Comet 3I/ATLAS, the third confirmed interstellar object observed in our solar system, has captivated scientists worldwide. Unlike regular comets, it follows a hyperbolic trajectory, originating from beyond the Sunโs gravitational influence. This path ensures it will eventually leave the solar system permanently.
Researchers are particularly intrigued by its potential age. Early studies indicate 3I/ATLAS could be as old as 14 billion years, possibly forming before the Sun and planets. This makes it a unique window into the earliest stages of the universe.
Interstellar Origins and Trajectory
Prior to 3I/ATLAS, only 1I/สปOumuamua in 2017 and 2I/Borisov in 2019 were confirmed interstellar objects. However, neither suggested ages comparable to the universe itself.
Orbital measurements show that 3I/ATLAS entered our solar system at a velocity beyond what the Sun alone could explain. Its hyperbolic orbit confirms that it formed around a different star and has spent billions of years traveling through interstellar space.
This discovery also suggests that such ancient interstellar objects may be more common than previously thought, though they are difficult to detect due to their faintness and short visibility.
Age Estimation and Stellar History
Scientists estimate the cometโs age to be between 8 and 14 billion years. This analysis relied on kinematic modeling of its velocity and trajectory relative to the Sun and nearby stars.
Researchers propose that 3I/ATLAS originated from an ancient stellar population formed early in the universe. If confirmed, these findings imply that solid bodies can survive for billions of years while drifting through interstellar space.
Chemical Composition and Observations
Spectroscopic studies reveal that 3I/ATLAS is chemically distinct from typical solar system comets. Observations detected strong emissions from atomic nickel and iron, elements rarely seen in cometary atmospheres.
Further analysis using the James Webb Space Telescope (JWST) found that the comet is unusually rich in carbon dioxide, suggesting formation in extremely cold environments far from its parent star. These differences support the idea that it originated in a stellar system unlike our own.
Physical Behavior and Rotation
Observations over 37 nights revealed jet-like structures on the sun-facing side of 3I/ATLAS. These jets exhibited a slow, repeating wobble rather than random bursts.
By tracking these motions, scientists determined a rotation period of 15.5 hours, with jets precessing roughly every 7 hours and 45 minutes. This indicates a stable internal structure, unlike loosely bound debris.
Close Approach and Future
3I/ATLAS made its closest approach to Earth on December 19, 2025, providing the most detailed compositional and activity data. After this encounter, it has been gradually fading as it moves away from the Sun.
Given its hyperbolic orbit, the comet will leave the solar system permanently, making further observation unlikely. This provides a rare opportunity to study material from early stars, refining models of star formation, chemical evolution, and the survival of solid bodies in space.
Conclusion: A Window into Cosmic History
The study of 3I/ATLAS offers unprecedented insights into the universeโs early history. While some have speculated about artificial origins, current evidence fully supports natural astrophysical processes.
By examining its chemical composition, trajectory, and physical behavior, astronomers gain valuable knowledge about ancient interstellar objects and their role in understanding cosmic evolution.
