All language subtitles for The Sky at Night S2025E08 Space Mysteries The Sky at Night Meets Curious Cases 1080p iP WEB-DL AAC2 0 H 264-RAWR[EZTVx.to]

Space.

It's vast, mysterious,

and sometimes just plain weird.

It keeps us up at night
asking the big questions.

Will I be on time? Hmm.

But what is time, anyway?

Where am I even going?

Tonight, we're teaming
up with two other curious minds,

Hannah Fry and Dara O Briain,

to tackle the space mysteries
that have you scratching your head.

So, the main thing about Wolverine
is where do the blades go?

- Yeah, I know, and is he just not
uncomfortable all the time?
- Hi.

- Hello. How are you?
- How are you doing?

- Nice to meet you.
- Hi.
- How are you?
Thanks for having us.

I think we're currently
on your show.

- But then you're really on our
show.
- I see, OK.

- There's more of us, though, aren't
there?
- It's not a democracy.
- Yeah.

Buckle up for a cosmic chat about
the weird,

the wonderful,
and the possibly extraterrestrial.

After you, George.

We had a long discussion earlier as
to whether this was

a Sky at Night meets Curious Cases,

or Curious Cases meets
The Sky at Night.

There was some fisticuffs backstage.
I think you won.

Look at that.

Welcome to The Sky at Night.

Well, hello and welcome to a special
edition of Curious Cases,

where we're going to do things
a little bit differently tonight,

because Dara and I are currently
in the BBC Radio Theatre at London's

Broadcasting House,
and we have an audience.

CHEERING

Look at that!

We are going to tackle quite a few

of your questions on
one single theme, space mysteries.

And to help us out, we have called
on some people

who know their way around
the universe.

The presenters from
The Sky at Night.

Yes, the longest running science
programme in the world,

older than Blue Peter,
Coronation Street and Doctor Who.

68-years-old,
The Sky at Night is now.

Wow, what an amazing guests for this
evening. Welcome to all of you.

Do you know how special
The Sky at Night is, Dara?

They had... They had an asteroid
named after them, after their show.

What was it called, your asteroid?

It's Asteroid 57424 Caelumnoctu,

which is sort of Latin
for The Sky at Night.

But the number was the broadcast
date of the first episode,

and it looks like a dot,
I've seen it in a telescope.

Caelumnoctu, that sounds very fancy,
doesn't it? I looked

- up what Curious Cases would be
if it was in Latin.
- What is it?

It's curiosa casibus.

- I've got one named after me.
- Have you?
- Yeah, I do.

- Am I the only one?
- Trying
to pull rank in the room!

So, yeah, it's Asteroid 4901,

and it's just called O Briain,
which is Latin for Dara O Briain.

AUDIENCE LAUGH

What does yours look like through
a telescope?

Mine is a binary system.

Oh, you're just showing...

I mean, I was kind of forced into
it, but it is very much my brag.

Yeah, it's a really interesting
system.

- There's actually papers about mine.
- OK, well...

I got a pretty good one.

And also, it's not going
to wipe out life on Earth.

And that's kind of... That's
an upside to have.

- Yeah. That's also a flex.
- Yeah.

"Dara O Briain's coming in,

"he's going to wipe out the Earth,"
is not good.

You'd get one really
good week of publicity out of it.

- After that, it's downhill.
- You know,
honestly, I'd be on everything.

Booked on everything.

Graham Norton finally returned
my calls.

OK, over the past few weeks,
we've been asking you to send

in your questions
about space mysteries.

And we're kicking off with Arianne
in Ireland who asked,

"What sound do stars make?" Right.

Big shout out to the literalists
who'll go, "Oh, it's space.

"There's no sound in space."
Like, whatever.

George, why is this a brilliant
question?

It's totally a brilliant question.
Because stars make sounds.

So they have sound waves travelling
through them,

and we actually detect these sound
waves on the surface of stars.

And the field of study of this
is called asteroseismology.

So, yeah, it's really, really cool,

because we can look at
the waves as we detect them,

and it tells us something
about how big a star is

or what it's made of,
or how dense it is.

Unfortunately, though, because of
the vacuum of space,

and all the... Those sound waves
can't travel to us as sound waves.

But, you know, we can detect them
still by looking at the light.

It makes the star wobble.
It makes the starlight wobble.

And do we ever turn those
measurements

into a sound wave we can hear?

Yeah, absolutely. So you just take
any wave and you say,

"This is what it would sound like
if it was a sound wave of the same

"kind of shape and frequency."

So, yeah, sonification of stars is
definitely a thing.

What's also really cool is
that, like, they work...

The stars work really similar
to instruments. So, you know,

like, small stars are like flutes,
and big stars are like trombones.

- Like an orchestra.
- Yeah, exactly.

You've brought
in some space sounds to play for us,

because you've picked
different forms

of intergalactic audio to play
for us.

Maggie, what were you... What did
you bring in?

I wanted to actually go for
something that is actually a sound.

- Yeah.
- And the Cassini-Huygens space
mission was a mission to Saturn,

and Cassini went into
orbit around Saturn,

got some great data, but Huygens
was a little probe,

made by the European Space Agency.

And it actually landed
on this moon, Titan.

And as it actually fell through
the atmosphere,

because there was an atmosphere,

and there was a medium to carry
the sound,

we could actually listen to it.

And I think this is a small section

of the end as it actually sort of
lands.

I am, as always in these situations,
wary of building it up too much.

I know.

- I know, Dara.
- Let's take a moment.

I've not heard this,

but I'm taking a wild guess
that everyone's imagination

is probably imagining

something maybe more majestic than
we're about to play here.

- Come on.
- It's OK.
- Yeah. OK.

So this is the sound of the Huygens
probe landing on Titan.

Manage your expectations, everybody.

WHOOSHING

POP

That was very good.
That was very good.

- Can we turn this into a competitive
thing?
- Ooh.

Giving that a seven out of ten...

All right, George,
what sound did you choose?

So can we hear mine first,

- and then see if you can figure out
what it is?
- Oh.

- Oh, twist.
- OK. OK.

- All right.
- OK. Here it is.

UNDULATING RUMBLE

- Was it a space elephant?
- No.
- Was it a buried choir?

So to me,
that sounds like utter despair.

- Yeah!
- It's not...
- Not an upbeat noise.
- Right?

This is actually a sonification of

a black hole at the centre of
a galaxy cluster.

And so, like, if you can

picture those really cool images
that we have of black holes,

and what they've done is kind
of like swept around

and, like, made the profile of
the wave into a sound.

So this is the sound of kind
of sweeping around a black hole,

and it just sounds like the despair
at the end of the universe.

- Mm-hm.
- I love it.
- Absolutely.
- Yay!
- Yay.

Hey, you know what, George?
Nothing says light entertainment

like the impending death
of falling into a black hole.

So, you know, I'm going
to give you an eight out of ten.

So did I!

LAUGHTER

Damn. Upbeat and cheery never wins!

Sorry. You went
for the kind of big smiler -

- it doesn't work.
- Yeah.
- The actual...

The sense of existential despair
that we got from that was too good.

- Chris, what have you brought?
- Well, I have spared no expense,

and I thought we'd go for the
grandest

and most important sound of all.

So just after the Big Bang,

when the universe was in a hot,
dense state,

there was enough matter around
that you could have

sound waves propagating through
the universe.

And we could still see the effects
of this in something called

the cosmic microwave background,

which is the oldest light of all.

So that means we know
what sound waves were there,

and we can work out
what the spectrum is.

- And so that is the big sound.
- He's built it up.

He's built it up.
Go on, then.

So this is
the whole universe as an instrument.

RUMBLING

- Good, isn't it?
- It's sort of space ASMR.

So the reason it sounds terrible is
that you had

all these frequencies at once.

So the point is, the universe
didn't just have one note playing.

It was all of them.
So you get this sort of white noise.

But that was the whole universe.

- Well, ten for honesty.
- Yeah.

For sound, I think you oversold it.

Do you know the bit on the M25
where it changes from tarmac...

Yes!

- No, I think George wins
that round.
- I think George wins.

Do you agree everybody?
Yeah. There we go!

APPLAUSE

Well obviously we are
not going to do

a show about space mysteries
without talking about aliens.

And this is a question
in from Richard, in Whitley Bay.

Venus and Jupiter are deemed
unsuitable for life.

But aren't there points in the upper
atmospheres where the temperatures

and pressures are similar to
where life is found on Earth?

Could airship drones be sent to look
for exotic, simple forms of life?

So there's two parts to this,
obviously.

George, what exactly are airship
drones,

and why would we be sending them
to Jupiter or Venus?

So airship drones,
think "a balloon" but you can...

They're kind of robotic, and you can
operate them like drones, remotely.

There have been, previously,

kind of balloons dropped through
Venus's atmosphere,

and they want to do it again because
they want to measure what's there.

I think the issue, though, maybe

with sending something like this to
Jupiter,

is that it very rapidly, like...

The pressure gets out of hand.

So, you know, the whole thing would
just...

SHE BLOWS A RASPBERRY

- That's the technical term.
- It is the technical term, yeah.

And I think for Venus,
you've also got to be careful.

There's a lot of sulphur.
It's a bit acidic.

So, yeah, you've got to design
your airship drone pretty carefully.

I mean, you're basically trying

to float a hot-air balloon over
a death planet. That's...

A little bit. Yeah, yeah, yeah.
Little bit, yeah.

So, like, you know, think, like,

weather balloons, but maybe more
high-tech.

There is an exciting history,
though,

of the series of Russian probes
that attempted to land on Venus

with almost hilarious misadventures.

Yeah, they send out one picture
and then they melt.

- Yeah, I think the temperature
pressure...
- Just melts?

Yeah, it's so high.
I think it was 23 minutes

that it survived on the surface.

So one picture...

SHE WHIMPERS

Just melted away
because it's horrendous.

OK. These exotic life forms
that we're...that we're describing.

I mean, what do you think? Do you
think that there could be

some, genuinely, on Venus or
Jupiter, or elsewhere?

There is this layer
in Venus's atmosphere,

which is about room temperature
and pressure.

It's still acidic, as you say.
And that's... What's interesting

is that's the layer that,
our mate Jane Greaves,

a few years ago announced
that she'd found

a chemical called phosphine in.

And phosphine on Earth is made
mostly, frankly, by penguins.

It's a biosignature.

It's made by life.
It's in penguin poo,

amongst other things.

And so the fact
that we found it on Venus,

maybe it's the product of some
volcanism,

or some weird chemical process,

but it could also be life hanging on
in this...

- Venus penguins!
- Venus penguins.
Very, very small Venus penguins.

Venus penguin fart, specifically.

We always talk about life,

but we put conditions of
"life as we know it."

And I think that's the...

Life could be so varied or so
different from what we anticipate.

Just to name drop,

I did have this conversation with
David Attenborough once.

- Sure, sure.
- Yeah, yeah.
- As you do.

Well, you know, Dame, Sir,
I imagine

- you all have dinner together every
week.
- We all stick together.

It was a number of years ago
and I was having a debate.

I feel terrible because I was
having an argument

with our national treasure,

and saying that I don't know
if we actually need water for life.

Life as we know it, yes,
but maybe not...

Maybe life not as we know it.
And so how do you define life?

There might be a whole variety of
life that we just don't anticipate.

I don't want microbes, though.
I want little green men.

Luckily for Hannah, our friends
at BBC Ideas

have been looking
at two approaches to finding them.

- Hello?
- Can you hear us?
- I can hear you.

- Can you hear me?
- Hello?
Is there anybody out there?

Well, that's the question, isn't it?

Has been for as long
as anyone can remember.

Are we alone?

It might sound like science fiction,
but the universe is so vast,

many scientists think
it's unrealistic

to imagine we're
the only form of life in it.

The universe is full
of natural radio waves generated

by stars and planets and galaxies,

but that emission
is really very smooth.

That's Mike Garrett,
an astrophysicist,

an active member of SETI, the Search
for Extraterrestrial Intelligence.

Artificial radio waves
are very spiky

because they convey information.

So we're looking for anomalies,
signature of potentially

other intelligent civilisations out
there broadcasting to the universe.

What SETI assumes is that

the aliens are very motivated,

that they're going out of their way

to send us intentional signals
for our benefit.

And that's Douglas Vakoch,
the founder of METI,

which stands for Messaging
Extraterrestrial Intelligence.

They think listening is not enough.

Maybe we should do the heavy
lifting by reaching out first.

Someone has to make the first move.

Making the first move
in any relationship has its risks.

Opening oneself up to rejection,
or worse.

Stories of alien fleets
visiting Earth

with the sole intention
of wiping us out

are common ground for science
fiction. But there is a theory

that, if we're not careful,
this could become science fact.

I think one of the things
that Stephen Hawking,

famous cosmologist, said
about this idea

of transmitting signals is

that it might not turn out very well
for us here on this planet,

just like it didn't
turn out very well

for the Native Americans
when Columbus first settled there.

But Meti is amongst those

who see this argument
as a red herring.

It's too late to hide.
We're already known in the universe.

Douglas and his colleagues believe

that, through TV
and radio broadcasts,

not to mention mobile phone towers,
Earth has been leaking

radiation into space for decades.

This leakage is exactly

what SETI looked
for as signs of life elsewhere.

So it stands to reason
that, if aliens are listening,

they could probably already hear us.

Though not against communicating
per se,

Mike argues that we need
to think much more carefully about

what we want to say
and how we want to say it.

Who speaks for Earth
and who has the right?

When I see a lot
of these signals being sent,

they don't represent all of
this planet.

You know, just arbitrarily sending

signals out into space
is not very democratic.

The first message sent into space

for the benefit of aliens
was in 1974, more than 50 years ago.

It became known
as the Arecibo message.

And so far we've received nothing
in return.

Which returns us to Enrico Fermi's
question - where is everybody?

There is a conundrum, though, right?
That when we turned on

the opportunity to listen
into space,

it was strange that there wasn't
a cacophony of sounds.

Yes, I think the space age was
a bit of a disappointment.

That we found
that Mars just had craters,

that Venus was this hellhole,
and so on.

And I think people just expected it

to be obvious
that there was life in the cosmos.

And it's not.
But the universe is a big place.

Actually, this is just a tiny sort
of diversion.

Last time I met David Attenborough,
um...

THEY LAUGH

..I was, um... No, no,

because we were both doing
the pre-Christmas,

selling books on radio interviews,

and I had some kids book out
about space. And I...

When he sat down, we're chatting
away, and I said,

"By the way, I should tell you -
the book I've written, yeah?

"It has some stuff
about animals in it."

And Attenborough genuinely
leaned in and went,

"You have planets, I have animals."

LAUGHTER

APPLAUSE

That's good.

Meti will continue reaching out
to those planets

that orbit within what's known
as the Goldilocks Zone.

Not too hot, not too cold,
just right for potential life.

Meanwhile, Mike and SETI will keep
an ear to the sky,

advancing techniques to pick
up signals from other worlds.

And maybe one day, just maybe...

If we detect a signal and we know

that we're not alone
in the universe,

I think
that should make people happy.

If we discover another civilisation
and they're very different from us,

we'll realise, actually, how similar
we are to our neighbours.

Next up, we've got a question
from one of our younger listeners.

See what you make of this.

Hello, my name is Marlon.
I'm 11 and I live in Croydon.

My curious question came to mind

when I was watching a video about
the edge of space,

and I thought,
"What is the edge of space?

"What's it made of
and how can we perceive it?"

Space must have an edge,
if it's expanding, right?

But then how can it be infinite?

- Hmm.
- Deep, deep.
- Yeah.
- Yeah.

- OK.
- Marlon is already the boss
level of this particular....

I know. All right, Maggie, give us,
like,

at least a rope barrier and a
bounce.

- Yes.
- You know what I mean?

- That's what I want.
- The answer is -
we don't know. There. So I think,

because it's trying to understand,
sort of,

the concept of the universe.

And so our current understanding of
the universe

is it began with something called
the Big Bang.

So it's sort of a singularity

expanded out to create space and
time. And so if you ask,

"What is beyond space and time?"

It's a very hard concept to grapple.

We don't know where its limits are.

With things like
the James Webb Space Telescope,

we look at, sort of, light coming
from the early universe,

but we can't go beyond that because

the light won't reach us, if you see
what I mean.

So, yes, we are limited in what we
know and what we can see,

and we interpret that,

but we believe it began and it's
expanding outwards.

Any guesses though, Chris?

Well, we do have this edge to the
observable universe.

So as long
as you're a practical astronomer,

this question is easy to answer,
because the edge of the observable

universe is the bit whose light
is only just reaching us.

So we could see the bit of
the universe which,

in the last 13.8 billion years,

has had time to send us light.

And that's... You can put a line
around that.

If we froze the expansion
of the universe, we could say

what part of the universe that is.
It's a guess.

But the guess is that we live
in this tiny fraction of the whole.

So we've got this little bubble

that we can see, and that has an
edge.

But the whole thing, well,
that could easily be infinite.

And the thing that's impossible
to get your head around,

I think, intuitively, is the idea
that our universe

could have started in this Big Bang,
this point in time,

but it could have been infinite
then,

it could still be infinite now,
and it's expanding ever since.

I don't have an intuitive
answer to it.

- It's just the maths tells us that.
- Wow.

- Great question, unsatisfying answer.
- Yes, I know.

LAUGHTER

We have a lot of cosmological
questions,

a lot of questions about
the shape of the universe.

This one is from Stephen.

When everything was created
in the Big Bang,

it all exploded outward
and is still going.

So why is the universe
not shaped like

a big doughnut with nothing
in the middle?

There's no central point,
presumably.

There's no one central point
that we've pushed away from.

Because I think the idea of
an explosion

is a bit of a misunderstanding.

You have been saying explosion

- for 80 years now. You've been going
about...
- Big Bang.

- Big Bang.
- Rapid expansion,
not explosion.

Because explosion.. Pow!

And, sort of, matter starts here

- and then it's thrown outwards.
- Yeah.

But I think this is sort of
the singularity,

but it expands rapidly,
but it expands outwards.

So it isn't like an explosion,

where all the matter that was there
is thrown outwards,

but it's the matter
itself is expanding outwards.

And so I think, getting... So, then,
it's less likely

to be a sort of a doughnut
or a toroid.

It's more likely to be sort of a
continuum,

but sort of expanding outwards.

But on the name, actually, the BBC
is to blame for the name,

the fact it's called the Big Bang.

In this very building, Fred Hoyle in
1948, I think, who...

Fred Hoyle was the Cambridge
astronomer

who didn't believe in the Big Bang
theory.

And he gave a talk
about modern cosmology on the radio.

and he wanted to disparage it.

So he said, "this Big Bang theory,"

- and the name stuck.
- So it was an insult.

So it was actually named by
the theory's opponent.

So it's his fault. But it's
so memorable, so it stuck.

In the '90s, American Astronomy
magazine got so fed up

of this explosion problem that they
had a competition

for people to suggest other names
for the Big Bang.

- And about...
- Bangy McBangface.

Yeah, yeah, that's what would happen
now.

But 10,000 people wrote in and,

at the end, they had an expert
panel judge them,

and they decided that Big Bang
was the least worst name.

And so Big Bang won.

"Horrendous Space Kablooie" was
second,

which still has the explosion
problem.

- Yes.
- Yeah. So it's not an explosion,
it's a stretching of space,

- and that's how you should think
about it.
- Nonetheless,

a doughnut is different to a sphere
because its curvature is different.

We can estimate the curvature
of space? Is it doughnut-shaped?

Like, there is a theory about this,
right?

Because, like, you know, so,

the four-dimensional fabric of
spacetime

people do actually research,
you know.

"Is it flat? Is it curved?

"And if it's curved, is it like a
saddle? Is it open? Is it closed?"

And some people think that it might
be shaped like a doughnut, a torus,

which would be kind of like, you
know, like going around like that,

which is pretty cool,
because then it means that, like,

as you travel through the universe,

eventually you'd come back
on yourself.

Like if you're inside a video game
and it's like,

you know, you can kind of go
in a loop.

But it's important to say that we
know that, if it's a doughnut,

it's a very big doughnut,

and we live only on a small part of
the doughnut.

- So we're not ruling out the
doughnut?
- We're not.

But we see that the bit of the
universe we can see is pretty flat.

And so, therefore,
for it to be on a doughnut,

we have to only have a tiny bit
the doughnut.

The same way that, if you stood on a
football, you'd notice it was round.

You stand on the earth, you have
to do a bit more work.

If you stand on something a billion
times the size of the Earth,

it's very difficult to tell
that you're on a sphere at all.

And so we know that our universe
appears to be flat.

So you can have these exotic shapes,

your doughnuts or your crumpets,

or whatever it is that you want the
universe to be like.

But we only see a tiny bit of it.

Are we eliminating
what you hinted at there?

That it would be enclosed.

So, I mean, like Chris says,

we can't fully rule it out,
but it's really unlikely.

It looks pretty flat. So, you know,

either the universe really is
so much bigger than

we can even imagine, and everything
that we can see

for billions of light years is only
a tiny bit.

Or it's flat as a pancake. So we
should go for "Pancake Universe."

I really like the idea
that in maybe 100 years' time,

people will be sitting
in this theatre and going,

"Now, they call it a Pancake
Universe because the BBC..."

"It was an insult, actually."

OK, so maybe a doughnut,
maybe a pancake.

Definitely some sort of baked good.
All right.

That is almost all we have time for.

Have we solved anything,
do we think?

- No, no.
- That's astronomy.
- Do we ever?

Do we ever really solve anything?

No. But look, they've been going
for 68 years.

They need to go for another
68, so that's fine by me.

While the cosmos remains mysterious,
the skies never fail to inspire.

So he can't finish up without

Pete taking us through some of
the upcoming sights.

Since the clocks
went back last month,

darkness arrives an hour earlier,

and that gives us some great
opportunities

to enjoy the night sky.

Early evening, we've still got
the stars of summer,

including the Summer Triangle,

which includes the impressive
constellation of Cygnus the Swan.

Now, in the core of Cygnus the Swan,

you've got an asterism
called the Northern Cross.

Later in the evening, you've got

the stars of winter beginning
to appear,

and that also includes
the magnificent

constellation of Orion the Hunter,

which is a great navigational aid.

And from Orion we can find other
constellations,

such as Gemini, the twins.

To find Gemini from Orion,

identify the two brightest stars
in Orion,

Rigel in the bottom right,
and Betelgeuse in the upper left.

Extend the line they make up and
left for twice the distance...

..and you'll arrive at the pair

of stars which represents the heads
of the twins, Castor and Pollux.

Gemini is one of
those unusual constellations

that actually looks like
what it's supposed to represent.

Well, with a bit of imagination,
at least.

From the UK, it gets to its highest
position in the sky

between mid-November and
mid-December,

in the early hours of the morning.

Now, that puts it in a position
which lifts it

well above any turbulent atmosphere,

which you'll find lower down,

which makes it perfect
for stargazing.

Gemini is currently home to the gas
giant Jupiter.

It's easy to find, being the bright,

star-like object located just below
Castor and Pollux,

and there is a treat starting to
come into view.

Due to a Jovian equinox approaching
in December 2026,

Jupiter's moon Callisto
will be seen appearing

to cross Jupiter's disc
for the next two years or so.

A great time to watch is
in the early

hours of the 21st of November,
when you'll be able to see

the shadows of Io and Callisto

crossing Jupiter's disc at
the same time.

Another treat coming at the end of

the year is the Geminid
meteor shower.

As its name suggests,
the shower's radiant is in Gemini,

the radiant being the small area
of sky

that associated meteors appear
to emanate from.

The shower is active between
the eighth and 16th of December,

the peak occurring on the night of
the 13th into the 14th of December.

With the moon passed last quarter,

and 12 hours of night sky darkness,

it has the potential
for a great show this year.

The night sky is something which
all of us can enjoy.

So whether you're just looking
up at beautiful stars above you,

or you're out in the early hours
with a telescope and camera,

I hope you get some
great, clear skies.

As ever, there is an extended
online star guide which

is available on our website,

which is at
www.bbc.co.uk/skyatnight.

We love seeing any images
you've taken.

These are some of the
highlights from

what you've recently sent
in via our Flickr account.

Well, that's all for this
year's series of The Sky at Night.

We've had a fun-packed trip across
the cosmos,

covering everything from
potentially-hazardous asteroids,

to the expanding universe,
and all our

episodes are still available on
the BBC iPlayer.

We'll be back with all the latest
astronomical news

in spring next year but, until then,
happy stargazing and...

..goodnight.