The James Webb Space Telescope observed a large amount of methane around 3I/ATLAS, revealing just how different it is from comets from our solar system.

Interstellar comet 3I/ATLAS is blasting out a bunch of methane. Here's why that's weird

Source: space
Source Link: https://www.space.com/astronomy/comets/interstellar-comet-3i-atlas-is-blasting-out-a-bunch-of-methane-heres-why-thats-weird