Interstellar Comet 3I/ATLAS Exhibits Unusual Acceleration and Color Change Near Sun

Comet 3I/ATLAS, the third interstellar object identified in our solar system, has exhibited unexpected behavior as it nears the Sun. Discovered on July 1, 2025, by the ATLAS telescope in Chile, the comet has shown signs of non-gravitational acceleration and a noticeable blue coloration.

NASA's recent observations indicate that outgassing from the comet could lead to a significant loss of mass, potentially resulting in a substantial debris plume in the coming months. However, Earth-based telescopes currently face challenges in observing 3I/ATLAS due to its position behind the Sun. The comet is expected to reappear in early December, allowing for more detailed ground-based studies.

Avi Loeb, Baird Professor of Science at Harvard University, has suggested that the non-gravitational acceleration might be indicative of an internal engine. In response to public inquiries, NASA Acting Administrator Sean Duffy stated that 3I/ATLAS is the third interstellar comet to pass through our solar system, emphasizing that there is no threat to Earth.

The European Space Agency (ESA) plans to observe the comet using its Jupiter Icy Moons Explorer (Juice) on November 2 and November 25. 3I/ATLAS is projected to make its closest approach to Earth on December 19, at a distance of approximately 167 million miles. This period will provide scientists with an opportunity to determine whether the object is a natural comet or something else.