Scientists have dramatically improved predictions of the path taken by interstellar comet 3I/ATLAS, narrowing its projected trajectory by a factor of ten thanks to observations from the European Space Agency’s (ESA) ExoMars Trace Gas Orbiter. This breakthrough enhances the ability to study this rare visitor from beyond our solar system as it continues its one-way journey outward.
A Comet From Another Star System
3I/ATLAS is only the third confirmed interstellar object ever detected. First spotted in early July, it travels at over 130,000 mph (210,000 km/h) and is believed to have originated from a star system up to 7 billion years ago. Its unusual characteristics, including an irradiated surface and a puzzling “anti-tail,” have fueled speculation—though unsubstantiated—about non-natural origins.
Mars Flyby Provides Critical Data
The comet recently made its closest approach to the sun and re-emerged into Earth’s view. Prior to this, 3I/ATLAS passed within 18.6 million miles (30 million kilometers) of Mars on October 3. The ESA’s ExoMars orbiter seized the opportunity to capture detailed images, which proved critical for refining trajectory predictions.
Tenfold Accuracy Improvement
The initial expectation was a modest improvement in accuracy. Instead, the ESA team achieved a ten-fold reduction in uncertainty regarding the comet’s location. This allows astronomers to focus their instruments with greater confidence, maximizing the scientific return from this unique observation.
Triangulation From an Unusual Vantage Point
Traditionally, tracking such objects relies on ground-based observatories or Earth-orbiting spacecraft. The Mars flyby provided a unique triangulation point, similar to how intelligence agencies track mobile devices using multiple cell towers.
Overcoming Technical Hurdles
The process was not straightforward. The ExoMars orbiter’s Colour and Stereo Surface Imaging System (CaSSIS) is designed to photograph the Martian surface, not distant space objects. Despite this, the team successfully extracted valuable data.
First of Its Kind Data Accepted by IAU
The success is significant enough that the data has been accepted into the International Astronomical Union’s (IAU) Minor Planet Center database – a first for observations made by a planetary orbiter. This sets a precedent for future studies using similar methods.
Future Observations Planned
ESA plans to repeat this approach with its Jupiter Icy Moons Explorer (JUICE) later this month. The agency suggests that its Hera and Europa Clipper missions could also pass through the comet’s tail as it moves away from the sun. NASA’s Mars Reconnaissance Orbiter captured potentially high-resolution images during the flyby, but their release has been delayed due to the recent government shutdown.
Upcoming Closest Approach to Earth
3I/ATLAS will reach its closest point to Earth on December 19, at a distance of 168 million miles (270 million kilometers). This event offers a final opportunity for detailed observations before the comet continues its outbound journey.
This refined trajectory data represents a major step forward in understanding interstellar objects and their composition, providing valuable insights into the environments beyond our solar system
