Astronomers using the James Webb Space Telescope have identified GS18660 as the most distant ring galaxy ever found, observed as it appeared just 2.1 billion years after the Big Bang, according to Live Science.

The team had not set out to find a ring galaxy: GS18660 merely looked stretched out in older Hubble Space Telescope images.

When researchers observed it with JWST's Near-Infrared Spectrograph, the sharper data revealed a prominent ring of newborn stars and let them study the galaxy in three dimensions. The study was published Sept.

8 in the journal Astronomy & Astrophysics, Live Science reports.

Ring galaxies form when a small 'intruder' galaxy plunges head-on through the disk of a larger one, sending a wave of dense gas rippling outward like ripples from a stone dropped in a pond. Gas piles up along the wave and ignites a ring of star formation.

These systems are rare in the local universe — roughly 1 in 10,000 galaxies — and distant candidates have been hard to confirm.

Live Science quotes Christopher Conselice, an extragalactic astronomy professor at the University of Manchester who was not involved in the study, saying such a snapshot of a merger is rare given the timescales involved, and that the system is 'quite unique' and may yield important information about early galaxy formation.

Several clues point to an intruder, per Live Science. The team spotted a small companion galaxy receding from GS18660 at about 264 miles per second (425 km/s), with a bridge of gas linking the two whose velocity changes along its length — a sign the pair may be interacting.

The companion also sits along the main galaxy's minor axis, where an intruder would be expected after a head-on plunge.

Using the companion's speed and distance, the researchers estimated the collision happened roughly 17 to 42 million years earlier in the galaxy's history, and that 10% to 20% of the stellar mass in the ring formed in the past few tens of millions of years.

'It is not, by itself, definitive proof of a collision, but together with the bridge and the ring morphology, it strengthens the case for a recent impact,' study first author Michele Perna told Live Science.

If GS18660 is confirmed as a collisional ring, Live Science reports that Perna says estimates of how frequently these systems occur in the distant universe would need revisiting, since head-on collisions may have been more common early on than previously thought.

A competing explanation remains: GS18660 also shows a north-to-south bar-like structure, and stellar bars can funnel gas into rings — though no clear bar-driven ring has yet been found this early in cosmic history.

Either way, Perna told Live Science, the result would show how galaxies were already becoming structurally organized when the universe was only a few billion years old.

Webb's hot streak continues elsewhere: ScienceDaily reports JWST phase-curve observations of the lava world TOI-561 b suggest a thick atmosphere reflecting about 75% of starlight, possibly shielded by silicate clouds.