3I/Atlas
Astronomers using the James Webb and Hubble telescopes are tracking unusual gas jets from interstellar object 3I/ATLAS, which may be experiencing cryovolcanic “ice volcano” activity as it nears the Sun. YouTube

Astronomers studying the interstellar object 3I/ATLAS say its behaviour is becoming stranger by the week, with new observations indicating the visitor may be experiencing cryovolcanism —violent eruptions of gas and dust driven by buried ices.

The discovery, reported across NASA Science, could transform scientific understanding of how small bodies form in distant star systems.

Only the third confirmed interstellar object ever observed, 3I/ATLAS, is shedding chemical and geological clues that researchers say do not match anything typically seen in comets inside the Solar System.

As the object races toward deep space on a one-way trajectory, scientists are working urgently to decode its origin and the unusual volcanic activity it displays.

A Rare Interstellar Visitor With Unusual Speed And Size

3I/ATLAS was first detected on 1 July 2025 by the ATLAS telescope in Chile, which quickly flagged its hyperbolic trajectory as evidence that it originated beyond the Solar System, according to NASA Science.

Early modelling based on Hubble Space Telescope data placed its size between 440 metres and 5.6 kilometres. When it made its closest approach to the Sun in late October, NASA calculated it was travelling at roughly 246,000 kilometres per hour.

Its interstellar speed and substantial size would already make it scientifically valuable, but researchers say the real intrigue lies in the strange activity emerging from its surface.

Evidence Of CO₂-Rich Cryovolcanism Stuns Researchers

Imaging from multiple telescopes shows jets of gas and dust erupting from 3I/ATLAS—behaviour that Live Science and IFLScience note is far more consistent with cryovolcanic plumes than standard sunlight-driven outgassing.

Infrared data from the James Webb Space Telescope reinforces that idea. A preprint on arXiv reports that the object's surrounding gas cloud is dominated by carbon dioxide, with smaller amounts of water, carbon monoxide, OCS, water ice, and dust.

Crucially, the CO₂-to-water ratio is roughly 8 to 1, among the highest ever recorded in a comet-like body.

Nature World News adds that the combination of volatile ices and metal-rich material strengthens the case for cryovolcanism, suggesting deep deposits of frozen gas erupt as the object heats.

Chemical Signatures Hint At A Distant, Primitive Origin

Spectral data compared with carbonaceous chondrites points to a chemically primitive composition rich in metals and ancient compounds, according to arXiv analysis.

Scientists say the object may preserve material that formed around another star before the Sun even existed, offering a rare opportunity to examine unaltered debris from a distant protoplanetary disk.

IFLScience notes that if cryovolcanism is confirmed, it would show that geological activity seen on icy moons like Europa and Enceladus is not unique to our Solar System.

'3I/ATLAS may preserve chemical signatures from conditions very different from those that shaped the Solar System'.

Key Questions Remain As Time Runs Out

Despite rapid study, scientists still cannot determine whether the eruptions are caused solely by sunlight heating volatile ices or whether unknown processes are involved.

Live Science reports that the unusually high metal content challenges traditional comet models, which usually assume softer, ice-dominated interiors.

With 3I/ATLAS already on its outbound path, researchers have only months left to gather data before it disappears back into interstellar space.

A Messenger From Elsewhere

For astronomers, 3I/ATLAS is more than a scientific oddity. It is a physical remnant of another star's history, a piece of frozen material carrying clues from an unknown corner of the Milky Way.

As Nature World News wrote in a recent commentary, objects like this may contain 'foundational materials' from long-vanished planetary systems.

Whether or not cryovolcanism is confirmed, scientists say the insights from 3I/ATLAS will help rewrite models of how small bodies evolve and how planets form.

With every new plume detected and every chemical signature analysed, researchers are piecing together a story written far beyond the Sun's reach.