Welcome back, and thanks for spending another evening here. Tonight we have seventeen stops, and a lot of them are about things that are still changing while we watch.
We'll argue over what a giant star has turned into, visit an asteroid where a day lasts five minutes, find a black hole that took 20 years of patience to spot, watch a new ten-sided pattern appear on Saturn, and follow a family of comets back to a single ancestor. At the end, we'll find out that the Solar System has been surfing a wave across the galaxy.
Get comfortable. 🌙
1. ⭐ WOH G64 is a giant star that won't stay labeled
WOH G64 is one of the biggest stars we know, about 2,000 times wider than the Sun. It lives in the Large Magellanic Cloud, a small galaxy that orbits our own, about 160,000 light-years away.
In 2024, a team led by Keiichi Ohnaka used ESO's Very Large Telescope Interferometer, which combines several telescopes into one very sharp eye, to take the first zoomed-in picture of a star in another galaxy. It showed WOH G64 wrapped in an egg-shaped cocoon of dust. It had also dimmed over the previous decade.
Then the arguments began. Giant red stars like this one, called red supergiants, are expected to end as supernovae. One team argued that WOH G64 had suddenly changed into a yellow hypergiant, a hotter, unstable stage that may come just before the end. They also found it has a hot companion star. Their paper came out in Nature Astronomy in February 2026.
Jacco van Loon's team took fresh spectra from late 2024 to late 2025, and saw titanium oxide, a molecule that survives only in cool stellar atmospheres. Their reading, published in January 2026: it's still a red supergiant, with its atmosphere stretched out by the companion. "We are essentially witnessing a 'phoenix' rising from the ashes," van Loon said.
Either way, we're watching one of the biggest stars in the sky change in a human lifetime.
2. ☄️ 1998 KY26 is an asteroid where a day lasts five minutes
Japan's Hayabusa2 spacecraft has already visited one asteroid, Ryugu, and brought pieces of it back to Earth in 2020. It still had fuel left, so it's on its way to a second target, which it should reach in 2031: 1998 KY26.
To prepare, astronomers led by Toni Santana-Ros watched the asteroid with ESO's Very Large Telescope and other large telescopes during a close pass by Earth. What they found was not what anyone had planned for. Earlier data suggested a rock about 30 meters across, turning once every 10 minutes or so. It's actually just 11 meters wide, small enough to fit inside the dome of the telescope that observed it, and it spins about twice as fast. "One day on this asteroid lasts only five minutes!" Santana-Ros said.
Ryugu is about 900 meters across, and every asteroid visited before has been hundreds or thousands of meters wide. This one is about the size of the spacecraft. Touching down on a small, fast-spinning rock will be much harder than anyone expected.
Its bright surface suggests a single solid chunk, maybe a broken-off piece of a planet or a bigger asteroid. It's only a little smaller than the rock that exploded over Chelyabinsk, Russia, in 2013.
In 2031, a spacecraft will try to touch a rock no bigger than itself, while that rock spins through a whole day every five minutes.
3. 🕳️ Omega Centauri finally gave up one of its hidden black holes
Omega Centauri is a ball of about 10 million stars, the biggest star cluster in the Milky Way. Its biggest stars should have died long ago, leaving roughly 10,000 small black holes behind. Yet nobody could find one.
So Matthew Whitaker's team tried patience. They went through Hubble images taken from 2002 to 2023, added sharper data from Webb, and measured the positions of stars to a fraction of a single pixel. One star, about 18,000 light-years away, was moving in a slow loop around something heavy and invisible.
The star has about 0.78 times the Sun's mass. Its partner, now called oMEGACat BH-2, has 4.46 times the Sun's mass. That's too heavy to be a neutron star, so it must be a black hole. An earlier study had suggested a neutron star.
The two take 94 years to go around each other, the longest orbit known for any black hole and its companion. They probably didn't start out together, but met in the crowded cluster. A pair like this should last less than a billion years before passing stars tear it apart.
The black hole is also lighter than expected for a cluster this poor in heavy elements, which gives modelers a new puzzle. After decades of searching, the first of the ten thousand has finally turned up.
4. 🪐 Cha 1107-7626 is a rogue planet having a growth spurt
Most planets orbit a star. Cha 1107-7626 doesn't. It's a rogue planet with 5 to 10 times Jupiter's mass, drifting on its own about 620 light-years away in the constellation Chamaeleon.
It's also still forming, fed by a disk of gas and dust that keeps falling onto it. In 2025, Víctor Almendros-Abad's team used ESO's Very Large Telescope and the James Webb Space Telescope to watch that feeding, and caught it speeding up. By August, the planet was gaining mass about eight times faster than a few months earlier: six billion tonnes every second. No planet of any kind has been seen growing faster.
That's not the only star-like thing about it. Magnetic activity seems to have helped drive the burst, something seen before only in stars. Water vapor appeared in its disk during the burst, though it wasn't there before.
Astronomers still don't know whether rogue planets form like tiny stars, or form like planets and get thrown out of their home systems. This one suggests some of them, at least, are born like stars.
"This discovery blurs the line between stars and planets," said Belinda Damian. Alone in the dark, this planet is growing up the way a star does.
5. 🌌 Andromeda keeps most of its small galaxies on one side
The Andromeda Galaxy, our big neighbor, has a swarm of small dwarf galaxies orbiting it. The standard picture of how galaxies grow, built from countless small mergers, says such swarms should be scattered fairly randomly around their host.
Andromeda's isn't. Using distance measurements for 37 of its satellites, Kosuke Jamie Kanehisa and colleagues at the Leibniz Institute for Astrophysics Potsdam found that more than 80% sit on one side. All but one lie within a wedge of space covering 64% of Andromeda's surroundings, and that wedge points toward the Milky Way.
The team searched two large computer simulations of the universe for galaxies like Andromeda. "We have to look at more than three hundred simulated systems to find just one that is similarly extreme," said Marcel Pawlowski. That's about 0.3%.
There's a second oddity. About half of Andromeda's satellites orbit together in a thin, flat sheet, like planets around the Sun. That shouldn't be common either, and Andromeda has both at once.
It might just be a rare history. Or the simulations might be missing something about how small galaxies form. Our nearest big neighbor is holding its family in a way our best models struggle to explain.
6. 💥 GRB 250702B is an explosion that kept going off
Gamma-ray bursts are the most powerful explosions known, usually from a giant star collapsing or a star being torn apart. They last from milliseconds to minutes, and they never repeat, because whatever made them is destroyed.
On July 2, 2025, NASA's Fermi telescope caught one that did. It saw three bursts from the same spot over several hours. The Einstein Probe X-ray telescope had already seen the source active almost a day earlier. Altogether, GRB 250702B lasted about a day, 100 to 1,000 times longer than most.
It seemed to come from inside the Milky Way, but ESO's Very Large Telescope traced it to a distant galaxy. Then Webb measured the distance: its light left about 8 billion years ago. If it shone equally in all directions, it released well over a thousand times the energy the Sun will give off in its whole life.
Its host galaxy is strange too: unusually big, dusty and massive, unlike any other gamma-ray burst host. The discovery team favored a white dwarf being shredded by a medium-sized black hole, but no explanation fits everything yet.
Something in a faraway galaxy exploded, and then did it again.
7. 🌀 Saturn has grown a ten-sided pattern at its south pole
Saturn's north pole is famous for its hexagon, a six-sided jet stream that has shown up in every look for more than 40 years. Astronomers have long searched the south pole for a matching pattern, in Hubble images since 1990 and through Cassini's whole mission from 2004 to 2017. There was nothing.
Now there is. As Saturn's seasons slowly brought its south pole back into view, amateur astronomers Trevor Barry and Jean-Paul Oger, working with researcher Agustín Sánchez-Lavega, noticed a faint wavy band near the south pole in 2024. Hubble images taken each year then confirmed a giant, ten-sided wave, with early hints going back to 2023.
The decagon isn't only a pattern in the clouds. It runs through several layers of Saturn's atmosphere, and it seems to be getting stronger.
"The most intriguing part to me is that this seems to have just formed recently," said Amy Simon, who leads Hubble's yearly survey of the outer planets. "The question is, why did it suddenly form now?"
Nobody knows yet whether it will settle down into a lasting shape like the hexagon. We may be watching a new feature on a giant planet being born.
8. 🪐 HS 0209+0832 may have a planet built from its star's death
For more than 25 years, a Hubble spectrum of a white dwarf called HS 0209+0832 sat in the archive with about 100 lines nobody could identify. Then Jamie Williams, a PhD student at the University of Warwick, checked them against an updated chemical database. Many matched niobium, an element never before reported in any white dwarf.
That mattered because elements heavier than iron, including niobium, aren't made by ordinary fusion in a star's core. They're forged in dying stars and thrown out as the star sheds its layers.
NASA's TESS satellite then saw the white dwarf brighten and dim on a regular cycle, hinting at a planet about the size of Jupiter, about 6 million kilometers from the star. That's much closer than Mercury is to the Sun. The team thinks this planet formed from material the dying star cast off. It's the first candidate for a second-generation planet, built from a star's death rather than its birth.
The hot young white dwarf is probably stripping the planet's atmosphere, and some of that niobium-rich gas falls onto the star, where Hubble saw it.
It's still a candidate. But a star's afterlife might begin a whole new chapter of planets.
9. 🧲 Swift J1818.0−1607 is a magnetar that's only about 240 years old
Magnetars are neutron stars with the strongest magnetic fields known. This one's field is up to 1,000 times stronger than an ordinary neutron star's, and about 100 million times stronger than the most powerful magnets people have built.
On March 12, 2020, NASA's Swift observatory caught a sudden burst of X-rays from the constellation Sagittarius, about 16,000 light-years away. Follow-up observations by ESA's XMM-Newton and NASA's NuSTAR showed it came from a magnetar, now called Swift J1818.0−1607. They also gave astronomers enough to estimate its age: about 240 years, the youngest magnetar known.
If that's right, light from the supernova that made it would have reached Earth around the time George Washington became the first US president. For something in space, that's practically a newborn.
It's also unusual among magnetars. At the time, only 31 were confirmed, out of more than 3,000 known neutron stars, and this is one of just five that also sends out regular radio pulses like a pulsar.
"This object is showing us an earlier time in a magnetar's life than we've ever seen before," said Nanda Rea. Somewhere in Sagittarius, a star's ghost is still in its infancy.
10. 🌌 The Cosmic Gems arc shows star clusters from the universe's childhood
Our galaxy is surrounded by globular clusters, tight balls of ancient stars that have survived for billions of years. They're fossils from an early burst of star formation, but nobody has known exactly where or when they formed.
In 2024, Angela Adamo's team pointed Webb at a galaxy nicknamed the Cosmic Gems arc. A massive cluster of galaxies in front of it bends and magnifies its light like a lens, stretching it into a long arc. "We saw a little chain of bright dots, mirrored from one side to the other," Adamo said. "These cosmic gems are star clusters!"
We see them as they were when the universe was about 460 million years old, looking back across 97% of cosmic time. They're the first star clusters ever found in a galaxy that young.
There are five of them, young, heavy and packed far more densely than clusters near us. Together they make most of their galaxy's ultraviolet light. Radiation like that helped clear the fog of hydrogen that filled the early universe.
They might be what globular clusters looked like as babies. The oldest star clusters around us may once have shone like these gems.
11. ☄️ The Kreutz sungrazers are the pieces of one giant comet
The SOHO spacecraft was launched in 1995 to study the Sun. It blocks out the Sun's bright face with a metal disk to see its faint outer atmosphere. That also lets it see something no other telescope can: comets that plunge straight past the Sun.
It has found more than any other observatory in history, and most were discovered by volunteers combing through its images. Its 4,000th comet, found in June 2020, was only about 5 to 9 meters across. About 85% of SOHO's comets share one path, which takes them skimming through the Sun's outer atmosphere. They're called the Kreutz sungrazers.
They look like a family because they are one. Astronomers think they're pieces of one huge comet that broke apart, and that they keep splitting each time they swing past the Sun. Some of the pieces have been spectacular, including the Great September Comet of 1882 and Comet Ikeya-Seki in 1965.
In one detailed model, Zdenek Sekanina and Rainer Kracht trace both of those back to a comet the Chinese recorded in 1138, and link the family to daylight comets a Roman historian described in AD 363. They even suggest the original parent might have been a comet Aristotle saw.
Every few days, another crumb of an ancient comet falls toward the Sun.
12. 🪐 2M1510 (AB) b orbits two brown dwarfs at right angles
Planets that orbit two stars, like Tatooine in Star Wars, are real. They usually circle in the same flat plane in which their two stars orbit each other.
2M1510 is already unusual. It's a pair of young brown dwarfs, objects too small to shine like real stars, that pass in front of each other as we watch. Only one other pair like it is known.
While Thomas Baycroft, a PhD student at the University of Birmingham, was refining the pair's orbit with ESO's Very Large Telescope, he noticed their path being pushed and pulled in odd ways. "We reviewed all possible scenarios, and the only one consistent with the data is if a planet is on a polar orbit about this binary," he said.
That planet, 2M1510 (AB) b, is the first strong evidence for a planet orbiting a pair of stars at 90 degrees, passing over one pole and then the other. Theory said such orbits could be stable, and astronomers had seen planet-forming disks tilted this way. Nobody had found a planet doing it. A third, distant star in the system is too far away to cause the tugging.
The team wasn't even looking for planets. The sky from that world would show its two suns circling at right angles to its own path.
13. 🕳️ Runaway stars point to a black hole in the Large Magellanic Cloud
When a pair of stars wanders too close to a supermassive black hole, the black hole can capture one and fling the other away at enormous speed. Astronomers have found such hypervelocity stars racing out of the Milky Way, and assumed they all came from Sagittarius A*, the black hole at our galaxy's center.
Jiwon Jesse Han and colleagues looked again at 21 of them, using precise motions from ESA's Gaia satellite and newer models of how the Large Magellanic Cloud orbits us. Half of them don't trace back to the Milky Way's center at all. They trace back to the Large Magellanic Cloud.
That points to a supermassive black hole there. From the stars' speeds and numbers, the team estimates it at about 600,000 times the Sun's mass. That's small next to Sagittarius A*, which has about 4 million.
It also explains why many of these stars bunch up in the direction of the constellation Leo. The Large Magellanic Cloud's own motion adds about 300 kilometers per second to stars thrown in that direction, making them more likely to show up as hypervelocity stars.
Nobody has seen this black hole directly. But stars thrown across the sky have shown us where it hides.
14. 📡 FRB 20240304B is the farthest fast radio burst yet, from a tiny galaxy
Fast radio bursts are flashes of radio waves that last about a thousandth of a second, but carry enough energy to be seen across billions of light-years. Most go off once and never again, so finding out what makes them has been hard.
On March 4, 2024, the MeerKAT radio telescope in South Africa caught one called FRB 20240304B. Its signal suggested it came from very far away, but even the largest telescopes on the ground saw no galaxy at its position. Webb did. Manisha Caleb's team measured that galaxy's distance: we see it as it was only 3 billion years after the Big Bang, making it the most distant fast radio burst found so far.
The galaxy was a surprise. Fast radio bursts usually come from big, star-forming galaxies, but this one is a little dwarf, about 1,000 times less massive than expected, and most of its stars may have formed within just 30 million years.
That's a clue. If the bursts came from merging neutron stars, they'd take billions of years to appear. A young galaxy fits better with magnetars, young neutron stars with extreme magnetic fields that form soon after a supernova.
The burst's signal also picked up traces of a galaxy cluster nobody knew about. "A fast radio burst is almost like a cosmic flashlight," said J. Xavier Prochaska. It lights up everything along the way.
15. ⏱️ A day on Uranus is 28 seconds longer than we thought
How do you measure a day on a planet with no solid surface? You can't watch a mountain come back into view. NASA's Voyager 2 estimated Uranus's rotation when it flew past in 1986, but that number wasn't precise enough to keep track of which side of the planet was facing us for long.
So Laurent Lamy's team tracked the planet's aurorae, the glowing lights near its magnetic poles, in more than a decade of Hubble images. Those lights turn with the planet's interior, so following them over years revealed the rotation.
The answer: Uranus turns once every 17 hours, 14 minutes and 52 seconds. That's 28 seconds longer than Voyager 2's estimate, and the new value is about 1,000 times more precise.
Twenty-eight seconds sounds like nothing. But it adds up over years of turning. With the old value, maps of Uranus quickly drifted out of step with the real planet, and it was impossible to follow its magnetic poles over time. The new clock lets astronomers compare nearly 40 years of aurora observations, and gives a future Uranus mission a reliable map.
Sometimes a discovery is a single, careful number, finally right.
16. 🪨 Extreme debris disks show young planets colliding
Early in the Solar System's history, something the size of Mars, called Theia, smashed into the young Earth. Some of the debris came together to form our Moon. Collisions like that are part of how rocky planets are built.
Around other young stars, we can see the dust from such crashes. NASA's Spitzer telescope found a rare kind of system, called an extreme debris disk, with huge amounts of warm dust close to the star, right where rocky planets would orbit. Only about 1% of young stars show one.
Kate Su's team used Webb to study 21 of these disks, more than ever before, and sorted them by what the dust is made of. About a third are rich in silica, like volcanic glass. That points to violent impacts between Mars-sized bodies, hot enough to turn rock to vapor. The other two-thirds are silica-poor, more like green sand, suggesting smaller, glancing crashes between Moon-sized bodies.
The silica-rich disks only appear around stars younger than 300 million years. That's when rocky planets like Earth are thought to finish forming.
"We have no other way to study these planetary embryos directly," said Agnes Kospal. Somewhere out there, worlds are being built the way ours was: by crashing together.
17. 🌌 The Solar System has been surfing the Radcliffe Wave
In 2020, astronomers using data from ESA's Gaia satellite made a 3D map of the gas and dust near the Sun and found something nobody expected: a giant wave. It's a thin chain of star-forming clouds about 9,000 light-years long, rising and falling up to 500 light-years above and below the flat disk of the Milky Way. They named it the Radcliffe Wave.
"No astronomer expected that we live next to a giant, wave-like collection of gas," said Alyssa Goodman. At its closest, it's only about 500 light-years from the Sun. "It's been right in front of our eyes all the time," said João Alves, "but we couldn't see it until now."
The Sun doesn't sit still, though. It's always moving around the galaxy. In 2025, Efrem Maconi, Alves and colleagues traced both the Sun's path and the wave's, and found that we passed through it, right through the Orion star-forming region, most likely between 14.8 and 12.4 million years ago. New clusters of stars were forming around us as we went.
That denser region may have squeezed the bubble the solar wind blows around the Solar System, and let in more interstellar dust. It happened around the time Earth's climate cooled and Antarctica's ice sheet grew, but the team stresses that no link has been shown.
Look toward Orion on a winter night. "Our solar system came from that direction!" Alves said. We're travelers, and the stars of Orion are where we've been.
🌙 One last thought before you sleep
So much of tonight was about patience.
A black hole in Omega Centauri showed itself only after 20 years of Hubble pictures. A day on Uranus came out right only after more than a decade of watching its lights. A white dwarf's strange lines sat in an archive for over 25 years before someone recognized them. And Saturn's decagon first showed up in pictures taken by amateur astronomers, who keep watching the planet year after year.
The universe doesn't usually announce itself. It changes slowly, and leaves faint clues, and waits for someone to keep looking.
And all the while, the Sun has been carrying us quietly through the galaxy, past the nurseries of Orion and on into the dark, on a journey far longer than all of human history.
We're always moving, even when we're lying perfectly still.
That's all for tonight. Thanks for wondering along with me. Good night, and clear skies. 🌌
— Kasi