We may be on the verge of solving the mystery of the Martian moons. On 20 October, the Martian Moons eXploration (MMX) spacecraft launches towards the larger of the two moons, Phobos, with the goal of bringing back a sample that may finally explain how Phobos and its sibling, Deimos, formed.

MMX will launch from Tanegashima Space Center in Japan. If all goes to plan, it should arrive at Mars in August 2027, entering an orbit that keeps it alongside Phobos so it can build a detailed map of the surface. Along the way, it will also observe the surface of Deimos.

Once the map is complete enough, the spacecraft’s operators at the Japan Aerospace Exploration Agency (JAXA) will use it to pick out a spot on Phobos for MMX to land. During one or two brief landings, it will take on two tasks: to drop off a small rover called IDEFIX and to pick up samples. The rover is the first anyone has ever placed on such a small cosmic body, so part of its purpose aside from scientific observations is to confirm that a wheeled rover even works on an object with such low gravity.

The samples, though, are the most important part of the mission. MMX has two different sampling devices: one that shoots a puff of gas onto the surface, blowing dust and pebbles back up into a sampling container, and another that blasts a hollow cylinder into the ground to take a sample a several centimetres deep. After the samples are taken, they will be stowed away inside the spacecraft, which will then head back towards Earth. It is expected to arrive home in 2031.

Once these samples get back to Earth and are analysed by scientists on the ground, they should finally solve the mystery of how Phobos and Deimos formed. For more than a century, researchers have debated whether the two are captured asteroids or formed from an impact on Mars, similar to how Earth’s moon formed. On first look, their shapes and surfaces resemble asteroids, but their circular orbits around Mars’s equator are more consistent with the impact hypothesis. Figuring out what they are made of should settle it once and for all.

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This will also help illuminate what the solar system was like billions of years ago when these strange moons formed. “Having the answer will help illuminate that early era when Earth and the other inner planets may have been acquiring much of their water and organic compounds,” said , part of the NASA team that is collaborating on the MMX mission, in a .

If we are very lucky, the samples from Phobos may even contain bonus bits of dust and debris from Mars itself. Impacts on the planet could have launched material into space, which would have collected on the moon’s surface and been preserved there for billions of years. That means that these samples could illuminate not just the history of Phobos and Deimos, but also of Mars.

A newly formed crater on the moon is teaching us about our nearest neighbour’s complex geology. The crater, formed by an asteroid impact in 2024, is the largest that we’ve ever watched form in real time.

It was first spotted last year, when researchers compared sets of images taken by in both 2024 and 2025, and was named McGetchin crater. According to models of how often impacts occur on the moon, one this big – about 222 metres across – is only expected to occur about once every 132 years.

While the moon has many larger craters, watching one as it forms and evolves presents a unique opportunity to learn about the lunar surface and its geology. “Cratering is probably the most common process that happens in the solar system, so we spend a lot of time trying to understand how a new crater will modify a surface and watching that degrade over time,” says at Johns Hopkins University in Maryland. “Having a baseline for a pristine crater that can serve as our calibration point for how these processes start is really incredible.”

Powell and his colleagues measured the surface temperature in the region around McGetchin crater, and found that the impact had formed a spot about 7 kilometres wide that is a handful of degrees colder than the rest of the area during the lunar night. These cold spots form when the lunar dust fluffs up after an impact, so it cools down faster after the sun sets.

Another team, led by at Intuitive Machines in Texas, found that the impact flung dust and rocks more than 120 kilometres from the crater itself. “Over the last several years, we’ve developed this understanding that these impacts modify more than just the region right where the crater is,” says Powell. “It’s really striking that a crater can modify the lunar surface to distances far larger than the crater itself.”

This will helps us understand and study the history of the moon and other airless, cratered objects in the solar system, but it could also aid in future exploration. “If we’re trying to send rovers or astronauts or build things on the moon, we want to understand the properties of the surface,” says Powell. And watching a huge new crater form and change over time is one of the best remote probes of the surface we’ve ever had.

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.

What changes will occur on Earth as the moon moves further away?

From tides to eclipses, the slow departure of our moon will affect life on Earth, say our correspondents

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.