellar comet 3I/ATLAS, detected in early November 2025. The object, discovered in July by the ATLAS telescope in Chile, exhibited non-gravitational acceleration incompatible with known natural effects. Data from the Jet Propulsion Laboratory (JPL) indicate that the speed variation occurred about 203 million kilometers from the Sun.
Measurements reveal transversal components of up to 60 km per day, behavior that deviates from the standards expected for comets on a hyperbolic trajectory. Scientists note that the acting force does not follow the typical direction of outgassing or solar radiation pressure.
Trajectory presents successive adjustments
3I/ATLAS had already attracted attention when it emerged without a visible tail after passing close to the Sun. In October, the object reached perihelion 29 million kilometers from the star.
The new slowdown occurred within the orbit of Mars and lasted several days. Terrestrial telescopes and Hubble have recorded partial inversion of the CO2 tail, a rare phenomenon in natural bodies.
Non-gravitational acceleration in detail
Orbital parameters show radial variationpersistent negative. The observed force maintains a constant direction relative to the Sun.
- Intensity higher than expected for solar wind
- Absence of gas jets visible in high-resolution images
- Periodicity detected in the light curve suggests controlled orientation
- Composition rich in CO2 and low presence of water vapor
These elements differentiate 3I/ATLAS from objects like ‘Oumuamua and Borisov.
Chemical composition reinforces uniqueness
Spectroscopic analyzes indicate an icy core formed in extremely cold regions of the galaxy. The CO2/H2O ratio remains abnormally high. The estimated size varies between 3.5 and 5.6 kilometers according to Hubble.
The age of the material may exceed the 4.5 billion years of the solar system. The trajectory passed close to Mars on October 3 and is now approaching Venus.
Observations mobilize global telescopes
JPL teams maintain continuous monitoring with networks of telescopes in Hawaii and Chile. ESO’s Very Large Telescope (VLT) prepares new observing sessions for December.
Computational models try to reproduce the deceleration with natural mechanisms. To date, no simulation fully explains the recorded vectors.
Hipótthese under analysis by the scientific community
Some of the researchers consider the presence of a light artificial structure possible. Others defend natural explanations that have not yet been identified.
The observed acceleration would require precise control of timing and direction. The distance from the Sun at the time of the maneuver makes a conventional thermal effect unlikely.
The data remains public in the Minor Planet Center database. New measurements should clarify whether the behavior persists during the exit from the solar system scheduled for 2026.
