Whirlpools Found on the Sun’s Surface for the First Time

0:00 Anna: G' day and welcome to Astronomy AstroDailyPod. I'm Anna. Avery: And I'm Avery. It's the weekend wrap for Saturday 8th August, and this is one of those rare weekends where the sky itself is the headline. We are four days out from a total solar eclipse and the peak of the Perseids landing on the very same night. Anna: We'll get you set for all of that in the sky watch at the end. Both hemispheres, proper local times and one eye safety rule. None of us are allowed to skip. But we start where the whole week has quietly been pointing at the sun.

0:32 Avery: Then, um, three storeys at the find the week. A rocket stage that finally hit The Moon, a 48 year old spacecraft that just bought itself another year of life, and the rescue mission that spent, uh, the week rescuing itself. Let's go. Anna: Here's the question that sounds simple and isn't. What does the surface of the sun actually look like up close? Not the postcard, the fine detail right down at the scale where the physics happens. This week for the first time, we got to see it. And the answer is it's covered in whirlpools.

1:04 Avery: Whirlpools on the sun. Anna: Tiny ones, some only about 20 kilometres across, which on the sun is almost microscopic. In a paper published Wednesday in Nature, a team led by David Kureads at the U.S. national Solar Observatory in Hawaii, the biggest solar telescope ever built, a four metre mirror on Haleakala, zoomed in on the edges of the sun's granules. And where earlier telescopes saw a smooth, slightly blurry boundary, Inoue saw structure curling, breaking, wave like swirls forming and dissipating everywhere along the magnetic boundaries.

1:45 Avery: And, um, these have a name. They're not a total surprise, physically. Anna: Right, exactly right. And that's what makes it satisfying rather than baffling. They're called Kelvin Helmholtz instabilities. If you've ever watched wind peel the top of an ocean wave, or seen those rows of curling cloud that look like a breaking sea in the sky, that's the same effect. It happens whenever two fluids slide past each other at different speeds. Lord Kelvin and Hermann Helmholtz described the math back around 1870.

2:17 Avery: So the physics is 150 years old. The picture of it on the sun's surface is four days old. Anna: That's the whole storey in one line. We've seen these swirls in Earth's clouds, in the atmospheres of Jupiter and Saturn, even hinted at high up in the sun's outer corona. But never before down on the visible surface, the Photosphere where the solar wind and all that magnetic energy actually originate. The resolution simply wasn't there. Inui changed that. Avery: Walk me through why the surface is the important place to catch them.

2:51 Anna: Because that's where the sun's magnetic field tangles with its boiling convection. Picture the granules, those bright cells of hot plasma, rising, cooling, sinking like a pot of porridge on the boil at the edges. Flows crash into each other, and the magnetic field lines get squeezed together. Bundle field lines tighter, and the field gets stronger. The stronger field resists the plasma flow. And that sudden change in speed is exactly the shear you need to set a Kelvin Helmh vortex spinning.

3:24 Avery: And they didn't just eyeball it and declare victory. Anna: No, this is the part I like. They ran the same magnetic region through a state of the art physics simulation, A model called Maram, built purely from the laws of physics. No fudging. And the simulated sun grew the same swirls in the same places with the same shapes. Observation and theory shaking hands. The Max Planck team called the agreement remarkable. And that's the word that earns this a, uh, nature paper. Not we saw something odd, but we saw it.

3:57 We understand why. And the model agrees. Avery: So why should someone with feet firmly on the ground care about micro whirlpools 93 million miles away? Anna: Two reasons, and they're both big. The first is one of the great unsolved puzzles in solar physics. The corona problem. The sun's surface is around 6,000 degrees. Its outer atmosphere, the corona, is millions of degrees, hundreds of times hotter. Further away from the heat source. That should be impossible. Like standing back from a campfire and getting warmer.

4:33 Something is carrying energy upward and dumping it into the corona. And these ubiquitous little vortices are a very good candidate for part of that pipeline. Avery: And the second reason is the one that reaches down and touches U.S. base weather. Anna: Those same swirls could feed the buildup of magnetic energy that the sun eventually releases as flares and coronal mass ejections. The blasts of charged particles that, when they're aimed our way, can knock satellites about, degrade GPS and stress power grids.

5:06 The next step is to turn pattern recognition algorithms loose on long runs of ENOYE data to measure how much these instabilities actually shift. Nail that number, and you sharpen the models that forecast solar storms. Avery: Which is a lovely place to be starting an eclipse week. Honestly, everyone's about to point their attention at the sun anyway. Anna: It really is. For decades, this was a prediction on a chalkboard. This week, it became a picture. The Sun's surface isn't a smooth glowing ball, it's a sea and it's full of breaking waves from the sun to Avery: the moon and to a storey.

5:45 This show first flagged back in the autumn. Early Wednesday morning, a spent SpaceX Falcon 9 upper stage slammed into the far western edge of the moon near Einstein Crater at around half past two in the morning US Eastern time. Anna: This is the one astronomer Bill Grey had been tracking since April. Avery: The very one. Catalogue number 2025 010D. Roughly four tonnes of hollow metal, about 12 metres long. It launched in January last year, carrying two commercial lunar landers, Firefly's Blue Ghost and I. Space's resilience.

6:19 Under NASA's Commercial Lunar Programme, its job done, it was left drifting. And for 19 months, sunlight and gravity nudged it around cislunar space until the numbers lined up on a collision course. Anna: And it hit at genuinely startling speed, Avery: about 5,400 miles an hour, seven times the speed of sound, releasing energy like roughly three tonnes of TNT. The catch for skywatchers, it came down on sunlit ground, so any flash was washed out by daylight. Nobody on Earth got the fireworks. Anna: So how do we actually confirm it happened and see the scar from orbit?

6:59 Avery: And this is where it gets good. NASA's Lunar Reconnaissance Orbiter and South Korea's Dhanuri spacecraft are retasking to photograph the site. Because we know almost exactly where and when it struck. We get a rare before and after. A fresh crater expected somewhere between 18 and 30 metres wide, appearing on a patch of moon we already had mapped. I'll be honest, those high resolution images aren't in hand yet. They depend on lighting and orbital geometry over the coming weeks. But the impact itself is confirmed.

7:30 Anna: And there's a bigger point sitting underneath the spectacle. Avery: There is. This is only the second known unintentional lunar impact by a rocket stage. The first was a Chinese Booster back in 2022. But the traffic up there is climbing fast and there's still no binding rulebook for disposing of hardware on these high energy paths. SpaceX says this stage was passivated by the book and is now working with NASA on prevention. Fittingly, the international meeting that produced the latest recommendations for the moon was held right here in Sydney.

8:03 The recommendations are real. The requirements aren't there yet. Anna: A new crater and a, uh, nudge to write some rules before the next one. Now to the most distant good news, Storey, you'll hear all year. Voyager 2, launched in 1977, now more than 21 billion kilometres away out in Interstellar space has just been given at least another full year of science by engineers who can't touch it, can't send it apart and have to wait about 19 and a half hours just for a command to arrive. Avery: And they've given the manoeuvre a wonderful name.

8:39 Anna: They're calling it the Big Bang. Here's the problem it Voyager runs on plutonium radioisotope generators that turn heat from decay into electricity and that supply drops by about 4 watts every single year. It's a spacecraft slowly running out of power. And for years the fix has been to switch instruments off one by one without action. Voyager 2 would have had to shut down another of its three remaining instruments before the end of this year. Avery: So why Big Bang? What's dramatic about a power swap?

9:14 Anna: Because it all had to happen at once. They switched off a set of power hungry devices and swapped in lower power alternatives. But the catch is that the very same power also produces heat. And out there, near absolute zero, if the wrong component gets too cold, it freezes and dies permanently. You can't do it gently, one step at a time. The thermal sums only balance if you throw the switches simultaneously. As one of the engineers put it, they couldn't afford to be wrong. And it worked exactly to plan.

9:49 Avery: And Voyager 1 is next in the queue. Anna: It is. The team is stepping through the same process on Voyager 1 in the coming weeks. And the early tests have gone smoothly. Two probes, 48 years old, still humanity's only instruments physically out in interstellar space, kept alive by people rewriting how the hardware is used from 13 billion miles back. That's not a rescue. That ends the storey. The power keeps falling. But it's another year of listening to the space between the stars. Avery: And now our, uh, running saga of the week.

10:24 The rescue mission that spent the week being rescued. You'll remember the setup. NASA Swift Observatory, 22 years old, a first responder for gamma ray burst is sinking. Its orbit is decaying and it can't lift itself. And without help, it's likely to re enter this spring, our time. Once it drops below about 300 kilometres. Anna: Enter link. Built at extraordinary speed to go up and give Swift a boost. Avery: A commercial servicing spacecraft from Catalyst Space built clean sheet in about nine months.

10:56 Launched last month. First of its kind. A private robot grabbing a government satellite that was never designed to be serviced, except that during commissioning, Link itself tumbled into a multi axis spin up to 9 degrees a second. With two of its three reaction wheels out of action and some loss in its cold gas thrusters. The rescuer needed a rescue. Anna: And this week is where that turned a corner. Avery: It genuinely did. Using thruster burns, the team has wrestled that spin all the way down from 9 degrees a second, uh, to 1.47 degrees.

11:31 And they're holding it steady there. The D spin effectively is one the mission has now shifted from a stabilisation problem to a software one. Because so much of the original attitude control system is offline, they're preparing a major flight software upgrade to restore full control using what still works. Anna: And only once that lands can the chase actually begin. Avery: Right, software update first, then the phasing manoeuvres to line Link's orbit up with Swift. Then a rendezvous and, uh, a grapple with its three robotic arms targeted around the end of August.

12:06 If it all comes off, Lynx slowly walks Swift back up toward its old orbit over a couple of months, then peels away and burns up itself. It's down to the wire. But a week ago, this looked close to lost. And today it looks like a spacecraft catching its breath. Breath before the hardest part. Anna: We will absolutely keep you posted as that end of August window comes up. And so to the sky. And What a, uh, four days we're heading into. On Wednesday 12th August, two of the year's marquee events land together.

12:37 A, uh, total solar eclipse and the peak of the Perseid meteor shower. Avery: Let's be straight with everyone about who sees what, because this one is lopsided. Anna: It is. So let's do it. Honestly, the total eclipse, the full daytime darkness, corona blazing spectacle, belongs to the far north. The path of totality crosses the Arctic, eastern Greenland, western Iceland and clips northern Spain and the very northeast of Portugal near sunset. If you're anywhere near there, you're in for one of the sky's greatest sights, under two and a half minutes of it.

13:12 Avery: And, um, for our North American listeners, our largest audience, the honest picture is a partial and only in one corner. Anna: That's right. No part of North America sees totality this time. But in the afternoon on the 12th, Eastern Canada and the northeastern United States get a genuine partial in parts of Atlantic Canada, roughly half the sun covered at maximum. A smaller bite across New England and the Northeast further west, it fades to little or nothing. If you're in that eastern window, cheque local times for your exact town.

13:45 It's an afternoon event. And dig out your eclipse glasses. Avery: Which brings us to the rule we Anna: never, ever skip the non negotiable. To look at any partial phase of the sun safely, you need proper solar filters. That meet the ISO 123122 standard certified eclipse glasses or a safe solar viewer M ordinary sunglasses do not work no matter how dark. Only someone standing inside the path of totality may remove them and only during the brief total phase. Everyone seeing a partial, that's all of North America and most of Europe keeps them on the entire time.

14:25 Damage to your eyes is painless and permanent. Please don't risk it. Avery: And if you're nowhere near the track, which includes all of us down here in the south, NASA streams the whole thing live from about a quarter past one eastern. Anna: Now the Perseids that same night and here the news is good for the northern half of the world. The peak lies the night of the 12th into the 13th and this year the peak is essentially moonless. The eclipse falls on a new moon so the sky is dark and the faint meteors get their moment from the mid northern latitudes after midnight that's potentially dozens an hour under clear skies.

15:02 North America, Europe, this is your gift of the week. Avery: But the Perseids are a northern shower. The radiant barely lifts above the horizon. Anna: For those of us down here it barely clears it. So from Sydney or Auckland you'll catch only a stray few low in the north before dawn. So here's what the southern hemisphere actually gets and it's worth setting an alarm for before sunrise. This week the morning sky is stacked a long line of planets Saturn, Mars, Uranus and Neptunewith Jupiter low and Mercury climbing strung across the pre dawn.

15:37 Venus is your brilliant evening star after sunset and for the patient Comet 10P Tempel 2 is rising late in the evening around half past nine. If you've got binoculars and a dark Avery: horizon so nobody misses out. North gets the eclipse and the meteors. South gets the planet parade and a comet and the livestream is there for all of us. Anna: Both hemispheres eyes up all week, just protect them around that sun. Avery: That's the weekend wrap for Saturday 8th August. The Sun's hidden whirlpools, a fresh crater on the moon, Voyager 2's extra year and a rescue mission back on its feet.

16:14 Anna: We're back with your daily fix on Monday and all week we'll be counting down to that eclipse and Perseid Wednesday. Find the full back catalogue, the news feed and the newsletter@uh astronomydailyio and say hello@astronomydailypod until Monday from Anna and me. Avery: Look after those eyes and clear skies.