Welcome back, and thanks for spending another evening here. Tonight we have fifteen stops, and a surprising number of them were hiding in plain sight.
We'll finally see the companion Betelgeuse has kept hidden for a century, meet an asteroid shaped like a dog bone that made its own moons, visit the shiniest planet we know, watch two of Saturn's moons swap places, and solve a spacecraft mystery that had people talking about new laws of physics. At the end, we'll go looking for the stars that were born alongside our Sun.
Get comfortable. 🌙
1. ⭐ Betelgeuse finally shows its hidden companion
Betelgeuse, the red shoulder of Orion, is one of the most watched stars in the sky. Its brightness rises and falls in ways that led astronomers, about a century ago, to suspect it had a partner. Nobody could find one.
In 2024, two studies predicted that the companion would swing farthest from Betelgeuse that December, giving the best chance to spot it. A team led by Miguel Montargès pointed the Very Large Telescope's SPHERE instrument at the star that month, then spent months processing the data.
The result, published in July 2026, is the clearest image yet of what is very likely Betelgeuse B. It turned out to be bigger than expected, about two to three times the Sun's mass rather than roughly one. That's partly why it could be seen at all. "I jumped from my chair when I saw the processed images," Montargès said.
The team wants one more look, in about a year, when the companion should be on the other side of the star. They also want to know whether it will affect Betelgeuse's eventual supernova.
Even one of the most famous stars in the sky can still be keeping a secret that's brighter than our own Sun.
2. ☄️ Kleopatra is a dog-bone asteroid that made its own moons
Out in the asteroid belt, between Mars and Jupiter, there's an asteroid shaped like a chew toy. Kleopatra has two lobes joined by a thick neck, and it's about 270 kilometers long.
Radar first revealed the shape around the turn of the century. In 2008, astronomers found two small moons circling it and named them AlexHelios and CleoSelene, after Queen Cleopatra's children.
Sharper images from the Very Large Telescope pinned down both the shape and the moons' orbits. That gave the asteroid's mass, and it came out 35% lower than earlier estimates. Kleopatra is thought to be metal-rich, yet its density is less than half that of iron. So it's probably a rubble pile, loose material that gathered again after a giant impact.
It also spins almost fast enough to fly apart. Even small impacts could lift pebbles off its surface, and the team thinks such debris may have built the two moons.
Imaging it from Earth was like photographing a golf ball about 40 kilometers away. And what it showed was an asteroid that seems to have given birth to its own moons.
3. 🕳️ S301 is a star close enough to feel a black hole spin
At the center of our galaxy sits Sagittarius A*, a black hole about four million times the mass of the Sun. Astronomers have tracked stars around it for decades. In August 2026, they reported the most extreme one yet.
S301 completes an orbit every 8.7 years. At its closest, it passes just 1.78 billion kilometers from the black hole, only a little farther than Saturn is from the Sun, moving at about 25,000 kilometers per second. That's more than 8% of the speed of light, and about 100,000 times faster than a passenger jet. No star in the Milky Way is known to move faster.
Finding it took the VLT Interferometer, which combines four 8-meter telescopes. S301 appears two billion times fainter than Betelgeuse.
Stars can't form that close to a black hole, so S301 probably had a partner once. Astronomers think the black hole tore the pair apart, capturing S301 and flinging its companion away, perhaps out of the galaxy altogether.
Here's why it matters. A spinning black hole drags space around with it, and S301 comes close enough to feel that twist. By following it through its next close pass, in 2031, and beyond, astronomers hope within a decade to measure the spin of a supermassive black hole directly for the first time.
4. 🪐 LTT 9779b is a planet that works like a mirror
Most planets are dark. Earth reflects about 30% of the sunlight that reaches it. Venus, wrapped in bright clouds, reflects about 75%, which is why it outshines everything in the night sky except the Moon.
LTT 9779b beats them both. In 2023, ESA's Cheops telescope measured how much light dropped when the planet slipped behind its star. The answer was that it reflects about 80% of its starlight, making it the shiniest exoplanet known.
That's strange, because its day side is about 2,000 °C, which seems too hot even for clouds of metal. Its clouds are thought to be mostly silicate, the stuff of sand and glass, mixed with metals such as titanium. One researcher compared them to a steamed-up bathroom: you don't have to cool the air if you keep pumping in vapor until it can't hold any more.
The planet is also in a place it shouldn't be. It's about Neptune's size and circles its star in 19 hours, where planets that size are almost never found. Its reflective clouds may keep it cool enough to hold on to its atmosphere.
It's the biggest known mirror in the universe, and its shine might be the reason it survives.
5. 🌌 The Smith Cloud is a gas cloud boomeranging back into the Milky Way
In the early 1960s, a doctoral student named Gail Smith picked up radio waves from a huge cloud of hydrogen outside the disk of our galaxy. Today it's called the Smith Cloud, and it's falling toward us at nearly 700,000 miles per hour, more than a million kilometers per hour.
It's about 11,000 light-years long. If our eyes could see it, it would stretch across the sky about 30 times wider than the full Moon.
For years, astronomers wondered whether it was a failed galaxy or fresh gas falling in from intergalactic space. Either way, it should be nearly pure hydrogen and helium. So a team used Hubble to look through it at three distant bright galaxies and measured how much sulfur absorbed their light.
The cloud turned out to be as rich in sulfur as the Milky Way's own outer disk, so it's gas the galaxy made itself. Astronomers think it was thrown out of the disk about 70 million years ago. In roughly 30 million years, it should crash back in, possibly with enough gas to make 2 million suns.
The Milky Way isn't a still pinwheel. It throws gas out and catches it again, and makes new stars where it lands.
6. 📡 GLEAM-X J162759.5−523504.3 pulsed every 18 minutes, then went quiet
In 2020, an undergraduate student named Tyrone O'Doherty was searching radio data from the Murchison Widefield Array in Western Australia for sources that change. He found one that appeared in early 2018 and then vanished.
When the astronomer leading the survey looked closer, the signal turned out to repeat about every 18 minutes, like clockwork. Pulsars, spinning neutron stars, repeat in seconds or less. This was far too slow. Yet each pulse outshone everything else in the field of view, and the source lies only about 4,000 light-years away.
The pulses were almost completely polarized, a sign of a strong magnetic field. A search of the telescope's archive turned up 70 more detections across three months in 2018, and none before or after. The leading ideas were an unusual magnetar or a white dwarf.
Since then, more of these long-period radio transients have turned up. In 2025, astronomers showed that one of them, ILT J1101+5521, is a white dwarf orbiting a small red star every 125.5 minutes. Its pulses arrive once per orbit, when the two stars line up.
That solves one case, not all of them. Astronomers suspect that more than one kind of object is sending these slow cosmic heartbeats.
7. 🌙 Janus and Epimetheus trade places every four years
Saturn has two small moons that share almost the same orbit, and they never collide.
Janus and Epimetheus circle Saturn about 151,000 kilometers out, taking less than 17 hours per lap. One orbit is about 50 kilometers farther out than the other, so the inner moon moves slightly faster and slowly catches up.
About every four years, it gets close. But instead of a crash, their gravity pulls on each other and they swap orbits. The inner moon moves outward, the outer one moves inward, and the chase starts over in reverse. They never get closer than about 15,000 kilometers. As far as we know, nothing else in the Solar System does this.
The dance confused astronomers for years. Sightings in 1966 were thought to be a single moon. Only in 1978 did astronomers realize the observations were best explained by two objects sharing an orbit, and Voyager 1 confirmed it in 1980.
Both are potato-shaped, icy and so light for their size that they're probably loose piles of rubble. They might even be two halves of a single moon that broke apart long ago.
Two moons sharing one road, politely changing lanes every four years for who knows how long.
8. 💥 SN 2024ggi showed the shape of a star exploding
On April 10, 2024, astronomers spotted a new supernova in the galaxy NGC 3621, about 22 million light-years away. Astronomer Yi Yang had just landed in San Francisco after a long flight. Within 12 hours, he had sent a request for time on the Very Large Telescope.
The telescope was on target 26 hours after the first detection. That timing mattered. The star, a red supergiant 12 to 15 times the Sun's mass and some 500 times its width, had just exploded, and the blast was breaking through its surface. That phase lasts only hours.
A supernova this far away looks like a single point of light, so astronomers can't simply photograph its shape. Instead, they used spectropolarimetry. Light from a perfectly round explosion has no overall polarization, so any polarization that shows up reveals a lopsided shape.
The first burst of material was shaped like an olive. As the blast hit the gas around the star, it flattened, but it kept the same axis. That suggests the engine behind many massive-star explosions has a clear, built-in direction, and it already rules out some supernova models.
Because a team moved fast, we caught the shape of a star's death in the first hours after it broke free.
9. ⭐ R Coronae Borealis hides behind its own soot
Most variable stars brighten. R Coronae Borealis does the opposite. Usually it's just visible to the naked eye in the Northern Crown. Then, at random moments, it fades by up to 8 magnitudes in a few weeks, becoming over a thousand times dimmer, and can take months or a year to recover.
The cause is soot. R CrB and the few stars like it are supergiants with almost no hydrogen and lots of carbon. Every so often, a cloud of carbon dust condenses above the star's surface and blocks our view. During one fading in the 1990s, amateur observers watched the star disappear in visible light while ESA's ISO space telescope saw it still glowing in infrared. As one astronomer put it, "We caught this star smoking."
Where do such odd stars come from? One clue is oxygen. In the Sun, there are about 500 atoms of common oxygen for every atom of heavy oxygen-18. In these stars, the two are nearly equal, orders of magnitude different from other stars. That points to a violent past. One leading explanation is that they formed when two white dwarfs merged, a collision that may take only a few days.
It's a star built from two dead stars, and now every so often it disappears behind a cloud of its own making.
10. 🪐 Beta Pictoris d was hiding in the archives for a decade
Beta Pictoris, about 63 light-years away, is one of the best-studied young planetary systems. Its giant planets, b and c, are each about ten times the mass of Jupiter. In July 2026, astronomers announced a third.
The team was studying planet b when they noticed something else in their Very Large Telescope images. When they searched old data, they found the new planet in images going back 11 years, including one where it was barely visible beside planet b's glare. An independent team found it in James Webb Space Telescope data too.
Beta Pictoris d is about 2.4 times the mass of Jupiter, orbits much farther out, and is cold. It's about 100 times fainter than planet b, making it the faintest planet ever imaged directly from Earth, once distance is accounted for.
It also explains a mystery. The planet has just the right mass and position to sculpt the system's debris disk into its odd shape.
Only one other system, HR 8799, has more than two planets photographed directly. And the best part is that the planet was in the data all along, waiting for someone to look again.
11. 🛰️ The Pioneer anomaly turned out to be heat
Pioneer 10 and 11 launched in the early 1970s and are now drifting out of the Solar System. Their trajectories hid a puzzle. Even after accounting for the gravity of everything in the Solar System, both spacecraft were slowing down slightly more than expected.
The extra slowing was tiny but measurable, and it puzzled scientists for more than 20 years. Some proposed explanations involved new physics, perhaps even a change to gravity itself.
Solving it meant finding much more data. More than 19 years of tracking records sat on old 7- and 9-track magnetic tapes. With funding from Planetary Society members, a team at NASA's Jet Propulsion Laboratory recovered much of the spacecrafts' 30-year histories, along with old design drawings and temperature readings.
They then built a detailed thermal model of the spacecraft. The Pioneers' nuclear power sources warmed the back of the big dish antennas, which pointed back toward Earth, and the dish sent that heat forward. The warm electronics box sat on the leading side too. More heat leaving the front than the back acted like a gentle brake.
In 2012, the team concluded that once this thermal push is included, no anomaly remains. Gravity was fine. The spacecraft were simply being nudged by their own warmth.
12. 🧲 RXJ0528+2838 is a dead star making waves it shouldn't
About 730 light-years away, a white dwarf and a Sun-like star orbit each other. Astronomers noticed odd, faint nebulosity around them, and when they mapped it with the Very Large Telescope, they found a beautiful shock wave.
A shock like this forms as material streaming from a star plows into the gas between stars, like the wave in front of a ship's bow. The usual source is a disk of gas the white dwarf steals from its partner, which flings some material back out.
But RXJ0528+2838 has no disk. Its strong magnetic field funnels the stolen gas straight down onto its surface instead. Even so, the size and shape of the shock suggest the system has been pushing material out for at least a thousand years.
The magnetic field is the team's best suspect, but there's a problem. By their measurements, it's only strong enough to power such a shock for a few hundred years. The researchers call the missing power source a "mystery engine."
A quiet, disk-less dead star is doing something nobody thought it could, and we don't yet know what's driving it.
13. 🕳️ GW231123 merged black holes that shouldn't exist
On November 23, 2023, the two LIGO detectors in the United States felt a brief shiver in spacetime. It came from two black holes, about 100 and 140 times the mass of the Sun, spiraling together.
The merger left a black hole more than 225 times the Sun's mass, the heaviest ever made by a merger detected in gravitational waves. The previous record holder, GW190521, totaled about 140 solar masses.
The masses are the puzzle. Black holes this heavy are hard to make from the collapse of a single star. "Black holes this massive are forbidden through standard stellar evolution models," said Mark Hannam, a member of the collaboration.
Both black holes were also spinning rapidly, which is a clue. A leading idea is that each of them was already the product of earlier mergers of smaller black holes.
If so, the signal we caught may be the latest generation of a family tree of black holes.
14. 🌞 The faint young Sun should have left Earth frozen
The Sun is slowly getting brighter. In 1958, Martin Schwarzschild and Fred Hoyle independently worked out that early in Earth's history it shone only about 70% as brightly as it does today.
That creates a problem. Put today's Earth under that dimmer Sun and, one estimate says, the average temperature would be about −7 °C, cold enough to freeze. Yet the rocks say Earth had liquid water as early as about 4.4 billion years ago, and life appeared not long after.
This is the faint young Sun paradox. In 1972, Carl Sagan and George Mullen suggested a stronger greenhouse effect, and proposed ammonia. That didn't work, because sunlight destroys ammonia. Attention turned to carbon dioxide from volcanoes, along with other ideas about early Earth's air, clouds and oceans.
Many researchers now think the outline of an answer is in place, though the details are still debated. One NASA-supported study even suggests the earliest Earth may have stayed fairly cold, with alkaline oceans, and still held liquid water.
Our planet stayed habitable through a long stretch when the Sun alone wasn't enough to keep it warm.
15. ⭐ The Sun's siblings are scattered across the galaxy
The Sun wasn't born alone. It probably formed in a cluster, with somewhere between a thousand and a hundred thousand siblings made from the same cloud of gas and dust. Over 4.5 billion years, that family drifted apart, each star following its own path around the Milky Way.
Could we find any of them? In 2014, a team led by Ivan Ramírez at the University of Texas at Austin studied 30 candidates. They checked each star's chemistry, which should match the Sun's closely, and traced its orbit backward through the galaxy.
Only one passed both tests: HD 162826, a star about 15% more massive than the Sun, 110 light-years away in Hercules. You can't see it with your naked eye, but low-power binoculars will show it, not far from bright Vega. It's probably a sibling, not a certain one.
Years of observations ruled out any hot Jupiters around it, though smaller rocky planets could still be there. The team's bigger goal was a method for finding more siblings in data from Gaia, which charts the positions and motions of a billion stars, far beyond our neighborhood.
Somewhere out there, scattered across the galaxy, are the stars that grew up in the same nursery as ours.
🌙 One last thought before you sleep
So much of tonight was about looking again.
Betelgeuse's companion was suspected for a century before it finally showed up. A planet sat in Beta Pictoris images for eleven years until someone noticed it. A slow radio heartbeat lay in an archive until a student went searching, and the Pioneer mystery was solved partly because people saved data from old magnetic tapes.
Patience matters in astronomy. The universe doesn't hide things on purpose, but it's big and faint, and our first look is rarely our best.
Maybe that's true of the sky above you tonight. That faint point near Vega might be a star that was born alongside our Sun, and it has been crossing the galaxy on its own ever since.
There's still so much waiting to be noticed, if we keep looking.
That's all for tonight. Thanks for wondering along with me. Good night, and clear skies. 🌌
— Kasi