Webb Detects Methane on Interstellar Comet 3I/ATLAS, Finding High CO2 236 Million Miles Out
Updated
Updated · SciTechDaily · Jun 6
Webb Detects Methane on Interstellar Comet 3I/ATLAS, Finding High CO2 236 Million Miles Out
3 articles · Updated · SciTechDaily · Jun 6
Summary
James Webb captured the first mid-infrared chemical fingerprint of an interstellar object, showing comet 3I/ATLAS carries methane gas and unusually high carbon dioxide.
Methane appeared after the comet’s close pass by the Sun, suggesting the volatile had been buried below the surface and was released only as deeper ice layers warmed.
Two MIRI observations on Dec. 15-16 and Dec. 27 tracked 3I/ATLAS at 205 million and 236 million miles from the Sun, with gas production dropping sharply as it moved outward.
High methane and carbon-dioxide levels relative to water differ from most solar-system comets, pointing to formation in a markedly different planetary system around another star.
What alien star system could create a comet with a chemical fingerprint so unlike our own?
This interstellar visitor's chemistry is bizarre. What if our solar system is the true cosmic exception?
Could the strange chemicals on this alien comet hint at entirely new pathways for life on other worlds?
JWST Reveals Methane and Extreme CO2 Dominance on Interstellar Comet 3I/ATLAS: Unprecedented Insights into Alien Chemistry and Planetary Origins
Overview
NASA’s James Webb Space Telescope (JWST) made the first direct detection of methane gas on interstellar comet 3I/ATLAS as it exited our solar system, using its highly sensitive MIRI instrument. The methane, originally preserved as ice in the comet’s nucleus during its journey through interstellar space, sublimated into gas as the comet warmed near the Sun, making it detectable. JWST’s observations also revealed a chemical fingerprint strikingly different from solar system comets, with a CO2-dominated coma and unusually high CO2 to water ratios. These findings provide new insights into the formation environments and thermal histories of objects from beyond our solar system.