Postcards From Mars

Anna: Picture Mars a small rusty

coin hanging in the dark. Now watch it

swell over a month until it fills your

window and then shrink away behind you as

you slingshot off toward a world made of

metal.

Avery: That's not a movie trailer, that's a real

time lapse. A NASA spacecraft just sent

home and it's where we're starting today.

Anna: You're listening to Astronomy Daily. I'm

Anna.

Avery: And I'm avery. It's Tuesday 21st

July, 2026, and this is your

daily tour of the universe.

Anna: On the show today, a metal asteroid probe

phones home from Mars. Europe's next great

planet hunter passes its final exam. And a

shoebox sized satellite that could buy us

hours of warning before the next solar storm.

Avery: Plus, how the sun's quiet spell might

forecast its next tantrum. The first

pieces of a radio telescope that'll dwarf the

one from the film Contact. And the meteor

shower that for once is ours to keep down

here in the south.

Anna: Lots to get through. Let's go.

So let's start with that time lapse. NASA's

Psyche spacecraft is on a long, patient

road trip. It launched back in 2023 and

it's heading for one of the strangest

destinations in the solar system. A metal

rich asteroid called 16 Psyche. It

won't arrive until 2029.

Avery: Um, and to get there, it needed a shove back.

On 15 May, it swung past Mars

for a gravity assist, using the planet's

gravity like a slingshot to bend its path and

pick up speed.

Anna: Right, but here's the lovely part. The news

this week isn't the flyby itself. It's what

came home afterwards. Over the last few

weeks, the team has been downlinking and

crunching the data and they've just released

it along with a genuinely mesmerizing month.

Long time lapse of Mars growing and then

receding.

Avery: Why bother running the instruments during a

flyby, though? Mars has been studied to

death.

Anna: Two reasons. First, it's a dress rehearsal.

Ours was a stand in for the asteroid. A

chance to put Psyche science instruments

through their paces under real deep space

conditions before the main event. And second,

after two and a half years in space, you

want to know your gear still works.

Avery: So how did it do?

Anna: Really well. The star of the show was the

Gamma Ray and Neutron Spectrometer. That's

the instrument built with Johns Hopkins

Applied Physics Laboratory with a gamma ray

sensor from Lawrence Livermore. As they came

in close to Mars, the neutron spectrometer

picked up exactly the kind of signal boost

they were hoping

Avery: for the teen science lead David Lawrence

put it nicely. He said around closest

approach, the detector caught a count rate

bump and that it was, quote, very gratifying

to see.

Anna: They were actually too far out about

4,600km to catch

Gamma rays coming off Mars itself. But that

was fine. The point was to prove the

instrument performs. And it did. The

magnetometer and the imager delivered too.

Avery: And all this matters because of what Psyche

16 actually is exactly.

Anna: Most asteroids are rock or ice.

Psyche looks like it might be mostly metal,

iron, nickel and a, uh, scattering of other

elements. The leading idea is that it's the

exposed core of a baby planet.

Planetesimal that got stripped of its outer

rocky layers in the chaos of the early solar

system.

Avery: Which means it's the closest we may ever get

to standing on a planetary core.

Anna: We can't drill down to Earth's core. The

pressure and heat make that impossible. But

we might be able to visit one that's sitting

out in the open. That gamma ray and neutron

spectrometer is the tool that'll read its

chemistry when we arrive. Iron,

nickel, silicon, sulfur,

and tell us what a planetary core is really

made of.

Avery: So the Mars flyby was the warmup and the band

is tuned. 2029 suddenly feels

closer.

Anna: It does. And if you get a chance, do look up

that time lapse. It's a beautiful reminder

that even a routine gravity assist can be

pure poetry.

Avery: From a mission on its way out, uh, to one

getting ready to leave, Europe's next great

planet hunter, ESA's Plato has

just passed its last big test before launch.

Anna: Plato remind everyone what it's built to do.

Avery: It's a, uh, planet detective with 26

cameras working together. And its mission is

a specific to find Earth. Like

rocky planets orbiting in the habitable zone

of sun like stars. Not just any planets.

Worlds where you could plausibly imagine

liquid water on the surface.

Anna: 26 cameras is a lot of eyes.

What was the test?

Avery: It's called electromagnetic compatibility

testing. Engineers sealed the whole

spacecraft inside a chamber at ESA's

technical center in the Netherlands, a room

called the Maxwell chamber, which is

essentially a 9 meter tall Faraday cage

lined with foam spikes to soak up every stray

radio signal. It mimics the electromagnetic

silence of deep space.

Then they switched everything on at once.

All 26 cameras, all the subsystems

humming together to make sure none of them

interfere with each other or with the radios.

No cross talk, no chatter, no one

instrument drowning out another.

Anna: Because up in orbit, if your own electronics

are shouting over each other, you've got a

very expensive problem you can't fix.

Avery: Precisely. And Plato passed. This was the

last major qualification hurdle. Earlier this

year, it survived the violent shaking and

noise of launch simulations and the long

stint in a giant vacuum chamber to prove it

can take the cold and the emptiness of space.

Anna: So what's next for it?

Avery: It's on track to fly on an Ariane 6 rocket.

The current target is 2027. Heading out

to the Sun, Earth, L2 point, that

gravitational parking spot about 1.5 million

kilometers beyond Earth, where the James Webb

Telescope also lives.

Anna: And once it's there, it'll stare at hundreds

of thousands of stars, waiting for the tiny

regular dips that betray a planet crossing in

front.

Avery: That's a dream. If Plato finds a genuine

Earth twin around the genuine sun twin,

that's a headline we'll all remember. For

now, the electronics are ready and the ride

is booked.

Anna: Now, a lot of this week's science is pouring

out of one place. The Royal Astronomical

Society's National Astronomy meeting, which

kicked off in Birmingham yesterday and runs

all week. And one of the first results is a

little satellite with a big job.

Avery: This is the space weather. One which feels

timely given how much we talked about solar

storms on Saturday.

Anna: It does. But this is the other side of that

coin. On Saturday, we talked about how bad

a big solar storm could get. This is about

how much warning we'd have when one's coming.

And right now, the honest answer is not

much.

Avery: How much are we talking?

Anna: For the fastest storms, the really dangerous

coronal mass ejections, we get roughly

15 minutes. That's because our early

warning satellites sit at a point called

L1, about 1.5 million

km sunward of Earth. It passes

them, they call ahead, and 15 minutes later

it hits us.

Avery: 15 minutes to protect satellites and power

grids is not a lot.

Anna: It's barely enough to send an email. So

here's the idea presented at the meeting.

It's a mission called Hanon. It's a

cubesat think shoebox sized, but it

would fly out to about 15 million

kilometers upstream of Earth, 10

times farther than L1.

Avery: Ten times farther out means you see the storm

10 times sooner.

Anna: That's the whole pitch. It could stretch our

warning from around 15 minutes to two or

three hours. And it carries a UK built

magnetometer called Magic, developed at

Imperial College London to measure the

magnetic field carried in the solar wind

alongside instruments from teams in the Czech

Republic and Finland.

Avery: Hours instead of minutes. That changes what

grid operators and satellite controllers can

actually do. Power down safe

mode Reposition.

Anna: Exactly. And Henon is a proving ground,

a technology demonstrator that paves the way

for a bigger permanent European early warning

mission down the line. It's a small box

aiming to give the whole planet a head start.

Avery: Staying with the sun and staying at the

national astronomy meeting. Here's a clever

piece of detective work. It's about

predicting how fierce the next Sun's active

period will be by studying how it goes quiet.

Anna: This is the solar cycle, the roughly 11 year

rhythm where the sun ramps up to a stormy

maximum, then winds down to a sleepy

minimum.

Avery: Right. And forecasting the strength of the

next maximum. How many sunspots, how many

storms has always been notoriously hard.

But a researcher presenting at the meeting

has found a promising clue hiding in the wind

down phase.

Anna: So the secret to the next cycle is written

into how the current one switches off.

Avery: That's the argument. She looked at the Sun's

declining phase and found the precursor, a

signature that seems to foreshadow the size

of the next maximum. And along the way,

there was a neat bit of physics about what

kind of storms we get as the sun quietens

down.

Anna: Go on.

Avery: After the sun switches off from its active

phase, the storms we still get become less

extreme and they start marching to a 27

day beat.

Anna: 27 days. That's roughly one rotation

of the Sun.

Avery: Exactly. And that rhythm is the fingerprint

of a different kind of space weather. Instead

of explosive coronal mass ejections firing

off at random, these calmer storms are driven

by long lived streams of fast solar wind

that sweep past us once per rotation, like

a Lycos beam coming around.

Anna: So it's not just a forecasting trick. It

tells you which mechanism is doing the

driving at different points in the cycle.

Avery: That's what makes it useful. If you can read

the declining phase properly, you get a

running start on predicting the next maximum

and better. Long range space weather

forecasting helps everyone from airlines to

satellite operators.

Anna: Two sun stories in a row. But I love that

they're opposite ends of the same problem.

One's the warning system, one's the long

range forecast.

Let's change the scenery completely from the

sun to some Ceres hardware. Back on the

ground in the United States, three big

players are teaming up to start building the

future of radio astronomy.

Avery: The National Science foundation, the National

Radio Astronomy Observatory,

and this is the interesting1, the U.S.

naval Observatory.

Anna: That last one raises an eyebrow. What's the

Navy doing in radio astronomy?

Avery: Well, more than you'd think. We'll come back

to that. The Headline is they're funding a

Pathfinder, a first installment of something

called the next generation Very Large Array,

the ngvla.

Anna: And listeners will know the original Very

Large Array, even if they don't know the

name. That field of huge white dishes in the

New Mexico desert. It's the telescope from

the film Contact with Jody Foster sitting on

the bonnet of her car, headphones on,

listening to the sky.

Avery: The very one. It's been working for over

45 years. The NG VLA is

its heir. And it's enormous by comparison.

The full vision is 266

antennas with the core in New Mexico. But

this is spread right across the American

Southwest and beyond, roughly 10

times m more sensitive than today's array.

Anna: So what does this pathfinder actually do?

Avery: It focuses on a technique called very Long

Baseline interferometry.

The idea is you link antennas that are

enormously far apart and combine their

signals so together they act like one

telescope, as wide as the whole continent.

That gives you staggeringly sharp images.

Anna: And that's where the Navy comes in.

Avery: That's where the Navy comes in. Those ultra

precise measurements also underpin the

celestial reference frame, the master grid of

fixed points in the sky that we use to know

exactly where we are and which way we're

pointing. It's astronomy and navigation

hand in hand.

Anna: So one instrument helps map black holes

and helps keep the world's clocks and

coordinates honest.

Avery: Beautifully put. Construction and early

operations are expected before the end of the

decade. It's the quiet, unglamorous

groundwork that great discoveries are built

on.

Anna: And that brings us to Skywatch. And

tonight, finally, the southern sky gets the

good seats.

Avery: This is our shower, isn't it? The southern

Delta Aquariids.

Anna: It really is. So many of the famous

meteor showers favor the northern hemisphere,

but the Delta Aquariids are the exception.

Their radiant, the point they appear to

stream from, sits near a star called Skat in

Aquarius. And from Sydney or across New

Zealand, that's high overhead. We get the

front row view.

Avery: When do they peak?

Anna: Officially around the 29th and 30th of

July. But and this is the important

bit, there's a catch. This year the peak

lands right on a near full buck moon.

And that much moonlight will wash out these

meteors because they tend to be faint.

Avery: So the peak date, uh, is actually the wrong

night to go out for once.

Anna: Yes, the smart move is to go out this week

instead. Right now, the moon is still waxing

and sets before dawn, which leaves the sky

nice and dark in those early morning hours.

And this shower is generous. It rambles along

for days rather than spiking on one night.

So the moon free mornings this week are your

best window.

Avery: What are we actually looking for?

Anna: Under a proper dark sky, maybe 15

to 20 meters an hour. They're on the faint

side, long and graceful rather than

flashy. And a nice fraction of them leave a

glowing trail that lingers for a second or

two after they've gone. The suspected parent,

by the way, is a comet called

96PMachholz.

Avery: Any tips for getting the most out of it?

Anna: Get away from town lights if you can wrap up

warm. It is winter down here. And give your

eyes a good half hour to adapt. Buy

back, take in as much sky as you can rather

than staring at one spot. And be patient.

And a bonus, toward the very end of the

month, a second shower. The Alpha

Capricornids joins in with slow, bright

fireballs. So keep watching into early

August, faint

Avery: and graceful with the odd fireball for drama.

That's a lovely winter's night under the

stars.

Anna: It is.

Rug up. Look up.

Avery: Before we go, a quick one to chew on. We

mentioned Psyche is heading for a metal

asteroid. Here's the teaser. If you could

somehow bring that metal to market. Its value

has been estimated at a number so large

it's essentially meaningless. More than the

entire world economy. We'll leave the exact

figure for the trivia cards.

Anna: A quintillion dollar rock. File that one

away.

Avery: So today, Psyche sent home its Mars

flyby data. And the gorgeous time lapse

Plato passed its final test on the road to

launch. A shoebox satellite called Hainan

could turn 15 minutes of storm warning into

three hours.

Anna: The sun's quiet spell may help us forecast

its next loud one. The first pieces of the

mighty NGVLA are being funded.

And the Delta Aquarids are lighting up our,

uh, Southern skies this week.

Avery: That's a full show. Everything we covered is

linked in the show notes at astronomydaily

IO and you can find us on all the

socials astrodaily Pod.

Anna: If today taught you something new, share it

with a friend who looks up. I'm Anna.

Avery: And I'm Avery. Thanks for spending part of

your day with us.

Anna: Until tomorrow, clear skies.

In this episode