Every 8.5 years, something beside the dying red giant V Hydrae fires a cannonball: a blob of gas about twice the mass of Mars, racing out at 800,000 kilometers per hour. That's fast enough to cross from Earth to the Moon in half an hour. The likely gunner is an unseen companion star that dips into the giant's puffed-up atmosphere, and it has kept this rhythm for at least 400 years.
Also tonight: a jet from a neutron-star crash that seemed to outrun light, the first planet found around a Sun-like star, which almost nobody believed, and a galaxy whose stars circle in both directions at once. The last stop is a kind of star that won't exist for trillions of years.
1. ⭐ V Hydrae fires cannonballs every eight and a half years
About 1,200 light-years away, a bloated red giant called V Hydrae is dying. It has probably already shed at least half its mass into space. And something near it is shooting.
Raghvendra Sahai of NASA's Jet Propulsion Laboratory and his colleagues watched the star with Hubble from 2002 to 2004 and again from 2011 to 2013. They found a string of superhot blobs of gas, each about twice the mass of Mars, hotter than 9,000 degrees Celsius. They race outward at around 800,000 kilometers per hour, fast enough to cross from Earth to the Moon in half an hour.
Mapping where the blobs had reached let the team trace the first of them back to 1986. Fainter, older clumps farther out suggest that this cannon fire has gone off once every 8.5 years for at least 400 years.
The red giant itself can't be the gunner. The best explanation is an unseen companion star on a stretched orbit that dips into the giant's puffed-up outer atmosphere every 8.5 years. It scoops up gas into a disk around itself, and the disk launches the blobs. Sahai thinks this kind of shooting may help sculpt the elaborate shapes of glowing shells that dying stars leave behind.
A dying star's last years can keep time like a clock.
2. ☁️ Venus's pale clouds may hold something dark
To our eyes, Venus is a smooth, pale yellow ball. In ultraviolet light, it changes completely: dark and bright streaks sweep across its sulfuric acid clouds. Astronomers have watched these patterns for about a century, and they still don't know what makes them. The culprit is simply called the "unknown absorber."
In 2026, a team led by Jan Spacek of the Foundation for Applied Molecular Evolution asked a new question: what would Venus's cloud droplets look like if you could collect them in a flask and study them in a laboratory?
The answer may be surprising. Venus's cloud particles are about the same size as those in cigarette smoke. Smoke looks white because its tiny particles scatter light so well, yet gathered together it's a dark, tarry sludge. Venus's clouds may work the same way. Using a model of how sunlight bounces around inside them, the team worked out that the liquid in the droplets must absorb ultraviolet and blue light extremely strongly.
That rules a lot out. Many proposed mineral culprits would need to be present in enormous amounts. Carbon-based molecules could do it, though the team stresses that this says nothing about life. "Paradoxically, by placing additional constraints on the unknown absorber, we might have made the mystery even more intriguing," said Janusz Petkowski.
A planet that looks pale from afar may be dark inside every droplet.
3. 🕳️ GW170817 shot out a jet that seemed to outrun light
In August 2017, two neutron stars collided in a distant galaxy. The crash shook spacetime with gravitational waves, and some 70 observatories turned to watch. The wreckage collapsed into a black hole, and a jet blasted out from around it.
Two days later, Hubble was looking. Years of careful work followed, combining Hubble with Gaia and with radio telescopes spread across the globe. In 2022, Kunal Mooley of Caltech and his colleagues reported the result: the jet appeared to move at seven times the speed of light. Later radio measurements had it slowing to "only" four times light speed.
Nothing can really travel faster than light. This is an illusion called superluminal motion, and it happens when something moves almost straight toward us at nearly the speed of light. The jet keeps chasing its own light. Light it gives off later has a shorter trip to make, so it arrives hot on the heels of earlier light, squeezing a long journey into what looks like a short time.
Run the trick backward, and the illusion becomes a speedometer. The team worked out that the jet left the crash at no less than 99.97% of the speed of light.
Sometimes the impossible number is the most precise measurement we have.
4. 🪐 51 Pegasi b was a planet in the wrong place
On October 6, 1995, at a conference in Florence, Michel Mayor and Didier Queloz announced the first planet ever found orbiting a Sun-like star. The trouble was that almost nobody believed it.
The planet, 51 Pegasi b, about 50 light-years away, is a gas giant like Jupiter. But Jupiter takes almost 12 years to circle the Sun. 51 Pegasi b goes around its star in just four days, only about 8 million kilometers out, roasted to over 1,000 degrees Celsius. Theory said giant planets form far from their stars, so the planet was in the wrong place. Hunters had been looking for long, slow orbits, and missing the fast ones.
Mayor and Queloz couldn't see the planet itself. They saw its star wobble. As a planet circles, it tugs its star back and forth, and that motion shifts the star's light slightly bluer as it approaches us and redder as it moves away.
Paul Butler and Geoffrey Marcy soon confirmed the wobble, then found more planets. The puzzle eventually led to a new idea: giant planets can form far out and then spiral inward toward their stars.
The discovery earned a share of the 2019 Nobel Prize in Physics. Today, thousands of planets are known.
The first planet we found around another sun broke the rules of how planets were supposed to be.
5. 🌌 NGC 4550's stars circle in both directions at once
In most disk galaxies, nearly all the stars go around the same way, like traffic on a racetrack. NGC 4550 looks perfectly ordinary. Then, in 1992, Vera Rubin and two colleagues spread its light into a spectrum and found the dark absorption lines neatly split in two.
The galaxy holds two disks of stars, sharing the same space but turning in opposite directions. Later work showed the two are remarkably alike, with similar sizes and masses. Picture two crowds of runners on the same track, one going clockwise and one counterclockwise, passing through each other endlessly.
How do you build that? The obvious answer is to merge two galaxies spinning opposite ways. But collisions between two similar disk galaxies are usually destructive, and they tend to leave a puffed-up blob rather than neat disks. Only a carefully arranged collision seems to work.
The other idea is gentler. If the galaxy slowly gathered gas flowing in the "wrong" direction, that gas could build a second disk of stars over time. Studies of the two disks found that the second one is younger and poorer in heavy elements, which fits that story, with the event dated to around 7 billion years ago.
In one survey of 260 nearby galaxies of a similar type, only about 2% had two opposing disks of similar mass.
Some galaxies hide a second history, going the other way.
6. ☄️ Bennu's boulders are cracked through
When NASA's OSIRIS-REx spacecraft reached the asteroid Bennu in 2018, the team got a shock. Instead of patches of fine gravel to sample, Bennu was covered almost entirely in boulders.
That clashed with older measurements. In 2007, NASA's Spitzer Space Telescope had seen Bennu's surface heat up and cool down quickly as it turned. Fine material like beach sand behaves that way. Big solid rocks, like concrete, should hold on to warmth and release it slowly. So how could a world of boulders cool like a beach?
Now that samples are back on Earth, Andrew Ryan of the University of Arizona and his colleagues have the answer. Bennu's rocks are very porous, but that wasn't enough. At NASA's Johnson Space Center, the team scanned the pieces with X-rays, each sealed in its own airtight "spacesuit" so it never touched Earth's air. The scans revealed networks of cracks running all through them.
When the team scaled those cracks up to boulder size in computer simulations, they reproduced exactly the quick cooling the spacecraft had measured. "It turns out that they're really cracked too, and that was the missing piece of the puzzle," Ryan said.
That matters beyond Bennu, because astronomers often judge what an asteroid's surface is like from how it holds heat.
On a small asteroid, a boulder can be more crack than rock.
7. 💥 SN 1987A finally showed signs of its neutron star
In February 1987, a star exploded in the Large Magellanic Cloud, about 160,000 light-years away. SN 1987A was the first supernova visible to the naked eye since 1604, and theory said it should have left behind a neutron star or a black hole.
Astronomers looked for that remnant for more than three decades, finding only indirect hints.
The James Webb Space Telescope turned to SN 1987A in July 2022, among its very first targets. A team led by Claes Fransson of Stockholm University found a strong signal from argon atoms at the very center of the debris. Webb also spotted argon stripped of five of its 18 electrons.
Tearing that many electrons off an atom takes very energetic light, and something at the center has to be making it. "In the paper we discuss different possibilities, finding that only a few scenarios are likely, and all of these involve a newly born neutron star," Fransson said.
We still haven't seen the neutron star itself, only its glow on the gas around it. But it's the best evidence yet that the explosion left one behind.
After 37 years, the most famous supernova of our time is giving up its heart.
8. ⭐ Stars like the Sun superflare about once a century
The Sun has violent days. But how violent can it get? We've only measured it directly since the space age, far too short to catch its rarest outbursts.
So Valeriy Vasilyev of the Max Planck Institute for Solar System Research and his colleagues looked at 56,450 stars like the Sun, watched by NASA's Kepler telescope from 2009 to 2013. Together, that's like watching one Sun for 220,000 years.
They hunted for superflares, outbursts releasing more energy than a trillion hydrogen bombs, that make every flare ever recorded on the Sun look small. Carefully ruling out passing asteroids, cosmic rays and neighboring stars, they found 2,889 superflares on 2,527 stars. On average, a Sun-like star produces one roughly every hundred years.
Earlier surveys had estimated once every thousand or even ten thousand years. Evidence stored in tree rings and ancient ice, from storms of particles hitting Earth, points to the most extreme events arriving about once every 1,500 years. It's still unclear whether superflares always throw off the huge clouds of particles that leave those marks.
"We were very surprised that sun-like stars are prone to such frequent superflares," Vasilyev said.
Our calm, steady star may have a temper we haven't seen yet.
9. 🔴 Mars is hotter deep beneath its south
Mars has two faces. Its southern half is high, mountainous and covered in craters. Its northern half is mostly low, smooth plains. Now it turns out that the split runs deep.
As Mars travels its slightly stretched orbit, tilted on its axis, the Sun's pull on it changes with the seasons and flexes the planet very slightly. Alexander Berne, who began the work at Caltech, and his colleagues tracked how three orbiting spacecraft sped up and slowed down over decades, and used those tiny changes to map how Mars responds.
The planet doesn't flex evenly. Parts of its gravity field differed by up to 300% from what a planet with a uniform interior would show. The best explanation is that the rock deep beneath the southern highlands is 200 to 400 degrees Celsius hotter than under the north, and may be partly molten.
That might explain why NASA's InSight lander found that quake waves lose energy faster in the south. Nobody knows yet what caused the difference. It could be a giant impact that let heat escape from the north, slow churning inside the planet, or the thick southern crust trapping heat like a blanket for billions of years.
Mars's two faces aren't just skin-deep.
10. 🪐 Upsilon Andromedae's planets orbit 30 degrees apart
In our Solar System, the eight planets circle the Sun in nearly the same flat plane, a fossil of the disk they formed from. For a long time, astronomers assumed other planetary systems would be just as tidy.
Upsilon Andromedae is a star a little younger, heavier and brighter than the Sun, about 44 light-years away, with three known giant planets. In 2010, Barbara McArthur of the University of Texas at Austin and her team combined two kinds of measurement. Ground-based telescopes tracked the star's wobble toward and away from us, and Hubble tracked its tiny side-to-side motion on the sky, precise enough to measure the width of a coin across a continent.
Together, they revealed the planets' orbits in three dimensions. Two of them, Upsilon Andromedae c and d, orbit about 30 degrees apart. It was the first time anyone had measured the tilt between two planets around another star.
Something violent must have happened. Rory Barnes's calculations suggest the system once had another planet that was thrown out. Even now, the planets pull on each other so hard that the system sits "right on the precipice of instability."
Not every family of planets grows up flat and calm.
11. 🌌 The universe is making fewer stars, but hasn't run out of hydrogen
The universe has been slowing down its star-making for billions of years. The obvious explanation is that galaxies are running out of fuel. In 2026, a team led by scientists at the Chinese Academy of Sciences checked, and found that the fuel tank is still fairly full.
The fuel in question is neutral hydrogen gas, which glows faintly in radio waves. A single distant galaxy's signal is far too weak to detect, so the team combined two giants. China's FAST, the 500-meter radio dish, supplied the sensitivity, and the DESI survey supplied precise distances to about 2.5 million galaxies across nearly a third of the sky. Lining up and stacking all those faint signals let the average one rise out of the noise.
Looking back 4.5 billion years, the universe was forming stars about 2.5 times faster than today. But it held only about 1.4 times as much neutral hydrogen.
So the gas hasn't disappeared. What's changed may be how well galaxies turn it into stars. Stars are born in dense, cold clouds of molecular hydrogen. As the flow of fresh gas from the cosmic web weakens, galaxies may struggle to squeeze their hydrogen into those clouds.
The universe still has its fuel. It's losing the knack of using it.
12. 🌌 The oldest light in the sky is slightly lopsided
The cosmic microwave background is the afterglow of the Big Bang, released when the universe was about 380,000 years old. Its tiny hot and cold patches are the seeds of every galaxy. In 2013, ESA's Planck satellite mapped them in more detail than ever, and the map fit the standard model of cosmology beautifully, with a few odd exceptions.
On the largest scales, the patches are weaker than the smaller ones predict. One half of the sky is, on average, slightly warmer than the opposite half, though the standard model says the universe should look much the same in every direction. And one cold spot is bigger than expected.
NASA's WMAP satellite had hinted at these oddities before, but many doubted they were real. Planck's sharper view changed that. "They are real and we have to look for a credible explanation," said Paolo Natoli of the University of Ferrara.
Planck's final 2018 analysis confirmed the anomalies in the temperature map, while its maps of polarized light, a second, independent view, show no clear sign of them yet. Nobody knows whether they are rare flukes or a sign that the universe is less uniform on scales larger than we can see.
The baby picture of the universe matches our theory almost perfectly, and "almost" is where the questions live.
13. ⚛️ Helium from the first five minutes, measured to half a percent
In the first few minutes after the Big Bang, the universe was a hot, dense nuclear furnace. Before it cooled, it forged hydrogen into helium, and the amount it made depended on the conditions at that moment.
To measure that original helium, you need gas that stars haven't touched, because stars make helium too. So the LBT Yp Project used the Large Binocular Telescope to observe glowing gas clouds in 54 small galaxies poor in heavy elements, and picked out 15 of the most pristine, almost untouched since the beginning. Spectrographs that took 12 years to build read more than 10 helium lines and 15 hydrogen lines at once, letting the team catch small errors earlier studies missed.
The result: helium made up 24.58% of ordinary matter by mass when the furnace shut down, measured to 0.5%, three times better than before. It agrees with what the Big Bang theory predicts from Planck's map of the oldest light.
The helium also counts invisible particles. How much was made depends on which light particles were around at the time, including ghostly neutrinos. The measurement points to about three kinds, just as the Standard Model of particle physics says.
"We promised a half-percent uncertainty in our proposal, and we got there," said Evan Skillman of the University of Minnesota.
Nearly a quarter of the universe's ordinary matter was forged in its first few minutes.
14. 🔵 The smallest stars will one day turn blue
The most common stars in the universe are thought to be small, cool red dwarfs. The smallest weigh about 80 times as much as Jupiter, less than a tenth of the Sun. They're dim and modest, and they'll outlive everything else that shines.
Unlike the Sun, a small red dwarf is stirred all the way through, like a pot at a rolling boil, so it can burn nearly all its hydrogen, not just what's in its core. In 1997, Fred Adams and Gregory Laughlin traced what happens next. Over trillions of years, the smallest stars slowly brighten about tenfold and more than double their surface temperature. After about 11 trillion years, the fuel finally runs low. They never swell into red giants as the Sun will. Instead, they glow hotter and bluer, then shrink into dim white dwarfs.
That hot, blue stage has a name: a blue dwarf. No one has ever seen one, because none exists yet. The universe is 13.8 billion years old, and even its oldest red dwarfs are not 1% of the way through their lives.
Around the same time, galaxies will run out of the gas they need to make new stars. Some of the last starlight in the universe may come from these tiny stars, grown bright and blue in their old age.
Some of the universe's last sunsets may be blue.
🌙 One last thought before you sleep
Tonight was about second looks.
A jet seemed to outrun light, until we understood it was chasing its own glow. Pale clouds turned out to hide something dark. Boulders that should hold heat turned out to be full of cracks. An ordinary galaxy turned out to be two crowds of stars passing in opposite directions. Even the oldest light in the sky, so nearly perfect, has a slight tilt we can't yet explain.
Sometimes the second look changes the story completely, like a giant planet in a four-day orbit. Sometimes it confirms it beautifully, like helium measured to half a percent.
And some things we can't look at yet at all. The blue dwarfs are still trillions of years away, and we know them only because the physics lets us look ahead.
The universe rarely lies, but it almost always rewards a second look.
That's all for tonight. Thanks for wondering along with me. Good night, and clear skies. 🌌
— Kasi