Anna: Welcome to Astronomy Daily, your regular dose
of cosmic insights with your host, Anna.
Today, we're diving into how a massive
ancient impact shaped our planet for life,
uncovering new secrets about ice and space,
and getting the latest on exciting space
missions and rocket launches. Plus, we'll
guide you through observing, uh, July's
beautiful Buck Moon and commemorating a
historic lunar anniversary. Let's get started
with a story about our home planet.
Earth, alone among the rocky planets in our
solar system, is a vibrant home for life.
It's warm, hospitable and teeming with
activity, a stark contrast to the frigid
lifelessness of its neighbours. How did our
planet become so uniquely suited for life?
The answer is incredibly complex. But a
significant part of it lies in the
fascinating field of cosmochemistry, which
explores how chemical elements are
distributed across the cosmos. Imagine
our solar system. 4.5 billion years ago,
it was a far more chaotic place than it is
today, with planets still in their infancy
and countless planetesimals and planetary
embryos whizzing around constantly crashing
into each other. Amidst this
cosmic demolition derby, something
extraordinary happened. Earth somehow
received an exceptionally generous delivery
of carbonaceous chondrites. These
aren't just any space rocks. They're packed
with amino acids and other essential
chemicals, the very building blocks that
enable life. Cosmochemistry studies have
revealed that between 5 and 10% of Earth's
entire mass originated from these
carbonaceous chondrites that collided with
our young planet. What's even more astounding
is that a substantial portion of this life
enabling material is believed to have arrived
during the colossal impact, eventually that
formed our moon. The THEIA impact.
To rigorously test this profound idea, a
team of researchers led by Duarte Branco
from the Institute of Astrophysics and Space
Sciences in Portugal, utilised sophisticated
dynamical simulations of the solar
system's formation. Their groundbreaking
work, titled Dynamical Origin of Theia uh,
the Last Giant Impactor on Earth, is set to
be published in the journal IT icarus.
In cosmochemistry, a critical distinction is
made between carbonaceous chondrites, or ccs,
and non carbonaceous meteorites.
This effectively divides the solar system's
meteorite population into two distinct
material reservoirs. Ccs formed much
farther from the sun, likely beyond Jupiter,
and are rich in volatiles like water and
organic compounds. Ncs, on the other
hand, include things like iron meteorites and
contain far fewer volatile elements. The
core question for the researchers was whether
Theia uh, could have delivered these crucial
CCS and volatiles to early Earth.
To investigate this, the team ran detailed N
body simulations focusing on the later stages
of terrestrial planet growth, specifically
after the solar system's gaseous disc had
dissipated. These simulations included
CCs that were scattered inward as gas giants
like Jupiter and Saturn were still growing.
The researchers explored three main
scenarios, one with only small CC
objects or planetesimals, another with only
large CC objects or planetary embryos, and
a mixed scenario that included both.
A subset of these simulations also factored
in the giant planet dynamical instability,
better known as the NICE model in astronomy.
This model describes how the giant planets
shifted their orbits from their initial
formation positions. The goal was
multifaceted to understand how ccs and
ncs were distributed, why Earth ended up with
significantly more ccs than other rocky
planets, particularly Mars, and whether the
Theia impact was indeed responsible for
delivering a large amount of Earth's C C
material. One of the most striking results
showed that the giant planet instability,
especially Jupiter's orbital shift, had a
profound effect on Earth's accretion of C C
material. As the giant planets moved,
they caused a strong pulse of eccentricity
excitement, leading to a wave of collisions
and ejections, effectively flinging CC rich
material into the inner solar system.
Crucially, the simulations strongly supported
the idea that THEIA itself was a carbonaceous
object. In the mixed scenario simulations
without giant planet instability, Earth's
final impactor, Theia, included a
carbonaceous component in more than half of
all simulations. In 38.5%
of cases, Theia was a pure carbonaceous
embryo, and in another 13.5%,
it was an NC embryo that had previously
accreted a C C embryo. This paints a
vivid picture of the early solar system. Two
distinct rings of planetesimals, an inner
ring of rocky material and an outer ring of
carbonaceous chondrites. As uh, the ice
giants migrated inward, they propelled this
CC material into the inner solar system, with
more massive ones preferentially scattered
into the orbits of rocky planets. This
explains not only the masses and orbits of
the terrestrial planets and the distribution
of asteroids, but also why Earth has a higher
CC mass fraction compared to Mars. The work
strongly suggests that Earth's final giant
impact was indeed with Theia, and that this
object had a higher concentration of
carbonaceous material directly contributing
to our planet's habitability. The
simulations indicate this last impact
occurred between 5 and 150-million years
after the gas disc dispersed, with a large
fraction happening within 20 to 70 million
years, timings consistent with current
understanding of the Theia impact. Moreover,
the research emphasises Jupiter's pivotal
role in shaping the solar system's
Architecture not just by truncating the
asteroid belt, but also by scattering crucial
carbonaceous material from the outer solar
system into the path of the rocky planets,
especially Earth. Ultimately, the
formation of a life sustaining world like
Earth required an astonishing number of
variables to align perfectly. This research
highlights that it may take more than simply
being in a habitable zone for an exoplanet to
support life. The complex dance of outer
giant planets migrating and delivering carbon
to inner rocky worlds might be another
critical, often overlooked ingredient in the
recipe for life in the universe.
Alright, moving on. Prepare to have your
perceptions of space ice completely
shattered. For decades, scientists have
largely viewed water frozen in the depths of
space as a shapeless, amorphous fog. Too
cold and still to ever form orderly crystals,
it was believed to simply freeze straight
from vapour onto cold surfaces like dust
grains and comets or icy moons without any
structured shape whatsoever. But a
groundbreaking new study by researchers from
University College London and the University
of Cambridge is challenging that long held
belief. By combining incredibly detailed
computer simulations with carefully
controlled lab experiments, this team has
discovered that space ice is not entirely
amorphous after all. Instead, it holds
tiny hidden crystal structures within its
disordered form. These small organised
patterns could fundamentally shift what we
know about ice, water and even the very
origins of life in the universe. On Earth,
ice typically forms a neat crystalline
pattern visible in the intricate symmetry of
a snowflake. But in the extreme cold and
vacuum of interstellar space, we where
temperatures plummet far below freezing. It
was thought that ice formed without any
order. This form of water was known as low
density amorphous ice, and the prevailing
view was that it lacked any internal
structure. However, that view is now
rapidly changing. The researchers began
by freezing virtual boxes of water molecules
down to an incredibly chilly negative
120 degrees Celsius. This allowed them
to simulate how ice forms at various rates.
Some simulations indeed produced nearly
perfect disordered ice. But others revealed
something fascinating. Tiny crystals
roughly 3 nanometers wide that's just
slightly larger than a strand of DNA, began
to form within the chaos. The result that
most accurately matched existing X ray
diffraction data wasn't fully disordered ice.
Instead, it was found to be approximately 20%
crystalline and 80% amorphous.
Dr. Michael B. Davies, the lead author of
this pivotal study, noted, we now have a
good idea of what the most common form of ice
in the universe looks like at an atomic
level. He emphasised the importance of this
finding, explaining that ice is involved in
many cosmological processes, for instance, in
how planets form, how galaxies evolve,
and how Matter moves around the universe.
The team didn't stop at simulations. They
meticulously created real samples of
amorphous ice in their lab using several
methods. One method directly mimicked how
ice forms in space by depositing water
vapour onto a surface chilled far below
freezing. Another involved crushing normal
ice at very low temperatures to produce high
density amorphous ice. After creating
both types, the researchers carefully warmed
the samples, allowing crystals to develop.
Here's where it got even more interesting.
They observed that each sample produced a
different crystal pattern once it warmed.
This was a critical observation. If the ice
had truly been fully amorphous, completely
without any order, it shouldn't have retained
any memory of its earlier form. But
because it did, the scientists concluded that
even space ice, despite its seemingly
shapeless appearance, retains some hidden
structure within. As Professor Christoph
Salzman, a co author of the study, put it,
ice can remember its previous structure. The
order of hydrogen atoms in a crystalline
state can be preserved even as conditions
change. This suggests that space ice is far
more complex than previously thought,
carrying clues about its origin and the
environment in which it formed. These
findings have significant implications,
particularly for theories regarding the
origin of life beyond Earth. One prominent
theory, known as panspermia, suggests that
life's essential ingredients, such as amino
acids, may have arrived on Earth from space,
perhaps carried by comets. This idea
relies on space ice being able to effectively
trap and protect complex molecules during
their long journeys across the cosmos.
However, this new discovery complicates that
idea slightly. As Dr. Davies
explained, our, uh, findings suggest this ice
would be a less good transport material for
these origin of life molecules. That is
because a partly crystalline structure has
less space space in which these ingredients
could become embedded. While this might
weaken the panspermia argument slightly, it
doesn't rule it out entirely. Davies added
that the theory could still hold true, as
there are amorphous regions in the ice where
life's building blocks could be trapped and
stored. Ultimately, these
results provide a more realistic picture of
the conditions life's precursors might
encounter while travelling through the vast
emptiness of space. The implications of this
research extend far beyond just the origin of
life. Amorphous materials are incredibly
common in modern technology. For example, the
glass used in fibre optic cables, which
transmit data across the globe, must remain
in a disordered state for optimal
performance. If these materials contain tiny
hidden crystals that could affect their
performance, understanding how to remove them
could lead to significant advancements and
better technology. Professor Saltzman
also highlighted this, stating,
our results also raise questions about
amorphous materials. In general, these
materials have important uses in much
advanced technology. If they do contain tiny
crystals and we can remove them, this will
improve their performance. Furthermore,
this knowledge could help space agencies
design more effective spacecraft. Ice in
space isn't just a passive substance. It has
the potential to serve as radiation shielding
or even as a source of fuel. If broken down
into hydrogen and oxygen. Knowing more about
its various forms and structural properties
could lead to smarter and more efficient uses
for this vital cosmic resource. As Dr.
Davies noted, ice is potentially a high
performance material in space. It could
shield spacecraft from radiation or provide
fuel in the form of hydrogen and oxygen. So
we need to know about its various forms and
properties.
Next up today, let's take a look at launch
plans. As you well know, we're
constantly looking to the future in space,
and some truly ambitious plans are on the
horizon. Chinese scientists have put forward
a fascinating proposal for the country's very
first ice giant mission. Their goal is to
launch a radioisotope powered spacecraft by
2033, destined to orbit
Neptune and conduct an in depth study of its
mysterious moon Triton. This
mission promises to shed new light on one of
the most distant and least understood worlds
in our solar system. Closer to home, it's
been a bustling period for rocket launches.
Even in what was described as a quiet week
for orbital flights, SpaceX
recently achieved a monumental milestone,
completing the 500th orbital flight of its
workhorse Falcon 9 rocket launchers. This
incredible feat was part of their Starlink
Group 1028 mission, which lifted off from
Cape Canaveral Space force station. The
Falcon 9 has certainly earned its reputation,
celebrating over 15 years since its
inaugural flight in June 2010.
This 500th launch saw Booster
B1077 make its 22nd
flight, a testament to the reusability
pioneered by SpaceX. With the Booster aiming
for its 490th recovery attempt on the drone
ship, a shortfall of gravitas in late
June, SpaceX also set new records with back
to back launches from Florida and California,
marking their 80th and 81st Falcon missions
of the year. They even achieved a new pad
turnaround record of just over 56 hours at
Space Launch Complex 40. This
relentless pace has contributed to a
significant increase in global launch
cadence, with 142 orbital launches
worldwide in the first half of the year, a
16% jump compared to 2024.
Keep an eye out as another Falcon 9 launch is
anticipated soon, possibly carrying the
Israeli Dror 1 communications satellite into
geostationary transfer orbit.
Meanwhile, on the other side of the world,
Australia is gearing up for a historic moment
in its space programme. Gilmour Space
is preparing for the highly anticipated
maiden launch of its Eris small satellite
rocket. This will be their second attempt
after the previous one in May was postponed
due to a power surge that prematurely
triggered the fairing separation system, an
issue that has since been successfully
mitigated. The Eris rocket is set
to lift off from the Bowen Orbital Spaceport
at Abbott Point, making it the first orbital
launch from Australian soil performed by a
sovereign built vehicle. Standing at 25
metres tall and boasting a payload capacity
of up to 215 kilogrammes to a 500
kilometre sun synchron orbit, Eris is
comparable in size and capability to Rocket
Lab's Electron. Its first stage is propelled
by four proprietary Sirius Hybrid engines
which use a unique 3D printed solid fuel
grain and hydrogen peroxide as the
oxidizer. A successful orbital launch would
also mark a significant first for a hybrid
rocket design showcasing a new frontier in
propulsion technology.
Now let's turn our gaze to the night sky,
because July 2025 promises a spectacular
lunar event. The Full Moon, affectionately
known as the Buck Moon, is set to rise on
Wednesday, July 10. This celestial display is
perfect for both seasoned stargazers and
budding astrophotographers. A full
moon occurs when our moon is perfectly
positioned opposite the sun in the sky,
allowing it to appear completely
illuminated from our perspective here on
Earth. The Buck Moon gets its
evocative name from the time of year in North
America when male deer or bucks
are actively growing out their impressive
antlers. It's also sometimes referred to as
the Thunder Moon, a nod to the frequent
summer storms that rumble across parts of the
US In July this year. The Buck
Moon holds another distinction. It arrives
less than a week after Earth reaches
aphelion, its farthest point from the sun in
its orbit, making it the most distant Full
Moon from the sun in 2025. While the
Moon technically reaches its fullest phase at
4:36pm Eastern Daylight Time
or 20:36 GMT on July 10,
it won't be visible to us until it rises
above the southern horizon at sunset in your
local time zone. For instance, if
you're in New York City, you can expect
moonrise around 8:53pm local time.
Remember that exact timings for moon phases
can vary depending on your location, so it's
always a good idea to check a trusted website
like in the sky.org or timeanddate.com for
precise local timings. You might notice
something particularly striking about July's
Full moon. It will appear exceptionally low
in the sky after sunset. This phenomenon is
largely due to its proximity to the summer
solstice, the time when the sun is at its
highest point in the daytime sky.
Consequently, the Moon tracks a
correspondingly low path through the night.
This effect is even more pronounced in 2025
thanks to a fascinating occurrence known as a
major lunar standstill. This happens
approximately every 18.6 years when the
Sun's gravity influences the Moon's tilted
orbit, pushing it to its most extreme
inclination relative to Earth's celestial
equator. This orbital dance causes the Moon
to appear either exceptionally high or, as in
this case, notably low in our sky, depending
on the time of year. As you observe the
Buck Moon, especially in the hours following
moonrise on July 10, you might experience a
common optical illusion, the Moon
illusion. This is when the lunar disc
appears larger than it actually is when it's
positioned close to the horizon. Our
brains, for reasons still debated by
scientists, trick us into thinking it's
bigger than it appears when directly
overhead, even though its actual size in the
night sky remains constant. You might also
notice the Buck Moon take on a beautiful
golden or reddish hue shortly after it rises.
This warm coloration is caused by Rayleigh
scattering, the very same atmospheric effect
that paints our sunsets and sunrises with
vibrant colours. When the moonlight reflected
off the Moon's surface travels through more
of Earth's atmosphere to reach us at the
horizon, the shorter, bluer wavelengths
of light are scattered away, allowing the
longer, redder wavelengths to pass through
more directly beyond the enchanting
display of the Buck Moon. The this month also
marks a significant anniversary in human
spaceflight history. The 56th
anniversary of the Apollo 11 moon landing.
On July 20, 1969, Neil
Armstrong and Buzz Aldrin became the first
humans to walk on the Moon, while Michael
Collins expertly orbited above. To
commemorate this incredible achievement, we
invite you to try and locate the six historic
Apollo era landing sites on on the lunar
surface. With the naked eye, you can
often spot the general region visited by each
Apollo mission, but if you have access to a 6
inch telescope, it will greatly enhance your
viewing experience, helping to reveal finer
details in the rugged moonscapes and smooth
lunar seas surrounding each of these historic
zones. It's a wonderful way to connect with a
pivotal moment in our shared human journey of
exploration.
That's all for this episode of Astronomy
Daily. We hope you enjoyed our journey
through cosmic origins, the secrets of space
ice, and the latest in space exploration and
sky watching. A quick reminder before I log
off Visit Astronomy Daily IO to sign
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podcasts. Until tomorrow, this is Anna
reminding you to keep looking up and
marvelling at our wonderful universe.