The cosmos has a new visitor. Astronomers have published a scientific paper detailing what’s currently known about 3I/ATLAS, the third interstellar object ever detected passing through our solar system. The discovery, made by NASA’s Asteroid Terrestrial-impact Last Alert System (ATLAS), has ignited a flurry of research aimed at understanding the object’s composition, trajectory, and origins.
Darryl Seligman, an assistant professor at Michigan State University and lead author of the paper, described the frantic early hours after the object’s initial sighting. “I heard something about the object before I went to bed, but we didn’t have a lot of information yet,” Seligman explained. “By the time I woke up around 1 a.m., my colleagues…were emailing me that this was likely for real.” The race to gather data and document their findings began immediately, with telescopes around the globe turning their gaze towards the newly discovered interstellar traveler.
ATLAS, comprised of four telescopes strategically positioned around the world, constantly scans the sky for moving objects. Larry Denneau, a member of the ATLAS team, expressed his excitement—tempered with caution—upon reviewing the initial observations. “We have had false alarms in the past about interesting objects, so we know not to get too excited on the first day. But the incoming observations were all consistent, and late that night it looked like we had the real thing.” What followed was unexpected, a surge of activity as astronomers worldwide coordinated their efforts to observe and analyze 3I/ATLAS.
John Tonry, another key figure in the ATLAS project, emphasized the significance of the discovery. “It’s really gratifying every time our hard work surveying the sky discovers something new, and this comet that has been traveling for millions of years from another star system is particularly interesting.”
“Once 3I/ATLAS was identified as likely interstellar, we mobilized rapidly,” said Karen Meech, faculty chair for the Institute for Astronomy at the University of Hawaii. “We activated observing time on major facilities…to capture early, high-quality data and build a foundation for detailed follow-up studies.”
While many questions remain unanswered due to the object’s distance, here’s a summary of what scientists currently know about 3I/ATLAS:
- It’s the third interstellar object detected in our solar system.
- It might be emitting gas, like a comet, but this needs confirmation.
- It’s incredibly fast, moving at 60 kilometers per second (134,000 mph) relative to the Sun.
- Its orbital path is shaped like a hyperbola, meaning it will not return.
- It is notably bright.
- Scientists will have several months to study it before it leaves our solar system permanently.
One particularly intriguing aspect of 3I/ATLAS is its brightness. Seligman and his team are closely monitoring its coma, the cloud of dust and gas surrounding the object, to see how it evolves as 3I/ATLAS moves and rotates. They are also looking for any sudden outbursts, which could provide valuable insights into its composition.
James Wray, a professor at Georgia Tech, cautions that definitive conclusions are difficult to draw at this stage. “We have these images of 3I/ATLAS where it’s not entirely clear and it looks fuzzier than the other stars in the same image,” Wray said. “But the object is pretty far away and, so, we just don’t know.” The James Webb Space Telescope and the Hubble Space Telescope are expected to provide more detailed data in the coming months, potentially revealing information about its size, composition, and spin.
For students like Tessa Frincke, a doctoral candidate at MSU, the discovery of 3I/ATLAS presents a unique opportunity. “I’ve had to learn a lot quickly, and I was shocked at how many people were involved,” said Frincke. “Discoveries like this have a domino effect that inspires novel engineering and mission planning.” A missprint in her initial calculations even led to a breakthrough in understanding the object’s trajectory.
Atsuhiro Yaginuma, an undergraduate student on Seligman’s team, is even exploring the possibility of launching a spacecraft to intercept 3I/ATLAS. “The closest approach to Earth will be in December,” Yaginuma explained. “It would require a lot of fuel and a lot of rapid mobilization from people here on Earth. But getting close to an interstellar object could be a once-in-a-lifetime opportunity.”
Seligman emphasized the importance of continued funding for astronomical research, particularly in light of current congressional discussions on science funding. He and Aster Taylor, a former student, co-authored a statement highlighting the broader impact of such discoveries. “The fact that this science is not funded by commercial enterprise indicates that our field does not provide a financial return on investment, but instead responds to the public’s curiosity about the deep questions of the universe: Where did we come from? Are we alone? What else is out there? The curiosity of the public…is the reason that astronomy exists.”
The detection of 3I/ATLAS serves as a powerful reminder of the vastness and dynamism of the universe, and the crucial role that scientific exploration plays in answering fundamental questions about our place within it. Posts on X.com and Facebook show a growing public fascination with space exploration as a result.
The research paper is currently available on the arXiv preprint server.
