Investigador español del CSIC resuelve el misterio del cometa 3I/ATLAS

A Spanish researcher has solved one of astronomy's recent puzzles: the strange behavior of comet 3I/ATLAS, an interstellar visitor that sparked wild speculation about alien contact and hidden experiments. Josep Trigo, lead investigator of the Meteorites, Minor Bodies, and Planetary Sciences Group at Spain's CSIC research council, published findings that strip away the mystery and replace it with something far more elegant—a comet that behaves exactly as physics predicts, once you understand where it came from.

The comet formed in a different solar system billions of years ago, making it fundamentally alien to our corner of space. Yet its composition, while distinct from objects born around our sun, resembles the icy bodies that orbit beyond Neptune in our own system. This similarity is the key to understanding its unusual activity. When 3I/ATLAS approached within 378 million kilometers of the sun, temperatures rose to around minus 71 degrees Celsius—warm enough to trigger the sublimation of frozen carbon dioxide. That phase change unleashed the comet's most dramatic feature: cryovolcanism, a process in which internal pressure forces gases and particles outward across the surface.

What made 3I/ATLAS so conspicuous to observers was the sheer volume of material it ejected. As carbon dioxide ice transformed directly into gas, different regions of the comet's surface activated in sequence, multiplying the production of gas and dust. The coma—the glowing envelope surrounding the nucleus—brightened dramatically. This is not the behavior of a typical solar system comet, which tends to release methane or ammonia as it warms. The carbon dioxide emissions at such great distance from the sun caught scientists' attention and fueled speculation that something unusual was happening.

Trigo's team determined that the comet rotates on its axis every 16 hours, a detail that helps explain the timing and intensity of the outbursts. The research, published on the arXiv preprint platform, reveals that 3I/ATLAS remained largely intact during its journey through space—it was not significantly altered by radiation or collisions. This preservation allowed the team to read its composition like a fossil record, revealing clues about how planets form in distant systems.

The broader implication of the work is striking: the chemistry that builds planets appears to be universal. Despite forming around a different star, 3I/ATLAS contains materials fundamentally similar to those in our solar system. This suggests that the same physical and chemical processes that created Earth and its neighbors operate throughout the galaxy. The comet's visit, far from being a harbinger of extraterrestrial contact, is instead a messenger from the cosmos confirming that we are not unique—that the universe builds worlds the same way everywhere. As December approaches and observers turn their telescopes skyward to catch a glimpse of this famous visitor, they will be looking at evidence that the laws of nature are written in the same language across the stars.