NASA confirmed that comet 3I/ATLAS, discovered on July 1, 2025 by the ATLAS telescope in Chile, follows a hyperbolic orbit and will leave the solar system after passing by the Sun. The object reached perihelion on October 29, 1.4 astronomical units (210 million km) from the Sun. Its speed increased to around 244 thousand km/h.
The comet will approach Earth in December, at 1.8 astronomical units (270 million km), without risk of collision. Composition rich in carbon dioxide and absence of typical tail generate scientific interest.
- Current speed: 244 thousand km/h.
- Minimum distance from Earth: 270 million km.
- Perihelion date: October 29, 2025.
Unusual chemical composition
Observations by the James Webb telescope, carried out in August, identified a predominance of CO2 in the comet’s coma. The proportion of carbon dioxide exceeds that of water by eight times. Carbon monoxide and hydroxyl vapors indicate formation in a cold, distant environment.
The absence of a visible tail differentiates 3I/ATLAS from comets such as 2I/Borisov. Estimated ages range from 7 to 14 billion years.
Coordinated monitoring
NASA coordinates observations with Hubble telescopes and space missions. The Mars Express probe collected data in October. The comet was invisible during the solar conjunction, but will reappear in December for professional telescopes.
International Asteroid Warning Network refines orbital measurements. The object will pass Venus in November, 97 million km away, and Jupiter in March 2026, 54 million km away.
Interstellar origin confirmed
Hyperbolic orbit with eccentricity greater than 6 ensures that the comet will not be captured by the Sun. Trajectory suggests ejection from another stellar system billions of years ago. Analysis of gravitational interactions provides data on planetary formation in other stars.
Global Observation Campaign
Observatories in Chile, Hawaii and Australia participate in monitoring that began in November 2025. Hubble images from July show a reddish coma rich in silicates. Data will be collected until January 2026, when visibility decreases.
Scientific contribution
3I/ATLAS study allows advances in interstellar chemistry. The presence of organohalogenated compounds and the absence of iron linked to nickel question traditional comet models. Information aboutformation and trajectory expand knowledge about extrasolar objects.
Comet 3I/ATLAS represents the third detection of an interstellar object, after 1I/’Oumuamua and 2I/Borisov. Its passage offers a unique window into the analysis of primordial material from another star system, with composition preserved for billions of years in cold regions of space.