An interstellar comet that has fascinated astronomers this year narrowly became the first object named for the Vera C. Rubin Observatory.
The event occurred on June 20, 2025, when Rubin was training his imaging system at night for the first time and discovered 3I/ATLAS, which occurred ten days before ATLAS discovered it on July 1.
Had the Chilean telescope’s data processing pipelines been in place, it could have claimed the discovery.
University of Washington scientists, led by Colin Orion Chandler, came to this conclusion while reviewing commissioning data.
The 27.6-foot telescope, which is still undergoing scientific validation, did not have automated data pipelines used to make regular observations.
To even view the stored footage, Chandler’s team had to write their own software to access the data. The team observed the comet at least thirteen times in twelve nights and managed to see the dusty coma, the bright halo around a comet that indicates activity.
Rubin is designed to discover about 10,000 new comets in the first ten-year research cycle. Given the expected performance during the early research phase, Rubin will detect one interstellar comet passing through our solar system per year.
Based on 3I/ATLAS observations, it’s safe to say that while the current object won’t be named Rubin, many more future visitors likely will.
In October 2025, when 3I/ATLAS was closest to the Sun, two NASA and ESA probes en route to Jupiter, Europa Clipper and JUICE, captured an interesting event. Using their ultraviolet spectrograph instruments, they discovered hydrogen, oxygen and carbon atoms produced by the photodissociation process of molecular gas escaping from the nucleus.
