NASA and Gemini North Unveil Interstellar Comet 3I/ATLAS's Eerie Green Glow

Astronomers using the Gemini North telescope in Hawaii have released new images of Comet 3I/ATLAS, a rare interstellar object passing through the Solar System.

The images show the comet glowing with a distinctive green hue as it travels through space, a result of gases released from its surface interacting with solar radiation.

The comet was discovered in 2025 and is only the third known object identified as originating from beyond the Sun's gravitational influence.

Scientists believe 3I/ATLAS may also be the oldest comet ever observed, offering a unique opportunity to study material formed around another star system. Observations were carried out from the Gemini North Observatory, located on the summit of Maunakea, a dormant volcano in Hawaii.

Having formed around a distant, unknown star, it is a fossil of a different solar system altogether, and it is currently putting on a spectacular show as it prepares to vanish into the void forever.

A Ghostly Metamorphosis: The Green Glow Of Comet 3I/ATLAS

When astronomers first tracked the comet using the Gemini South telescope in the Chilean Andes, the visitor appeared with a subtle, rusty red hue. However, as it reemerged from behind the Sun in late 2025, the transformation was undeniable.

The new images, captured on 26 November 2025, reveal a vivid green coma, the envelope of gas and dust surrounding the comet's nucleus.

Scientists explain that this dramatic colour shift is a direct result of the Sun's punishing heat. As 3I/ATLAS made its close approach, the frozen ice deep within its ancient frame began to vaporise, venting gases into the vacuum of space.

Specifically, the presence of diatomic carbon is responsible for the emerald tint, as these molecules emit light at green wavelengths when excited by solar radiation. It is a chemical 'scream' from a visitor that has been frozen for billions of years, only to be thawed out by our local star.

Precision Tracking: How Gemini North Captured Comet 3I/ATLAS

Capturing a high-resolution portrait of a guest moving at such breakneck speeds is no small feat. Because comets like 3I/ATLAS move incredibly fast relative to the background stars, the Gemini North telescope had to track its movement with surgical precision to keep it in frame for long photographic exposures.

Using the Gemini Multi-Object Spectrograph, astronomers utilised four distinct filters: blue, green, orange, and red to compile the final image. During the raw exposure process, the background stars appeared as elongated streaks due to the telescope's focus on the moving comet.

However, through sophisticated processing, the team at NSF NOIRLab managed to fix the stars in place, providing a clear, 'front-row view' of the interstellar visitor. Bryce Bolin, a research scientist from Eureka Scientific who led the science program, noted that this initiative helps 'demystify the scientific and data collection process', offering the public a rare level of transparency into how we study these fleeting celestial events.

The Long Goodbye: The Final Journey Of Comet 3I/ATLAS

Unlike the familiar comets that return to our skies every few decades, 3I/ATLAS is on a one-way trip. It is not bound by the Sun's gravity in a closed loop; instead, it entered our system from the interstellar deep and is currently on its way out.

As it recedes, it will eventually cool down, but the drama may not be over just yet.

Astronomers warn that some comets experience 'delayed outbursts'. As solar heat slowly penetrates the comet's interior, pockets of trapped gas could suddenly erupt, even as the object moves further away into the cold.

The Gemini telescopes will continue to monitor the object's departure until it is gone from our view for eternity. It serves as a poignant reminder of our place in a much larger, more mysterious universe, a brief, glowing handshake from a star system we will likely never visit.