Astronomers capture new images of interstellar comet 3I/ATLAS approaching Earth
Fresh observations of comet 3I/ATLAS reveal its unusual structure and dynamic tails as it nears its closest approach to Earth later this month. The interstellar visitor, which originated beyond our solar system, has sparked intense interest among scientists since its discovery in July 2025.
Comet 3I/ATLAS is only the third interstellar object ever detected traveling through our solar system, making every observation crucial for understanding its trajectory, composition, and behavior. Both the Hubble Space Telescope and the European Space Agency’s Jupiter Icy Moons Explorer (Juice) mission have captured detailed images of the comet, offering unprecedented insight into this rare cosmic phenomenon.
The comet’s teardrop-shaped coma is unveiled by Hubble
Hubble first observed 3I/ATLAS shortly after its discovery in July 2025, when the comet was roughly 277 million miles from Earth. Using its Wide Field Camera 3, Hubble documented a distinctive teardrop-shaped halo of dust extending from the comet’s icy nucleus. This glowing cocoon of material highlights the ongoing sublimation of gases and particles as the comet warmed while approaching the sun.
Observations continued on November 30, when the comet was 178 million miles (286 million kilometers) from Earth. Hubble captured even sharper images, allowing astronomers to study the comet’s evolving shape and gas emissions in greater detail. These images are vital for tracking the comet’s path and understanding how interstellar bodies behave when exposed to the sun’s energy.
The Juice spacecraft records two tails
While Juice’s main goal is to examine Jupiter and its largest moons—Ganymede, Callisto, and Europa, which might harbor subsurface oceans that could sustain life—it utilized its path to observe comet 3I/ATLAS in early November. From approximately 41 million miles (66 million kilometers) away, the spacecraft employed five scientific instruments and its onboard Navigation Camera (NavCam) to document the comet’s activity.
The spacecraft sent a segment of the NavCam data prior to the complete download timeline. The images display a luminous coma surrounding the comet, accompanied by two separate tails: a plasma tail made up of electrically charged gases and a more subtle dust tail composed of solid particles. This dual-tail formation is typical of comets in our solar system; however, witnessing it on an interstellar object offers valuable insights into its physical and chemical characteristics.
Juice’s full dataset, expected to arrive on Earth between February 18 and 20, will include high-resolution images, composition analysis, and particle measurements. These data could shed light on the comet’s origin and the environment it traveled through before entering our solar system.
Close approach to Earth and visibility
Comet 3I/ATLAS is anticipated to come within 167 million miles (270 million kilometers) of Earth on December 19, situating it on the far side of the sun and presenting no danger to our planet. To put this in perspective, Earth orbits at approximately 93 million miles (150 million kilometers) from the sun, underscoring that the comet will stay safely remote while remaining visible to telescopes and space missions.
Even after its nearest pass, the comet is anticipated to stay visible for numerous months as it proceeds on its path out of the solar system. During this time, observations will enable scientists to examine how the comet engages with solar radiation and the solar wind, further enhancing our comprehension of interstellar bodies.
Insights into interstellar origins
Studying 3I/ATLAS provides a rare window into material formed outside our solar system. The comet’s icy core, enveloped in a halo of dust and gas, may contain clues about the chemical makeup of distant star systems. The tails, driven by heat and solar radiation, allow researchers to examine how volatile compounds react when exposed to the sun.
Every interstellar visitor brings unique opportunities to compare our own solar system’s formation with that of other star systems. By analyzing the composition of 3I/ATLAS, scientists hope to uncover information about the types of materials that exist in other parts of the galaxy and how they evolve over time.
Future observations and research potential
The data collected by Hubble and Juice represent only a portion of the potential insights this comet can provide. Upcoming observations from both ground-based and space-based telescopes will help track the comet’s motion, measure its brightness variations, and refine models of its trajectory.
As additional data are received from Juice, scientists expect to gain insights into the dispersion of dust and gas within the coma and tails, the dimensions and spin of the comet’s nucleus, and possible isotopic markers that might unveil the interstellar environment it emerged from. These discoveries could broaden our comprehension of planetary formation, interstellar chemistry, and the frequency of comets moving between star systems.
The unique opportunity presented by 3I/ATLAS underscores the importance of coordinated observations from multiple space missions. By combining high-resolution imaging from Hubble with in-situ measurements from Juice, scientists can create a comprehensive picture of an object that has traveled across the galaxy to reach our solar system.
In conclusion, comet 3I/ATLAS offers an extraordinary glimpse into the wider universe beyond our solar system. Its teardrop-shaped coma, dual tails, and interstellar origins provide invaluable data for astronomers, while its safe approach allows continued observation from Earth. The ongoing analysis of images and measurements from Hubble and the Juice spacecraft promises to deepen our understanding of how interstellar objects behave, paving the way for future discoveries about the cosmos.
