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An Interstellar Visitor Rekindles the Fascination of Science. The Comet 3I/ATLAS Surprises with Its Origin Outside the Solar System, Early Brightness, and Composition Rich in Carbon Dioxide, Factors that Intrigue NASA Astronomers.
NASA activated the planetary defense protocol and issued alerts after detecting behavior deemed unusual in comet 3I/ATLAS, an interstellar object that has sparked great interest from the scientific community due to its peculiar chemistry.
The technical alert was released last Tuesday (21), through the MPEC bulletin (2025-U142) from Harvard’s Minor Planet Center.
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The goal is to improve the accuracy of the comet’s orbital measurements, which present “unique challenges,” according to the statement.
This initiative aims to safely predict its trajectory over the coming weeks, as 3I/ATLAS follows a hyperbolic path and is expected to reach perihelion — the point closest to the Sun — on October 29, 2025.
A Visitor from Outside the Solar System
Astronomers who observed 3I/ATLAS for the first time were surprised by its characteristics. The object is only the third interstellar visitor ever detected entering the Solar System, making it a rare opportunity for scientists to study bodies from other planetary systems.
Astrophysicist Jacqueline McCleary from Northeastern University stated that “interstellar objects are the only things we have ever obtained physical observations of from outside our solar system.”
Researchers believe that 3I/ATLAS was part of another planetary system and was ejected after a gravitational disturbance, traveling millions of years through deep space until it reached our cosmic territory.
An Early and Mysterious Brightness
The first observation of 3I/ATLAS occurred in July and caught attention due to an intriguing detail: it was already shining intensely, even from a great distance from the Sun.
Normally, comets only exhibit significant brightness when they get close enough for solar heat to begin melting their icy surfaces, forming the characteristic tail of gas and dust.
McCleary explained that “most comets need to be closer than Jupiter for this process to begin,” but 3I/ATLAS formed a coma even beyond Jupiter’s orbit, something considered highly unusual.
This early activity raised speculation about a possible artificial origin, but later analyses confirmed that it is a naturally active and anomalous comet.
Rich in Carbon Dioxide
Observations from the James Webb Space Telescope showed that 3I/ATLAS is extraordinarily rich in carbon dioxide.
The ratio of CO₂ ice to water ice is about eight to one — one of the highest ever recorded in any comet. This composition provides valuable clues about the environment in which the celestial body formed.
According to McCleary, the original system of 3I/ATLAS may have been “exceptionally rich in carbon dioxide” or exposed to radiation conditions that preserved the CO₂ and evaporated other volatile elements.
The comparison between 3I/ATLAS and other interstellar comets may reveal how different planetary systems have developed and may even indicate how unique our own is.
A Sample from Another Planetary Nursery
Due to its origin outside the Solar System, 3I/ATLAS offers scientists a rare opportunity to examine primitive material from another stellar system.
Studying its composition helps to understand the conditions that led to the formation of planets in other regions of the galaxy and possibly the reasons why some worlds can support life.
“It’s a window into what primitive material represents for other solar systems,” McCleary emphasized. “This helps us refine our models of planetary formation and understand why our system may be capable of sustaining life.”
Last Chance for Close Observation
Later this year, comet 3I/ATLAS will pass near Jupiter’s orbit again on its way out of the Solar System. NASA expects the Juno spacecraft to have the best opportunity to observe it up close during this final passage, which may reveal more details about its structure and composition.
“We may potentially observe it very closely,” McCleary said. She added that by then, the comet will have lost much of its carbon dioxide, allowing scientists to analyze what exists beneath its surface.
Each new observation of 3I/ATLAS expands knowledge about how other planetary systems form and evolve — and reinforces NASA’s role in monitoring cosmic objects that cross Earth’s path, even when they come from places so distant that challenge the limits of our understanding.
Não acredito ser uma nave,como vem de outro sistema solar pode sim ser um cometa com órbitas bem diferenciadas