By Samuel A. Lopez, USA Herald – October 24, 2025
USA HERALD – When the interstellar object now known as 3I/ATLAS was discovered this summer by NASA’s ATLAS telescope in Chile, astronomers expected another ordinary cosmic traveler, much like ʻOumuamua or Borisov. They were wrong. The strange visitor, now hurtling through our solar system on a hyperbolic escape path, is rewriting what scientists thought they knew about comets—and possibly about how planets form across the galaxy.
For months, headlines have repeated the same talking points: “third interstellar object,” “no danger to Earth,”“passing through the solar system.” But the real story, one buried beneath the routine coverage, is that 3I/ATLAS behaves in ways that defy the norms of cometary science. Behind the scenes, telescopes from Earth orbit to Mars are watching it like detectives at a crime scene—because this one doesn’t match any known profile.
A Chemical Mystery Written in Gas and Ice
The James Webb Space Telescope has revealed something extraordinary: 3I/ATLAS’s vapor cloud, or coma, is dominated by carbon dioxide rather than water. In most comets, water ice is the main volatile, sublimating into gas as the comet nears the Sun. But for 3I/ATLAS, the CO₂-to-water ratio is about eight to one—an extreme outlier never observed in our solar system.
