Universidade Estadual scientists from Michigan have published an analysis of possible interstellar comet collisions with Terra. The study, led by Darryl Seligman, focused on comet 3I/Atlas, the third such object detected by Sistema Solar. Simulations indicate an average speed of 72 kilometers per second at the moment of impact.
The research took place in collaboration with experts from European institutions and used observational data from three known interstellar comets. The computational models reproduced real trajectories of these objects. There is no immediate risk of collision with 3I/Atlas, which passed perihelion in October 2025.
Comet 3I/Atlas entered Sistema Solar in July 2025, with an initial speed of 58 km/s relative to Sol. Sua hyperbolic orbit confirms origin external to Via Láctea. Observações and Telescópio Hubble estimate the core to be between 440 meters and 5.6 km in diameter.
Calculated trajectories and speeds
The simulations generated thousands of possible scenarios for impacts. The speed of 72 km/s emerged as the most frequent value in the analyzed distribution. Essa rate results from the combination between the hyperbolic input and the orbital motion of Terra.
Researchers considered parameters such as orbital eccentricity and non-gravitational acceleration. Interstellar comets maintain high speeds due to the lack of prolonged gravitational capture by Sol. The analysis reinforces that such events are rare in the short term.
Observed characteristics of 3I/Atlas
The comet exhibits emissions of cyanide gas and nickel vapor, similar to objects in Sistema Solar. Sua coma is formed by the sublimation of ice as it approaches Sol. Observações from Very Large Telescope confirmed active cometary activity.
The object’s color varied from reddish to blue during the solar approach, an atypical behavior. Telescópios terrestrials detected ejection of material before perihelion. The core diameter, refined by Hubble data, is below 1 km at the most accurate estimate.
International collaboration on the project
Dušan Marčeta, from Universidade of Belgrado, contributed orbital dynamics modeling. Eloy Peña-Asensio, from Politecnico di Milano, analyzed fragmentation in high-speed impacts. The team integrated data from missions like ExoMars Trace Gas Orbiter.
The results were validated against ‘Oumuamua and 2I/Borisov trajectories. The simulation considered 2.6 billion synthetic objects based on M dwarf stars. The Essa approach increased the accuracy of relative velocity predictions.
The publication took place in a specialized scientific journal, focusing on dynamic astrophysics.
Formation of craters in impacts
Collisions at 72 km/s generate craters with shapes different from those caused by local asteroids. The fragmentation of the material is greater due to the high kinetic energy. Plate tectonics and erosion make it difficult to identify ancient interstellar landmarks on Terra.
The simulations predict impact concentrations at low latitudes, close to Equador. The orbital geometry favors direct encounters in this region during Terra’s annual movement. Até Small objects would cause significant damage at this speed.
Studies indicate that the ejected dust could temporarily alter weather patterns. The rarity of these events, estimated at a very low chance, is based on galactic distributions of stars.
Probable origin of the comet
3I/Atlas originates from the thick disk of Via Láctea, a region of intense star formation. Sua’s age may exceed 7 billion years, higher than that of Sistema Solar. The relative velocity of 58 km/s at the entrance suggests ejection from another star system.
James Webb Space Telescope observations revealed chemical composition altered by billions of years of travel. The trajectory points towards the thin or thick disk of the galaxy. Modelos indicates acceleration due to the gravitational slingshot effect of Sol.
Details of the computer simulations
- Thousands of hyperbolic trajectories have been tested based on observed velocities.
- The speed distribution concentrated on 72 km/s as the probable peak.
- Parameters included eccentricity of 6.2 and outgassing disturbances.
- Models incorporated data from three interstellar comets for calibration.
- Results validated the rarity of collisions, with a lower probability than annual asteroid events.
These computational tools made it possible to predict dynamics without direct observations of real impacts.
Recent telescopic observations
Hubble captured images in August 2025, refining the core size. JWST analyzed ultraviolet emissions in November. ESA recorded the passage of Marte at 30 million km in October.
These observations confirmed the absence of an initial tail and non-gravitational acceleration. The comet remains visible until September 2026 for ground-based telescopes. Dados of Atacama Large Millimeter Array detected deviations of 4 arcseconds in the trajectory.
The exit speed will be equivalent to the entry speed, around 58 km/s, after the solar flyby.
