Lunar Secret Unveiled, Galactic Waves Discovered, and SpaceX's Starship Countdown

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Avery: Welcome to Astronomy Daily, the podcast that

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brings you the universe, one story at a time.

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I'm Avery.

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Anna: And I'm Anna. Today we're journeying

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from our own cosmic backyard to the

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vast structures of our galaxy.

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Avery: That's right. We'll be looking at surprising

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new data from the Moon's far side. A

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colossal wave of stars discovered in the

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Milky Way, and an update on SpaceX's next

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big launch.

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Anna: And we'll wrap up with a look at the

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invisible asteroids lurking closer to the

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Sun. A potential threat yet we're only just

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beginning to understand. Let's get started.

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Avery: First up, Anna, uh, let's talk about the

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Moon. We tend to think of it as this static,

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unchanging rock. But China's Chang'

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E6 mission is telling us a different story.

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Anna: It certainly is. The rock and soil samples

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returned from the far side are revealing a

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fascinating thermal asymmetry. In

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simple terms, the interior of the Moon's far

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side, the side we never see from Earth, is

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significantly cooler than the near side.

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Avery: Cooler. How much cooler are we talking?

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Anna: Around 180 degrees Fahrenheit

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or 100 degrees Celsius cooler? That

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might not sound like a huge number on a

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planetary scale, but it's enough to explain

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some long standing mysteries about the Moon's

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two faces.

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Avery: Like why the near side is covered in those

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dark volcanic plains, the maria. While

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the far side is so much more rugged and

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cratered.

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Anna: Exactly. A hotter nearside mantle would

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have been more molten, leading to more

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widespread and prolonged volcanic activity.

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This heat also explains why the near side

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crust is thinner. The cooler far side mantle

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solidified earlier, resulting in a thicker

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crust and far less volcanism.

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Avery: So the big question is why? Why

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would one side be so much hotter than the

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other?

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Anna: That's the billion dollar question. The

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leading hypothesis is an uneven distribution

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of heat producing radioactive elements like

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uranium and thorium. For some reason,

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these elements were concentrated on the near

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side when the Moon was forming.

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Avery: And how would that have happened?

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Anna: There are a couple of compelling theories.

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One suggests that a massive ancient impact

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could have essentially splattered these

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elements across one hemisphere. Another,

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more dramatic theory posits that early in its

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history, Earth had two moons and a

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smaller companion moon had a slow motion

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collision with the larger one, depositing its

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element rich material onto what is now the

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MIR side.

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Avery: Wow. So the face of the Moon we see every

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night might actually be the result of a

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cosmic fender bender. It really highlights

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how dynamic and violent the early solar

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system was.

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A truly incredible discovery from the Chang'

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E6 mission.

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Anna: From our closest neighbor to the grand scale

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of our entire galaxy. Avery. Data

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from the European Space Agency's Gaia space

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telescope has revealed something truly

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monumental.

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Avery: Gaia is always turning up amazing things.

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What has it found this time?

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Anna: It's been described as a great wave of

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stars. A colossal ripple moving

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outwards from the center of the Milky Way.

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We're talking about a structure that spans

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tens of thousands of light years.

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Avery: A wave of stars. What does that even

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look like? Are the stars themselves moving in

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a wave pattern, like water?

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Anna: In a way, yes. This isn't a wave of light,

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but a literal wave of motion. The

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collective positions and velocities of

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millions of stars. Stars are perturbed,

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causing them to move up and down as this

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ripple propagates through the galactic disk.

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It's a subtle effect, but on a galactic

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scale, it's enormous.

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Avery: That's mind boggling. A wave that's tens

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of thousands of light years across. What

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could possibly cause something that huge?

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Anna: The most likely culprit is a collision. Not a

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recent one, but an event that happened

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perhaps a few billion years ago. The thinking

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is that a dwarf galaxy plunged through

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the center of the Milky.

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Avery: Way's disk like drop a stone into a pond.

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But the pond is our galaxy, and the stone

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is another, smaller galaxy.

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Anna: That's the perfect analogy. The dwarf

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galaxy's gravity would have punched through

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the disk, setting off these ripples that

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are still expanding outwards today.

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It's a testament to the power of big data

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in astronomy. By mapping out the 3D

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motion of billions of stars, we can

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uncover these hidden dynamics.

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Avery: And does this wave affect us here in our

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solar system?

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Anna: That's a great question. We are likely caught

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up in this wave, just like all the other

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stars in our neighborhood. The effect on our

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solar system's orbit is probably very small,

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but it's a powerful reminder that we are part

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of a much larger dynamic system

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shaped by events that took place long before

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the Earth even formed.

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Avery: All right, let's bring it back a little

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closer to home. It's time for an update from,

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uh, SpaceX. Mark your calendars because they

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are targeting October 13th for the

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11th flight of the Starship Mega

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Rocket Flight 11.

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Anna: They are certainly keeping a rapid pace.

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This will be another crucial test for the

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most powerful rocket ever built. What are

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the main objectives for this flight? Avery?

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Avery: The mission profile will look very similar to

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the successful Flight 10. The main goal is to

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demonstrate reliability and reusability. Uh,

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they'll launch the super heavy booster, will

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separate and perform a boostback burn, aiming

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For a soft splashdown in the.

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Anna: Gulf of Mexico and the starship upper

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stage.

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Avery: The ship will continue on a suborbital

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trajectory, Coasting for about an hour before

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performing its own re entry and attempting a

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controlled splashdown in the Indian Ocean.

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They'll also be testing the payload bay door

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again, this time by deploying some mock

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Starlink satellites.

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Anna: Deploying mach satellites is an important

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step towards the vehicle becoming operational

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for its primary mission. Launching the

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next generation of Starlink.

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Avery: Exactly. It's also worth noting that this

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will be the final flight for the current

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version 2 of the Starship vehicle.

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The next flights will feature significant

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upgrades aimed at even faster turnaround

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times and greater reliability.

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Anna: So it's both a validation of the current

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design and a, uh, final farewell before

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we see the next evolution of starship.

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Each of these flights, even when they seem

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repetitive, gathers an immense amount of

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data that feeds directly into those future

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improvements.

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Avery: That's the key iteration we'll be watching on

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October 13th to see if they can stick the

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landing or at least to splashdown.

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Anna: For our final story, we're looking at

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something that's, um, a bit unsettling. The

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idea of hitting dangers in our own solar

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system. Astronomers are suggesting there

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could be a large undiscovered population of

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asteroids lurking near the orbit of

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Venus.

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Avery: Undiscovered asteroids are always a concern.

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Why are these ones particularly hard to spot?

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Are they very small or very dark?

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Anna: It's neither of those actually. It's a

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problem of location. These asteroids are

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believed to be orbiting the sun in a

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resonance with Venus. From our viewpoint

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on Earth, this means they spend almost all

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their time in the direction of the Sun.

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Avery: Ah, uh, so they're lost in the glare. You

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can't really point a telescope at the sun to

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look for faint objects.

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Anna: Precisely. It's like trying to spot a

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firefly next to a searchlight. You ground

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based telescopes are limited to searching the

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sky at twilight, just after sunset

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or before sunrise, which gives them a very

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narrow window to hunt in that direction.

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This creates a huge observational blind

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spot.

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Avery: So we have this potential swarm of asteroids

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nearby, and we can barely see them. Should we

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be worried? Do they pose a threat to Earth?

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Anna: The potential is there. The models show

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that the gravitational pull of Venus can

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nudge these asteroids into chaotic orbits

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over millions of years. Some of those

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chaotic orbits could eventually intersect

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with Earth's orbit, creating a collision risk

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down the line.

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Avery: So this isn't an immediate threat, but a long

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term hazard we need to map out. Is there any

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hope in finding them?

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Anna: Yes, there is. Upcoming missions

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are specifically designed to tackle this

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problem. The Vera Rubin Observatory, with

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its massive field of view, will be able to

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survey the sky much more rapidly during

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twilight. And even better,

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NASA's NEO Surveyor mission will be a, ah,

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space based infrared telescope.

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Avery: A space telescope wouldn't be hampered by the

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sun's glare in the same way, right?

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Anna: Exactly. By operating in space

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and observing in the infrared where asteroids

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glow from the Sun's heat, NEO

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Surveyor will be able to find these elusive

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objects regardless of their position in the

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sky. It's designed to fill in these dangerous

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blind spots in our planetary defense network.

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Avery: That's reassuring. It's a good reminder that

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the sky isn't empty and we need to keep our

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eyes open even in the places that are hardest

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to look.

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And that's all the time we have for today on

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Astronomy Daily. We've journeyed from our two

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face Moon to a great wave in the Milky Way,

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checked in on Starship, and peered into the

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Sun's glare for hidden asteroids.

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Anna: It's a constant reminder that there are

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always new discoveries to be made, both near

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and far. Thanks so much for joining us.

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Avery: You can find Astronomy Daily wherever you get

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your podcasts or simply visit our website at

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astronomydaily IO Be sure

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to subscribe so you don't miss an episode.

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Until next time, keep looking up and keep

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wondering.