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Anna: Welcome to Astronomy Daily,

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your source for the latest news and

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discoveries from across the cosmos.

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I'm Anna.

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Avery: And I'm Avery. We've got a fabulous show

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lined up today with some truly mind bending

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science. We're talking about how our Moon

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is slowly but surely drifting away from

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Earth, why alien civilizations might be

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much rarer than we thought, and how

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NASA guides spacecraft through the vast

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emptiness of space.

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Anna: Plus, we'll catch you up on this week's busy

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launch schedule. So let's dive right in

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with something that might surprise you.

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Did you know that every single day the

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Moon gets a tiny bit further away from

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us?

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Avery: It's true. The Moon is drifting away from

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earth at about 1.5 inches per

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year. That might not sound like much, but

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over millions of years, it really adds up.

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And we can measure this incredibly precisely,

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thanks to something left behind by the Apollo

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astronauts.

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Anna: You're talking about those retroreflector

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mirrors, right? The Apollo crews place these

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special mirror arrays on the lunar surface,

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and scientists have been bouncing laser beams

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off them ever since to measure the exact

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distance to the Moon. It's one of the most

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precise measurements in all of astronomy.

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Avery: Exactly. And the reason this is happening is

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actually pretty fascinating. It all comes

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down to tidal forces. The Moon's gravity

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creates those familiar ocean tides on Earth.

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But here's the Earth's rotation

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is faster than the Moon's orbital period.

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This creates a slight bulge in Earth's

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oceans that's actually ahead of the Moon as

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it orbits.

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Anna: So that tidal bulge is essentially

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pulling the Moon forward in its orbit, which

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increases its orbital energy and makes it

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spiral outward. It's like a cosmic

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dance where Earth is gradually pushing its

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partner away. And there's another

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consequence. This process is also making

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Earth's days slightly longer over time.

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Avery: The evidence for this is really cool.

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Scientists have studied fossilized clamshells

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that show growth patterns from 70 million

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years ago during the age of dinosaurs. Those

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patterns tell us that back then, a day

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was only about 23.5 hours

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long. The Moon was closer, Earth spun

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faster, it was a different world.

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Anna: And if we go way back to when the Moon

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first formed four and a half billion years

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ago, after that massive collision between

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Earth and a Mars sized object, the Moon

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would have been dramatically closer. We're

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talking about it appearing maybe 10 times

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larger in the sky. The tides would have been

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enormous and days would have been just a

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few hours long. That early Earth Moon system

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must have been absolutely spectacular to

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witness. Can you imagine those

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massive tides? We're talking about ocean

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tides, potentially hundreds of feet high,

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Surging across the planet Every few hours,

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the moon would have looked like this enormous

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disk Dominating the sky.

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Avery: And here's what's really fascinating about

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the physics. This process Won't continue

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forever. Eventually, Earth and the moon

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Will become tidally Locked to each other,

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which means Earth's rotation Will slow down

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until one day equals one lunar month,

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roughly 47 of our current days. At

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that point, the same side of Earth Will

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always face the moon, Just like the same side

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of the moon Always faces us.

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Anna: Now, that brings up something that really

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hits home for eclipse enthusiasts like us.

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The moon is gradually moving away,

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which means total solar eclipses Are becoming

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rarer and, and will eventually disappear

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altogether. Right now, the moon is

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just the perfect size to block out the sun's

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disk During a total eclipse. But as it moves

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away and appears smaller in our sky, we'll

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start seeing more annular eclipses, where you

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get that beautiful ring of fire effect

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Instead of totality.

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Avery: The timeline is mind boggling, though. We're

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talking about Hundreds of millions of years

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before total solar eclipses Become

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impossible. So while future generations Will

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miss out on one of nature's most spectacular

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shows, Human has plenty of time to catch

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these incredible events. In fact, we're

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living During A cosmically special time, the

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brief window when the moon and sun Appear

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Almost exactly the same size in our sky. It's

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incredible to think about how that ancient

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catastrophe Shaped not just our planet, but

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continues to influence us today.

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Speaking of planetary formation and what

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makes world habitable, um, there's some new

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research that's pretty sobering about our

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prospects of finding alien civilizations.

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Anna: Oh, this is the study about plate tectonics.

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Right. The researchers are arguing that

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technological civilizations Might need plate

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tectonics and something called the carbon

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silicate cycle to survive long enough to

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actually develop advanced technology.

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Avery: Exactly. The basic idea is that without plate

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tectonics, Constantly recycling carbon

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through volcanic activity and rock

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weathering, CO2 levels would just keep rising

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and rising. Eventually, you'd get A runaway

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greenhouse effect that would make the planet

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uninhabitable, Kind of like what happened to

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Venus. The carbon silicate cycle

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Is really the planetary thermostat that keeps

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earth habitable. Here's how it works. When it

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gets too hot, More water evaporates and

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creates more rain, which increases rock

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weathering. That weathering pulls

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CO2 out of the atmosphere and locks

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it into carbonate rocks. When it gets too

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cold, Volcanic activity releases

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stored CO2 back into the atmosphere

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While warming things up again. It's this

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incredible self regulating system that's

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kept Earth's temperature relatively stable

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for billions of years.

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Anna: And Venus is the perfect cautionary tale

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here. Venus probably started out much more

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Earth like, but without active plate

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tectonics to recycle carbon, CO2

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just kept building up in the atmosphere. The

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result, surface temperatures hot enough to

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melt lead, cool, crushing atmospheric

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pressure and sulfuric acid clouds. It's a

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hellscape that shows us exactly what happens

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when a, uh, planet loses its carbon silicate

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cycle.

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Avery: This research has huge implications for seti,

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the search for Extraterrestrial intelligence.

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It suggests we might need to focus more on

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planets with clear signs of active geology,

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not just planets in the habitable zone. We'd

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want to look for atmospheric signatures that

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indicate active volcanism and weathering

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cycles. And it's also related to what

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scientists call the Great Filter, the idea

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that there might be some extremely difficult

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step in the evolution from simple chemistry

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to a galaxy spanning civilization.

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Anna: The numbers are pretty staggering. The study

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estimates that it might take anywhere from a

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thousand to a million rocky planets for

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just one to develop into an Earth like world

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with the kind of long term climate stability

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needed for complex life to evolve and, and

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eventually develop technology.

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Avery: And if this research is correct, it pushes

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the nearest potential extraterrestrial

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intelligence way out to maybe

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33,000 light years away. Even

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more challenging for alien civilizations to

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exist at the same time as us, they'd need to

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last an average of 280,000 years or more.

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That's a long time for any technological

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species to survive.

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Anna: It really makes you appreciate how special

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Earth might be. We've got this perfect

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balance of plate tectonics, the right

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distance from the sun, a large, large

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stabilizing moon, and probably

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dozens of other factors that had to line up

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just right. Of course, we're still looking.

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And that's where missions like the ones

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launching this week come in.

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Avery: Let's talk launches. It's going to be a busy

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week. SpaceX has four missions on the

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schedule, including three Starlink launches

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to continue building out their satellite

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Internet constellation. Plus one mission

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called NROL 48 for the national

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Reconnaissance Office. That's the secretive

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one where we probably won't get many details

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about the payload.

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Anna: The mission I'm most excited about is Blue

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Origin's New Shepard NS35,

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finally launching Thursday after several

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delays. This one's carrying over 40

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different experiments, including 24

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student payloads from NASA's TechRise student

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challenge. Plus they're taking thousands of

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postcards to space, which I think is just

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delightful. The New Shepard mission is

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particularly Interesting from a scientific

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standpoint. Among those 40 plus

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experiments, they're testing everything from

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crystal growth in microgravity to plant

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biology studies. Several experiments are

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investigating how different materials behave

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in the brief microgravity environment, which

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is incredibly valuable for manufacturing

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research. Um, the student payloads are

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testing things like seed germination,

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fluid dynamics, and even how social

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media algorithms might work in space

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environments.

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Avery: The Starlink launches are pretty impressive

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from, uh, a technical standpoint, too. The

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Constellation now has over 5,000 active

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satellites in orbit, making it by far the

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largest satellite constellation ever

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deployed. And SpaceX's booster

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reuse program continues to break records.

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Some of these Falcon 9 first stages have

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flown more than 15 times each.

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That's revolutionary when you consider that

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just a few years ago rockets were completely

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expendable. The cost savings are allowing

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them to launch these massive Constellation

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buildouts that would have been economically

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impossible before.

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Anna: I love that. And there's something

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wonderfully old fashioned about sending

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postcards to space in this digital age.

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And don't forget about Tuesday's Chinese

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launch and, uh, a Chang Zang 2C rocket

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carrying what's described only as an unknown

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payload. The mystery always adds a bit of

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intrigue.

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Speaking of space missions, we've had a query

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from one of our listeners, Josh, asking how

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on Earth do we maintain contact with all of

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our spacecraft in deep space? Good question,

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Josh. Once these spacecraft get beyond

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Earth orbit, they enter a realm where GPS

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doesn't work and navigation becomes

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incredibly complex. And that's where

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NASA's Deep Space Network comes in. It's

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honestly one of the most impressive

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technological achievements that most people

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have never heard of.

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Avery: The DSN is basically NASA's lifeline to

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everything we've sent beyond Earth orbit.

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It's a network that is made up of three

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massive antenna complexes, one in California,

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one in Spain, and one in Australia,

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spaced exactly 120 degrees apart around

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the globe. This means that as Earth rotates,

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at least one complex always has line of sight

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contact with any spacecraft in the solar

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system. The navigation challenges are

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absolutely staggering when you really think

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about them. Take Voyager 2, for example.

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It's currently at about 12.8 billion

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miles from Earth in a completely unique

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position below the plane of the solar system.

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Command sent to Voyager 2 take over 18 hours

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just to reach the spacecraft, and then

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another 18 hours for any response to come

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back. That means if something goes wrong,

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mission controllers have to wait more than a

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day and a half just to know if their fix

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worked.

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Anna: The precision required for antenna pointing

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is just incredible. These dishes need to be

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aimed so Accurately that they can target a

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spacecraft millions of miles away to within a

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fraction of a degree. It's like trying to hit

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a coin with a laser pointer from across an

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entire city. And they have to constantly

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adjust for the motion of both Earth and the

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spacecraft, which plus account for things

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like atmospheric refraction and even

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the slight bending of radio waves by the

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Sun's gravity.

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Avery: This incredible precision is what enables

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those amazing gravity assist maneuvers that

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would be impossible Otherwise. When Voyager 2

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flew by Jupiter, Saturn, Uranus and

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Neptune, each encounter had to be timed

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within minutes and positioned within hundreds

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of miles to get the trajectory exactly right

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for the next target. One small navigation

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error early in the mission and Voyager 2

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would have missed Uranus by millions of

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miles. The fact that we can execute these

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cosmic billiard shots across decades of

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flight time is testament to the incredible

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engineering of the Deep Space Network.

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Anna: The precision is mind boggling. These

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antennas can track spacecraft millions of

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miles away by measuring incredibly tiny

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time delays in radio signals and

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detecting minute Doppler shifts in

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frequency. They're essentially doing

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celestial GPS calculations using

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the time it takes for signals to travel at

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the speed of light to determine exact

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positions and velocities.

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Avery: And, um, the range of missions it supports is

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incredible. We're talking about the Voyager

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probes, which are now in interstellar space

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over 15 billion miles away. Mars

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rovers like Perseverance and Curiosity, all

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the lunar missions and everything in between.

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Each one requires constant communication for

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telemetry commands and navigation updates.

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Anna: The future is getting even more exciting with

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optical communications. NASA's testing

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something called the Deep Space Optical

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Communications Experiment, or

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dsoc, on the Psyche mission.

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Instead of radio waves, they're using laser

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light to send data back to Earth. It's like

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upgrading from dial up to fiber optic

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Internet, but for spacecraft. If you'd like

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to find out more about the Deep Space

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Network, head over to our

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website@astronomydaily.IO and check

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out our latest blog post where we take a deep

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dive into the subject. I hope that answers

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your question, Josh.

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Avery: Before we wrap up, let's quickly touch on a

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couple more stories. Firefly Aerospace got

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some good news. Their Alpha rocket has been

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cleared to fly again after April's failure.

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The investigation found that extreme heat and

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something called plume induced flow

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separation caused the problem, but they've

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apparently worked out the fixes.

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Anna: And mark your calendars for September 23rd.

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NASA's launching three space weather

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missions, all at IMAP. The

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Carruthers, Geocarona Observatory

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and SWFOL1.

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These will study how solar activity affects

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our solar system and help us better predict

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space weather that could could impact

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satellites and astronauts.

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Avery: That's particularly timely because the sun's

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activity has been ramping up significantly

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since 2008 after decades of

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relatively quiet behavior. This has major

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implications for space weather and the safety

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of astronauts on future long duration

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missions to the Moon and Mars.

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Anna: That's all for today's Astronomy Daily. From

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our slowly departing moon to the search for

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alien civilizations, from busy launch

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schedules, to the incredible engineering that

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keeps us connected to robotic explorers

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across the solar system, there's never a dull

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moment in space science.

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Avery: Thanks for joining us today. Keep looking up

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and we'll see you tomorrow with more news

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from the final frontier. I'm, um, Avery.

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Anna: And I'm Anna. Until tomorrow, stay

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curious about the cosmos.