Methane on a star-hopping comet
Comet 3I/ATLAS, only the third interstellar object ever confirmed to pass through our solar system, has yielded a remarkable chemical fingerprint. Using the James Webb Space Telescope — a joint mission of NASA, ESA, and the Canadian Space Agency — researchers announced in early June 2026 the detection of methane in the comet's coma. It marks the first time an organic molecule of this kind has been directly identified on a body originating from another star system.
Methane holds a privileged place in discussions about prebiotic chemistry. Its presence aboard 3I/ATLAS raises a compelling possibility: volatile organic compounds may travel between stellar systems carried by wandering small bodies, seeding the interstellar medium with the raw materials that, under the right conditions, could participate in the chemistry of life. Whether this makes 3I/ATLAS a representative sample of interstellar material or an exceptional case remains an open question that astronomers are eager to investigate.
Time, however, is short. Like its predecessors 'Oumuamua and Borisov, 3I/ATLAS is moving through the solar system at high velocity and is already receding. Webb, stationed at the Sun-Earth Lagrange point L2 some 1.5 million kilometres from Earth, is one of the very few instruments with the spectroscopic sensitivity to analyse such a faint, fast-moving object at this range.
Shedding light on Webb's Little Red Dots
Almost simultaneously, a separate international team using Webb targeted one of the telescope's most debated early findings: the so-called Little Red Dots. These compact, reddish, intensely luminous sources appeared in Webb's deep fields from the very first observation campaigns and have since challenged standard models of galaxy formation, appearing far too massive and too active for their cosmic age.
By pointing Webb at the galaxy cluster Abell 2744 — which acts as a natural gravitational lens, magnifying background objects — the team identified a quasar designated Abell2744-QSO1. The supermassive black hole at its core appears to have assembled an enormous mass within a surprisingly short time after the Big Bang. Published in late May 2026, the findings offer the most concrete evidence yet that at least some Little Red Dots are powered by black holes undergoing exceptionally rapid accretion in the early universe.
The leading explanation involves bursts of intense accretion activity, potentially interspersed with obscuration by dense dust clouds, which would account for both the characteristic red colour and the way these objects behave differently depending on the wavelength used to observe them. The picture is not yet complete, but it is coming into sharper focus.
A telescope rewriting the textbooks
Taken together, these back-to-back results underline the extraordinary breadth of Webb's scientific reach, spanning everything from small bodies drifting through the solar neighbourhood to galaxies at the edge of the observable universe. Launched in December 2021 on an Ariane 5 rocket from the Guiana Space Centre, Webb has now been fully operational for over three years, and the data it continues to gather push well beyond what Hubble or Spitzer could achieve.
The deeper questions remain wide open. If the Little Red Dots represent a previously underestimated population of fast-growing black holes, how many of them are out there, and what does that imply for cosmological models? And if methane-bearing interstellar comets like 3I/ATLAS are common, how much organic material is quietly circulating across the galaxy, undetected until now? Webb may only be beginning to show us how much we have yet to learn.
