Moon Hides Mercury Tonight, Artemis II Tests Tomorrow, Saturn Ring Origin Revealed

0:00 Speaker 1: Hello, and welcome to Astronomy Daily.

0:03 Speaker 2: I'm Anna and I'm Avery. You're listening to Season five,

0:07 Speaker 2: episode forty two for Wednesday, the eighteenth of February twenty

0:11 Speaker 2: twenty six, And what a day to be a spaceman.

0:14 Speaker 1: Absolutely tonight right now, in fact, the Moon is sliding

0:19 Speaker 1: so close to mercury that it's actually hiding it from

0:22 Speaker 1: view for skywatchers in parts of the southern United States.

0:26 Speaker 1: A genuine celestial magic trick happening as you listen.

0:30 Speaker 3: And that's just one of six stories we're bringing you today.

0:33 Speaker 3: We've got NASA's Artemis two on the verge of a

0:36 Speaker 3: crucial fueling test, a European rocket making a big move

0:40 Speaker 3: in the satellite broadband race, a genuinely new twist in

0:43 Speaker 3: the ongoing saga of our interstellar Visitor, and two stories

0:47 Speaker 3: that I promise will make you rethink some things you

0:50 Speaker 3: thought you knew about the Solar System.

0:52 Speaker 1: Big show, let's get into it, so Anna.

0:55 Speaker 3: Let's start with the biggest space story of the week,

0:57 Speaker 3: and honestly the one that could define the Artemis two.

1:01 Speaker 1: Yes, for anyone who needs a quick refresh, Artemis two

1:05 Speaker 1: is NASA's first crude mission around the Moon since Apollo

1:09 Speaker 1: seventeen in nineteen seventy two. Four astronauts Reed Wiseman, Victor Glover,

1:15 Speaker 1: Christina Cock, and Canada's Jeremy Hansen are preparing to fly

1:19 Speaker 1: a ten day loop around the Moon and back. No

1:22 Speaker 1: lunar landing, but a crucial proving flight before we put

1:26 Speaker 1: boots on the surface.

1:28 Speaker 3: And they are so close. The rocket is sitting on

1:31 Speaker 3: Path thirty nine B at Kennedy Space Center right now.

1:34 Speaker 3: But before NASA will commit to a launch date, they

1:37 Speaker 3: need to successfully do what's called a wet dress rehearsal,

1:41 Speaker 3: a full practice countdown where they actually load the rocket

1:44 Speaker 3: with fuel and take it right to the edge of launch,

1:47 Speaker 3: then drain it all out again.

1:49 Speaker 1: They did that once already on February third, and it

1:53 Speaker 1: didn't go smoothly. A liquid hydrogen leak cropped up, the

1:57 Speaker 1: exact same kind of problem that plagued Artemis one one

2:00 Speaker 1: three years ago. The countdown was terminated at T minus

2:04 Speaker 1: five minutes and fifteen seconds, close but not close enough.

2:08 Speaker 3: Which pushed the February launch window off the table entirely.

2:13 Speaker 3: NASA administrator Jared Isaacman was fairly philosophical about it. He

2:17 Speaker 3: said This is exactly why you do a rehearsal to

2:19 Speaker 3: find these issues before you're flying with crew. But the

2:23 Speaker 3: clock is ticking.

2:24 Speaker 1: Since then, engineers have replaced two seals and a clogged

2:28 Speaker 1: filter in the hydrogen fueling system. They ran a partial

2:31 Speaker 1: confidence test on February twelfth to check the repairs, and

2:35 Speaker 1: now tomorrow, February nineteenth, they begin tanking day for the

2:39 Speaker 1: second full wet dress rehearsal.

2:42 Speaker 3: This is the one that counts. If the test goes cleanly,

2:45 Speaker 3: no oud of limits, hydrogen concentrations countdown proceeds all the

2:49 Speaker 3: way to the terminal phase, NASA will analyze the data

2:53 Speaker 3: and set a launch date. The current earliest possibility is

2:56 Speaker 3: March six.

2:57 Speaker 1: It's worth noting just how historic mission is beyond the

3:01 Speaker 1: Moon return angle, Victor Glover will become the first person

3:05 Speaker 1: of color to travel beyond low Earth orbit. Christina Cock

3:09 Speaker 1: will be the first woman, Jeremy Hansen will be the

3:11 Speaker 1: first non American. Every single person on that crew is

3:15 Speaker 1: making history in their own right.

3:17 Speaker 3: So tomorrow is genuinely a day to watch. We'll be

3:20 Speaker 3: keeping a close eye on how the tanking goes, and

3:23 Speaker 3: we'll have updates as they come through.

3:24 Speaker 1: All right. Let's bring it back to Earth, or rather

3:27 Speaker 1: to the sky above Earth, because tonight is one of

3:30 Speaker 1: those rare evenings where if you happen to be in

3:33 Speaker 1: the right place and you look up at the right moment,

3:36 Speaker 1: you'll see something genuinely extraordinary.

3:39 Speaker 3: Two things actually, First, the moon and mercury. Tonight, February eighteenth,

3:44 Speaker 3: a slender, one and a half day old crescent moon

3:47 Speaker 3: is passing extremely close to Mercury in the western sky

3:50 Speaker 3: just after sunset, and I mean extremely close.

3:54 Speaker 1: For observers along a narrow band of southern US states.

3:58 Speaker 1: We're talking Arizona and New Mexico, Texas, Louisiana, Mississippi, and Georgia,

4:04 Speaker 1: the moon will actually pass directly in front of Mercury

4:08 Speaker 1: and block it from view entirely. That's called an occultation.

4:12 Speaker 1: Mercury literally disappears behind the moon's dark limb and reappears

4:17 Speaker 1: on the other side.

4:18 Speaker 3: For everyone else across North America and beyond, it won't

4:21 Speaker 3: be a full occultation, but you'll still see a dramatically

4:24 Speaker 3: close pairing. East Coast observers will see Mercury sitting just

4:28 Speaker 3: north of the moon as twilight falls. By the time

4:31 Speaker 3: darkness reaches the west coast, the Moon will have shifted

4:34 Speaker 3: to within about one degree of the planet. Venus hangs

4:38 Speaker 3: brilliantly below them as a helpful reference point.

4:41 Speaker 1: Now the window is tight. Mercury sets not long after

4:45 Speaker 1: the sun, so you want to get outside as soon

4:47 Speaker 1: as the sky darkens. Look low in the west southwest

4:51 Speaker 1: if you can spot Venus, and you'll have no trouble

4:54 Speaker 1: doing that. It's blazingly bright. Mercury will be nearby. The

4:58 Speaker 1: moon makes it easy tonight.

5:00 Speaker 3: And if that warn enough, Jupiter watchers have a tree

5:02 Speaker 3: two tonight. Ganymede, Jupiter's largest moon and the biggest moon

5:07 Speaker 3: in the entire Solar System, is transitting across Jupiter's face.

5:11 Speaker 3: East coast observers can see it underway as soon as

5:14 Speaker 3: it gets dark. It takes just over three hours to

5:17 Speaker 3: cross the disk, and then Ganymede's shadow follows it across,

5:20 Speaker 3: creating that striking black dot effect on Jupiter's cloud tops.

5:25 Speaker 1: So tonight really is a two for one skywatching event.

5:28 Speaker 1: Mercury and the Moon in the west at dusk, Jupiter

5:31 Speaker 1: and Ganymede in the southeast through the night. If you

5:34 Speaker 1: have binoculars or a small telescope. Even better, get outside,

5:39 Speaker 1: staying with today's news, and this one happened literally today.

5:43 Speaker 1: Europe's Arion six rocket has successfully launched thirty two satellites

5:47 Speaker 1: into orbit for Amazon's Project Kuiper.

5:50 Speaker 3: For those not familiar with Kuyper, Amazon has been quietly

5:54 Speaker 3: building a large constellation of broadband Internet satellites designed to

5:58 Speaker 3: take on space exist. This is a big commercial play.

6:03 Speaker 3: Darlink currently leads the market with thousands of operational satellites,

6:07 Speaker 3: but Amazon has the resources and ambition to make this

6:10 Speaker 3: a genuine competition.

6:12 Speaker 1: What's notable about today's launch is that it used the

6:15 Speaker 1: most powerful configuration of Airon six, flying with four strap

6:19 Speaker 1: on boosters rather than two. It was essentially a statement

6:23 Speaker 1: of capability from the European side of the commercial launch industry.

6:27 Speaker 1: This rocket can handle serious payloads.

6:30 Speaker 3: There's also a bigger picture here. Arion six has had

6:34 Speaker 3: somewhat of a turbulent road. It came in behind schedule

6:37 Speaker 3: and face some early technical hurdles, but launches like this,

6:41 Speaker 3: winning commercial contracts for a high profile constellation like hyper

6:45 Speaker 3: are exactly what Europe needs to keep its launch industry

6:48 Speaker 3: competitive in an era dominated by SpaceX and an increasingly

6:52 Speaker 3: capable Chinese launch sector.

6:54 Speaker 1: The broadband satellite race is one of the defining infrastructure

6:58 Speaker 1: stories of this decade. I'd argue Starlink has already changed

7:02 Speaker 1: what connectivity looks like in remote areas and conflict zones,

7:06 Speaker 1: hyper Amazon's one Web investments, the Chinese Go Wong constellation.

7:11 Speaker 1: They all point to a future where low Earth orbit

7:14 Speaker 1: becomes genuinely critical economic territory.

7:17 Speaker 3: Today's launch is one tile in that much larger mosaic

7:21 Speaker 3: thirty two satellites closer to that future.

7:24 Speaker 1: Now an update on our Interstellar Visitor, and I do

7:27 Speaker 1: mean update. There is genuinely new information here happening right now.

7:32 Speaker 3: I know we've given three i at Lists quite a

7:35 Speaker 3: run over recent episodes, but this one earns its place today.

7:39 Speaker 1: Completely for new listeners. Three i at Lists is only

7:42 Speaker 1: the third interstellar object ever confirmed to pass through our

7:46 Speaker 1: Solar System. It arrived from outside our stellar neighborhood, swung

7:50 Speaker 1: around the Sun last October, and is now heading back

7:53 Speaker 1: out into the galaxy forever. We will never see this

7:56 Speaker 1: object again.

7:58 Speaker 3: Here's what's happening right now. Issa's Juice spacecraft. That's the

8:02 Speaker 3: Jupiter icy Moons Explore currently en route to Jupiter pass

8:07 Speaker 3: with an observational range of three I atlas back in

8:10 Speaker 3: November last year. Due to the challenging thermal conditions during

8:15 Speaker 3: Juice's transit through the Inner Solar System, the data collected

8:18 Speaker 3: couldn't be downlinked straight away. That data is now being

8:22 Speaker 3: transmitted to Earth. The window is February eighteenth to the

8:26 Speaker 3: twentieth today.

8:28 Speaker 1: If successful, these would be the closest ever observations of

8:31 Speaker 1: an interstellar object by a spacecraft. Now, Juice didn't do

8:35 Speaker 1: a dedicated flyby, its trajectory is locked in for Jupiter,

8:40 Speaker 1: but even opportunistic observations from its suite of cameras, spectrometers,

8:44 Speaker 1: and particle detectors could give us a perspective on three

8:48 Speaker 1: I at lists that no Earth based telescope can provide.

8:51 Speaker 3: And the data would complement an extraordinary recent run of discoveries.

8:56 Speaker 3: Hubble has directly imaged the nucleus for the first time.

9:00 Speaker 3: JWST detected methane in its atmosphere, a molecule never before

9:05 Speaker 3: seen in an interstellar object, and the object is still

9:08 Speaker 3: spinning faster than it was before its solar encounter, a

9:12 Speaker 3: legacy of all that outgassing as it's swung close to

9:15 Speaker 3: the Sun.

9:16 Speaker 1: Three I atlass is now about three and a half

9:18 Speaker 1: astronomical units from the Sun in the constellation Gemini. It's fading,

9:23 Speaker 1: but still reachable with a decent amateur telescope, and it

9:26 Speaker 1: has one more big act to play, a close pass

9:29 Speaker 1: by Jupiter in March, which may trigger fresh outbursts as

9:33 Speaker 1: Jupiter's tidal forces stress the nucleus.

9:36 Speaker 4: An extraordinary object, and the fact that we have a

9:39 Speaker 4: spacecraft data downlink happening as we record today makes it

9:43 Speaker 4: entirely current. What report would Juce found as soon as

9:46 Speaker 4: the science teams release their analysis.

9:48 Speaker 1: Right deep time now. I genuinely love this next story

9:52 Speaker 1: because it takes something you thought you understood Saturn's rings

9:56 Speaker 1: and reframes the entire origin of the system.

10:00 Speaker 3: New research by mattia Chuk at the SETI Intitude, about

10:03 Speaker 3: to be published in the Planetary Science Journal, proposes a

10:06 Speaker 3: dramatic two stage catastrophe that reshaped the entire Saturturnian system

10:12 Speaker 3: roughly four hundred million years ago, and I mean reshaped everything. Titan,

10:17 Speaker 3: the rings, Iapetus, Hyperion, all of it connected to one

10:21 Speaker 3: ancient collision.

10:23 Speaker 1: Let's set the scene. Saturn has puzzled planetary scientists for

10:27 Speaker 1: a long time. Its axial tilt is an unusually steep

10:31 Speaker 1: twenty six point seven degrees. You don't expect gas giants

10:35 Speaker 1: to form that way. Titan is migrating away from Saturn

10:39 Speaker 1: at a surprisingly rapid rate. The moon Iapetus sits at

10:42 Speaker 1: an oddly inclined orbit, and the rings are far younger

10:46 Speaker 1: than the planet itself, only a few hundred million years old.

10:49 Speaker 1: Geologically speaking, one thing after another that didn't quite add up.

10:54 Speaker 3: Juke and colleagues ran simulations and found the scenario that

10:57 Speaker 3: explains it all at once. The key player is a

11:00 Speaker 3: moon they're calling Proto Hyperion. Saturn used to have this

11:04 Speaker 3: additional mid sized satellite orbiting in the Outer System. When

11:08 Speaker 3: saturn Spin orbit resonance with the other planets in the

11:11 Speaker 3: Solar System broke down, Proto Hyperion was destabilized, it drifted inward,

11:16 Speaker 3: and it collided with a Proto Titan.

11:19 Speaker 1: The merger of those two moons roughly four hundred million

11:23 Speaker 1: years ago set off a chain reaction. Some of the

11:26 Speaker 1: collision debris accreted around what would become today's Titan, explaining

11:30 Speaker 1: why Titan's surface looks surprisingly young despite the moon itself,

11:35 Speaker 1: being ancient, Titan absorbed new material and essentially reset its surface.

11:40 Speaker 3: Other debris from the collision perturbed the inner moon system.

11:44 Speaker 3: Titan's resonant gravitational interaction with Protodone and Proto Rhea caused

11:49 Speaker 3: further instabilities, more collisions, more debris. Most of that material

11:54 Speaker 3: eventually reaccreted into the inner moons we see today mimis Enceladus.

11:59 Speaker 3: Test this Dione Rhea, but a fraction of it stayed dispersed.

12:04 Speaker 3: That fraction became Saturn's.

12:06 Speaker 1: Rings and Hyperion, the small, oddly shaped, walnut like moon

12:11 Speaker 1: that looks like it survived a very bad day. According

12:15 Speaker 1: to the model, it actually did survive a very bad day.

12:19 Speaker 1: It formed from the debris of that Proto Hyperion and

12:22 Speaker 1: Prototitan collision and was captured into resonance with Titan. The

12:27 Speaker 1: researchers note that in most of their simulations, Hyperion was

12:31 Speaker 1: lost entirely. Its survival in a relatively small number of

12:35 Speaker 1: runs suggests the real system was genuinely close to being

12:39 Speaker 1: quite different.

12:40 Speaker 3: What I find compelling about this is how elegantly one

12:43 Speaker 3: event connects everything. The tilt of the whole planet, the

12:47 Speaker 3: age of the rings, the orbits of Iapetus and Hyperion.

12:52 Speaker 3: Titan's migration rate one ancient merger explains it all.

12:57 Speaker 1: Now, the researchers are careful to say this is a hypothesis,

13:01 Speaker 1: not a confirmed history. Simulations can be suggestive without being definitive.

13:06 Speaker 1: But NASA's Dragonfly mission is heading to Titan. It launches

13:10 Speaker 1: in twenty twenty eight and arrives in twenty thirty four.

13:13 Speaker 1: One of the things Dragonfly will investigate is the age

13:17 Speaker 1: and history of Titan's surface. If the surface shows evidence

13:21 Speaker 1: of that ancient resetting, that would be a powerful confirmation.

13:25 Speaker 3: Four hundred million years of cosmic history hiding in a

13:29 Speaker 3: walnut shaped moon. I love the stuff.

13:32 Speaker 1: And finally a story that will make you rethink just

13:36 Speaker 1: how long it takes to get to Mars, or at

13:38 Speaker 1: least how long it might take one day.

13:41 Speaker 3: Russia State Nuclear Corporation rose Adam, through its Troyice Institute

13:45 Speaker 3: near Moscow, has been developing a nuclear powered magna plasma engine,

13:50 Speaker 3: and they're making a bold claim that this technology could

13:54 Speaker 3: get a crude spacecraft to Mars in thirty days.

13:57 Speaker 1: To put that in context, a can ventional chemical rocket

14:01 Speaker 1: takes roughly eight months to reach Mars thirty days would

14:05 Speaker 1: be a transformation, not just an improvement. It would fundamentally

14:09 Speaker 1: change the feasibility of human Mars missions. Less radiation exposure

14:14 Speaker 1: for the crew, less time, and microgravity, a completely different

14:18 Speaker 1: logistical calculus for resupply and emergency scenarios.

14:22 Speaker 3: The engine works by accelerating hydrogen using electromagnetic fields rather

14:27 Speaker 3: than combustion, to a velocity of one hundred kilometers per second.

14:32 Speaker 3: That's roughly twenty two times faster than the exhaust velocity

14:36 Speaker 3: of a conventional chemical rocket. The working body is plasma

14:40 Speaker 3: charged particles, and it's driven by an onboard nuclear reactor

14:44 Speaker 3: that provides the sustained electrical power the accelerator needs.

14:49 Speaker 1: Importantly, this isn't a launch engine. You'd still use conventional

14:53 Speaker 1: chemical rockets to get off Earth surface and into orbit.

14:57 Speaker 1: The plasma system switches on once you're in se for

15:00 Speaker 1: the interplanetary cruise, smooth continuous acceleration followed by a long

15:06 Speaker 1: deceleration burn.

15:07 Speaker 3: The prototype is currently running ground trials inside a fourteen

15:11 Speaker 3: meters vacuum chamber designed to replicate deep space conditions. The

15:15 Speaker 3: researchers say the engine has demonstrated sufficient longevity over twenty

15:20 Speaker 3: four hundred hours for a Mars transportation operation. A flight

15:24 Speaker 3: ready prototype is targeted for twenty thirty.

15:28 Speaker 1: Now, and this is important. There are real caveats here.

15:32 Speaker 1: No peer reviewed data has been published yet. The thrust

15:35 Speaker 1: is very low, around six newtons. Integrating a nuclear reactor

15:40 Speaker 1: into a crude spacecraft is an enormous engineering challenge in itself,

15:45 Speaker 1: with regulatory, thermal and radiation shielding hurdles that remain largely

15:50 Speaker 1: unsolved publicly.

15:51 Speaker 3: Fare points, but the broader context is genuinely interesting. NASA

15:56 Speaker 3: is investing in its own plasma propulsion programs. The Vasi

16:00 Speaker 3: mer engine from ad Astra Rocket Company in Texas targets

16:03 Speaker 3: a Mars trip of forty five to sixty days. China

16:07 Speaker 3: has plasma thrust or research under way.

16:09 Speaker 4: Two.

16:10 Speaker 3: There's a real multi nation push to solve the propulsion

16:13 Speaker 3: problem for deep space travel.

16:16 Speaker 1: Chemical rockets got us to the Moon. Getting to Mars regularly,

16:20 Speaker 1: safely and at human timescales requires something different. This is

16:25 Speaker 1: where that search is heading, wherever it ultimately leads.

16:29 Speaker 3: Thirty days to Mars, even as an aspiration. That's a

16:33 Speaker 3: sentence worth sitting with.

16:35 Speaker 1: And that's our six stories for Season five, Episode forty two.

16:39 Speaker 1: What a lineup from a rocket on a launch pad

16:42 Speaker 1: in Florida to a crescent moon swallowing Mercury to the

16:46 Speaker 1: debris of a four hundred million year old collision still

16:50 Speaker 1: orbiting Saturn, and.

16:51 Speaker 3: An interstellar comment sending us its last data from the

16:54 Speaker 3: edge of the Solar System while Russia dreams of getting

16:57 Speaker 3: to Mars in a month. Base never has a quiet week.

17:01 Speaker 1: If tonight's sky events caught your attention, there is still

17:04 Speaker 1: time to get outside Mercury and the Moon in the west,

17:08 Speaker 1: Jupiter and Ganymede in the southeast. You have your orders

17:12 Speaker 1: and keep.

17:12 Speaker 3: An eye on Artemis. Tomorrow's fueling test is one of

17:15 Speaker 3: those days where the news could come fast. We'll be

17:18 Speaker 3: on it.

17:19 Speaker 1: Thank you so much for spending part of your Wednesday

17:21 Speaker 1: with us. We'll be back tomorrow for more from the universe.

17:25 Speaker 3: Until then, clear sky is everyone, Sunny day

17:30 Speaker 4: Star is, Star is