Interstellar Objects Like 3I/ATLAS Pose Earth Impact Risk

A new study delves into the potential impact risk posed by interstellar objects (ISOs) like 3I/ATLAS, Oumuamua, and 2l/Borisov, which periodically visit our inner solar system. While the number of ISOs cannot be predicted, understanding their distribution and likely trajectories is crucial for assessing potential threats to Earth's atmosphere and airspace. This research aims to quantify the expected orbital elements, radiants, and velocities of Earth-impacting ISOs, providing vital data for future observation efforts and enhancing our preparedness for aerial phenomena.

The research, led by Darryl Seligman from Michigan State University, utilized simulations to model the behavior of approximately 10^10 synthetic interstellar objects with M-star kinematics, resulting in about 10^4 Earth-impacting scenarios. The findings indicate that ISOs are twice as likely to approach Earth from two specific directions: the solar apex, which is the direction of the Sun's movement through the Milky Way, and the galactic plane, where most stars reside. Objects from these regions tend to have higher velocities, yet paradoxically, the subset capable of impacting Earth often exhibits slower velocities due to the Sun's gravitational capture.

Further analysis revealed seasonal variations in impact probability. ISOs with the highest impact velocity are more likely to arrive in the Spring when Earth moves towards the solar apex. Conversely, Winter sees more frequent potential impactors as Earth is positioned towards the solar antapex. Geographically, low latitudes near the equator face the greatest risk, with a slightly elevated threat in the northern hemisphere, home to nearly 90% of the global human population. These insights are critical for developing robust monitoring systems and understanding regional vulnerabilities.

While the study intentionally avoids predicting the exact number of ISOs, its findings on their expected distribution are invaluable for upcoming astronomical projects. The results will feed into future observations by the Vera Rubin Observatory and its Legacy Survey of Space and Time (LSST), which will gather data to either support or refine these initial findings. This ongoing research represents a significant step in comprehending and mitigating the potential risks that interstellar objects could pose to Earth's environment and aviation safety.