Space agencies in the United States and Europe have released new, detailed images of the interstellar comet 3I/ATLAS. The photographs, captured by the Hubble Space Telescope and the Juice orbiter, show the visitor from another star system becoming increasingly active as it prepares for its closest approach to Earth on December 19.
The comet is currently traveling at an astonishing speed of approximately 130,000 mph (210,000 km/h) and is visibly shedding gas and dust after its recent pass by the sun. These new observations provide scientists with an unprecedented look at an object that originated outside our solar system.
Key Takeaways
- NASA and the European Space Agency (ESA) have released new images of interstellar comet 3I/ATLAS.
- The comet is shown to be highly active, with a glowing coma and developing tails, after passing the sun in October.
- Its closest approach to Earth is scheduled for December 19, at a distance of about 170 million miles.
- Multiple spacecraft, including Hubble and ESA's Juice, are coordinating observations to study the rare object.
Hubble Captures a Brighter Visitor
NASA released its latest image of 3I/ATLAS on December 4, captured by the Hubble Space Telescope on November 30. The photograph was taken when the telescope was about 178 million miles (286 million km) from the comet, offering a significantly clearer view than initial observations made in July.
The image reveals a bright, glowing core, which is a combination of the comet's solid nucleus and its surrounding atmosphere of gas and dust, known as the coma. As Hubble tracked the fast-moving comet, background stars appear as elongated streaks, emphasizing the comet's rapid journey through our solar system.
What Makes a Comet Active?
Comets are often described as cosmic snowballs made of ice, dust, and rock. As they approach a star like our sun, the heat causes the ice to turn directly into gas in a process called sublimation. This gas, along with dislodged dust particles, forms the coma and is pushed away by solar radiation and solar wind to create the iconic tails.
The new Hubble image faintly shows features consistent with this activity. The warming from its solar pass has clearly energized 3I/ATLAS, causing it to brighten considerably. Scientists are now analyzing the data from this observation to learn more about the composition of its coma, which could provide clues about the chemical makeup of its home star system.
ESA's Juice Gets an Even Closer Look
The European Space Agency also shared a remarkable view of the comet, taken by its Jupiter Icy Moons Explorer (Juice) spacecraft on November 2. Juice was significantly closer to the comet than Hubble, at a distance of only 41 million miles (66 million km), providing a more intimate portrait of the object's activity.
The image from Juice is detailed enough to hint at the presence of two distinct tails. An ESA spokesperson noted the visibility of the comet's plasma tail, composed of charged gas, and a fainter dust tail made of solid particles.
"Not only do we clearly see the glowing halo of gas surrounding the comet known as its coma, we also see a hint of two tails," an ESA statement explained.
Juice utilized five of its scientific instruments during its observation window. However, the full dataset will not be available for some time. The spacecraft is currently using its main antenna as a heat shield during its journey, meaning the complete scientific findings are not expected to reach Earth until late February 2026.
A Rare Interstellar Object
3I/ATLAS is only the third confirmed interstellar object ever detected passing through our solar system. Initial estimates suggest it could be the largest yet, with a nucleus width between 1,400 feet (440 meters) and 3.5 miles (5.6 km).
A Coordinated Global Observation Effort
The study of 3I/ATLAS has evolved into a widespread international campaign, leveraging spacecraft positioned across the solar system. What makes this effort unique is that many of the participating probes, like Juice, were not originally designed for comet tracking.
At least a dozen different spacecraft have observed 3I/ATLAS, including Mars rovers, solar orbiters, and asteroid trackers. This impromptu network of observatories is providing a multi-point perspective on the comet's behavior and trajectory as it moves away from the sun and toward its rendezvous with Earth's orbit.
This collaborative approach highlights the adaptability of modern space exploration, where instruments can be repurposed to seize rare scientific opportunities.
What's Next for 3I/ATLAS
The scientific community is preparing for the comet's closest approach to our planet on December 19. While it will pose no threat, passing at a safe distance of about 170 million miles (270 million km)—nearly twice the distance from Earth to the sun—it represents a prime opportunity for observation.
Upcoming observation plans include:
- The James Webb Space Telescope is scheduled to take another look at the comet, using its powerful infrared instruments to analyze its composition in greater detail.
- Ground-based scientific observatories around the world will be tracking its path.
- Amateur astronomers will also have a chance to spot the interstellar visitor as it brightens in our skies.
Every piece of data gathered from this unique object is valuable. By studying its size, speed, and chemical makeup, scientists hope to gain a better understanding of planetary systems beyond our own. As 3I/ATLAS completes its brief tour of our inner solar system, it leaves behind a wealth of information that will be studied for years to come.