Is Interstellar Comet 3I/ATLAS a cosmic time capsule? Spanish astronomers trace its 10-million-year path

An early image shows interstellar comet 3I/ATLAS gliding through our solar system. (Image: International Gemini Observatory/NOIRLab/NSF/AURA/K. Meech (IfA/U. Hawaii)Image Processing: Jen Miller & Mahdi Zamani (NSF NOIRLab))

Astronomers in Spain have traced an interstellar comet that carries secrets older than our Sun. Known as 3I/ATLAS, the comet is revealing clues about how distant worlds formed in other corners of the galaxy.

Interstellar Visitor from Beyond Our Solar System
Scientists from the Center for Research in Information and Communication Technologies (CITIC) at the University of A Coruña confirmed that 3I/ATLAS is not a typical comet. First detected on July 1, 2025, by the Asteroid Terrestrial-impact Last Alert System (ATLAS) in Chile, the object’s unusual path and makeup suggest that it came from beyond the Solar System, as reported by Union Rayo.

CITIC researcher Xabier Pérez Couto said the team reconstructed the comet’s orbit across 10 million years, tracing its origin to another stellar system. “Each interstellar comet opens a window to the Universe’s past,” Pérez Couto said. “It lets us study material that formed around other stars, under very different conditions from our Sun.”

Researchers confirmed that 3I/ATLAS will not approach closer than 270 million kilometres from Earth, allowing safe telescope observations from the ground.

Tracking 3I/ATLAS with Gaia Data
The Spanish team used data from the European Space Agency’s Gaia mission, which has mapped the Milky Way in remarkable detail. Gaia’s data allowed scientists to trace how 3I/ATLAS journeyed across the galaxy before entering our Solar System.

The researchers compared the comet’s motion with nearby stars to determine its path and likely origin. Pérez Couto explained that Gaia’s data serves as a kind of “time machine”, letting astronomers look into the distant past and study conditions around other stars.

A Frozen Archive of Ancient Space
Comets are often called relics of early solar formation, but interstellar comets like 3I/ATLAS offer an even deeper look into the origins of planetary systems. Pérez Couto said studying the comet was like “examining the DNA of other solar systems.”

The comet’s icy composition holds ancient chemical signatures that could change our understanding of how planets and organic molecules first formed. Scientists believe such interstellar visitors are crucial to studying how life’s essential ingredients may have developed elsewhere in the galaxy.

Spain’s Role in Global Astronomy
The CITIC team is among the few in the world using advanced simulations to track unobservable cosmic objects. “We literally rewind time to uncover the Universe’s past,” a researcher said. Their findings place Spain among the leading contributors to international astronomy and the study of interstellar travellers like 3I/ATLAS.

As the comet continues its journey beyond the Solar System, astronomers see it as a rare opportunity to study materials formed around other stars. Pérez Couto noted, “Every interstellar object we detect takes us closer to understanding where we come from and what lies beyond our Sun.”