Postcards From Mars

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Anna: Picture Mars a small rusty

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coin hanging in the dark. Now watch it

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swell over a month until it fills your

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window and then shrink away behind you as

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you slingshot off toward a world made of

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metal.

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

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time lapse. A NASA spacecraft just sent

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

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

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Anna.

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

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July, 2026, and this is your

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daily tour of the universe.

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Anna: On the show today, a metal asteroid probe

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phones home from Mars. Europe's next great

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planet hunter passes its final exam. And a

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shoebox sized satellite that could buy us

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hours of warning before the next solar storm.

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

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forecast its next tantrum. The first

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pieces of a radio telescope that'll dwarf the

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one from the film Contact. And the meteor

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shower that for once is ours to keep down

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here in the south.

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

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

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Psyche spacecraft is on a long, patient

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road trip. It launched back in 2023 and

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it's heading for one of the strangest

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destinations in the solar system. A metal

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rich asteroid called 16 Psyche. It

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won't arrive until 2029.

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

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On 15 May, it swung past Mars

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for a gravity assist, using the planet's

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gravity like a slingshot to bend its path and

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pick up speed.

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

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

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came home afterwards. Over the last few

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weeks, the team has been downlinking and

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crunching the data and they've just released

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it along with a genuinely mesmerizing month.

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Long time lapse of Mars growing and then

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receding.

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Avery: Why bother running the instruments during a

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flyby, though? Mars has been studied to

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death.

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

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Ours was a stand in for the asteroid. A

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chance to put Psyche science instruments

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through their paces under real deep space

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conditions before the main event. And second,

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after two and a half years in space, you

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want to know your gear still works.

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Avery: So how did it do?

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

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Gamma Ray and Neutron Spectrometer. That's

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the instrument built with Johns Hopkins

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Applied Physics Laboratory with a gamma ray

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sensor from Lawrence Livermore. As they came

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in close to Mars, the neutron spectrometer

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picked up exactly the kind of signal boost

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they were hoping

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Avery: for the teen science lead David Lawrence

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put it nicely. He said around closest

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approach, the detector caught a count rate

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bump and that it was, quote, very gratifying

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to see.

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Anna: They were actually too far out about

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4,600km to catch

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Gamma rays coming off Mars itself. But that

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was fine. The point was to prove the

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instrument performs. And it did. The

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magnetometer and the imager delivered too.

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Avery: And all this matters because of what Psyche

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16 actually is exactly.

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Anna: Most asteroids are rock or ice.

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Psyche looks like it might be mostly metal,

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iron, nickel and a, uh, scattering of other

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elements. The leading idea is that it's the

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exposed core of a baby planet.

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Planetesimal that got stripped of its outer

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rocky layers in the chaos of the early solar

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system.

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

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to standing on a planetary core.

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

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pressure and heat make that impossible. But

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we might be able to visit one that's sitting

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out in the open. That gamma ray and neutron

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spectrometer is the tool that'll read its

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chemistry when we arrive. Iron,

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nickel, silicon, sulfur,

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and tell us what a planetary core is really

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made of.

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

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is tuned. 2029 suddenly feels

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closer.

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

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that time lapse. It's a beautiful reminder

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that even a routine gravity assist can be

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pure poetry.

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

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getting ready to leave, Europe's next great

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planet hunter, ESA's Plato has

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just passed its last big test before launch.

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

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

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cameras working together. And its mission is

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a specific to find Earth. Like

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rocky planets orbiting in the habitable zone

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of sun like stars. Not just any planets.

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Worlds where you could plausibly imagine

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liquid water on the surface.

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Anna: 26 cameras is a lot of eyes.

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What was the test?

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Avery: It's called electromagnetic compatibility

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testing. Engineers sealed the whole

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spacecraft inside a chamber at ESA's

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technical center in the Netherlands, a room

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called the Maxwell chamber, which is

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essentially a 9 meter tall Faraday cage

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lined with foam spikes to soak up every stray

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radio signal. It mimics the electromagnetic

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silence of deep space.

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Then they switched everything on at once.

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All 26 cameras, all the subsystems

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humming together to make sure none of them

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interfere with each other or with the radios.

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No cross talk, no chatter, no one

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instrument drowning out another.

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Anna: Because up in orbit, if your own electronics

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are shouting over each other, you've got a

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very expensive problem you can't fix.

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Avery: Precisely. And Plato passed. This was the

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last major qualification hurdle. Earlier this

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year, it survived the violent shaking and

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noise of launch simulations and the long

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stint in a giant vacuum chamber to prove it

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can take the cold and the emptiness of space.

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Anna: So what's next for it?

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

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The current target is 2027. Heading out

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to the Sun, Earth, L2 point, that

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gravitational parking spot about 1.5 million

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kilometers beyond Earth, where the James Webb

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Telescope also lives.

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

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of thousands of stars, waiting for the tiny

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regular dips that betray a planet crossing in

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front.

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

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Earth twin around the genuine sun twin,

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

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now, the electronics are ready and the ride

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is booked.

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

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out of one place. The Royal Astronomical

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Society's National Astronomy meeting, which

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kicked off in Birmingham yesterday and runs

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all week. And one of the first results is a

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little satellite with a big job.

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Avery: This is the space weather. One which feels

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timely given how much we talked about solar

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storms on Saturday.

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

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coin. On Saturday, we talked about how bad

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a big solar storm could get. This is about

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

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And right now, the honest answer is not

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much.

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Avery: How much are we talking?

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Anna: For the fastest storms, the really dangerous

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coronal mass ejections, we get roughly

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15 minutes. That's because our early

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warning satellites sit at a point called

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L1, about 1.5 million

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km sunward of Earth. It passes

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them, they call ahead, and 15 minutes later

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it hits us.

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Avery: 15 minutes to protect satellites and power

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grids is not a lot.

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

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here's the idea presented at the meeting.

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

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cubesat think shoebox sized, but it

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would fly out to about 15 million

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kilometers upstream of Earth, 10

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times farther than L1.

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Avery: Ten times farther out means you see the storm

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10 times sooner.

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

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warning from around 15 minutes to two or

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three hours. And it carries a UK built

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magnetometer called Magic, developed at

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Imperial College London to measure the

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magnetic field carried in the solar wind

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alongside instruments from teams in the Czech

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Republic and Finland.

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Avery: Hours instead of minutes. That changes what

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grid operators and satellite controllers can

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actually do. Power down safe

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mode Reposition.

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Anna: Exactly. And Henon is a proving ground,

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a technology demonstrator that paves the way

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for a bigger permanent European early warning

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mission down the line. It's a small box

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aiming to give the whole planet a head start.

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Avery: Staying with the sun and staying at the

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national astronomy meeting. Here's a clever

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piece of detective work. It's about

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predicting how fierce the next Sun's active

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period will be by studying how it goes quiet.

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

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rhythm where the sun ramps up to a stormy

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maximum, then winds down to a sleepy

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minimum.

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Avery: Right. And forecasting the strength of the

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next maximum. How many sunspots, how many

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storms has always been notoriously hard.

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But a researcher presenting at the meeting

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has found a promising clue hiding in the wind

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down phase.

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Anna: So the secret to the next cycle is written

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into how the current one switches off.

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

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declining phase and found the precursor, a

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signature that seems to foreshadow the size

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of the next maximum. And along the way,

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there was a neat bit of physics about what

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kind of storms we get as the sun quietens

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down.

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Anna: Go on.

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Avery: After the sun switches off from its active

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phase, the storms we still get become less

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extreme and they start marching to a 27

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day beat.

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Anna: 27 days. That's roughly one rotation

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of the Sun.

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Avery: Exactly. And that rhythm is the fingerprint

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of a different kind of space weather. Instead

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of explosive coronal mass ejections firing

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off at random, these calmer storms are driven

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by long lived streams of fast solar wind

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that sweep past us once per rotation, like

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a Lycos beam coming around.

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

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tells you which mechanism is doing the

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driving at different points in the cycle.

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

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the declining phase properly, you get a

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running start on predicting the next maximum

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and better. Long range space weather

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forecasting helps everyone from airlines to

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satellite operators.

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

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they're opposite ends of the same problem.

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

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range forecast.

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Let's change the scenery completely from the

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sun to some Ceres hardware. Back on the

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ground in the United States, three big

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players are teaming up to start building the

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future of radio astronomy.

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Avery: The National Science foundation, the National

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Radio Astronomy Observatory,

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and this is the interesting1, the U.S.

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naval Observatory.

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

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Navy doing in radio astronomy?

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

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to that. The Headline is they're funding a

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Pathfinder, a first installment of something

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called the next generation Very Large Array,

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the ngvla.

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Anna: And listeners will know the original Very

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Large Array, even if they don't know the

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name. That field of huge white dishes in the

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New Mexico desert. It's the telescope from

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the film Contact with Jody Foster sitting on

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the bonnet of her car, headphones on,

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listening to the sky.

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

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45 years. The NG VLA is

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its heir. And it's enormous by comparison.

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The full vision is 266

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antennas with the core in New Mexico. But

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this is spread right across the American

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Southwest and beyond, roughly 10

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times m more sensitive than today's array.

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Anna: So what does this pathfinder actually do?

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Avery: It focuses on a technique called very Long

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Baseline interferometry.

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The idea is you link antennas that are

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enormously far apart and combine their

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signals so together they act like one

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telescope, as wide as the whole continent.

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That gives you staggeringly sharp images.

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

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

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precise measurements also underpin the

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celestial reference frame, the master grid of

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fixed points in the sky that we use to know

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exactly where we are and which way we're

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pointing. It's astronomy and navigation

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hand in hand.

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Anna: So one instrument helps map black holes

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and helps keep the world's clocks and

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coordinates honest.

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Avery: Beautifully put. Construction and early

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operations are expected before the end of the

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decade. It's the quiet, unglamorous

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groundwork that great discoveries are built

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on.

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Anna: And that brings us to Skywatch. And

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tonight, finally, the southern sky gets the

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good seats.

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

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Delta Aquariids.

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Anna: It really is. So many of the famous

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meteor showers favor the northern hemisphere,

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but the Delta Aquariids are the exception.

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Their radiant, the point they appear to

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stream from, sits near a star called Skat in

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Aquarius. And from Sydney or across New

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Zealand, that's high overhead. We get the

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front row view.

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Avery: When do they peak?

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Anna: Officially around the 29th and 30th of

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July. But and this is the important

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

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lands right on a near full buck moon.

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And that much moonlight will wash out these

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meteors because they tend to be faint.

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

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night to go out for once.

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

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instead. Right now, the moon is still waxing

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and sets before dawn, which leaves the sky

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nice and dark in those early morning hours.

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And this shower is generous. It rambles along

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for days rather than spiking on one night.

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So the moon free mornings this week are your

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best window.

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Avery: What are we actually looking for?

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Anna: Under a proper dark sky, maybe 15

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

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side, long and graceful rather than

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flashy. And a nice fraction of them leave a

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glowing trail that lingers for a second or

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two after they've gone. The suspected parent,

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by the way, is a comet called

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96PMachholz.

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

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

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warm. It is winter down here. And give your

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eyes a good half hour to adapt. Buy

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back, take in as much sky as you can rather

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than staring at one spot. And be patient.

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And a bonus, toward the very end of the

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month, a second shower. The Alpha

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Capricornids joins in with slow, bright

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fireballs. So keep watching into early

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August, faint

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Avery: and graceful with the odd fireball for drama.

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That's a lovely winter's night under the

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stars.

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Anna: It is.

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Rug up. Look up.

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

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mentioned Psyche is heading for a metal

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asteroid. Here's the teaser. If you could

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somehow bring that metal to market. Its value

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has been estimated at a number so large

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it's essentially meaningless. More than the

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entire world economy. We'll leave the exact

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figure for the trivia cards.

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Anna: A quintillion dollar rock. File that one

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away.

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Avery: So today, Psyche sent home its Mars

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flyby data. And the gorgeous time lapse

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Plato passed its final test on the road to

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launch. A shoebox satellite called Hainan

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could turn 15 minutes of storm warning into

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three hours.

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

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its next loud one. The first pieces of the

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mighty NGVLA are being funded.

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And the Delta Aquarids are lighting up our,

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uh, Southern skies this week.

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

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linked in the show notes at astronomydaily

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IO and you can find us on all the

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socials astrodaily Pod.

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Anna: If today taught you something new, share it

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

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

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your day with us.

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Anna: Until tomorrow, clear skies.