Saturn has a new, odd weather pattern resembling a decagon near its south pole. This may have formed due to a large storm nearby, but researchers aren’t totally sure.

The pattern has clearly defined sides shaped by powerful winds, looking like a decagon – a geometric polygon with 10 sides and 10 angles – from above. It is similar to a hexagonal weather pattern first seen at the planet’s north pole more than 40 years ago.

“[But] the one at the north is a bit smaller,” says at NASA’s Goddard Space Flight Center in Maryland. The south pole pattern also seems to be moving a bit more with the rotation of the planet.

The feature was first spotted by amateur astronomers in 2024. Simon and her colleagues then examined images taken by the Hubble Space Telescope from 2023 to 2025. “We confirmed the existence of the decagon with absolute clarity,” says team member at the University of the Basque Country in Spain.

It is unclear exactly when the pattern formed, with no spacecraft having orbited Saturn since 2017. “It most certainly wasn’t expected,” says Simon. “The hexagon has been there for decades, but this is something new.”

The decagon measures about 13,000 kilometres across, slightly wider than Earth. It is thought to result from a large atmospheric wave shaped by wind from a powerful jet stream that meanders near the planet’s south pole.

Its formation may be linked to a large nearby storm, although the exact cause is a bit of a mystery. “It’s a very complicated fluid dynamics sort of thing,” says Simon. “It’s telling us something about what’s going on deeper below the clouds.”

Saturn’s rings form a giant dusty doughnut encircling the planet

The rings of Saturn are normally thought to be flat, but measurements by the Cassini spacecraft show that some of their particles fly hundreds of thousands of kilometres above and below the thin main discs

at the California Institute of Technology says the discovery highlights that Saturn is a dynamic, changing world. “It’s very interesting to see these features,” he says.

No similar pattern has been observed on any other planets, although Jupiter does have an at its poles. “People didn’t really predict that such an organised, polygonal pattern would exist on another planet,” says Ingersoll.

We don’t know how long the pattern will last. Other telescopes, including the James Webb Space Telescope, are poised to study it in more detail, but many scientists are vying for access to those. “We’ll look as frequently as anyone will let us,” says Simon.

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Venus has no moon, but a modelling study suggests it probably did have one for nearly 2 billion years – before the planet ate it. Understanding this could help us learn about Venus’s previous habitability.

Many large objects probably hit Venus in the early solar system, which could have formed a moon, similar to the giant impact that is thought to have formed Earth’s moon. “There’s a very good chance that Venus did have a moon-forming impact,” says at the University of California, Riverside.

The lack of a moon today is therefore quite unusual, but Kane and his colleagues might have an answer. They modelled what would have happened if Venus did have a moon, and found that in almost all scenarios, it would have been consumed by the planet, long erased from existence by the present day.

Venus rotates quite strangely with respect to the sun, completing a rotation once every 243 days, compared with its orbit of 225 days. This is possibly a result of its thick atmosphere slowing its spin.

In contrast, Earth’s much faster spin transfers angular momentum to our moon, meaning it is moving away a few centimetres each year. For Venus, the opposite would have been true. “The moon is transferring angular momentum inward instead of outward,” says Kane. “It causes the moon’s orbit to catastrophically collapse.”

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The researchers found that at the upper limit of their models, a moon about half the mass of our own could have survived around Venus for 1.7 billion years. At twice the mass of our moon, it would have survived just 30 million years, because of the stronger tidal effect.

Once the moon reached a distance of about 15,000 kilometres, it would have encountered a boundary known as the Roche limit. “That’s where Venus’s gravity rips the moon apart and consumption occurs,” says Kane, with the moon’s debris temporarily forming a ring around Venus until it fell into the atmosphere.

at Washington University in St Louis, Missouri, says the model is interesting but hard to prove. “It’s exceedingly hard to test this idea because there is basically nothing left behind.” This is because Venus’s surface has been repeatedly resurfaced by volcanism, he says.

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Kane, however, says a future mission to the surface of Venus could include a seismometer, a device that measures seismic waves to study the interior of the planet. This could look for evidence of a consumed moon buried underground. “That would tell us a lot,” he says.

If Venus did have a moon, it may have played a role in the planet’s habitability, with Venus once thought to have had oceans on its surface. It is possible a moon could be linked to the planet’s runaway greenhouse effect, in which it lost all its water for reasons unknown and developed a thick, deadly atmosphere.

“If there was an early habitable period of Venus, then the big question is what brought that to an end,” says Kane. A moon crashing into the planet could have evaporated much of its water. “It could definitely be connected to Venus’s runaway greenhouse state,” says Kane.

The Neil Gehrels Swift Observatory is doomed to burn up in Earth’s atmosphere in the coming months, after a high-risk effort to save it failed.

On Wednesday 19 August, NASA said in a that an ongoing issue with the LINK spacecraft, built by US start-up Katalyst Space, meant that an effort to dock with and boost Swift in orbit would no longer be attempted.

“NASA should be willing to move quickly and take smart risks when the potential return is worth it, and that is exactly what we did with this mission,” NASA Administrator Jared Isaacman said in the statement. “This is not the outcome we were working toward, but it does not change why this mission was worth attempting.”

LINK was launched in July on a mission to save Swift, a rapid-response telescope used to observe brief celestial events such as gamma-ray bursts. Swift has been steadily dropping in orbit since its launch in 2004 due to atmospheric drag. The $30 million rescue mission, designed and built in less than a year, was a last-ditch attempt to boost the telescope back into a higher orbit.

Soon after launching, however, LINK began to spin out of control. While Katalyst later stabilised the spacecraft, it was deemed to have to make the boost possible.

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“Katalyst designed, developed, and launched an experimental spacecraft to go after an ambitious mission on an aggressive timeline,” the company’s CEO, Ghonhee Lee, said in a statement. “We took on this high-risk, high-reward challenge and are proud of the milestones we reached along the way.”

LINK will still rendezvous with Swift, but will no longer attempt to grab the telescope with its robotic arms. That means Swift will have a limited amount of final observations it can do before it re-enters the atmosphere by the end of the year, with no replacement telescope currently in the works.

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