A star near the centre of the Milky Way is hurtling through its orbit with a peak speed of more than 8 per cent the speed of light, making it both the fastest star and the closest to a supermassive black hole that has ever been spotted. Named S301, this astonishing star could help us unravel the secrets of gravity.

at the Max Planck Institute for Extraterrestrial Physics in Germany and his colleagues found S301 using the Very Large Telescope in Chile. They have been watching it since 2023 to get enough data to pin down its orbit, and the results are unprecedented.

At its closest approach, S301 is only about 1.8 billion kilometres from Sagittarius A*, the supermassive black hole at the centre of our galaxy. That’s just 12 times the distance between Earth and the sun, 10 times closer to Sagittarius A* than the previous record-holder. “If you were living on a planet around this star, the size of the black hole at the closest approach would appear similar to the full moon from Earth – it would be absolutely stunning,” says Gillessen.

Such a close pass by the black hole means that S301 spends part of its orbit in one of the most extreme gravitational environments in the universe. Next to a black hole, space-time stretches and warps. If a black hole is spinning, it should warp space-time even more, twisting it up in what is known as the frame-dragging effect.

“Earth does this as well, and we can measure with satellites around Earth that there is a very, very slight frame dragging from Earth’s rotation,” says at the University of California, Los Angeles, who wasn’t involved in the research. “This is doing the same thing, just with much different objects.”

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Measuring Earth’s spin is relatively easy, but a black hole’s spin is much harder to determine because of its lack of a visible surface. The most precise way to measure it would be by measuring frame dragging, and S301 is the first star close enough to feel that effect.

“We drop a leaf in the wind and see how the air is moving by measuring that leaf,” says Gillessen. “A star is just the perfect leaf to drop to see the movement of space-time.”

Actually measuring the spin of Sagittarius A* using this method will probably take around a decade, he says, but that may speed up if we find more stars like it.

“With one star, it would take a while, but it would still be the best constraint on spin that we’ve ever had by far,” says at University College London. “If you can find another star that’s even closer, that’s better still. If you can find a population of these stars, then you’re in business.”

Gillessen and his team have several candidates for stars slightly further from the black hole than S301, but none yet that are closer, he says.

But when we finally do measure the spin of a black hole, it will be a crucial piece of the cosmic jigsaw. It will not only help us understand how black holes have contributed to the evolution of the universe, but will also provide a probe into the behaviour of gravity in extreme environments, which has proved extremely difficult to study.

“A black hole only has three measurable properties: a mass, a spin and possibly an electric charge. The mass was worth a Nobel prize in 2020, so, if you find the spin, you might expect a call from Stockholm in 20 years,” says Gillessen.

Around the nearby star Fomalhaut, asteroids are smashing into each other in a series of cosmic cataclysms, creating huge clouds of dust. For the first time, astronomers are watching one of these collisions as it occurs, which could provide a window into the early days of our own solar system.

Fomalhaut has a history of strange observations: in 2008, at the University of California, Berkeley, and his colleagues reported what seemed to be a giant planet in orbit around the young star, based on observations with the Hubble Space Telescope made in 2004 and 2005. Over the years, though, as more observations have rolled in, researchers have hotly debated over what this strange object, called Fomalhaut b, might be. It was either a planet a bit larger than Jupiter, or a cloud of debris.

Now, Kalas and his team have used Hubble to look at Fomalhaut once again. “In 2023, we used the same instrument we’d used [before], and we did not detect Fomalhaut b – it wasn’t visible anymore,” says Kalas. “But what really shocked us was [that] there was a new Fomalhaut b.”

This new bright spot, called Fomalhaut cs2 (short for “circumstellar source”), couldn’t be a planet, or it would have been seen sooner. The best explanation is that it is a cloud of dust created by the collision of two large asteroids, or planetesimals, each around 60 kilometres in diameter. The disappearance of Fomalhaut b hints that it was probably a similar dust cloud all along.

“These sources are noisy and erratic, so we’re still some ways off a firm conclusion,” says at Columbia University. “But, all of the evidence to date seems to fit neatly under the umbrella explanation of collisions between proto-planets in a nascent system.”

Spotting two such smash-ups is unexpected, though. “Theory dictates that you shouldn’t see these collisions except once every 100,000 years or rarer. And yet, for some reason, we’ve seen 2 events in 20 years,” says Kalas. “Fomalhaut is sparkling like a holiday tree, and that is a surprise.”

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It may mean that collisions between planetesimals are more common than we had thought, at least around relatively young stars like Fomalhaut. Kalas and his colleagues have more observations scheduled over the next three years with both Hubble and the more powerful James Webb Space Telescope (JWST) to watch how Fomalhaut cs2 behaves moving forward and to try to find the now-dimmer Fomalhaut b.

This is a unique opportunity to study these collisions in real time. “We no longer have to depend solely on theory to understand these violent impacts; we can actually see them,” says Kalas. More observations could teach us not just about young planetary systems in general, but also about our own early solar system and where it fits in the cosmic menagerie.

“We’ve long wondered if the moon-forming impact was typical or not beyond our cosmic shore, and here we see compelling evidence that collisions are par for the course,” says Kipping. “Perhaps we’re not as unusual as some have speculated.”

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Astronomers have found what appears to be one of the strangest known worlds in the universe. It orbits a type of rapidly spinning neutron star called a pulsar – this in itself is unusual, but it is far from the weirdest thing about the exoplanet PSR J2322-2650b.

at the University of Chicago and his colleagues spotted the odd planet, which is more than 2000 light years away from Earth, via the James Webb Space Telescope, and immediately noticed that something about it was unusual. The spectrum of light they measured coming from it didn’t show the usual water and carbon dioxide we would expect to find on a Jupiter-mass world like this one, but instead molecules of carbon.

We have never seen molecular carbon in the atmosphere of any exoplanet before, because any carbon in a planet’s atmosphere is far more likely to bind to other atoms than to itself. “In order to have molecular carbon in the atmosphere, you have to get rid of pretty much everything else, all of the oxygen, all of the nitrogen, and we just don’t know how to do that,” says Zhang. “We don’t know of any other planetary atmosphere that looks anything like this.”

The planet is so close to its host star, and the host star is so massive, that it is thought to have been pulled by the pulsar’s gravity into an oblong, lemon-like shape. A full year there lasts only 7.8 hours, and even the coldest points on the planet are about 650°C (1202°F). Unlike most other giant planets, the winds there blow in the opposite direction to the planet’s rotation. “You can imagine that this planet would look deep red, with clouds of graphite in the atmosphere”, like a sort of evil lemon, Zhang says. “I would say it’s definitely the weirdest exoplanet.”

All of these oddities make it difficult to explain how PSR J2322-2650b could have possibly formed – it seems to defy the established models of planet formation. For now, this utterly strange, distant world is a total mystery.

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Earth may owe some of its properties to a nearby star that blew up just as the solar system was forming. This pattern, which saw a supernova bubble envelop the sun and shower it with cosmic rays, may be ubiquitous across the galaxy – implying there could be a far greater number of Earth-like planets than previously thought.

We know, thanks to ancient meteorite samples, that the solar system used to be filled with heat-producing radioactive elements that quickly decayed. The heat from these elements drove off large amounts of water from the space rocks and comets that came together to form Earth, ensuring the planet had the right amount of water for life to later develop.

It is unclear, however, how these elements reached the solar system. Many of them are commonly found in supernova explosions, but simulations of close-by supernovae have struggled to produce the exact ratios of radioactive elements inferred from meteorite samples to have been present in the early solar system. One problem is that these nearby blasts may also have been so powerful that they would have blown apart the fragile early solar system before any planets had formed.

Now, at the University of Tokyo in Japan and his colleagues have found that a supernova could have provided the necessary radioactive ingredients for Earth without upsetting the planet formation process, as long as it was slightly further away.

In their model, a supernova that is around 3 light years from the solar system could produce the required radioactive elements in a two-stage process. Some, such as radioactive aluminium and manganese, would be produced directly in the supernova and then travel on shock waves from the exploded star to reach the solar system.

Then, high-energy particles called cosmic rays emanating from the supernova would follow behind these shock waves and hit other atoms in the solar system’s still-forming disc of gas, dust and rocks, a process that would produce the remaining radioactive elements needed, such as beryllium and calcium. “Previous models of solar system formation focused only on the injection of matter. I realised we were ignoring the high-energy particles,” says Sawada. “I thought, ‘What if the young solar system was simply engulfed in this particle bath?’”

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Because this process works with a supernova that is further away than previous studies, Sawada and his team estimate that between 10 to 50 per cent of sun-like star and planetary systems could have been seeded with radioactive elements in this way and produced planets with Earth-like abundances of water. For previous models, with close-by supernovae, being hit was “like winning the lottery”, says Sawada. But moving the supernova further away implies that “the recipe for Earth is likely not a rare accident, but a universal process happening all over the galaxy,” he says.

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“It’s quite novel, because it’s a fine balance between destruction and creation,” says at Cardiff University, UK. “You need the right elements and the right distance.”

If this mechanism is correct, it could help guide future searches for Earth-like planets by planned telescopes like NASA’s Habitable Worlds Observatory, by looking for traces of ancient supernovae and finding star systems that were close to them at the time, says Inserra.

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