The Sun's Hidden Power, Atmosphere on a Nearby Planet, and Starship's Five-Act Drama

0:00 Anna: Welcome to Astronomy Daily and our weekend

0:03 space and astronomy news wrap for Saturday,

0:06 the 18th of July, 2026.

0:09 I'm Anna.

0:10 Avery: And I'm Avery. Every Saturday, we bring you

0:12 two brand new stories, plus the four biggest

0:15 headlines from the week that was. And

0:17 honestly, Anna, what a week it was.

0:19 Anna: It really was. Coming up, new research

0:22 suggesting we may have been underestimating

0:25 just how hard the sun can hit us. A

0:28 planet 48 light years away that turns out to

0:31 have air. A week of high drama at

0:34 Starbase. A hidden black hole in the Southern

0:37 Hemisphere's favorite star cluster,

0:39 Landslides on Pluto. And to

0:42 finish the most delightful space story of the

0:45 week involving a cup of tea.

0:47 Avery: Only on this show does that sentence make

0:50 sense. Let's get into it.

0:51 Our, uh, lead story this weekend is one of

0:53 those quiet papers with very loud

0:55 implications. New research published in the

0:58 journal Nature suggests the most powerful

1:00 solar storms to strike Earth may pack a

1:03 bigger punch than scientists realized,

1:05 because the limit we thought Nature had built

1:07 in may never have existed at all.

1:10 Anna: Set this up for us, Avery. What limit are we

1:12 talking about?

1:13 Avery: So, for decades, space weather scientists

1:16 have observed something reassuring in the

1:18 data. As the solar wind, that stream of

1:21 charged particles flowing off the sun, gets

1:23 stronger during a storm, the electrical

1:25 currents it drives through the upper

1:27 atmosphere increase up to a point. And then

1:30 the response seemed to flatten out, saturate,

1:33 as if the Earth had a ceiling on how badly it

1:35 could react no matter how hard the sun

1:37 pushed.

1:38 Anna: Which would be very good news for anyone who

1:41 owns a satellite or a power grid.

1:43 Avery: Exactly. That assumed ceiling has been

1:46 quietly baked into risk models for extreme

1:48 space weather. But the new study, led by Dr.

1:51 Nithin Cividas of NASA's Goddard Space Flight

1:53 center, with co author Dr. Maria Wallach of

1:56 Lancaster University, asked a deceptively

1:59 simple. Is that saturation real

2:02 physics, or is it an artifact of how we've

2:04 been measuring the solar wind?

2:06 Anna: And the answer?

2:08 Avery: Very likely an artifact. The team analyzed

2:11 more than a million solar wind measurements

2:12 from spacecraft orbiting much closer to

2:15 Earth, where the solar wind actually meets

2:17 our magnetic field. And in that data, the

2:20 electrical currents in the upper atmosphere

2:22 just kept climbing as a solar wind got

2:24 stronger. No flattening, no sealing.

2:27 Anna: The paper's title gives away the mechanism,

2:29 doesn't it? Regression to the mean.

2:32 It's a statistical effect. Essentially, when

2:35 you average noisy measurements of extreme

2:37 events, the extremes get smoothed away.

2:40 And that smoothing can masquerade as a

2:43 physical limit.

2:44 Avery: Right. The ceiling was in the maths, not the

2:46 magnetosphere. And if there's no upper limit

2:49 to our planet's response. Then the rare

2:51 monsters, the so called once in a thousand

2:54 year geomagnetic storms could hit

2:56 satellites, gps, communic and power

2:59 grids harder than current estimates predict.

3:02 Anna: It's worth saying clearly this is not a

3:05 prediction that a catastrophic storm is

3:07 coming. Wallach herself makes the point that

3:10 these extreme cases are rare, which is

3:13 fortunate, but it also means we have very

3:16 little data on them.

3:17 Avery: And there's a timeliness to this because the

3:19 sun is still near the peak of its roughly 11

3:22 year activity cycle. For our listeners across

3:24 Australia and New Zealand, that's the same

3:26 solar activity that has delivered those

3:28 spectacular Aurora australis displ over

3:31 the past couple of years.

3:33 Anna: The aurora is the beautiful face of

3:36 space weather and this paper is a reminder

3:38 that the same physics has a much less

3:41 charming side. We'll come back to Aurora

3:44 watching in our Skywatch segment a little

3:46 later.

3:47 Now to our weekly highlights, the four

3:50 stories that defined the week. And if you

3:52 only heard one episode this week, I hope it

3:55 was Fridays because it carried what might

3:58 just be the story of the year. For the

4:00 first time, astronomers have detected an

4:03 atmosphere around a rocky Earth like

4:05 planet in the habitable zone of its

4:08 Avery: star LHS 1140B,

4:11 48 light years away, which in

4:13 galactic terms is barely down the street.

4:16 Anna: As we covered on Friday's show, the detection

4:19 was published in the journal Science. The

4:21 team found helium escaping from the planet's

4:24 atmosphere and that escaping envelope is

4:27 the fingerprint that told them an atmosphere

4:30 is there at all. Rocky planet,

4:32 habitable zone, confirmed atmosphere.

4:35 That combination has never been ticked off

4:37 before on any world anywhere,

4:40 and the

4:41 Avery: researchers believe the planet probably holds

4:43 a substantial amount of water too. With the

4:46 greenhouse atmosphere you have conditions

4:48 that could plausibly support liquid water at

4:50 Anna: the surface, with the lead author being very

4:53 careful, as we stressed on Friday, to

4:56 say nobody is claiming this planet has life.

5:00 What they're claiming is a the first

5:03 rocky temperate world where we can even ask

5:05 the question with real data.

5:08 Avery: Every generation of astronomers gets one or

5:10 two first time in history moments. This week

5:13 we got one. If you missed the full story,

5:16 it's Friday's episode. So

5:18 5e143.

5:20 In your feed right now, highlight number

5:23 two and it's less a story than a soap

5:26 opera. Starship Flight 13

5:28 gave us a full five act drama this week.

5:31 Anna: Walk us through it, Avery. Because we covered

5:34 a new twist Almost

5:35 Avery: every day, Act 1 Monday we

5:38 previewed the flight with SpaceX, aiming for

5:41 midweek and the first functional Starlink V3

5:44 satellites. Real working satellites this

5:47 time, not the mass simulators of earlier

5:49 flights. Act 2 Tuesday, the

5:52 launch slipped to ah, Thursday after a

5:54 successful 33 engine static fire.

5:57 Act 3 Wednesday, the FAA

6:00 formally closed its flight 12 mishap

6:02 investigation, clearing the path. Act

6:05 4 Thursday, the countdown reached

6:08 zero

6:08 Anna: and then stopped there the abort at

6:11 T0. As we reported on Friday's show,

6:14 some of the super heavy booster's Raptor

6:16 engines failed to ignite and the vehicle's

6:19 computers called an automatic abort. Just as

6:22 the engines lit, Elon Musk said two

6:25 Raptors would be removed and replaced.

6:27 Avery: Which brings us to Act 5 and um, this part's

6:30 new. Since yesterday's episode, SpaceX has

6:33 restacked the two stages at Starbase. And

6:36 Flight 13 is now scheduled for Monday

6:38 evening, July 20th, US time, which

6:41 Anna: means Tuesday morning for most of our

6:43 Australian and New Zealand listeners. And it

6:46 means we should have the results for you on

6:48 Tuesday's show. The story that ate this week

6:51 is about to headline next week, too.

6:53 Avery: Third time lucky? We'll find out Monday.

6:56 Anna: Highlight number three takes us to the

6:58 Southern Hemisphere's crown jewel, Omega

7:01 Centauri, the biggest and brightest globular

7:04 cluster in the entire sky. As we covered

7:07 on Wednesday's show, astronomers have found

7:09 the first confirmed stellar mass black hole

7:12 hiding among its 10 million stars.

7:16 Avery: Found not by seeing it, you can't see it,

7:18 but, uh, by watching stars move

7:21 precisely.

7:22 Anna: Using years of Hubble and James Webb

7:24 astrometry, the painstaking measurement of

7:27 stellar positions, the team tracked stars

7:30 being swung around by something massive and

7:32 invisible. The motions point to a stellar

7:35 mass black hole, the first of its kind

7:38 confirmed in the cluster.

7:40 Avery: And what made Wednesday's episode special for

7:42 our audience is that this isn't some faint

7:44 smudge in a telescope catalog. Uh, Omega

7:47 Centauri is a naked eye object from Australia

7:49 and New Zealand. At this time of year, you

7:52 can walk outside on a clear July evening,

7:55 look up and see the fuzzy star

7:57 Anna: that holds this black Hallie million

8:00 suns packed into a ball you can cover with

8:02 your thumbnail. And now we know at least one

8:05 of them left a black hole behind. It's riding

8:07 high in our winter sky right now. And we'll

8:09 tell you exactly where to look.

8:11 In the Skywatch segment, our final highlight

8:13 Avery: is the double bill from Thursday's two

8:16 discoveries from the Pluto system 10 years

8:19 after New Horizons flew past. Proving that

8:22 flyby is still the gift that keeps on giving.

8:25 Anna: First, Pluto itself. Researchers combing

8:28 through New Horizons imagery found evidence

8:30 of landslides down steep crater walls,

8:33 the first ever identified on Pluto. And

8:36 some are enormous large enough, as we said on

8:39 Thursday, to bury entire cities on Earth.

8:42 Avery: Landslides on a world where the bedrock is

8:45 water ice and the surface temperature sits

8:47 around minus 230 degrees

8:49 Celsius. Even in deep freeze,

8:52 Pluto's geology is alive enough to move

8:54 mountainsides.

8:56 Anna: And then part two of the double bill. Pluto's

8:58 giant moon Charon, where scientists showed

9:01 that its network of tectonic fractures

9:04 preserves a record of its ancient space spin

9:06 down as, uh, Charon's rotation slowed over

9:09 billions of years, locking one face

9:11 permanently toward Pluto, the stresses

9:14 cracked its crust in patterns we can still

9:17 read today.

9:18 Avery: A fossil record written in fractures.

9:21 Ten years after a nine year journey and a

9:24 nine hour flyby, the Pluto system is

9:26 still handing us front page science. Not bad

9:29 for a world some people try to demote out of

9:31 the headlines.

9:33 Anna: And now the story I've been saving all

9:35 episode because it's brand new, it's

9:38 historic and it's about tea.

9:40 Avery: The finest sentence ever spoken on this

9:42 Anna: program announced on Thursday. Seeds from

9:45 South Africa's famous Rovioche plant are

9:48 going to the International Space Station this

9:50 October. They will be the first indigenous

9:53 South African species and the first seeds

9:56 from the African continent ever to go to

9:59 space.

10:00 Avery: Robios for listeners who haven't tried it,

10:02 it's that lovely Swedish caffeine free

10:05 red tea grown in the Cederberg region north

10:08 of Cape Town and pretty much nowhere else on

10:10 Earth.

10:11 Anna: The mission is a partnership between the

10:13 South African Robios Council, the space

10:15 education company Max IQ Space and

10:18 the South African Space Agency. The

10:21 seeds travel in a sealed nanolab aboard an

10:24 ISS resupply flight, spend at least

10:26 six weeks exposed to microgravity and space

10:29 radiation and return to Earth around December

10:32 or January.

10:33 Avery: And here's the part I love most. When they

10:36 come back, the space flown seeds will be

10:38 planted alongside ground control seeds.

10:41 And the scientists doing that comparative

10:43 study tracking germination, growth,

10:45 resilience and yield are school students.

10:49 Kids from the Cederberg region, the very

10:51 region where Robios grows. Monitoring the

10:54 plans of over 18 months.

10:56 Anna: Kids from the birthplace of Robios running a

10:59 real space biology experiment on their own

11:01 hometown plant. If that doesn't launch a few

11:04 careers in science, nothing will.

11:06 Avery: It also joins a genuinely important research

11:09 thread. Lettuce, peas and soybeans have

11:12 all flown on the station as we work out how

11:14 to grow food beyond Earth. Robios is

11:17 hardy, drought adapted and packed with

11:19 antioxidants. Honestly, if humanity's going

11:22 to the moon and Mars, somebody should

11:24 absolutely be bringing the tea.

11:26 Anna: A story with warmth in every sense. We'll

11:29 follow the seeds when they fly in October.

11:31 Avery: Time for Skywatch what to look for from the

11:34 Southern Hemisphere this week the

11:36 Anna: Moon is returning to the evening sky as

11:39 a waxing crescent after Tuesday's new Moon,

11:42 low in the west after sunset and

11:44 climbing higher each night with

11:47 beautiful Earthshine on the unlit

11:49 portion in these early days. It

11:52 slit past brilliant Venus and the star

11:55 Regulus late this week and the pairing

11:57 is still worth a look as

11:59 Avery: twilight fades but the Moon young and

12:02 setting early, the evenings stay gloriously

12:05 dark and that means the winter Milky Way. The

12:08 galactic core in Sagittarius and Scorpius is

12:10 virtually overhead in the mid evening from

12:13 Australia and New Zealand. Right now from a

12:16 dark site, it's the finest naked eye sight in

12:19 nature.

12:19 Anna: And while you're under it, find Omega

12:22 Centauri, the very cluster from

12:25 Wednesday's Black hole story. Look to

12:27 the southwest in mid evening in the

12:30 constellation Centaurus above the Southern

12:33 Cross. To the naked eye it's a soft,

12:35 fuzzy star in binoculars it

12:38 swells into a glowing ball of ancient

12:41 suns.

12:42 Avery: Saturn rises late in the evening and stands

12:45 high in the predawn sky for early risers,

12:47 with Mars still tracking through Taurus near

12:50 the red star Aldebaran in the dawn twilight.

12:53 Anna: And given today's lead story, keep an

12:56 eye on the aurora alerts. We're near

12:59 solar maximum and one good

13:01 coronal mass ejection can light up

13:04 southern skies from Tasmania and the South

13:07 Island. The Aurora australis is the

13:10 friendly reminder of everything we discussed

13:12 at the top of the show.

13:14 Avery: And that's the week that was in space and

13:16 astronomy. A sun with fewer limits than we

13:19 thought, a rocky world with air, a rocket

13:22 with one more chance on Monday, a black hole

13:25 you can point at, landslides on Pluto and

13:28 tea leaves headed for orbit.

13:30 Anna: For all the show notes, links to every story

13:33 and our full episode archive, visit

13:36 astronomydaily IO and

13:38 you'll find us across social media.

13:41 AstroDailyPod we're back Monday

13:44 with all the news, including, we hope, a

13:46 starship launch.

13:48 Avery: Until then, thanks for spending part of your

13:50 weekend with us. I'm Avery.

13:52 Anna: And I'm Anna. Clear skies everyone.

13:55 Avery: Astronomy Day

13:58 stories we told.

14:04 Anna: You.

14:04 Avery: Mhm.