A team of astronomers has discovered something intriguing about the interstellar object 3I/ATLAS. This is our third confirmed visitor from outside our Solar System, and it’s showing some surprising changes, including a second color shift. As it neared perihelion—where it gets closest to the Sun—scientists noted signs of non-gravitational acceleration.
On July 1, astronomers first spotted 3I/ATLAS, confirming it as an interstellar object due to its high speed and unusual orbit. This comet acts like a cosmic time capsule, potentially offering clues about its origin in the galaxy. Earth-based telescopes, including the Solar Terrestrial Relations Observatory (STEREO) and the Solar and Heliospheric Observatory (SOHO), helped track it as it approached perihelion.
During this observation, scientists recorded that the object brightened significantly—about magnitude 9—making it visible through small telescopes or good binoculars. Notably, it also appeared bluer than the Sun, which raises questions about why it brightened so rapidly, far beyond the typical behavior of Oort cloud comets.
Some have speculated about its origin, leading to wild theories. Avi Loeb, a Harvard astronomer, suggested that 3I/ATLAS could be an alien spacecraft. Most scientists, however, view this idea with skepticism, pointing out its clear comet-like behavior.
As the comet got closer to the Sun, it started showing signs of non-gravitational acceleration. Loeb reported that measurements indicated some unusual movements that aren’t solely due to gravity. The acceleration could hint at outgassing—when the comet expels gas and dust as it heats up.
For instance, this might mean the comet could lose about 10% of its mass over a month due to evaporation, creating observable gas plumes. The European Space Agency’s Juice spacecraft might detect this change soon.
Still, many questions linger. Why is 3I/ATLAS brightening so differently from other comets? Scientists theorize that its water ice might have sublimated differently due to rapid changes in heat as it approached the Sun.
As we continue to observe this interstellar visitor, we can expect more surprises ahead. The next few months are key for understanding its behavior and mysteries.
For ongoing insights, you can check the study posted on arXiv.
