A Star's Violent End, Revolutionary Bioplastics for Mars, and the Fate of the Universe

Anna: Welcome to Astronomy Daily, your ultimate

guide to the latest in space and astronomy

news. I'm Anna, your host and today

we're diving into the groundbreaking visual

evidence of a star's double detonation

demise, shedding new light on cosmic

expansion. Then we'll explore how

revolutionary algae bioplastics could enable

self sustaining habitats on Mars. For all

you skywatchers, I'll share how you can spot

both the International Space Station and and

China's Tiangong Station in the pre dawn sky.

This week. We'll also discuss a new study

suggesting the universe might be headed for a

big crunch in billions of years. And

finally, we'll talk about the largest piece

of Mars ever found on Earth. A massive rock

set for auction and the debate surrounding

it.

It's going to be an exciting journey, so

let's get started. For the first

time ever, astronomers have captured stunning

visual evidence of a star's dramatic exit,

a double detonation that marks its explosive

death. This groundbreaking discovery

centres around a type of stellar explosion

known as a type 1a supernova, which plays an

absolutely crucial role in our understanding

of the universe. These specific supernovas

are not just spectacular cosmic fireworks.

They are vital for accurately measuring the

universe's expansion rate, a topic currently

at the heart of a major cosmological debate.

What's more, type 1A supernovas are also the

primary source of iron found throughout the

cosmos, making their explosion mechanisms a

puzzle astronomers are keen to solve. The

evidence for this twin eruption was found by

scientists studying two concentric rings of

calcium surrounding

SNR0509.67.5,

which is the remnant of a star that met its

explosive end centuries ago. While

astronomers have long theorised that white

dwarfs, the dense husks of dead stars,

typically explode after steadily accumulating

material from a companion star until they

reach a critical mass known as the

Chandrasekhar limit. Hints have suggested

other mechanisms might be at play. Using the

European Southern Observatory's Very Large

Telescope, researchers found those two

distinct calcium rings, which offer clear

proof that white dwarfs can indeed detonate

well before reaching the Chandrasekhar mass

limit. This confirms the existence of the

double detonation mechanism in nature. The

proposed scenario is fascinating. The white

dwarf first blankets itself in stolen helium

from its neighbour. This helium then ignites,

sending a shockwave inward that causes the

dead star's core to ignite in a second, much

larger explosion. Studying these dual

detonations has profound implications,

particularly for how we use type 1A

supernovas as standard candles,

cosmic benchmarks that explode with

consistent Brightness, allowing astronomers

to measure vast distances and calculate the

universe's expansion rate. This tangible

evidence not only helps solve a ah, long

standing mystery, but also offers a truly

visual spectacle revealing the inner workings

of such a dramatic cosmic event.

Moving on, let's head over to Mars. Imagine

building a home on Mars that literally grows

itself. It sounds like something out of

science fiction, but scientists are making

strides towards this very possibility with a

revolutionary new bioplastic derived from

green algae. This innovation could be a game

changer for human missions to other worlds,

tackling the immense challenge and cost of

transporting building materials from Earth.

The concept is elegantly simple. If a

habitat is constructed from this bioplastic

and it can grow algae within its structure,

that algae can then produce even more

bioplastic. This creates a self sustaining

closed loop system that could allow

extraterrestrial settlements to not only

sustain themselves, but also expand over

time. It truly echoes the living

ships seen in sci fi classics like Stargate

Atlantis or Star Trek. In lab

experiments, researchers successfully

recreated the challenging atmospheric

conditions of Mars, where the air pressure is

significantly lower and the atmosphere is

rich in carbon dioxide. Despite these

harsh conditions, a common green algae called

Dunaliella tertiolecta thrived inside

a 3D printed growth chamber made from this

new bioplastic, which is a type of

polylactic acid. The bioplastic

material proved crucial, blocking harmful UV

radiation while still allowing enough light

to penetrate for photosynthesis. Critically,

the chamber also created a pressure gradient

that allowed liquid water to stabilise within

its walls, a key element for life that is

otherwise unstable on the Martian surface.

This research indicates that even on

seemingly barren worlds, organic growth could

be harnessed to construct human habitats.

This builds upon previous work by the same

team, which showed that sheets of silica

aerogels could mimic Earth's greenhouse

effect to enable biological growth on other

planets. Combining these two lines of

research could pave the way for a truly

sustainable human presence beyond Earth. The

next step for the team is to demonstrate that

these bioplastic habitats can be grown in a

vacuum, simulating conditions for missions

to other deep space locations like the Moon.

Beyond the exciting prospects for space

exploration, this kind of biomaterial

technology is expected to have significant

spin off benefits for sustainability here on

Earth, offering innovative solutions for our

own planet's future.

Okay, let's make a quick trip back to Earth.

For skywatchers across most of the US and

southern Canada, and indeed for many in North

America and Europe, there's a fantastic

opportunity this week to witness two of

humanity's largest orbiting outposts within

minutes of each other. I'm talking about the

International Space Station or iss, and

China's Tiangong Space Station. If you're up

during the pre dawn hours, you might even

catch both in the sky at the same time on

certain mornings. It's truly remarkable how

many satellites now orbit Earth, though. Most

of the over 30,700 objects are space

junk, too small to see with the unaided eye.

But there are about 500 that are large enough

and low enough in orbit to be visible. As the

distinguished British scientist Desmond King

Healy once put it, a satellite looks like a

star that has taken leave of its senses and

decided to move off to another part of the

sky. The International Space

Station is by far the biggest and brightest

of these man made objects. Imagine

something almost the length of a football

field, including the end zones. Powered

by solar arrays longer than a Boeing

777's wingspan.

Orbiting at an average altitude of about

416 kilometres and moving at a

staggering 28,800 kilometres per hour,

the ISS completes roughly 15.5

orbits per day. Because of its massive

size and highly reflective solar panels, it

can appear up to two and a half times

brighter than Venus and sometimes even flare

to an incredible magnitude, making it much

brighter than any star. Then there's

Tiangong, China's Heavenly Palace Space

Station. While smaller than the ISS,

about 1/5 the size, it's still a prominent

object in the night sky. It orbits at a

slightly lower altitude of about 393

kilometres and can appear as bright as Venus

or Jupiter on its most favourable passes.

Currently, between the ISS and Tiangong,

there are 14 humans living and working in

space. Now, if you're wondering when and

where to look, it's easier than you might

think. From now through the end of July,

North Americans and Europeans will have

numerous chances to spot both stations,

primarily because nights are shorter,

allowing these low Earth orbit satellites to

remain illuminated by the sun for longer

periods. Since both stations circle

earth roughly every 90 minutes, you might

even catch them on several consecutive

passes. They have slightly different orbital

altitudes and inclinations, which makes

seeing them simultaneously a less common

event. But it is possible to find out the

exact viewing schedule for your specific

location. I highly recommend visiting either

Chris Peet's Heavens above website or NASA's

spot the station. Both are excellent

resources. Heavens above allows you to input

your precise latitude and longitude to

generate accurate sighting data for both the

ISS and Tiangong. NASA's

Spot the Station offers a widget where you

simply enter your location and it provides

details like the time of the flyover, how

long it will be visible, its maximum height

in the sky, and the direction it will appear

and disappear from your view. Just remember

that predictions can change slightly due to

orbital adjustments, so it's a good idea to

check frequently for updates. Happy sky

gazing.

Next up, let's talk about an old, yet

mysterious dark energy

for generations, humanity has looked up at

the stars and pondered the ultimate fate of

our universe. Will it expand forever into the

cold, empty vastness, or is there a more

dramatic end in store? A new study published

by physicists from Cornell University,

Shanghai, Jiao Tong University, and other

institutions suggests we might finally have a

surprising and specific answer. Using data

from several astronomical surveys, including

the Dark Energy Survey and the Dark Energy

Spectroscopic Instrument, researchers have

developed a model that predicts our universe

will meet its end in a big crunch in

approximately 33.3 billion years.

Considering the universe is currently 13.8

billion years old, this gives us roughly 20

billion years before the curtain falls. This

prediction challenges the long held

assumption that the universe will expand

indefinitely. Instead, it suggests that after

reaching its maximum expansion in about 7

billion years, the universe will begin to

contract until everything eventually

collapses back into a single point. The key

to this theory lies in understanding dark

energy, the mysterious force that makes up

about 70% of the universe and drives its

expansion. For a long time, it was assumed

that dark energy behaved like a cosmological

constant, maintaining a steady pressure that

pushed space apart indefinitely. However,

recent observations hint that dark energy

might actually be dynamic. The researchers

propose a model involving an ultralight

particle called an axion, combined with

what's known as a negative cosmological

constant. You can think of it like a massive

rubber band. Initially, the universe expands

as this rubber band stretches, but eventually

the elastic force becomes stronger than the

expansion, causing everything to snap back

together. According to this new model, the

universe will continue expanding, but at a

gradually slowing rate until it reaches its

maximum size, about 69%

larger than today in roughly 7 billion

years. Then gradual contraction

will begin as gravitational forces and

the negative cosmological constant take over,

leading to a rapid collapse in the final

moments. It's important to note that this

prediction comes with significant

uncertainty. The researchers acknowledge

that their model has large margins of error

due to limited observational data, and the

negative cosmological constant that drives

their prediction remains highly speculative.

Alternative scenarios, including eternal

expansion, are still very much on the table.

What makes this research particularly

exciting is isn't just the prediction itself,

but the fact that we may soon be able to test

it. Several m major astronomical

projects Launching in the coming years are

set to provide much more precise measurements

of dark energy's behaviour. These future

observations could potentially confirm,

refine or even rule out the Big Crunch

scenario entirely once and for all.

Even if confirmed, a 20 billion year

countdown hardly constitutes an immediate

crisis for us. To put it in perspective,

complex life on Earth has only existed for

about 600 million years. 20 billion

years represents a time frame so vast that

our sun will have died and our galaxy will

have collided with Andromeda long before any

cosmic collapse even begins.

Nevertheless, this research represents a

remarkable achievement in our understanding

of the cosmos, providing us with a concrete

timeline for what could be the most dramatic

event possible. The end of the universe

itself.

Shifting gears from the vast cosmic scale to

something a little closer to home, or at

least closer to Earth, we have a fascinating

story about a very special rock. The most

massive piece of Mars ever found here on

Earth could soon sell for up to US$4 million

in a Sotheby's auction later this month. This

incredible meteorite, officially named NWA

16788, weighs a staggering

24.67 kilogrammes, or about

54.39 pounds. That makes it

approximately 70% larger than the previous

record holder, another Martian meteorite

found in mali back in 2021.

This massive chunk of Mars was discovered by

a meteorite hunter in November

2023 in the sparsely populated

Agadez region of Niger, an area more

renowned for its dinosaur fossils than its

meteorites. The Shanghai Astronomy

Museum confirmed the rock's Martian identity

after a small sample was sent there. And now

this interplanetary treasure has a

significant price tag. According to the

Sotheby's listing, the meteorite shows

minimal terrestrial weathering, which means

its physical and chemical makeup haven't been

significantly altered since it landed in the

Sahara Desert. In other words,

NWA 16

is likely a relatively recent arrival on

Earth, having fallen from outer space not too

long ago. Its characteristics tell us a

lot about its journey. Based on a high

percentage of a glass called maskelynite,

along with some shock melted areas,

scientists believe this rock was likely sent

hurtling through space when a severe asteroid

crashed into Mars. The Sotheby's listing

further explains that the meteorite was

formed from the slow cooling of Martian magma

and and is characterised by a coarse grained

texture, primarily composed of pyroxene,

masculinite and olivine.

However, the sale of such a rare specimen has

sparked a debate among some scientists.

Palaeontologist Steve Brusot from the

University of Edinburgh expressed concern to

CNN stating that it would be a shame if it

disappeared into the vault of an oligarch,

suggesting it belongs in a museum where it

can be studied and enjoyed by the public. On

the other hand, planetary scientist Julia

Cartwright from the University of Leicester

offered a different perspective, telling CNN

that the scientific interest will remain and

the new owner may be very interested in

learning from it, meaning we could still

gather a lot of science from this unique

find. The Sotheby's auction is scheduled to

begin on July 16th.

That brings us to the end of another

fascinating episode of Astronomy Daily. I

hope you've enjoyed exploring the latest

cosmic revelations with me. From the

explosive end of distant stars and the

potential for life sustaining habitats on

Mars, to the visible wonders of our orbiting

space stations and the grand theories about

the universe's ultimate fate. And

of course, the journey of that very special

Martian rock. It's been a pleasure sharing

these stories with you. Before we sign off, I

want to extend a huge thank you for tuning

in. If you want to catch up on all the latest

space and astronomy news or listen to any of

our previous episodes, be sure to visit our

website at astronomydaily IO. That's

astronomydaily IO. You can

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an episode, I'm Ana, your host, and I look

forward to joining you again tomorrow for

more captivating insights from the universe.

Until then, keep looking up.

In this episode