Lunar Quakes, Stellar Explosions, and the Mystery of Missing Sulphur

Anna: Welcome back to Astronomy Daily, your go to

podcast for all the latest happenings in our

incredible universe. I'm Anna.

Avery: And I'm Avery. We've got a big episode lined

up for you today, packed with some truly

fascinating cosmic updates.

Anna: That's right, Avery. We'll be diving into new

research about lunar seismic activity

and what moonquakes could mean for future

bases on our nearest celestial neighbour.

Turns out the Moon is a lot shakier than you

might think.

Avery: And speaking of drama, we'll also explore the

explosive end of a massive star that had a

very close encounter with a black hole. It's

a story straight out of a sci fi movie, but

it's real.

Anna: Plus, we're tackling some long standing

cosmic mysteries, from the curious case of

the universe's missing sulphur to

groundbreaking new insights about Vesta, one

of the largest objects in the asteroid belt.

Which might be more than just an.

Avery: Asteroid, but so buckle up because

we're about to take a tour through the latest

and greatest in space and astronomy news.

Anna: Alright, let's kick things off with some big

news about our own Moon. We often think

of it as a quiet, unchanging place, but

new research is challenging that idea,

especially when we consider building long

term bases there.

Avery: That's right, Anna. It turns out our lunar

neighbour is more seismically active than

many might assume. A recent study focusing

on the Lee Lincoln Fault in the Taurus

Littrell Valley, where the Apollo 17

astronauts landed in 1972,

highlights that these moonquakes could pose

significant risks to future permanent lunar

structures.

Anna: This research, led by Smithsonian Senior

Scientist Emeritus Thomas R. Waters,

emphasises that the global distribution of

these young thrust faults and their potential

to still be active needs to be seriously

considered. We're talking about planning

locations and assessing the stability of any

permanent outposts on the Moon.

Avery: And, um, the evidence isn't new. It's based

on moonquakes in the region over the past 90

million years. Much of this evidence comes

from material gathered by the Apollo

astronauts themselves. Things like chunks of

rocks and landslides are silent. But clear

proof of the power of even magnitude

3.0 quakes to shift surface

materials around it really points to the Moon

still being geologically active.

Anna: It makes you wonder, why does the Moon even

have quakes here on Earth? We're very

familiar with earthquakes, primarily caused

by plate tectonics and volcanic activity.

Think of the San Andreas Fault or the Ring of

Fire. Magma movement also causes tremors,

like the recent events in Hawaii and Iceland.

Avery: But the Moon operates differently. Its quakes

are most Likely caused by two main

Earth's tidal pulling and the Moon's

continuous cooling and shrinking. The deep

moonquakes occurring hundreds of miles inside

are due to Earth's gravity pulling on her

satellite.

Anna: And the weaker quakes closer to the surface

are generally attributed to the Moon's

gradual cooling and shrinking. Since its

formation billions of years ago, the Moon has

actually lost about 150ft of

its diameter. There are also minor tremors

from meteoroid impacts or surface rocks

reacting to heating and cooling from the sun.

So it's a world that's constantly shaking.

Avery: When we talk about the risks to future bases,

it becomes quite significant. Short term

missions like the Apollo landings, where

astronauts were on the Moon for less than two

weeks, didn't face much danger. But for

permanent bases, the chances of damage during

a quake go up simply due to the extended

exposure.

Anna: Nicholas Schmer put it into perspective. He

said if astronauts are there for a day,

they'd just have very bad luck. If there was

a damaging event, they. But if you have a

habitat or crewed mission up on the Moon for

a whole decade, that's

3,650 days times 1

in 20 million. Or the risk of a hazardous

moonquake becoming about 1 in 5,500.

Avery: He likened it to, uh, going from the

extremely low odds of winning a lottery

to the much higher odds of being dealt a four

of a kind poker hand. It really illustrates

how much the probability increases over time.

Anna: And it's not just habitats. Countries like

Russia, China and the US are planning to put

nuclear power plants on the Moon. These

facilities would supply massive amounts of

power, but they'd also be susceptible to

quake damage. This means any construction

will need tough safety margins and shouldn't

be located near active fault lines.

Avery: Which is a tall order considering how many

fault lines thread through the Moon. That's

why this study of lunar paleoseismology

looking at evidence of past quakes is so

crucial. It will help us chart the safest

places to build these long term habitats and

power plants. It's all about understanding

our cosmic neighbourhood.

Before we make ourselves at home from

lunar shaking, let's zoom out to something

truly dramatic happening in the cosmos.

Scientists have captured the explosive end of

a massive star in a scenario unlike

anything they've seen before.

Anna: That's right, Avery. This event, more than

700 million light years away, began as

a faint flicker. Within days, the light

flared, faded, and then, surprisingly,

flared again. It was completely

unlike the standard playbook for dying stars.

Avery: What makes this even more incredible is that

an artificial intelligence System flagged the

event in real time. This allowed scientists

to capture every phase of what may be the

first recorded case of a massive star

exploding as it tried to devour a black

hole companion. Talk about cosmic drama.

This supernova, named

SN2023ZKD, was

first spotted in July 2023 by the Zwicky

Transient Facility and then analysed by a

team from the Centre for Astrophysics at

Harvard and Smithsonian mit. Their

findings, published in the Astrophysical

Journal, provide the clearest evidence yet

that such extreme binary interactions can

actually trigger a stellar detonation. It

was part of the Young Supernova Experiment, a

project designed to catch these exploding

stars in their earliest stages. The AI system

gave astronomers a crucial head start,

allowing them to follow the explosion in near

real time from both ground and space

observatories.

Anna: Alexander Agliano, the lead author of

the study, stated that their analysis shows

the blast was sparked by a catastrophic

encounter with a black hole companion,

providing the strongest evidence to date that

such close interactions can indeed

detonate a star.

Avery: The leading explanation is that this massive

star and black hole were locked in a decaying

orbit. As they drew closer, the black hole's

immense gravity pulled gas from the star into

a surrounding disc. This intense stress is

believed to have triggered the explosion

before the star could fully engulf the black

hole.

Anna: Another possibility is that the black hole

completely shredded the star, with the

debris's collisions then powering the

supernova's light. In either scenario,

the aftermath left behind a heavier black

hole.

Avery: What really stood out to astronomers were the

unusual light patterns from Earth.

SN2023ZKD initially

looked like a normal supernova. A single

burst of light followed by a gradual fade.

But then, months later, it did something

truly extraordinary. It brightened again.

Anna: Archival records showed that the system had

actually been slowly brightening for more

than four years before the explosion,

a rare and telling sign of pre death

instability. The analysis revealed that the

supernova's light was shaped by layers of gas

shed by the star in its final years.

Avery: The first brightening came from the blast

wave colliding with diffused gas, while while

that second peak was fueled by a slower

collision with a dense disc shaped cloud.

The structure and timing of these events

strongly point to extreme gravitational

forces from a nearby compact object.

Anna: It's clear that AI played a crucial role

here. As Gagliano mentioned, their machine

Learning system flagged

SN2023SKD months

before its most unusual behaviour, which gave

them ample time to secure the critical

observations needed to unravel this

extraordinary explosion V. Ashley Villar,

Avery: AH co author and assistant professor of

astronomy at cfa, added that this event shows

some of the clearest signs they've seen of a

massive star interacting with the companion

in the years before an explosion. They

believe this might be part of a whole class

of hidden explosions that AI will help them

discover in the future.

Anna: With new observatories like the veracy Rubin

Observatory soon scanning the entire sky

every few nights and projects like the Young

Supernova Experiment continuing to identify

new events quickly, astronomers expect expect

to catch more of these rare and complex

explosions in action. It's truly

a new era for observing the most extreme

cosmic events. That's an incredible story

of cosmic violence and detection.

Now let's shift gears a bit and delve into a

long standing cosmic mystery. The case of

the universe's missing sulphur.

Avery: It sounds like something out of a detective

novel. For years, scientists have been

puzzled because there simply isn't as much

sulphur floating around in deep space as they

expected. This is quite an enigma,

considering Sulphur is the 10th most abundant

element in the universe and crucial for both

planets and life.

Anna: Exactly. But a, uh, new international study

might have finally found its hiding place.

Researchers from the University of

Mississippi, the University of Hawaii at

Manoa and Georgia State University teamed

up to search for answers, publishing their

findings in Nature Communication.

Avery: So where has all the sulphur been? The team's

results suggest that it's not actually

missing at all. Instead, it's locked away in

solid forms, bound within icy grains of

interstellar dust.

Anna: In these frigid environments, sulphur atoms

can arrange themselves in two main

neat eight atom rings called

octasulfur crowns and chains of

sulphur atoms connected by hydrogen, known

as polysulfons. These structures

literally stick to icy dust grains,

essentially freezing the sulphur out of view.

Avery: It's fascinating how a common element on

Earth found in volcanoes and power plants

can be so elusive in space. Ralph

Kaiser, one of the lead researchers,

explained that the observed amount of sulphur

in dense molecular clouds is three orders of

magnitude less than predicted gas phase

abundances. That's a huge difference.

Anna: Astronomers typically identify elements in

space by detecting the unique patterns of

light they emit or absorb. While tools

like James Webb Space Telescope can easily

pick out oxygen, carbon and nitrogen,

sulphur just doesn't follow the rules in the

same way. As researcher uh, Ryan Fortenberry

noted, when you do that for sulphur, it's out

of whack.

Avery: Another challenge is sulfur's shape. Shifting

nature. Fortenberry likened it to a virus

always changing shape as it moves, making it

incredibly difficult to track. But this new

research points to stable molecular forms

that astronomers can now specifically hunt

for using advanced radio telescopes.

Anna: By recreating the conditions of deep space in

laboratory experiments, the researchers

confirmed that these solid sulphur compounds

could indeed form on icy surfaces.

And here's the Once these icy grains are

heated in young star systems, the sulphur can

sublime, meaning it transforms directly from

a solid to a gas, making it finally

detectable from Earth.

Avery: This work could finally help astronomers

piece together sulfur's role in both the

formation of planets and the very chemistry

that supports life. If they can pinpoint

exactly where sulphur is stored, it could

deepen our understanding of how essential

life building elements are distributed across

the cosmos. And, um, even improve models of

planetary atmospheres, especially for

exoplanets.

Anna: It's a perfect example of astrochemistry

forcing hard questions and leading to

creative solutions. As Fortenberry put it,

this kind of foundational research has the

potential for significant unintended positive

consequences for our broader understanding of

the universe.

Avery: That's a great point, Anna.

Speaking of profound insights into how

celestial bodies form, our next story

completely redefines what we thought we knew

about Vesta, one of the largest objects in

the asteroid belt. For years, astronomers

viewed Vesta as almost a miniature version of

Earth, something between a rock in space and

a full fledged planet due to its rocky

surface, distinct layers, and volcanic

history.

Anna: But new research is truly shaking up that

view. Data collected from NASA's dawn

spacecraft, reanalyzed years later,

is rewriting our understanding of how early

planets may have formed and what might have

gone wrong in Vesta's case.

Avery: M the Dante spacecraft orbited Vesta from

2011 to 2012, meticulously

mapping its surface and measuring its

gravity. Initially, this data suggested

Vesta had undergone planetary

differentiation, the process where dense

materials sink to form a core and

lighter materials create a mantle and crust.

The Just like Earth or Mars, Vesta's

volcanic surface seemed to confirm this.

Anna: However, a decade after Dawn's mission ended

in 2018, researchers at NASA's Jet

Propulsion Lab, or JPL, decided to take

a fresh look at the data, using better

calibration and updated processing tools.

And what they found completely challenged

that long held Vesta may not have

a core at all.

Avery: That's a huge revelation. Ryan Park, a

senior research scientist and principal

engineer at jpl, expressed excitement,

saying they were thrilled to confirm the

data's strength in revealing Vesta's deep

interior. By reanalyzing the dawn data,

the team made a more precise estimate of, uh,

Vesta's moment of inertia.

Anna: For those wondering, the moment of inertia is

a physics concept that reveals how mass is

distributed within a rotating body.

Assistant Professor Seth Jacobson of Michigan

State University explained it with a simple

Think of a figure skater. When they pull

their arms in, they spin faster. When they

stretch their arms out, they slow down.

Celestial bodies with dense cores behave like

skaters with their arms in rotating

differently.

Avery: And Vesta's behaviour simply didn't match

what scientists expected from a core bearing

body. Its moment of inertia and calculated

at only 6.6% lower than a

perfectly uniform structure suggests its

internal structure is. Surprisingly, even

this value points to only a mild difference

in density beneath its crust, not the

deep layering we see in fully differentiated

planets.

Anna: This new perspective has forced scientists to

rethink everything they thought they knew

about Vesta's formation. They're now

exploring two main ideas. The first

is that Vesta began to differentiate. Its

insides started to melt and separate into

layers. But something interrupted the

process. This could have been a late start in

forming or limited exposure to heat producing

elements like radioactive aluminium.

Avery: 26 the second theory is even more

dramatic. It suggests Vesta might be the

shattered remnants of a much larger

differentiated planet. That body could have

been destroyed in a massive collision during

the solar system's early years. And Vesta

would then be just one of the reassembled

pieces, essentially chunky space debris of,

uh, a growing world that never quite made

it. Seth Jacobson, who initially

considered this idea a stretch years ago,

now takes it seriously.

Anna: The mystery deepens when you consider Vesta's

meteorites. Researchers have collected

thousands of space rocks on Earth believed to

have come from Vesta. And these meteorites

look like they formed in a molten environment

showing signs of volcanic activity. However,

they don't obviously suggest incomplete

differentiation, which creates a problem for

the first hypothesis of partial melting.

Avery: That's quite the conundrum. The second idea,

where Vesta is a remnant of a larger

destroyed planet, might better explain the

rocks by. But it also raises new questions

about how such a colossal collision would

occur. Jacobson's lab is actively

modelling what those collisions m might have

looked like and how debris like Vesta might

have formed.

Anna: Ultimately, Vesta's internal structure holds

the key to understanding how planets grow

or fail to. For a long time,

Vesta seemed like a textbook

protoplanet, an object that started forming

but didn't quite make it. Now

that picture has become much blurrier.

Avery: Instead of being a failed planet, Vesta might

be something even more intriguing. A, uh,

survivor of cosmic violence. If it

truly is a chunk of a planet destroyed in the

early solar system, it could provide

scientists with invaluable insights into the

collisions and processes that shaped the

worlds we see today.

Anna: As Jacobsen puts it, no longer is the Vesta,

um, meteorite collection a sample of a body

in space that failed to make it as a planet.

These could be pieces of an ancient planet

before it grew to full completion. We just

don't know which planet that is yet.

Avery: This discovery is a powerful reminder that in

science, answers often lead to more

questions. This reanalysis of old

data isn't just changing our understanding of

one asteroid. It could reshape how

researchers think about early planetary

formation across the entire solar system.

Anna: And that's it for this episode. What a

journey we've had today. From the surprising

seismic activity of our moon and the critical

implications for future lunar bases, to the

mind boggling explosion of a star trying to

swallow a block whole, the universe

certainly keeps us on our toes.

Avery: Absolutely, Anna. Uh, and let's not forget

the cosmic mystery of the missing sulphur,

now believed to be hidden in icy dust, uh,

grains. And the groundbreaking reanalysis of

Vesta, which challenges its long held

status as a protoplanet, suggesting it might

be a fragment of a destroyed world.

Anna: It's been a day packed with fascinating

discoveries that push the boundaries of our

understanding.

Avery: Indeed. Thank you for joining us on Astronomy

Daily. We hope you enjoyed diving into the

latest space news with us.

Anna: We look forward to having you back next time

for more amazing insights from across the

cosmos. Until then, keep looking up.

In this episode