NASA’s Europa Clipper spacecraft will intersect the ion tail of interstellar comet 3I/ATLAS between October 30 and November 6, 2025. The probe, launched to study Jupiter’s moon Europa, requires no trajectory changes for the alignment. Solar wind is expected to carry ions from the comet into the spacecraft’s path, enabling direct detection of material from another star system.
Researchers Samuel Grant and Geraint Jones developed the prediction. They used Tailcatcher software to model solar wind interactions. The study, posted on arXiv, outlines the cosmic alignment opportunity.
- Comet 3I/ATLAS was discovered in 2025 by the ATLAS survey.
- It marks the third confirmed interstellar object in the Solar System.
- The ion tail forms from energized gases pushed by solar wind.
Predicted cosmic alignment
Samuel Grant from the Finnish Meteorological Institute and Geraint Jones from ESA identified the event. Simulations show solar wind transporting ions over millions of kilometers.
Europa Clipper will pass through the region passively. Onboard instruments will register any intercepted particles.
Features of comet 3I/ATLAS
The comet contains ice, rocks, and dust preserved for billions of years. Solar heating releases gases that create distinct tails.
Dust tail follows the comet’s orbit. Ion tail, made of charged gases, extends away from the Sun due to solar wind pressure.
Gemini South Telescope images display the comet’s structure. 3I/ATLAS retains original composition from its formation outside the Solar System.
Tailcatcher software simulations
Tailcatcher tracks solar wind effects on active comets. Grant and Jones ran models to forecast ion transport.
Findings indicate particle streams reaching the probe’s trajectory. Detection happens automatically during the fly-through.
Europa Clipper instruments
The spacecraft carries plasma and particle detectors. These sensors will capture ion tail data if conditions match predictions.
Primary mission targets Europa’s subsurface ocean. The comet encounter provides bonus scientific measurements.
Record of interstellar objects
Only two prior interstellar visitors are confirmed. 1I/’Oumuamua passed in 2017 without probe contact.
2I/Borisov appeared in 2019 with no direct sampling. 3I/ATLAS offers the third observed passage.
Value of collected samples
Comet particles preserve early planetary system records. Ion analysis will reveal chemical makeup from another star.
Results compare to Solar System materials. The event achieves first direct contact with extrasolar matter.
Comets maintain primitive formation conditions. Detected ions supply data on distant system development processes.
Solar wind monitoring
Solar wind variations control collection success. Changes can shift ion tail reach.
Researchers update forecasts using real-time observations. The detection window lasts until November 6.
