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Anna: Welcome to Astronomy Daily, your essential

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guide to the cosmos. I'm Anna, ready to

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explore the latest celestial happenings.

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Avery: And I'm Avery joining you with today's

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headlines. We have some truly fascinating

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stories lined up, from groundbreaking new

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methods for detecting gravitational waves to

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surprising discoveries about the water

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content of distant exoplanets.

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Anna: Indeed, we'll also cover a recent very close

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asteroid flyby that you might have missed.

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And get an update on Australia's growing

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space industry with Gilmour Space

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Technologies. It's a packed show, so let's

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get started.

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Our first stop takes us to the cutting edge

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of physics with an exciting new proposal for

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detecting gravitational waves. These ripples

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in space time predicted by Einstein are

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notoriously elusive.

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Avery: That's right, Anna. Physicists, uh, have put

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forward a novel approach to detect what they

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call mid band gravitational waves.

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Operating between

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0.001 and 1 Hz.

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This is a frequency range that existing

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instruments just can't reach effectively.

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Anna: And these mid band waves are crucial because

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they're generated by fascinating systems like

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binary white dwarfs and neutron stars within

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our own Milky Way, as well as the mergers of

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massive black holes.

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What's the secret to this new detection

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method?

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Avery: It relies on optical resonator technology

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originally designed for highly precise

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optical atomic clocks. Dr. Vera

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Guerrera from the University of Birmingham

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highlights that this extends our detection

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capabilities into a new frequency range using

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instruments that are laboratory sized.

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Anna: Laboratory sized? That's quite a departure

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from the massive LIGO and Virgo

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interferometers we're familiar with. This

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could open up a whole new realm of

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possibilities, perhaps even a, uh, global

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network of detectors sooner than anticipated.

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Avery: Precisely. The proposed system uses

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two optical cavities. Essentially mirrors

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bouncing laser light back and forth

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at right angles. While mid band gravitational

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waves don't deform the rigid cavity

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spacer, they subtly alter the phase of the

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light itself. And here's the genius.

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State of the art optical cavities are already

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sensitive enough to pick up these minute

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changes.

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Anna: So it's about exploiting existing super

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sensitive tech for a new purpose. Professor

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Xavier Calmette from the University of Sussex

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added that this detector will allow us to

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test astrophysical models of binary systems,

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explore massive black hole mergers, and even

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search for stochastic backgrounds from the

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early universe. Truly phenomenal

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indeed.

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Avery: While large space based laser interferometers

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like LISA are still about a decade away,

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this optical cavity detector offers an

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immediate and cost effective ground based

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solution for mid band exploration. It

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may be less sensitive, but its immediacy

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makes it a game changer.

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Okay, moving from the ripples of space time

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to the surfaces of distant worlds. We have

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new research challenging our understanding of

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exoplanets, Specifically their water content.

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It seems the universe might be a bit drier

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than we once thought.

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Anna: This is a big one, Avery. For years,

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theories have suggested that many exoplanets,

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particularly sub Neptunes like K2 18B,

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could be entirely covered by deep global

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oceans, Making them potentially habitable.

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These were often dubbed hycean planets, A

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portmanteau of hydrogen and ocean Assuming

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vast amounts of water.

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Avery: Exactly. Sub neptunes are

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larger than Earth, but smaller than Neptune.

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Very common in our galaxy, but absent

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from our own solar system. Many are thought

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to have formed far from their stars beyond

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the snow line, Accumulating ice before

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migrating closer. The prevailing

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idea was that they'd retain a massive water

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envelope.

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Anna: However, this new study, led by Eth Zurich

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and published in the Astrophysical Journal

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Letters, introduces a crucial

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chemical coupling between the planet's

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atmosphere and its interior. Caroline

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Dorn, professor of exoplanets at Eth Zurich,

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put it quite Water on planets is

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much more limited than previously believed.

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Avery: The researcher simulated sub neptunes going

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through a deep hot magma ocean phase with the

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hydrogen gas Shel. Their computer models

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show that during this phase, Chemical

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processes actually destroy most

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H2O water molecules. The

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hydrogen and oxygen atoms attach to metallic

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compounds and disappear into the planet's

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core. The conclusion is any water

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remaining on the surface is likely limited to

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just a few percent at most.

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Anna: That dramatically changes our perspective on

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habitability. If these larger exoplanets are

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far drier than we imagined, it makes the

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search for extraterrestrial life even more

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challenging. Conditions suitable for liquid

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water would likely only exist on smaller

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planets. And even those would require better

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telescopes than James Webb to observe

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clearly.

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Avery: Indeed, and here's a paradox. The

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study suggests that the most water rich

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atmospheres Might actually be found on

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planets formed within the snow line, where

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water wasn't initially accumulated ice,

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but rather produced chemically from hydrogen

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reacting with oxygen from from silicates in

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the magma ocean. It challenges the classic

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link between ice rich formation and water

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rich atmospheres, Emphasizing the role of

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magma ocean atmosphere equilibrium.

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Anna: A truly fascinating insight. So

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rather than being extraordinary, Earth might

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just appear as a typical planet in this new

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model. That in reality, we may not be as

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unique as we previously thought we were. This

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kind of research is critical for refining our

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understanding of planetary formation and the

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conditions for life in the vastness of space

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Space.

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Now let's turn our attention closer to home.

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Though still in space, there was a recent

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celestial visitor that made Quite a close

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approach to Earth, largely unnoticed by the

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general public.

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Avery: That's right, Anna, uh, a small asteroid

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designated 2025 TF

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safely zipped past Earth on Tuesday,

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September 30th at approximately

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8:49pm EDT. Its

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closest approach was roughly 250

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miles, or 400 kilometers above our

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planet's surface.

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Anna: For context, that's about the same altitude

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as the International Space Station. It wasn't

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a record, as asteroid 2020 VT4 flew by

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even closer at 230 miles five years ago.

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But still an incredibly close shave.

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Avery: Indeed. And how big was this particular

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cosmic pebble?

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2025 TF is

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estimated to be about the size of a

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couch, roughly 1.2

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to 2.7 meters in diameter.

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Interestingly, astronomers only spotted

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it a few hours after its closest approach,

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with the Catalina Sky Survey being the

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first to detect it.

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Anna: That's a testament to how challenging these

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smaller objects are to track, especially when

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they come from the sunward direction. Due to

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a government shutdown, NASA hasn't issued a

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formal statement. But data from JPL's

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CNEOS confirmed a uh, nominal distance of

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4,213 miles from Earth's

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center, which corresponds to that

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262 mile altitude over

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Antarctica.

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Avery: While NASA, uh, meticulously monitors larger

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asteroids that could pose a threat, smaller

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rocks like 2025 TF are much harder to

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spot. However, our technology is

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constantly improving and such close safe

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passes are now being detected several times a

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week. It's a reminder of the dynamic nature

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of our solar neighborhood.

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Finally today, let's head down under for an

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update on Australia's burgeoning space

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industry. Gilmour Space Technologies recently

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made its first orbital launch attempt for its

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Ares small launch vehicle.

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Anna: And while that launch attempt on July 30

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lasted only a few seconds, 14 to be precise,

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the company is surprisingly satisfied with

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the outcome and is already planning a return

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to flight next year. CEO Adam

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Gilmour stated that while the rocket was in

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flight for only 14 seconds and its engines

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fired for 23 seconds, it still provided

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invaluable data for their next generation

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rockets.

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Avery: That's certainly a pragmatic outlook after

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what sounds like a less than ideal initial

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launch. Gilmour Space is

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investigating the root cause, suspecting an

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issue that wasn't sufficiently tested under

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conditions closer to actual launch.

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But a significant factor in this first Launch

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was an 18 month delay between shipping the

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rocket and the actual launch.

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Anna: 18 months is an enormous delay for any space

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company. This was largely due to regulatory

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approvals. An astounding 24 permits from the

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Queensland government alone, plus approvals

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from the Australian Space Agency airspace,

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maritime and environmental permits. Adam

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Gilmour openly admitted they hadn't

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adequately resourced those complex regulatory

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processes and regretted not doing more

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testing during those prolonged delays.

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Avery: An incredible bureaucratic hurdle. Despite

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the very short flight, he was quite pleased

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it even managed to get off the pad, Candidly

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referring to it as an old, clunky rocket by

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the time it finally flew. It speaks volumes

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about the challenges of pioneering a new

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space launch capability.

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Anna: Absolutely. However, Gilmour Space

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anticipates a much smoother regulatory

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process for future launches after productive

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meetings with the Australian Space Agency now

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that they've navigated the initial

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complexities, he remains confident in future

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launches, aiming to provide a reliable

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domestic launch capability.

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Avery: And importantly, the company is well

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capitalized, planning to launch again next

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year. This is a crucial step for Australia,

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as Gilmour Space Technologies is a key

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player in fostering a, uh, growing and

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competitive Australian space industry on the

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global stage.

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Anna: What a journey through the cosmos today,

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Avery. From the subtle dance of

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gravitational waves to the surprisingly dry

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interiors of exoplanets, and from a close

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call with an asteroid to the determined

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efforts of Gilmore Space, it's been an

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episode packed with discoveries.

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Avery: Indeed, Anna. It's a vivid reminder of how

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quickly our understanding of the universe is

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evolving. Each new piece of research, whether

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it's about detecting unseen forces or

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rethinking planetary formation, pushes the

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boundaries of human human knowledge a little

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further.

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Anna: And it's not just the scientific discoveries,

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Avery. It's also about the incredible

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ingenuity in how we pursue these discoveries.

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From laboratory sized gravitational wave

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detectors to navigating complex regulatory

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landscapes for space launches, the

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human spirit of exploration is as vast as the

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cosmos itself.

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Avery: That's beautifully put, Anna. Ah, this

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continuous push for knowledge, coupled with

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innovation in technology and even policy,

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truly underscores our inherent drive to

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understand our place in the universe. It's a

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journey that constantly redefines what's

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possible.

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Anna: And that wraps up another episode of

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Astronomy Daily. Thank you for joining us on

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this exploration of the universe.

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Avery: We hope you enjoyed delving into these

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stories with us. Don't forget to subscribe

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wherever you get your podcasts to stay

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updated with all the latest from beyond our

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blue planet. Until next time, keep looking up