Anna: Welcome to Astronomy Daily and our weekend
space and astronomy news wrap for Saturday,
the 18th of July, 2026.
I'm Anna.
Avery: And I'm Avery. Every Saturday, we bring you
two brand new stories, plus the four biggest
headlines from the week that was. And
honestly, Anna, what a week it was.
Anna: It really was. Coming up, new research
suggesting we may have been underestimating
just how hard the sun can hit us. A
planet 48 light years away that turns out to
have air. A week of high drama at
Starbase. A hidden black hole in the Southern
Hemisphere's favorite star cluster,
Landslides on Pluto. And to
finish the most delightful space story of the
week involving a cup of tea.
Avery: Only on this show does that sentence make
sense. Let's get into it.
Our, uh, lead story this weekend is one of
those quiet papers with very loud
implications. New research published in the
journal Nature suggests the most powerful
solar storms to strike Earth may pack a
bigger punch than scientists realized,
because the limit we thought Nature had built
in may never have existed at all.
Anna: Set this up for us, Avery. What limit are we
talking about?
Avery: So, for decades, space weather scientists
have observed something reassuring in the
data. As the solar wind, that stream of
charged particles flowing off the sun, gets
stronger during a storm, the electrical
currents it drives through the upper
atmosphere increase up to a point. And then
the response seemed to flatten out, saturate,
as if the Earth had a ceiling on how badly it
could react no matter how hard the sun
pushed.
Anna: Which would be very good news for anyone who
owns a satellite or a power grid.
Avery: Exactly. That assumed ceiling has been
quietly baked into risk models for extreme
space weather. But the new study, led by Dr.
Nithin Cividas of NASA's Goddard Space Flight
center, with co author Dr. Maria Wallach of
Lancaster University, asked a deceptively
simple. Is that saturation real
physics, or is it an artifact of how we've
been measuring the solar wind?
Anna: And the answer?
Avery: Very likely an artifact. The team analyzed
more than a million solar wind measurements
from spacecraft orbiting much closer to
Earth, where the solar wind actually meets
our magnetic field. And in that data, the
electrical currents in the upper atmosphere
just kept climbing as a solar wind got
stronger. No flattening, no sealing.
Anna: The paper's title gives away the mechanism,
doesn't it? Regression to the mean.
It's a statistical effect. Essentially, when
you average noisy measurements of extreme
events, the extremes get smoothed away.
And that smoothing can masquerade as a
physical limit.
Avery: Right. The ceiling was in the maths, not the
magnetosphere. And if there's no upper limit
to our planet's response. Then the rare
monsters, the so called once in a thousand
year geomagnetic storms could hit
satellites, gps, communic and power
grids harder than current estimates predict.
Anna: It's worth saying clearly this is not a
prediction that a catastrophic storm is
coming. Wallach herself makes the point that
these extreme cases are rare, which is
fortunate, but it also means we have very
little data on them.
Avery: And there's a timeliness to this because the
sun is still near the peak of its roughly 11
year activity cycle. For our listeners across
Australia and New Zealand, that's the same
solar activity that has delivered those
spectacular Aurora australis displ over
the past couple of years.
Anna: The aurora is the beautiful face of
space weather and this paper is a reminder
that the same physics has a much less
charming side. We'll come back to Aurora
watching in our Skywatch segment a little
later.
Now to our weekly highlights, the four
stories that defined the week. And if you
only heard one episode this week, I hope it
was Fridays because it carried what might
just be the story of the year. For the
first time, astronomers have detected an
atmosphere around a rocky Earth like
planet in the habitable zone of its
Avery: star LHS 1140B,
48 light years away, which in
galactic terms is barely down the street.
Anna: As we covered on Friday's show, the detection
was published in the journal Science. The
team found helium escaping from the planet's
atmosphere and that escaping envelope is
the fingerprint that told them an atmosphere
is there at all. Rocky planet,
habitable zone, confirmed atmosphere.
That combination has never been ticked off
before on any world anywhere,
and the
Avery: researchers believe the planet probably holds
a substantial amount of water too. With the
greenhouse atmosphere you have conditions
that could plausibly support liquid water at
Anna: the surface, with the lead author being very
careful, as we stressed on Friday, to
say nobody is claiming this planet has life.
What they're claiming is a the first
rocky temperate world where we can even ask
the question with real data.
Avery: Every generation of astronomers gets one or
two first time in history moments. This week
we got one. If you missed the full story,
it's Friday's episode. So
5e143.
In your feed right now, highlight number
two and it's less a story than a soap
opera. Starship Flight 13
gave us a full five act drama this week.
Anna: Walk us through it, Avery. Because we covered
a new twist Almost
Avery: every day, Act 1 Monday we
previewed the flight with SpaceX, aiming for
midweek and the first functional Starlink V3
satellites. Real working satellites this
time, not the mass simulators of earlier
flights. Act 2 Tuesday, the
launch slipped to ah, Thursday after a
successful 33 engine static fire.
Act 3 Wednesday, the FAA
formally closed its flight 12 mishap
investigation, clearing the path. Act
4 Thursday, the countdown reached
zero
Anna: and then stopped there the abort at
T0. As we reported on Friday's show,
some of the super heavy booster's Raptor
engines failed to ignite and the vehicle's
computers called an automatic abort. Just as
the engines lit, Elon Musk said two
Raptors would be removed and replaced.
Avery: Which brings us to Act 5 and um, this part's
new. Since yesterday's episode, SpaceX has
restacked the two stages at Starbase. And
Flight 13 is now scheduled for Monday
evening, July 20th, US time, which
Anna: means Tuesday morning for most of our
Australian and New Zealand listeners. And it
means we should have the results for you on
Tuesday's show. The story that ate this week
is about to headline next week, too.
Avery: Third time lucky? We'll find out Monday.
Anna: Highlight number three takes us to the
Southern Hemisphere's crown jewel, Omega
Centauri, the biggest and brightest globular
cluster in the entire sky. As we covered
on Wednesday's show, astronomers have found
the first confirmed stellar mass black hole
hiding among its 10 million stars.
Avery: Found not by seeing it, you can't see it,
but, uh, by watching stars move
precisely.
Anna: Using years of Hubble and James Webb
astrometry, the painstaking measurement of
stellar positions, the team tracked stars
being swung around by something massive and
invisible. The motions point to a stellar
mass black hole, the first of its kind
confirmed in the cluster.
Avery: And what made Wednesday's episode special for
our audience is that this isn't some faint
smudge in a telescope catalog. Uh, Omega
Centauri is a naked eye object from Australia
and New Zealand. At this time of year, you
can walk outside on a clear July evening,
look up and see the fuzzy star
Anna: that holds this black Hallie million
suns packed into a ball you can cover with
your thumbnail. And now we know at least one
of them left a black hole behind. It's riding
high in our winter sky right now. And we'll
tell you exactly where to look.
In the Skywatch segment, our final highlight
Avery: is the double bill from Thursday's two
discoveries from the Pluto system 10 years
after New Horizons flew past. Proving that
flyby is still the gift that keeps on giving.
Anna: First, Pluto itself. Researchers combing
through New Horizons imagery found evidence
of landslides down steep crater walls,
the first ever identified on Pluto. And
some are enormous large enough, as we said on
Thursday, to bury entire cities on Earth.
Avery: Landslides on a world where the bedrock is
water ice and the surface temperature sits
around minus 230 degrees
Celsius. Even in deep freeze,
Pluto's geology is alive enough to move
mountainsides.
Anna: And then part two of the double bill. Pluto's
giant moon Charon, where scientists showed
that its network of tectonic fractures
preserves a record of its ancient space spin
down as, uh, Charon's rotation slowed over
billions of years, locking one face
permanently toward Pluto, the stresses
cracked its crust in patterns we can still
read today.
Avery: A fossil record written in fractures.
Ten years after a nine year journey and a
nine hour flyby, the Pluto system is
still handing us front page science. Not bad
for a world some people try to demote out of
the headlines.
Anna: And now the story I've been saving all
episode because it's brand new, it's
historic and it's about tea.
Avery: The finest sentence ever spoken on this
Anna: program announced on Thursday. Seeds from
South Africa's famous Rovioche plant are
going to the International Space Station this
October. They will be the first indigenous
South African species and the first seeds
from the African continent ever to go to
space.
Avery: Robios for listeners who haven't tried it,
it's that lovely Swedish caffeine free
red tea grown in the Cederberg region north
of Cape Town and pretty much nowhere else on
Earth.
Anna: The mission is a partnership between the
South African Robios Council, the space
education company Max IQ Space and
the South African Space Agency. The
seeds travel in a sealed nanolab aboard an
ISS resupply flight, spend at least
six weeks exposed to microgravity and space
radiation and return to Earth around December
or January.
Avery: And here's the part I love most. When they
come back, the space flown seeds will be
planted alongside ground control seeds.
And the scientists doing that comparative
study tracking germination, growth,
resilience and yield are school students.
Kids from the Cederberg region, the very
region where Robios grows. Monitoring the
plans of over 18 months.
Anna: Kids from the birthplace of Robios running a
real space biology experiment on their own
hometown plant. If that doesn't launch a few
careers in science, nothing will.
Avery: It also joins a genuinely important research
thread. Lettuce, peas and soybeans have
all flown on the station as we work out how
to grow food beyond Earth. Robios is
hardy, drought adapted and packed with
antioxidants. Honestly, if humanity's going
to the moon and Mars, somebody should
absolutely be bringing the tea.
Anna: A story with warmth in every sense. We'll
follow the seeds when they fly in October.
Avery: Time for Skywatch what to look for from the
Southern Hemisphere this week the
Anna: Moon is returning to the evening sky as
a waxing crescent after Tuesday's new Moon,
low in the west after sunset and
climbing higher each night with
beautiful Earthshine on the unlit
portion in these early days. It
slit past brilliant Venus and the star
Regulus late this week and the pairing
is still worth a look as
Avery: twilight fades but the Moon young and
setting early, the evenings stay gloriously
dark and that means the winter Milky Way. The
galactic core in Sagittarius and Scorpius is
virtually overhead in the mid evening from
Australia and New Zealand. Right now from a
dark site, it's the finest naked eye sight in
nature.
Anna: And while you're under it, find Omega
Centauri, the very cluster from
Wednesday's Black hole story. Look to
the southwest in mid evening in the
constellation Centaurus above the Southern
Cross. To the naked eye it's a soft,
fuzzy star in binoculars it
swells into a glowing ball of ancient
suns.
Avery: Saturn rises late in the evening and stands
high in the predawn sky for early risers,
with Mars still tracking through Taurus near
the red star Aldebaran in the dawn twilight.
Anna: And given today's lead story, keep an
eye on the aurora alerts. We're near
solar maximum and one good
coronal mass ejection can light up
southern skies from Tasmania and the South
Island. The Aurora australis is the
friendly reminder of everything we discussed
at the top of the show.
Avery: And that's the week that was in space and
astronomy. A sun with fewer limits than we
thought, a rocky world with air, a rocket
with one more chance on Monday, a black hole
you can point at, landslides on Pluto and
tea leaves headed for orbit.
Anna: For all the show notes, links to every story
and our full episode archive, visit
astronomydaily IO and
you'll find us across social media.
AstroDailyPod we're back Monday
with all the news, including, we hope, a
starship launch.
Avery: Until then, thanks for spending part of your
weekend with us. I'm Avery.
Anna: And I'm Anna. Clear skies everyone.
Avery: Astronomy Day
stories we told.
Anna: You.
Avery: Mhm.