NASA activated the planetary defense protocol after detecting variations in the trajectory and brightness of comet 3I/ATLAS. The interstellar object, discovered in July 2025 by the ATLAS telescope in Chile, presents challenges in orbital predictions. The agency collaborates with the International Asteroid Warning Network (IAWN) and the Minor Planet Center at Harvard to coordinate global observations.
There is no immediate risk to Earth, but the mobilization includes training campaigns in the coming months. The comet reaches perihelion on October 30, 2025, close to the orbit of Mars.
- Hubble and James Webb Telescopes record anti-solar tail.
- Particle jets aimed at the Sun distort calculations.
- Speed exceeding 210 thousand km/h confirms extrasolar origin.
Variations in brightness and position
Astronomers have identified an anti-solar tail on comet 3I/ATLAS. Particles ejected towards the Sun change the center of brightness.
This feature, observed for the first time in an interstellar visitor, complicates position estimates. Errors reach 20% in similar objects.
Chemical composition revealed
Data from James Webb shows coma rich in carbon dioxide. Levels eight times higher than water exceed known variations in solar comets.
OH emission occurs 450 million km from the Sun. Early activityce indicates an ancient nucleus, more than seven billion years old.
The core varies between 320 meters and 5.6 km in diameter. Models confirm origin in distant systems.
Challenges in orbital measurements
Gas release shifts the comet’s center of brightness. International observatories participate in simulations to standardize data.
Experts tweak tracking algorithms. Workshop on November 10th brings together technicians to discuss adaptations to hyperbolic trajectories.
Global Observation Campaign
IAWN organizes exercises from November 27, 2025 to January 27, 2026. Telescopes in Hawaii, Chile and Europe focus on the comet.
- Real-time data integration between agencies.
- Testing responses to unpredictable orbital deviations.
- Participation of ESA and Asian observatories.
Origin and predicted trajectory
3I/ATLAS follows ‘Oumuamua and 2I/Borisov as third interstellar on record. The direct objectto Jupiter before leaving the Solar System in 2026.
270 million km from Earth, the comet tests rapid response systems. Continuous monitoring prevents collisions despite safe hyperbolic path.
International technical cooperation
NASA considers the case an opportunity to study interstellar materials. Astrometry partnerships gain traction with lessons from missions like DART.
Data refines models of external planetary formation. The exercise prepares agencies for complex scenarios with atypical bodies.
