New York 42 The decagon on Saturn was in the archive for three years before anyone saw it
The discovery was not made by pointing a telescope at something new. It was made by looking again at pictures that had already been taken, filed and paid for.
What is there
A giant ten-sided atmospheric wave is circling Saturn’s south pole — the first large, regular-sided jet pattern found in the planet’s southern hemisphere. It was confirmed with NASA’s Hubble Space Telescope and published on 2 September 2026 in Science Advances, in work led by Agustín Sánchez-Lavega of the University of the Basque Country.
The order of events
Hubble frames from 2023 carry faint hints of a ten-vertex figure. In 2024, Sánchez-Lavega and the amateur astronomers Trevor Barry and Jean-Paul Oger noticed an undulating band along the southern pole from the ground. By August and September 2025 Hubble was returning a fully defined decagon.
Why it matters that it is growing
Saturn’s northern hexagon has been in every good look at the planet for more than forty years and has barely changed. Amy Simon of NASA Goddard, principal investigator of the Outer Planet Atmospheres Legacy programme, on the new one: «We’ve never seen anything quite like this in Saturn’s southern hemisphere. This feature is different — it appears to be strengthening.»
A feature caught while it is still forming can be watched from the beginning. Nobody got to do that with the hexagon.
OPAL is the reason this exists, and it is an argument for a kind of science that is hard to fund: photograph the same four planets every year and keep everything, whether or not anything is happening. Mike Wong of UC Berkeley made the point without embellishment — the discoveries come out of years and years of data rather than one observation. The corollary for a reader is smaller and more usable. When a result like this lands, the paper is rarely the moment of discovery; it is the moment the archive was re-read with a question that did not exist when the pictures were taken. That is also why two amateurs are named on a Hubble result: professional coverage of Saturn is annual, and the people watching it most nights are the ones positioned to notice a change begin.
Source: NASA Science checked against the source
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