Close encounter: 3I/ATLAS near Mars
Scientists around the world are preparing for a rare close-up study of the interstellar visitor 3I/ATLAS as it skims past Mars on October 3, 2025. First spotted on July 1, 2025, this enigmatic object has sparked intense debate about its nature and origin, inviting comparisons with the Solar System’s most famous comets and, for some, the possibility of alien technology. The latest observations suggest a busy few days ahead for both ground-based astronomers and Mars-bound spacecraft that will peer at the object in ultraviolet and infrared light.
Why 3I/ATLAS has captivated the scientific community
3I/ATLAS is recognized as an interstellar traveler, moving through the Solar System at speeds nearly twice that of the earlier visitors Oumuamua and Comet Borisov. Early data showed a lack of a prominent visible tail and several unusual properties, prompting some speculation about its origin. Harvard astrophysicist Avi Loeb drew wide attention by suggesting the possibility of an artificial object; however, the consensus among the majority of researchers has remained cautious, with many noting that the body behaves in ways consistent with known comets. As NASA’s Tom Statler summarized, “It looks like a comet. It does comet things.” The current view is that 3I/ATLAS is most likely a natural object, albeit one with some intriguing quirks worth closer examination.
Planned observations from Mars and Earth
With Mars serving as a nearby stage for this celestial pass, several missions already at the Red Planet will observe 3I/ATLAS as it travels past the world’s orbit. UAE’s Hope orbiter, NASA’s MAVEN, and ESA’s Mars Express and Trace Gas Orbiter will study the comet’s chemical makeup in ultraviolet and infrared wavelengths. On the surface, NASA’s Curiosity and Perseverance rovers are also expected to attempt viewing opportunities, providing complementary perspectives from the Martian vantage point. These coordinated observations aim to extract clues about the object’s composition, activity, and history, potentially revealing whether it is a pristine relic from another star system or a mildly evolved body that formed around a distant sun.
What scientists hope to learn
Researchers hope that analyzing 3I/ATLAS’ emissions will shed light on the materials that formed planetary systems beyond our own. Because interstellar objects carry the chemical signatures of their birth environments, scientists anticipate insights into the processes that governed star and planet formation billions of years ago. Some teams are especially keen to compare the object’s makeup with what is known about comets in our own Solar System and to assess any astrobiological implications—the idea being that even a primitive interstellar fragment could archive information about the conditions in its parent system.
Looking ahead: timing and follow-up observations
After its Mars flyby, 3I/ATLAS will disappear from Earth-based visibility as its trajectory takes it behind the Sun, re-emerging only in December 2025. That period coincides with the object’s most active phase, which makes Earth-based monitoring challenging. Nevertheless, solar observation platforms such as the Parker Solar Probe, along with future opportunities, are expected to contribute useful data during that window. In the longer term, missions operating around Jupiter—NASA’s Europa Clipper and ESA’s JUICE—are planned for late 2025 and into 2026, potentially offering additional vantage points as the object continues its journey through the outer Solar System.
Why this interstellar visitor matters in the grand scheme
Beyond its novelty, 3I/ATLAS offers a rare chance to study material that formed outside the Milky Way and traveled through interstellar space before entering our own neighborhood. Scientists see this as a potential window into the galaxy’s early epochs—often described as the Milky Way’s “cosmic noon”—when star formation and planetary assembly were in full swing. The object’s origin in the thick disk of the galaxy, estimated to be 9–13 billion years old, makes its study relevant for understanding long-running questions about how planets and life-bearing worlds emerge in diverse stellar environments. As a MIT-educated physicist and former NASA scientist Thomas Marshall Eubanks noted in research discussions, confirming interstellar origin and composition could illuminate both stellar and planetesimal formation processes and their broader astrobiological implications.
What the event means for the future of interstellar exploration
3I/ATLAS marks a watershed moment: a real-time laboratory that could validate models of how material is exchanged between star systems and how common interstellar objects may be in our galaxy. While the scientific community remains cautious, the multi-mission, multi-wavelength approach planned for this event demonstrates how coordinated observations—spanning Mars orbiters, rovers on the Martian surface, solar probes, and distant planetary missions—can maximize the scientific yield from such fleeting encounters. Regardless of whether 3I/ATLAS proves to be a natural relic or something more extraordinary, its passage near Mars is already catalyzing new questions about the cosmos and our place within it.
