Nasa issues alert for interstellar comet 3I/ATLAS due to unusual behavior observed in its hyperbolic trajectory. The object, detected on July 1, 2025, by the ATLAS system in Chile, exhibits a chemical composition dominated by carbon dioxide, prompting the activation of a planetary defense protocol. The International Asteroid Warning Network coordinates a training exercise from November 27, 2025, to January 27, 2026, to refine orbital measurements.
The comet reaches perihelion on October 29, 2025, traveling at over 210,000 km/h. Observations from the James Webb Space Telescope identified a coma dominated by CO2 and a ratio of eight times more carbon dioxide than water.
- Estimated nucleus between 320 meters and 5.6 kilometers in diameter.
- Water emission activity (OH) detected beyond three astronomical units from the Sun.
- Computational model indicates age over seven billion years.
Initial detection in Chile
The ATLAS system, located in Río Hurtado, recorded 3I/ATLAS on July 1, 2025. The telescope identifies potentially hazardous near-Earth objects.
Researchers confirmed interstellar origin through the hyperbolic orbit. Harvard’s Minor Planet Center published bulletin MPEC 2025-U142 on October 21.
Chemical composition revealed
James Webb observations showed a coma dominated by CO2. The ratio exceeds six times the expected limit for comets.
The comet emits OH at distances of 450 million km from the Sun. Scientists collect data before perihelion.
Extreme trajectory and speed
3I/ATLAS follows a hyperbolic orbit with perihelion on October 29. Speed exceeds 210,000 km/h, complicating predictions.
IAWN highlights unique challenges in orbital measurement. The training exercise aims to improve accuracy in coming weeks.
IAWN-coordinated exercise
The IAWN network starts training on November 27, 2025. The period extends to January 27, 2026, to simulate scenarios.
Participants refine comet trajectory calculations. Focus remains on prediction safety.
Estimated object age
Discovery team’s computational model indicates over seven billion years for 3I/ATLAS. Age surpasses the Solar System, formed 4.6 billion years ago.
The comet offers opportunity to study primitive universe formations. Chemical data provides clues about extrasolar environments.
Complementary observations
Ground and space telescopes continuously monitor 3I/ATLAS. Hubble images captured on July 21, 2025, show object structure.
Additional research analyzes coma variations during solar approach. Results update Minor Planet Center bulletins.
Defense protocol activated
Nasa activated planetary defense measures after detecting anomalies. Protocol includes coordination with international agencies.
Alerts emphasize need for precise monitoring. Updates depend on official Nasa responses.
