More than a dozen spacecraft captured images of interstellar comet 3I/ATLAS as it zipped past Mars and the sun during a 43-day government shutdown
NASA has finally pulled back the curtain on a collection of extraordinary images showing an interstellar visitor that has captivated astronomers and conspiracy theorists alike since its discovery this summer.
More than a dozen NASA spacecraft captured photos of comet 3I/ATLAS during September and October as it flew past Mars while approaching the sun. However, the space agency remained silent about what its instruments were observing during the 43-day government shutdown that kept these remarkable images under wraps until now.
A rare visitor from beyond our solar system
Researchers first spotted the interstellar comet on July 1 using the Asteroid Terrestrial-Impact Last Alert System in Chile. The discovery marked only the third time scientists have detected a confirmed interstellar object passing through our solar system, making 3I/ATLAS an exceptionally rare find.
Astronomers estimate the comet’s rock-and-ice core measures between 1,400 feet and 3.5 miles in diameter. While that range leaves significant uncertainty about its exact size, even the lower estimate represents a substantial cosmic object hurtling through space at incredible speeds.
The comet’s designation includes the letter I to indicate its interstellar origin, distinguishing it from the countless comets that originated within our own solar system. Only two other interstellar visitors have been documented before this one.
The closest encounters happened at Mars
Three NASA spacecraft stationed on or near Mars captured the most detailed views of 3I/ATLAS when it passed within 19 million miles of the Red Planet in early October. While that distance might sound vast, it represents an incredibly close approach in astronomical terms.
The Mars Reconnaissance Orbiter, typically focused on searching for evidence of water on the Martian surface, turned its attention skyward to photograph the passing comet. The High Resolution Imaging Science Experiment camera aboard the orbiter captured images showing the comet with a faint glow surrounding its nucleus.
Meanwhile, the MAVEN spacecraft, which normally investigates Mars’ upper atmosphere, took ultraviolet images that will help researchers determine the comet’s chemical composition. These UV observations reveal details about the gases and materials being released as the comet’s icy surface vaporizes under solar heating.
Even the Perseverance rover on the Martian surface managed to glimpse the interstellar visitor during its flyby, adding yet another perspective to the growing collection of observations.
Solar observers joined the photo opportunity
Spacecraft designed to study the sun also participated in documenting 3I/ATLAS during its closest approach to our star in late October. The STEREO and PUNCH missions, which typically focus on solar phenomena, redirected their instruments to capture the comet as it swung around the sun.
This marked the first time NASA heliophysics missions have intentionally studied an interstellar object, according to the agency. The observations provide valuable data about how the comet interacts with the solar wind and radiation as it passes through the inner solar system.
One particularly striking image captured by MAVEN shows the comet’s coma, a halo of gas and dust surrounding the nucleus that gives comets their characteristic fuzzy appearance. The blue coloration in the UV image reveals specific chemical compounds being released by the warming ice.
Addressing the conspiracy theories
The comet’s mysterious origins from beyond our solar system sparked inevitable speculation, with some people suggesting it might represent alien technology rather than a natural object. NASA officials felt compelled to directly address these conspiracy theories during a press conference on November 19.
Amit Kshatriya, NASA associate administrator, stated unequivocally that the object is a comet. He explained that it looks and behaves exactly like a comet, with all evidence pointing to a natural origin. The fact that it came from outside our solar system makes it scientifically fascinating without requiring any extraterrestrial intelligence explanation.
The comet displays all the expected characteristics of its type, including outgassing as it approaches the sun, a developing tail, and orbital behavior consistent with a body influenced primarily by gravitational forces. Nothing about its appearance or trajectory suggests artificial construction or propulsion.
Two previous interstellar visitors
The discovery of 3I/ATLAS adds to a short but growing list of confirmed interstellar objects passing through our cosmic neighborhood. The first documented visitor, a cigar-shaped object designated 1I/’Oumuamua, was spotted in 2017 and generated intense scientific interest due to its unusual elongated shape.
The second known interstellar visitor, comet 2I/Borisov, was discovered in 2019 by amateur astronomer Gennady Borisov. That comet displayed more typical characteristics, appearing quite similar to comets originating from within our solar system.
Each interstellar detection provides astronomers with precious opportunities to study material and objects from other star systems without needing to send spacecraft across the vast distances separating stars. These visitors bring samples of distant cosmic environments directly to our doorstep.
More observations coming soon
Additional NASA spacecraft will continue monitoring 3I/ATLAS in the coming weeks, building a comprehensive dataset about the comet’s features and chemical makeup. The accumulated observations will help scientists understand not just this specific object but the general characteristics of interstellar comets.
The James Webb Space Telescope plans to observe the visitor in December, potentially revealing unprecedented detail about its composition and structure. Webb’s powerful infrared capabilities can detect molecules and compounds that other instruments might miss.
Shawn Domagal-Goldman, NASA’s acting astrophysics division director, noted during the press conference that everyone controlling a telescope wants to look at the comet because it represents such a fascinating and rare opportunity. The astronomical community is mobilizing resources to gather as much data as possible before the visitor departs.
Earth’s turn for a closer look
The comet will make its closest approach to Earth around December 19, passing within approximately 170 million miles of our planet. That distance equals nearly twice the separation between Earth and the sun, ensuring the comet poses absolutely no threat while still allowing for detailed observations.
Following its Earth flyby, 3I/ATLAS will continue its journey through our solar system, passing by Jupiter in spring 2026. Soon after that final planetary encounter, the comet will leave our solar system forever, returning to the vast interstellar space from which it came.
Nicky Fox, associate administrator of NASA’s Science Mission Directorate, expressed pride in the agency’s fleet of scientific spacecraft distributed throughout the solar system. Their readiness to capture this rare event demonstrates the value of maintaining diverse observation capabilities across multiple locations and wavelengths.
The images released by NASA represent just the beginning of scientific analysis that will continue for years as researchers work to extract every possible insight from this fleeting encounter with a messenger from beyond our cosmic shores.