How Theia Made Earth Habitable, Surprising Discoveries About Space Ice, and Rocket Launch Updates

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.

In this episode