James Webb Just Detected a 1 Million Gigawatt Signal Coming From 3I/ATLAS

 

Sensational Headlines Fuel Speculation

On social media and other sensationalist sites (including one YouTube video with the title "James Webb Just Detected a 1 Million Gigawatt Signal Coming From 3I/ATLAS"), a sensational assertion has been making the rounds: that NASA's James Webb Space Telescope (JWST) had picked up a massive "1 million gigawatt signal" coming from interstellar comet 3I/ATLAS. Catchy though it is, it seems to be purely made-up and unsubstantiated by solid scientific sources

What Did JWST Actually See?

Actually, on August 6, 2025, the JWST employed its Near-Infrared Spectrograph (NIRSpec) to look at the interstellar comet 3I/ATLAS, and it found a coma dominated by carbon dioxide (CO₂) with significant—but lesser—quantities of water (H₂O), carbon monoxide (CO), and carbonyl sulfide (OCS)

The JWST data recorded one of the highest CO₂-to-H₂O ratios ever observed in a comet: approximately 8:1, which is 6σ above the typical cometary trend.

Cometary Composition: What It Tells Us

This unusually CO₂-rich composition suggests that 3I/ATLAS may have formed in a different environment than typical Solar System comets—perhaps closer to a CO₂ ice line in its parent protoplanetary disk, or exposed to higher levels of radiation

Other results from other instruments are:

Swift Observatory (UV): Found water activity via OH emission, which suggests a production of approximately 40 kg of water per second

SPHEREx observations (Aug 7–15): Also confirmed the existence of CO₂ and water ice in the coma of the comet Sky at Night Magazine.

TESS precovery data: Revealed that 3I/ATLAS could have been active far away (~6.4 AU from the Sun), suggesting remote activity prior to its detection.

New Discoveries Continue Unfolding

Space agencies such as ESA are preparing further observations as the comet passes Mars on October 3, 2025, which could provide additional compositional information from orbiters such as Mars Express and Trace Gas Orbiter

In addition, evidence indicates 3I/ATLAS can be incredibly old—potentially 7 to 14 billion years, suggesting a formation in the Milky Way's thick disk

Bottom Line: No "Gigawatt Signal," Just Cosmic Chemistry

Clarification: there is no scientific evidence that JWST has found a "1 million gigawatt signal" from 3I/ATLAS—this is apparently a completely sensational report with absolutely no support in the scientific literature or NASA announcements.

What JWST actually did find was much subtler—and more scientifically precious—a compositionally anomalous interstellar comet whose CO₂-rich coma is recalibrating our understanding of comet chemistry.

Why This Matters

Interstellar comets such as 3I/ATLAS give us occasional glimpses of material from outside our Solar System. JWST observations add to our knowledge of the conditions under which comets formed throughout the galaxy. That one such object could have a CO₂-dominated composition—and potentially be billions of years old—is much more fascinating than any hypothetical "gigawatt signal."