Making Water on the Moon, The Hubble Bubble Hypothesis, and Neptune's Unique Orbital Partner

Anna: Welcome to Astronomy Daily, your daily dose

of cosmic curiosities and stellar stories.

I'm your host, Anna, and I'm thrilled to have

you join us for another exciting journey

through the universe. Today, we're diving

into some fascinating breakthroughs. We'll

explore how new technology might allow us to

make water and fuel right on the moon,

potentially changing the future of lunar

exploration. We'll also ponder an intriguing

theory that suggests our entire galaxy might

be floating inside a massive cosmic void.

A Hubble bubble, if you. Which could reshape

our understanding of the universe's

expansion. And for those who love to look up,

we'll guide you on how to best catch an

upcoming celestial spectacle. The Southern

Delta Aquarian meteor shower. Plus, we've got

a quirky tale about a newly discovered space

rock doing a strange orbital dance with

Neptune. So buckle up because there's a lot

to unpack in today's episode.

First up, let's talk about something that

could truly revolutionise our future in

space. Making essential resources

directly on the moon. Imagine if

astronauts didn't have to haul every drop of

water or every breath of oxygen from Earth.

Well, a team of researchers from China is

working to make that a reality, developing a

new technology that they say could produce

water, oxygen and even fuel from lunar

soil. This is a game changer because shipping

just one litre of water to the moon currently

costs a staggering 33,000 Australian

dollars, which is roughly

US$22,000. So

finding ways to use the moon's own resources

will be absolutely critical if humanity

is going to return there and establish

temporary or even long term habitats.

The new approach uses what's called

photothermal technology, detailed in a paper

published in the journal Joule. Lunar soil

isn't just inert dust. It actually holds

stores of carbon dioxide and water, along

with other minerals that could be incredibly

useful for space mission crews. The real

puzzle has always been how to extract these

molecules efficiently on the moon's surface.

As co author Lu Wang from the Chinese

University of Hong Kong, Shenzhen, put it,

they never fully imagined the magic that the

lunar soil possessed. Wang's team had

previously analysed lunar soil samples

brought back by China's Chang's five

spacecraft, discovering that moon dust indeed

contains many useful compounds. Their latest

research builds on this, showing it's

possible to extract water from lunar soil.

But it gets even more exciting. They can then

use that extracted water and the carbon

dioxide exhaled by astronauts

to produce hydrogen gas and carbon monoxide.

These products in turn can be used to create

fuel and breathable oxygen. All

that's needed to power this remarkable

process is the photothermal technology,

which efficiently converts sun sunlight into

heat. The team was particularly

surprised by the tangible success of this

integrated method. They found that

combining lunar water extraction with

photothermal carbon dioxide catalysis could

significantly enhance energy utilisation

and reduce the cost and complexity of

developing the necessary infrastructure on

the Moon. It's a truly ingenious closed loop

system. Now, while these lab experiments are

a huge step forward, the researchers are also

very realistic about the challenges ahead.

They remind us that the Moon's extreme

environment poses unique hurdles for

implementing this technology. We're talking

about drastic temperature fluctuations, an

ultra high vacuum, intense solar radiation

and low gravity. All of these factors

complicate things considerably. Furthermore,

lunar soil doesn't have a uniform composition

across the Moon's surface. Some areas will

naturally be richer in resources than others.

And even with this innovative system, the

carbon dioxide exhaled by astronauts might

not be enough to meet all the water, fuel and

oxygen needs for a larger base.

Overcoming these technical hurdles, along

with the significant development, deployment

and operational costs, will be crucial to

making sustainable lunar resource utilisation

and space exploration a widespread reality.

But but it's certainly a very promising start

from the possibility of making our own

resources on the Moon.

Let's zoom out to a much grander scale.

Remember how they were theorising that we

might be living inside a black hole? Well, we

have a new theory to ponder with an

intriguing Are we here on Earth

and our entire Milky Way galaxy actually

trapped inside a giant cosmic void?

This fascinating theory, based on echoes from

the Big Bang, suggests exactly that.

Researchers presenting at the Royal

Astronomical Society National Astronomy

meeting unveiled fresh evidence that our

galaxy is suspended within a region of space

that is less dense than the cosmic average.

This vast 2 billion light year expanse has

been dubbed the Hubble Bubble and it's

estimated to be about 20% less dense than the

average matter density across the universe.

If this idea holds true, it it could provide

a much needed solution to a persistent

mystery in cosmology known as the Hubble

Tension. This tension arises from

conflicting measurements of the universe's

expansion rate, which also impacts our

understanding of its true age. One

method based on analysing the cosmic

microwave backgroundessentially. Cosmic

fossils from the universe's first light

suggests an expansion rate of 67 kilometres

per second per megaparsec. However,

a second method which measures distances

using Type Ia supernovas and variable stars

indicates a higher expansion rate of

73.2 kilometres per second per

megaparsec. That's a noticeable discrepancy

The Hubble bubble theory posits that if the

Milky Way is indeed situated within such a

less dense region, then the local expansion

inside this void would naturally appear

faster than in the denser, more distant parts

of the cosmos. Indranil Banik, the

study's lead author, explained that a large

local void would cause matter to be pulled by

gravity towards its higher density exterior,

making the void emptier over time. This

effect would accelerate local expansion. For

this theory to work, our galaxy would need to

be located quite close to the centre of this

low density Hubble bubble.

Bannock and his team used data from baryon

acoustic oscillations, the sounds of the Big

Bang, to support previous research from the

1990s that had already noted fewer

galaxies in our local universe than expected.

These ancient sound waves, frozen in place

when the universe cooled, act like a standard

ruler that allows astronomers to chart cosmic

expansion history. What's truly striking

is that their research found it's 100 times

more likely that we live in a cosmic void

than than in a region of average density.

This suggests we might be in a very unique

cosmic neighbourhood. The next steps for

Banik and his team will involve comparing

their void model to other cosmological

models and exploring potential adjustments

to the standard model of cosmology.

It's, uh, a truly mind bending concept that

could redefine our place in the universe

from the vastness of the cosmos and potential

cosmic voids.

Let's bring our focus a little closer to

home. Though still quite far out in our own

solar system, astronomers have recently made

an incredibly intriguing discovery. A

peculiar space rock at the very edge of our

solar system is locked in a fascinating

rhythmic dance with Neptune. This Object,

officially designated 2020 VN40,

belongs to a group of distant solar system

bodies known as Trans neptunian objects, or

TNOs. What makes 2020

VN40 so special is that it's the very first

object ever found that orbits the sun exactly

once for every 10 orbits Neptune completes.

Considering that one Neptunian year stretches

across a remarkable 164.8

Earth years, this means 2020

VN40 has an incredibly long year,

lasting approximately 1,648

Earth years, or nearly 20,000 Earth months.

Researchers believe this slow ponderous

orbital dance with Neptune might have begun

when the ice giant's gravity temporarily

snared it. This discovery is a significant

step in understanding the dynamics of objects

at the solar system's fringe. As

Rosemary pike from the Centre for

Astrophysics at Harvard and Smithsonian

noted, it shows that Even very distant

regions influenced by Neptune can contain

objects. And it gives us new clues about how

the solar system evolved. The unique

orbital rhythm of 2020 VN40

was unearthed from data collected by the

Large Inclination distant objects, or LIDO

survey. This survey specifically hunts for

TNOs with orbits that carry them far above

and below the main orbital plane of Earth

around the Sun. Exploring previously

uncharted areas of our solar system, what

truly sets 2020 VN4.0 apart is

its unusual perihelion alignment with

Neptune. Most other bodies in rhythmic

alignment with Neptune make their closest

approaches to the sun when Neptune is at its

farthest. But 2020 VN4.0

defies this trend, reaching its perihelion

when Neptune is also relatively close to the

Sun. While this might sound like they're side

by side, 2020

VN4.0's highly tilted path means it's

actually far below the solar system's plane

during this alignment. This new motion,

as Ruth Murray Clay from the University of

California, Santa Cruz described it, is

like finding a hidden rhythm in a song we

thought we knew. It suggests that objects

with highly tilted orbits can adopt novel and

unexpected types of, um, movement, revealing

more complexity in our solar system than

previously imagined. The hunt is now on for

more bodies like 2020 VN4.0, with the

new Vera C. Rubin Observatory poised to play

a crucial role in this exciting

investigation. This discovery truly opens a

new window into the solar system's past.

And now for something you can enjoy right

here on Earth, if you know where to look.

The 2025 Southern Delta Aquariad meteor

shower is upon us, with its peak expected on

July 29. This annual shower is

active from July 18 to August 12 as

our planet drifts through an ancient trail of

debris. This debris is thought to have been

shed by a 4 mile wide comet named

96PMachholz. When these tiny

particles hit Earth's atmosphere, the

friction makes them ignite, creating those

beautiful streaks of light we call shooting

stars. The shower is at its strongest in the

week around its July 29 peak, when you

might spot up to eight faint meteors per

hour. These shooting stars will appear to

emanate from a specific patch of sky known as

a radiant within the constellation Aquarius,

very close to the bright star Delta Aquarii,

which gives the shower its name. For the

best chance to spot a southern Delta

Aquariad, aim for the early morning hours in

the week surrounding July 29th. During

this time, the radiant will be highest in the

southern sky, and the waxing crescent Moon

will be well below the horizon, ensuring a

dark canvas for your meteor hunt. As its name

suggests, this shower is most visible to

stargazers in the southern hemisphere, where

the radiant will be higher in the post sunset

sky. However, don't despair if you're north

of the equator, the shower will still be

visible just at a slightly lower hourly rate.

To maximise your chances, first locate the

bright star Delta Aquarii in the

constellation Aquarius above the southern

horizon, or use a stargazing app to guide

you. Then find a patch of sky about

40 degrees away from this radiant in the

direction directly above your head. As a

handy guide, the width of your outstretched

fist, from your thumb to the outside of your

little finger, covers about 10 degrees in the

night sky. Meteors seen further from

the radiant wheel often have longer trails,

making them easier to spot. You'll also have

a much better chance if you head away from

city lights and give your eyes about 30

minutes to fully adapt to the darkness.

After that, simply lie back, perhaps in a

comfortable deck chair, and lose yourself in

the night sky. Keep an eye out for bright

meteors streaking across the sky from the

north too. If you see one, you might have

spotted a member of the Perseid meteor

shower, which is also active since mid July.

Happy stargazing? And that

brings us to the end of another fascinating

journey through the cosmos. Today we've

explored the innovative possibilities of

extracting water and fuel from lunar soil,

pondered whether our Milky Way galaxy is

truly nestled within a vast cosmic void,

and discovered a new, intriguing dance

partner for Neptune in the outer solar

system. And of course, we learned how to

catch a glimpse of the beautiful southern

Delta Aquarid meteor shower. Thank you

for joining me, Anna, on Astronomy Daily.

Don't forget, you can dive deeper into all

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In this episode