Interstellar Comet 3I/ATLAS Shows Increased Activity Ahead of Flyby

New images from NASA and the European Space Agency (ESA) indicate that interstellar comet 3I/ATLAS is exhibiting heightened activity as it approaches Earth for a flyby on December 19, 2023. The comet, which is currently about 270 million kilometres from our planet, has been racing through the inner Solar System and recent observations suggest that its close encounter with the Sun has triggered increased emissions of gas and dust.

NASA Images Capture Comet’s Brightening

The latest photographs of the comet, taken by the Hubble Space Telescope, reveal a bright nucleus surrounded by a rapidly expanding coma. This phenomenon occurs as material sublimates, or transforms from solid to gas, escaping into space. NASA explained that comets typically brighten as they heat up, and the jet-like features observed in the images suggest an active surface responding to solar radiation.

Since its confirmation as an interstellar visitor earlier this year, 3I/ATLAS has garnered significant scientific interest. NASA has detailed the comet’s size, speed, and unusual composition in a comprehensive report. The findings indicate that the nucleus measures between 440 metres and 5.6 kilometres wide, making it one of the largest interstellar objects detected to date.

ESA’s Juice Spacecraft Provides Additional Insights

The ESA’s Juice spacecraft, which is en route to Jupiter’s moons, has also contributed valuable data by capturing striking images of 3I/ATLAS from just 66 million kilometres away. This photograph highlights a glowing halo and two distinct tails, consistent with a comet undergoing rapid activity. The images were taken shortly after the comet’s closest approach to the Sun, offering researchers clearer insights into its behaviour as it warms.

Both Hubble and Juice are part of an expanding network of spacecraft monitoring the comet. Observatories across the Solar System are gathering complementary data, with each new set of images enhancing understanding of the materials that formed outside our planetary system. Scientists value this rare opportunity to study 3I/ATLAS, believed to be nearly 10 billion years old.

The comet will be visible to skilled observers during its Earth flyby, although a telescope with at least a 30-centimetre aperture is necessary due to its magnitude. Those wishing to view the comet are advised to look for it before dawn, positioned beneath the star Regulus in the constellation Leo.

Astronomers emphasize that 3I/ATLAS poses no risk during its closest approach. Nonetheless, they regard this event as an opportunity to measure how interstellar objects react to extreme heating while traversing our Solar System. The James Webb Space Telescope is expected to observe the comet again in the coming weeks, and both professional and amateur astronomers will continue to gather data from Earth.

These observations will not only enhance understanding of the comet’s current activity but will also aid in refining predictions for its future trajectory. Following its passage by Earth, 3I/ATLAS will head towards Jupiter, where a close encounter in March 2026 could alter its path. The extent of this change will likely depend on how much material the comet continues to release after its recent surge in activity.

As December approaches, scientists recognize that this will be the only time 3I/ATLAS comes this close to Earth, presenting a unique chance to study a remarkable visitor from beyond our Solar System.