Level 1 — Absolute Beginner
Saturn is a big planet in space. It has rings and strong winds. For a long time, scientists knew about a special six sided shape near its north pole. It looks like a hexagon.
Now scientists have a new discovery. They used the Hubble Space Telescope to look at the south pole of Saturn. They found a new shape there. It has ten sides. This shape is called a decagon.
This is the first time anyone has seen a big shape like this at Saturn's south pole. Scientists shared the news on September 2, 2026, in a science journal called Science Advances. The decagon is very big. It is about 104,250 miles wide.
An old spacecraft called Cassini looked at Saturn's south pole for many years, from 2004 to 2017. It never saw a shape like this. So this new ten sided shape must be new. Scientist Amy Simon says the shape seems to change more than the north pole hexagon.
- planet
- a large round object in space that moves around a star
- shape
- the outline or form of something
- telescope
- a tool used to see things that are far away, like planets
- space
- the area outside Earth where the planets and stars are
- pole
- the very top or bottom point of a planet
- wind
- moving air
- spacecraft
- a machine that flies in space
- scientist
- a person who studies the world to learn new things
Level 2 — Elementary
Saturn has long been famous for a giant six sided cloud pattern that circles its north pole, known as the hexagon. It has been watched by spacecraft and telescopes for many years.
Now astronomers using NASA's Hubble Space Telescope have found something completely new. A ten sided shape, called a decagon, is circling Saturn's south pole. This is the first time such a large and regular many sided pattern has ever been seen in Saturn's southern hemisphere.
The results were published on Wednesday, September 2, 2026, in the journal Science Advances. The decagon is enormous, about 104,250 miles wide, and each of its ten sides stretches roughly 10,425 miles.
By looking back at Hubble images taken since 2023, researchers found faint hints of the shape starting to appear, and it has grown clearer over time. NASA's Cassini spacecraft studied Saturn's south pole closely from 2004 to 2017 and only ever saw a swirling, hurricane like storm there, with no polygon shape at all. That means the decagon must have formed sometime after 2017.
- astronomer
- a scientist who studies stars, planets and space
- hemisphere
- one half of a planet, such as the northern or southern half
- journal
- a magazine that publishes scientific research
- enormous
- extremely large in size
- hurricane
- a powerful, spinning storm
- pattern
- a shape or design that repeats or has a clear form
- published
- made public in print or online
- discover
- to find something for the first time
Level 3 — Intermediate
Saturn has been known for decades for an extraordinary atmospheric feature at its north pole, a persistent, six sided jet stream pattern that planetary scientists call the hexagon. Its counterpart at the south pole, by contrast, had only ever revealed a rotating, hurricane like storm, at least according to everything NASA's Cassini spacecraft observed while orbiting the planet from 2004 to 2017.
That picture has now changed. Using NASA's Hubble Space Telescope, astronomers have identified a ten sided wave, a decagon, circling Saturn's south pole, marking the first time such a large and regular many sided jet pattern has been documented in the planet's southern hemisphere. The findings were published on September 2, 2026, in the journal Science Advances.
The decagon is substantial in scale, roughly 104,250 miles across, with each of its ten sides extending about 10,425 miles. Reassembling a sequence of Hubble images dating back to 2023, researchers detected subtle hints of the shape beginning to emerge, a pattern that has grown increasingly well defined in the years since.
Because Cassini never spotted any such polygon during its long period of close observation, the decagon must have formed sometime after the spacecraft's mission ended in 2017. Planetary scientist Amy Simon of NASA's Goddard Space Flight Center, who contributed to the discovery, has noted that in the limited observations gathered so far, the decagon appears to shift and evolve more than its long lived northern counterpart. The wave sits within one of Saturn's powerful jet streams and extends through multiple atmospheric layers, indicating that it is a genuine three dimensional structure rather than a superficial cloud pattern. Precisely why it has ten sides, or what triggered its appearance, remains unexplained.
- extraordinary
- very unusual or remarkable
- persistent
- continuing to exist over a long period of time
- jet stream
- a fast moving current of air high in an atmosphere
- counterpart
- a thing that matches or corresponds to another
- substantial
- large in size, amount or importance
- reassembling
- putting separate pieces back together
- polygon
- a shape with several straight sides
- superficial
- only on the surface, not going deeper
Level 4 — Advanced
For decades, Saturn's most celebrated atmospheric curiosity has been the hexagon, a persistent, six sided jet stream pattern that has encircled the planet's north pole, remaining strikingly stable across the intervening years. Its southern counterpart offered no such symmetry. NASA's Cassini spacecraft, which orbited Saturn and studied its south pole in detail from 2004 to 2017, recorded only a rotating, hurricane like vortex, with no hint of any polygonal structure.
That asymmetry has now been overturned. Astronomers working with NASA's Hubble Space Telescope have identified a ten sided wave, a decagon, encircling Saturn's south pole, the first instance of such a large, regular, many sided jet pattern ever observed in the planet's southern hemisphere. The results, published Wednesday, September 2, 2026, in the journal Science Advances, describe a structure of considerable scale, about 104,250 miles in diameter, with each of its ten sides measuring roughly 10,425 miles.
The shape's emergence can be traced with some precision. Piecing together Hubble observations dating back to 2023, the researchers found subtle, early intimations of the pattern that have sharpened progressively into the well defined decagon visible today. Since Cassini's exhaustive southern survey ended in 2017 without a single sighting of any polygon, the feature's formation must postdate that mission, placing its origin somewhere within the last decade.
Amy Simon, a planetary scientist at NASA's Goddard Space Flight Center who worked on the discovery, has observed that, within the admittedly limited set of observations gathered so far, the decagon appears considerably more mutable than its long lived northern relative. Crucially, the wave is not a mere superficial cloud marking. It occupies one of Saturn's powerful jet streams and extends through multiple layers of the atmosphere, confirming it as a genuinely three dimensional structure. What continues to elude explanation is why the pattern favors ten sides in particular, and what atmospheric conditions conspired to produce it when they did.
- asymmetry
- a lack of balance or matching form between two sides
- vortex
- a spinning, whirling mass, such as of air or water
- polygonal
- having the form of a shape with many straight sides
- intimations
- slight or indirect signs of something
- mutable
- likely or able to change
- superficial
- existing only on the surface, without depth
- conspired
- acted together, as if by agreement, to bring something about
- exhaustive
- thorough and complete, covering everything
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