A strange comet from another star system has given scientists a first-of-its-kind chemical clue.
The James Webb Space Telescope captured an image of a comet that was nearly 277 miles from Earth and directly detected it having methane, a first for an interstellar object.
The comet, named 3I/ATLAS, was found to be about 1.6 miles long, and its gas mix suggests that it formed in conditions unlike those found anywhere in our solar system, per Sci.News.
The detection came from Webb's Mid-Infrared Instrument, which analyzed the spectral signatures of materials escaping from 3I/ATLAS as it moved through space.
A Caltech astronomer, Matthew Belyakov, explained to Sci.News why the discovery is important. Belyakov said, "ISOs offer discrete glimpses into extrasolar small-body populations and provide a valuable point of comparison for assessing commonalities and differences in planetesimal formation processes throughout the galaxy."
Belyakov and his team of researchers went on to describe the chemical makeup of the comet's coma, the mix of dust and gas that surrounds it, in a study published in the peer-reviewed Astrophysical Journal Letters.
TCD Picks » EDF Spotlight
💡EDF's Vital Signs newsletter delivers stories about game-changing solutions close to home and around the world
The team explained that "ground-based spectroscopy at visible wavelengths yielded detections of gas-phase cyanogen and atomic nickel, while radio observations by the ALMA added methanol and hydrogen cyanide to the molecular inventory."
Webb's MIRI initially observed the comet twice in December 2025. Because the methane signal showed up after a delay, scientists concluded it was likely hidden beneath the surface until solar heat reached deeper icy layers.
The team of astronomers also confirmed that the comet remained unusually rich in carbon dioxide relative to water, adding to the evidence that it may have originated in a very different planetary system.
Tools like MIRI and the Webb telescope are expanding scientists' understanding of where water, carbon, and other compounds tied to life exist in space. The more clearly researchers can map those building blocks, the better they can refine theories about how solar systems form and evolve.
TCD Picks » Quince Spotlight
💡These best-sellers from Quince deliver affordable, sustainable luxury for all
Get TCD's free newsletters for easy tips, smart advice, and a chance to earn $5,000 toward home upgrades. To see more stories like this one, change your Google preferences here.
Cool Picks
