Webb Makes Astronomy History | Update - NASA Rolls Artemis Back to the Hangar | Is There Life on K2-18b?

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Hello and welcome to Astronomy Daily.

I'm Anna.

And I'm Avery.

It's Wednesday, February 25th, 2026,

and you are listening to Season 5 episode 48.

Big show today.

NASA's moon rocket is on the move again.

James Webb has achieved a genuine first

in a history of astronomy.

And we're going to talk about a world out there

that is becoming increasingly difficult

to explain without considering the word life.

Plus, the sun is taking a quiet day

for the first time in years.

There's some grippy new detail

from China's incredible space emergency last year.

And we close with something

that might just make you want to send a letter.

All that coming right up.

Let's get into it.

We start with an update on a story

we've been following closely all week.

And today, there's a genuinely new angle

that caught a lot of people off guard.

Right, so Artemis II.

As of this morning, the enormous space launch system rocket

and the Orion spacecraft have physically begun

their four mile journey from Launchpad 39B

back to the vehicle assembly building

at Kennedy Space Center.

That rollback started around 9 a.m. Eastern time

and could take up to 12 hours.

The reason, as we've covered,

is a helium flow interruption in the rockets upper stage.

Helium is critical.

It pressurizes the propellant tanks

without that working perfectly.

You cannot fly.

March is now completely off the table.

The next realistic opportunity opens on April 1st.

But here's what's new today.

And it's a bit of a talking point.

Last night, the four Artemis II crew members,

Reed Wiseman, Victor Glover, Christina Koch

and Canadian astronaut Jeremy Hanson,

they were sitting in the gallery at the US Capitol

for President Trump's State of the Union.

They were guests of House Speaker Mike Johnson.

And the speech ran for nearly two hours.

The president praised the Space Force extensively.

He called it, quote, his baby.

But he made no mention of the four astronauts

sitting right there in the room

and no mention of the Artemis program at all.

Which was noticed.

These are the first people who will travel

beyond low-earth orbit since the Apollo era.

And they were in the chamber.

Some in the space community found the omission

quite striking.

The crew have now been released

from their pre-launch quarantine

since there's no imminent launch.

NASA has said the whole the media briefing

in the coming days to lay out the path forward.

For now, April 1st is the earliest emission could fly,

pending successful repairs,

a likely second wet dress rehearsal,

and the clean flight readiness review.

We will absolutely keep you updated as this develops.

The mission itself is still on.

It's just going to take a bit longer.

This story has still got a long way to go, me thinks.

Now, this next story is a genuine landmark in astronomy.

Something researchers have been waiting years for.

It has to do with supernovae,

those spectacular explosions

that marked the depths of massive stars.

Astronomers have long wanted to look back

at archival images after a supernova occurs

and find the star that caused it,

the so-called progenitor star.

But for many of the most massive stars,

they just weren't there.

They seem to be missing.

Well, now we know why, and it's thanks to James Webb.

On June 29th, last year,

an automated sky survey detected a new supernova

in a galaxy called NGC 1637,

about 40 million light years away.

The explosion was designated 2025 PhD,

and a team at Northwestern University

immediately did something color.

Instead of pointing their telescopes at the new supernova,

they went to the archives

to images Webb had already taken of that same galaxy.

And there it was, a single red supergiant star

sitting exactly where the supernova now shines.

This is the first published detection

of a supernova progenitor by the James Webb telescope ever.

And here's the key thing, Hubble couldn't see it.

The star was completely invisible in Hubble images.

It was surrounded by so much dust

that shorter wavelengths of light were blocked entirely.

Only Webb's infrared instruments could pierce that veil.

Lead author Charlie Kilpatrick

from Northwestern described it as, quote,

the reddest, most dusty red supergiant

we've seen explode as a supernova.

And there was another surprise, the dust composition.

The expected silicate rich dust,

the kind astronomers usually find,

instead it was carbon rich.

The team thinks that carbon may have been dredged up

from deep inside the star

in its final moments before death.

This has direct implications for what's called

the mystery of the missing red supergiant.

Theory predicts these massive stars

should be easy to spot before they explode.

They should be bright and luminous.

But historically, they've often not shown up

in pre-supernova images at all.

Now we have a compelling answer.

They're there, they're just hidden in dust.

The findings are published in the astrophysical journal letters.

The team is now looking for similar dusty red supergiant

that might be the next to explode.

And Webb's successor missions,

including the upcoming Nancy Grace Roman's telescope,

should help that search enormously.

A beautiful piece of detective work.

From stellar deaths to potential life,

because our next story is one

that keeps getting more interesting

every time new data comes in.

The exoplanet K218B.

If you've been following exoplanet science

over the last couple of years, you'll know this name.

K218B is located 124 light years away

in the constellation Leo,

sitting squarely in the habitable zone

of its red dwarf host star,

and James Webb has been staring at it.

What Webb found was an atmosphere rich

in both carbon dioxide and methane.

That chemical combination is significant.

It points strongly towards what astronomers call

a high sea in world.

The idea is a planet with a warm liquid water ocean

beneath a thick hydrogen rich atmosphere.

And the intrigue doesn't stop there.

Earlier analyses of K218B's atmosphere

had also hinted at possible traces of dimethyl sulfide.

A molecule that, on Earth,

is produced almost exclusively by marine life.

Now, that hasn't been confirmed

and scientists are appropriately cautious.

There are non-biological explanations being explored.

But the ongoing analysis of Webb data

is continuing to add layers to the story.

The carbon dioxide and methane combination

is precisely what you'd expect

if there were a liquid ocean beneath that atmosphere.

The current focus is whether those chemical signatures

could have a biological origin.

And that's one of the most consequential questions

in all of science.

K218B is one of the most watched targets

in astrobiology right now.

And with Webb continuing to accumulate data,

we should expect more updates in the months ahead.

If it turns out there is life on K218B,

then everything changes.

That's all I'll say.

Okay, something a little different now.

A story about our own sun behaving unusually quietly.

On February 22nd, the sun's Earth-facing disc

went completely spotless for the first time

in 1,355 days.

That ends a streak stretching all the way back

to June 8th of 2022.

For nearly four years,

you could look at the sun on any given day

and find at least one active sunspot region.

Not anymore for a few days at least.

Sunspots are regions of intense magnetic activity

on the solar surface.

And they're the source of solar flares

and the coronal mass ejections

that can send charged particles hurtling toward Earth.

We are in solar cycle 25,

which peaked in October 2024

with a sunspot count significantly higher

than scientists initially predicted.

Here's a fun wrinkle.

While Earth was looking at a blank sun,

NASA's Perseverance Rover on Mars had a different view.

From the Martian service,

Perseverance could see sunspot groups blazing away

on the far side of the sun.

Invisible to us here on Earth,

but clearly visible from Mars's position

in the solar system.

The spotless period appears to have lasted

about two to three days before a new active region

began emerging around February 24th.

So the sun isn't shutting down,

it's just having a quiet moment.

Solar activity isn't expected to reach its next minimum

until around 2030.

But this little pause is a signal

that solar cycle 25 is beginning its long slow wind down

from that October 2024 peak.

For listeners who love Aurora hunting,

the good news is there's still plenty

of solar activity ahead.

But the best years of this cycle are behind us now.

Now to a story that we've touched on the four,

but which has taken on fascinating new depth this week

with the Shenzu 20 astronauts speaking out

in remarkable detail about last year's in-orbit emergency,

China's first ever human space flight crisis.

Just to recap the situation,

China's Shenzu 20 crew,

commander Chen Dong,

along with Chen Chongrui and Wang Ye,

launched in April 2025

for what was supposed to be a standard six-month mission

to the Tiangong Space Station.

During pre-return checks on the day before

they were supposed to come home,

Commander Chen went to inspect the return capsule.

And he spotted something on the viewport window,

something triangular.

His first thought, and he shared this in a new interview

with Chinese state broadcaster, CCTV,

was that a small leaf had somehow stugged

to the outside of the glass.

And then, as he told it,

he quickly realized that couldn't happen

because they were in space.

What he was actually seeing was a crack,

a triangular scar roughly two centimeters long

in the outer layer of the three layer viewport window,

most likely caused by a debris strike.

The crew used a pen-shaped microscope

to confirm the damage,

took photos immediately

and transmitted everything to the ground.

The decision that followed was extraordinary.

The crew could not safely return in their own spacecraft.

Instead, they transferred to the Shenzu 21 vehicle

that had just arrived days earlier,

carrying their relief crew.

An uncrewed Shenzu 22 was then emergency launched

carrying a porthole repair device.

The whole response from finding the crack

to the crew's safe return to Earth

took just over 20 days.

And the damage Shenzu 20 capsule?

It was eventually brought back to Earth uncrewed

on January 19th of this year

after spending 270 days in orbit,

90 days longer than plant.

It survived reentry,

which itself was a significant engineering achievement.

Commander Chen Dong summed it up beautifully.

The unexpected window cracks

ultimately became a precious testament

to the concerted efforts

and shared commitment for safety

between our two crews

and all ground-based space personnel.

A genuinely remarkable chapter in human space light.

The space debris problem is real

and this story illustrates exactly why it matters.

And finally, something a little lighter to close the show.

Avery, have you ever wanted to send a letter

that was also technically a window to the cosmos?

I feel like that's a rhetorical question,

but yes, obviously.

Well, the US Postal Service has you covered.

Yesterday, February 24th,

the USPS officially issued two brand new priority mail stamps,

both featuring images from the James Webb Space Telescope.

The first is the priority mail stamp,

priced at $11.95,

and it features the crab nebula,

the spectacular remnant of a star

that exploded in the constellation Taurus

about 6,500 light years away.

Webb captured it in the infrared,

revealing structural details

that have never been seen before.

The second is the priority mail express stamp

at $33.25,

and this one is a real showpiece.

It's a composite image called Galaxy Pair.

Two interacting spiral galaxies,

I-C-2163, and NGC-2207,

located about 80 million light years away.

The image combines Webb and Hubble data

across infrared, visible, and ultraviolet wavelengths.

It is genuinely stunning.

Kansas City, Missouri was the official city of issue,

though there was no public ceremony.

And here's a lovely detail for collectors.

You have until June 24th to send your stamps in

for a first day of issue postmark.

The Postal Service will even apply the postmark

for free up to 50 envelopes.

And this is actually the fourth consecutive year

the USPS has used Webb imagery on priority mail stamps.

In 2022, it was a forever stamp,

featuring a rendering of the telescope itself.

In 2024 and 2025,

the pillars of creation featured.

Now, the Crab Nebula and the Galaxy Pair.

Webb is becoming something of an annual tradition

at the post office.

Which, when you think about it, is rather wonderful.

A space telescope that cost $10 billion and took 30 years

to build is now sitting in people's junk drawers

next to the scissors and the tape.

That is the most poetic thing you have ever said

on this podcast.

I have my moments.

And that is Astronomy Daily for Wednesday, February 25th, 2026.

What a show.

Rollbacks, red super giants, possible ocean worlds,

a quiet sun, space debris emergencies,

and commemorative postage.

If you enjoyed today's episode,

please do leave us a review wherever you listen.

It makes a genuine difference.

And you can find us at astronomydaily.io

and on social media at AstroDailyPod.

For Avery, I'm Anna.

Stay curious, keep looking up, and we'll see you tomorrow.

Clear skies, everyone.

Astronomy Daily, the star is the toe.

The star is the toe.

The star is the toe.

The star is the toe.

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