Anna: Welcome to Astronomy Daily, your essential
guide to the cosmos. I'm Anna, ready to
explore the latest celestial happenings.
Avery: And I'm Avery joining you with today's
headlines. We have some truly fascinating
stories lined up, from groundbreaking new
methods for detecting gravitational waves to
surprising discoveries about the water
content of distant exoplanets.
Anna: Indeed, we'll also cover a recent very close
asteroid flyby that you might have missed.
And get an update on Australia's growing
space industry with Gilmour Space
Technologies. It's a packed show, so let's
get started.
Our first stop takes us to the cutting edge
of physics with an exciting new proposal for
detecting gravitational waves. These ripples
in space time predicted by Einstein are
notoriously elusive.
Avery: That's right, Anna. Physicists, uh, have put
forward a novel approach to detect what they
call mid band gravitational waves.
Operating between
0.001 and 1 Hz.
This is a frequency range that existing
instruments just can't reach effectively.
Anna: And these mid band waves are crucial because
they're generated by fascinating systems like
binary white dwarfs and neutron stars within
our own Milky Way, as well as the mergers of
massive black holes.
What's the secret to this new detection
method?
Avery: It relies on optical resonator technology
originally designed for highly precise
optical atomic clocks. Dr. Vera
Guerrera from the University of Birmingham
highlights that this extends our detection
capabilities into a new frequency range using
instruments that are laboratory sized.
Anna: Laboratory sized? That's quite a departure
from the massive LIGO and Virgo
interferometers we're familiar with. This
could open up a whole new realm of
possibilities, perhaps even a, uh, global
network of detectors sooner than anticipated.
Avery: Precisely. The proposed system uses
two optical cavities. Essentially mirrors
bouncing laser light back and forth
at right angles. While mid band gravitational
waves don't deform the rigid cavity
spacer, they subtly alter the phase of the
light itself. And here's the genius.
State of the art optical cavities are already
sensitive enough to pick up these minute
changes.
Anna: So it's about exploiting existing super
sensitive tech for a new purpose. Professor
Xavier Calmette from the University of Sussex
added that this detector will allow us to
test astrophysical models of binary systems,
explore massive black hole mergers, and even
search for stochastic backgrounds from the
early universe. Truly phenomenal
indeed.
Avery: While large space based laser interferometers
like LISA are still about a decade away,
this optical cavity detector offers an
immediate and cost effective ground based
solution for mid band exploration. It
may be less sensitive, but its immediacy
makes it a game changer.
Okay, moving from the ripples of space time
to the surfaces of distant worlds. We have
new research challenging our understanding of
exoplanets, Specifically their water content.
It seems the universe might be a bit drier
than we once thought.
Anna: This is a big one, Avery. For years,
theories have suggested that many exoplanets,
particularly sub Neptunes like K2 18B,
could be entirely covered by deep global
oceans, Making them potentially habitable.
These were often dubbed hycean planets, A
portmanteau of hydrogen and ocean Assuming
vast amounts of water.
Avery: Exactly. Sub neptunes are
larger than Earth, but smaller than Neptune.
Very common in our galaxy, but absent
from our own solar system. Many are thought
to have formed far from their stars beyond
the snow line, Accumulating ice before
migrating closer. The prevailing
idea was that they'd retain a massive water
envelope.
Anna: However, this new study, led by Eth Zurich
and published in the Astrophysical Journal
Letters, introduces a crucial
chemical coupling between the planet's
atmosphere and its interior. Caroline
Dorn, professor of exoplanets at Eth Zurich,
put it quite Water on planets is
much more limited than previously believed.
Avery: The researcher simulated sub neptunes going
through a deep hot magma ocean phase with the
hydrogen gas Shel. Their computer models
show that during this phase, Chemical
processes actually destroy most
H2O water molecules. The
hydrogen and oxygen atoms attach to metallic
compounds and disappear into the planet's
core. The conclusion is any water
remaining on the surface is likely limited to
just a few percent at most.
Anna: That dramatically changes our perspective on
habitability. If these larger exoplanets are
far drier than we imagined, it makes the
search for extraterrestrial life even more
challenging. Conditions suitable for liquid
water would likely only exist on smaller
planets. And even those would require better
telescopes than James Webb to observe
clearly.
Avery: Indeed, and here's a paradox. The
study suggests that the most water rich
atmospheres Might actually be found on
planets formed within the snow line, where
water wasn't initially accumulated ice,
but rather produced chemically from hydrogen
reacting with oxygen from from silicates in
the magma ocean. It challenges the classic
link between ice rich formation and water
rich atmospheres, Emphasizing the role of
magma ocean atmosphere equilibrium.
Anna: A truly fascinating insight. So
rather than being extraordinary, Earth might
just appear as a typical planet in this new
model. That in reality, we may not be as
unique as we previously thought we were. This
kind of research is critical for refining our
understanding of planetary formation and the
conditions for life in the vastness of space
Space.
Now let's turn our attention closer to home.
Though still in space, there was a recent
celestial visitor that made Quite a close
approach to Earth, largely unnoticed by the
general public.
Avery: That's right, Anna, uh, a small asteroid
designated 2025 TF
safely zipped past Earth on Tuesday,
September 30th at approximately
8:49pm EDT. Its
closest approach was roughly 250
miles, or 400 kilometers above our
planet's surface.
Anna: For context, that's about the same altitude
as the International Space Station. It wasn't
a record, as asteroid 2020 VT4 flew by
even closer at 230 miles five years ago.
But still an incredibly close shave.
Avery: Indeed. And how big was this particular
cosmic pebble?
2025 TF is
estimated to be about the size of a
couch, roughly 1.2
to 2.7 meters in diameter.
Interestingly, astronomers only spotted
it a few hours after its closest approach,
with the Catalina Sky Survey being the
first to detect it.
Anna: That's a testament to how challenging these
smaller objects are to track, especially when
they come from the sunward direction. Due to
a government shutdown, NASA hasn't issued a
formal statement. But data from JPL's
CNEOS confirmed a uh, nominal distance of
4,213 miles from Earth's
center, which corresponds to that
262 mile altitude over
Antarctica.
Avery: While NASA, uh, meticulously monitors larger
asteroids that could pose a threat, smaller
rocks like 2025 TF are much harder to
spot. However, our technology is
constantly improving and such close safe
passes are now being detected several times a
week. It's a reminder of the dynamic nature
of our solar neighborhood.
Finally today, let's head down under for an
update on Australia's burgeoning space
industry. Gilmour Space Technologies recently
made its first orbital launch attempt for its
Ares small launch vehicle.
Anna: And while that launch attempt on July 30
lasted only a few seconds, 14 to be precise,
the company is surprisingly satisfied with
the outcome and is already planning a return
to flight next year. CEO Adam
Gilmour stated that while the rocket was in
flight for only 14 seconds and its engines
fired for 23 seconds, it still provided
invaluable data for their next generation
rockets.
Avery: That's certainly a pragmatic outlook after
what sounds like a less than ideal initial
launch. Gilmour Space is
investigating the root cause, suspecting an
issue that wasn't sufficiently tested under
conditions closer to actual launch.
But a significant factor in this first Launch
was an 18 month delay between shipping the
rocket and the actual launch.
Anna: 18 months is an enormous delay for any space
company. This was largely due to regulatory
approvals. An astounding 24 permits from the
Queensland government alone, plus approvals
from the Australian Space Agency airspace,
maritime and environmental permits. Adam
Gilmour openly admitted they hadn't
adequately resourced those complex regulatory
processes and regretted not doing more
testing during those prolonged delays.
Avery: An incredible bureaucratic hurdle. Despite
the very short flight, he was quite pleased
it even managed to get off the pad, Candidly
referring to it as an old, clunky rocket by
the time it finally flew. It speaks volumes
about the challenges of pioneering a new
space launch capability.
Anna: Absolutely. However, Gilmour Space
anticipates a much smoother regulatory
process for future launches after productive
meetings with the Australian Space Agency now
that they've navigated the initial
complexities, he remains confident in future
launches, aiming to provide a reliable
domestic launch capability.
Avery: And importantly, the company is well
capitalized, planning to launch again next
year. This is a crucial step for Australia,
as Gilmour Space Technologies is a key
player in fostering a, uh, growing and
competitive Australian space industry on the
global stage.
Anna: What a journey through the cosmos today,
Avery. From the subtle dance of
gravitational waves to the surprisingly dry
interiors of exoplanets, and from a close
call with an asteroid to the determined
efforts of Gilmore Space, it's been an
episode packed with discoveries.
Avery: Indeed, Anna. It's a vivid reminder of how
quickly our understanding of the universe is
evolving. Each new piece of research, whether
it's about detecting unseen forces or
rethinking planetary formation, pushes the
boundaries of human human knowledge a little
further.
Anna: And it's not just the scientific discoveries,
Avery. It's also about the incredible
ingenuity in how we pursue these discoveries.
From laboratory sized gravitational wave
detectors to navigating complex regulatory
landscapes for space launches, the
human spirit of exploration is as vast as the
cosmos itself.
Avery: That's beautifully put, Anna. Ah, this
continuous push for knowledge, coupled with
innovation in technology and even policy,
truly underscores our inherent drive to
understand our place in the universe. It's a
journey that constantly redefines what's
possible.
Anna: And that wraps up another episode of
Astronomy Daily. Thank you for joining us on
this exploration of the universe.
Avery: We hope you enjoyed delving into these
stories with us. Don't forget to subscribe
wherever you get your podcasts to stay
updated with all the latest from beyond our
blue planet. Until next time, keep looking up