All language subtitles for BBC.The.Sky.at.Night.2025.Queen.of.Pulsars.1080p.HDTV.x264.AAC.MVGroup.org

Legends are few and far between,

but when you meet one,
it blows your mind,

and they make a real difference
to the whole of society.

Tonight, we're in Oxford
to tell the story

of an extraordinary physicist
who faced challenge after challenge,

yet made a famous discovery

that changed the face
of astronomy forever.

She has been a maverick
in the field, and, in fact,

her discovery actually started
a new subfield in astronomy.

Without Jocelyn, I wouldn't be here.

Welcome to The Sky At Night.

When I arrived in Cambridge,

I felt like a country yokel.

And I thought, "They've made
a mistake, admitting me.

"I'm not bright enough
for this place.

"They're going to discover
their mistake,

"they're going to throw me out.

"But, until they throw me out,
I will work my very hardest,

"so that when they throw me out,
I won't have a guilty conscience."

APPLAUSE

MAGGIE: Professor
Jocelyn Bell Burnell.

She's a discoverer,
an explorer of a distant cosmos,

and she's walked amongst the stars.

But in 1965,
she was just a student

about to start her PhD.

Radio astronomy was still
fairly new at that stage,

so there was a lot going on,

a lot of interesting
stuff happening.

It was an exciting time
to be involved.

Jocelyn's Supervisor,
Professor Antony Hewish,

had grand designs for a new
state-of-the-art radio telescope.

I didn't initially realise how big
a telescope Tony was planning.

At the point I arrived, he had
the money to build the telescope.

I think he had
at least rough designs,

but there was, so to speak,
nothing on the ground.

And when it became clear
it's 57 tennis courts in area,

it's huge,

it took two years to build.

There were about half a dozen
of us working on it.

I was doing quite a lot
of sledgehammering,

became quite strong.

And then we switched it on.

Radio telescopes
often don't work first time,

but this one did.

It worked!

With 120 miles of wiring,

the world's newest radio telescope
was complete.

So I was straight into observing.

And then I had miles and miles
and miles of chart paper

pouring out of chart recorders,

which I would take back
to my desk in Cambridge,

and sit and analyse.

We all use radio waves every day,

and, just as you can
tune your car radio

to hear your favourite music...

I wonder what else is on the radio.
STATION FLIPS

..by tuning a telescope
to the skies,

you can listen to
the universe's greatest hits, too -

if you can tune out the static.

The signals arriving
at Jocelyn's telescope

were buried
in a cacophony of interference.

But, with her sharp memory
and keen eye,

she spotted something
that no-one had before.

It was when I saw
this little bit of scruff

and said, "Oh, yeah, I've seen this
somewhere before, haven't I?"

My data comes out
on long rolls of paper chart,

and I have the previous rolls
stored in boxes.

So I get out the box
that covers this bit of sky.

I was fortunate, in that the grad
students worked in an attic,

and there was
a great, big, long space

down the middle of the attic
between our desks.

So I took over this space
and spread out my charts

for the observations
I'd already made

of that particular strip of sky.

Jocelyn had identified a signal,

measuring just a quarter inch,

in hundreds of feet of data.

Her diligence was about to pay off.

We needed an enlargement.

And, with paper chart,
rolls of paper chart,

the way you get an enlargement is to
run the paper faster under the pen,

and everything gets spread out.
Very neat.

And, right from the start,

as I ran the paper faster
under the pen,

I could see it going
blip, blip, blip, blip.

Always the same beat...

..but one and a third seconds apart,

which is totally unknown
in astronomy.

What the heck is this?

For an astronomer,
the rate of a pulsing signal

indicates the size of the object.

For something astronomical
to produce pulses

every one-and-a-third seconds,

it must be spinning
once every one-and-a-third seconds.

The thought was preposterous.

No object had ever been observed

that could be as powerful,
yet small.

I took the trouble
of phoning my supervisor, and said,

"Tony, it's a string of pulses
one-and-a-third seconds apart."

"Oh. Well, that settles it.

"It's man-made."

And put the phone down.

Artificial or not, what was
causing this strange signal?

So, one of the problems was,
is this some foible of my telescope?

Have I got some wires crossed?

Tony and I spoke to another academic
and his grad student

to see if they could help us.

They had a separate radio telescope,
separate receiver on the same site,

but working on the same frequency,
the same channel.

One day, four of us
went out to the observatory -

Robin and his supervisor,
me and Tony, my supervisor.

And the way the telescopes
were aligned.

my telescope would see it first,

and Robin would see it 20 minutes
later, or something like that.

My telescope observed it.

The thing was pulsing
nice and strong.

It was good and healthy.

And then we went and stood
by Robin's equipment.

And nothing happened.

And Tony and Paul,
the two academics,

started walking down
this long laboratory.

I was padding along behind them,
and they were saying,

"Now, what could it be
that shows in this radio telescope,

"but not that one?
Could it be da-da-da-da-da?"

"No, it can't be that because..."

"Oh. Could it be ba-ba-ba-ba-ba?"

Robin has stayed
by his pen recorder.

We've got down this long laboratory,

and suddenly there's a shriek
from way back there.

"Here it is!"

We all went charging back.

And there were the pulses coming in,
seen by a separate radio telescope

with its own receiver
and its own chart recorder.

Robin had miscalculated
by 15 minutes

when his telescope
would see that bit of sky.

If he'd miscalculated
by an hour and 15 minutes,

we'd have all gone home,

and the story would be different.

Jocelyn had discovered a pulsar.

A zombie.

The leftover core
of a cataclysmic explosion

at the end of a star's life.

One of the most extreme objects
in the universe.

When a star dies,
it sheds its outer layers,

but what remains collapses.

And, like an ice skater
going into a spin,

when an object shrinks,
it spins faster.

The more dramatic the collapse,
the faster the resulting spin.

And it's this spin
that means that pulsars pulse,

that we see regular bursts
of radio waves.

Like Earth,
pulsars have magnetic fields.

Particles are channelled along
the magnetic field lines

and, in the exotic environment
around a pulsar,

they produce jets of radio waves
aligned with each magnetic pole.

Now, the magnetic pole
won't be aligned, typically,

with the rotation axis
of the pulsar.

And what that means is that
we get something like this.

From Earth, we see flashes
of radio waves

as each beam sweeps across us.

A cosmic beacon, a lighthouse
shining out into the darkness.

Jocelyn had opened up
a whole new area of study.

Pulsars are laboratories
for extreme physics -

so extreme that scientists
are still investigating

their secrets to this day.

I've come to Royal Holloway,
University of London,

to meet Dr Vanessa Graber,

to find out
what we know about their guts.

Astronomers usually like to give,

like, names to certain
subclasses of things.

So neutron stars is like
the exact, like, the compact object

that we have outside in space.

And pulsars are
those specific neutron stars

that actually produce
this lighthouse type of radiation.

With incredibly high density. Yes.

So this is really like an object
that's the size of a city

like London, but weighs something
between one to two times

as much as our sun.

And if you think about sort of,
like, the quantities involved,

if you compress the sun, or twice
the sun into the size of a city,

you end up with
really extreme densities

that is something that
we really can't produce on Earth.

Seeing something in space
the size of London is challenging.

SHE LAUGHS
Very, very. Exactly.

I suppose that's why your work
is so important.

Because we're modelling this... Yes.

..because we can't really get up
close and personal to see it.

So, to a first instant,
we can either say,

"OK, look, this is like
a massive fluid ball,"

and then we can write down
a set of equations,

and then we build it up from there.
Yes, yes.

So you have to come up
with some additional, like, ideas

on how you can make this model
more realistic.

And in the case of the neutron star,

what's generally happening is that
we don't just have a fluid ball,

but this fluid interior
is surrounded by a solid crust.

Pulses of radiation
that are emitted from the star

will usually slow down over time.

Sudden changes in this pattern
can give away crucial clues

about the star's interior.

Now, this periodic signal,
I was told that it was

one of the most reliable things
in the universe. Yes, yes.

There's sort of, you know,
this pinpoint precision.

But not always.

Yes, that's true.
THEY CHUCKLE

Which is like, the thing
that my heart beats for, I guess.

SHE LAUGHS
This is your research?

Yeah, this is, like, what I work on,
on a daily basis,

which is, the fact that
some of the neutron stars,

where they spin down -
and this was actually observed

very early on after the first
neutron star was discovered -

is that some neutron stars show
what I like to call hiccups. Mm.

So they don't just spin down,

but there is
this occasional interruption

where the star suddenly
rotates a little bit faster.

By studying the pattern
of the hiccup,

the changing spin,

we can get an insight
into what's happening

inside the heart of the star.

To explain, we'll need the help
of a couple of eggs.

OK, so we have two different eggs,

and we're going to try and do
a little experiment

that you can also try at home.

So we'll start with this one.

And what I'm going to do is,

I'm going to rotate the egg,

and then I'm going to use my finger
to quickly stop the shell.

And then we're going to look
at what's actually happening.

OK. So this is the egg.

I'll stop it...
It stopped rotating. Exactly.

OK, let's try this with this one.

OK, let me try the same thing.

I'll stop the egg with the finger -

and what we see is it does rotate

a little bit more afterwards.

It does.

OK, we do exactly
the same thing for both eggs

and we do see something
very different happening.

Yes, yes! So should we reveal
what's happening?

THEY LAUGH
Or if I could guess? Yes, yeah.

What do you think...?
What do you think is the difference?

So I think one is more fluid
than the other.

Yes, the interior.

This one, I guess, is the raw egg.

Yes. And this is hard boiled?
That's correct. OK.

So in the case of
the hard boiled egg,

basically, the individual
components of the shell,

the egg white and the egg yolk,

are all just connected
as a single component.

So initially, when you spin it up,

everything rotates
at the same speed.

But, in the case of the raw egg,
if I rotate things,

it will take a little while
for the interior

to actually start to rotate,

and then, once it is rotating,
I just stop the shell.

I only stop the shell,

but the interior actually
continues to rotate. Lovely.

And I basically see the exchange
of angular momentum,

very similar to what's
happening in the neutron star,

between the internal component
that rotates faster

and the shell that had stopped.

In the case of the neutron star,

instead of egg white
and yolk inside,

it has exotic forms of matter
that can flow without friction.

A superfluid.

We started talking about
a neutron star being modelled

as like a fluid ball,

but the interactions of
the superfluid itself

are really not driven by
this, like, London-sized object,

but actually by,
like, tiny quantum effects.

So the superfluid
has a special property,

that it rotates in
a very different way

by forming
these tiny quantum tornadoes.

Really looking at the macro...
Exactly. ..and then at the micro,

a-and...well, the nano.

Since the first observation
of a pulsar,

over 4,000 more have been detected.

But Jocelyn was on a path

that would swiftly
take her away from Cambridge,

and away from her pulsars, too.

I got engaged to be married between
discovering pulsars two and three,

and was fool enough to wear
the engagement ring into the office.

I was very proud of it.

And that sent a message
that I was leaving.

Because, in those days,
married women didn't work.

It implied that your husband
couldn't earn enough,

if married women worked.

You were going to be
a housewife, a wife,

and probably a mother in due course.

This wasn't actually my plan,
but I see, with hindsight,

that that's the message
I was sending out.

Once married, Jocelyn's work
was entirely dependent

on her husband's postings.

Husband would say,
"It's time I moved to get promotion.

"There's a job going in X.

"Is there anything astronomical
anywhere near there

"that you might get a job?"

So I've had a
very disrupted career.

It's been great fun, great interest,

but a lot of it's been dictated
by where my husband was working.

CHRIS: Since Jocelyn's discovery,

the radio sky has continued
to surprise.

Dr Kaustubh Rajwade,
at the University of Oxford,

studies the oddballs
of the radio family,

and what these outsiders
can tell us about the cosmos.

Hey, how are you? Ah, hey, Chris.
Nice to see you. Yeah, you, too.

Now, look, you like to look
for weird things in the radio sky.

What have you found?

Over the past few decades,
we have found

all sorts of
unusual neutron stars.

Back in 2007, I mean,
people at that point

were looking for pulsars in data

taken by all these radio telescopes
around the world.

And often looking in archival data,
as well. Yeah, absolutely.

In West Virginia University,

Duncan Lorimer,
who's a professor there,

and his undergraduate student,
Dave Narkevic,

they were searching through
some of this data

taken by the Miryang
Radio Telescope in Australia,

looking for pulsars
in the Small Magellanic Cloud.

OK, our neighbouring galaxy, yeah.

Yeah, and so,
while going through the data,

Dave actually found this very
interesting single radio burst.

So not a repeat? Not like a pulsar,
where you get all these pulses?

Just one? Just one.

And, interestingly,
they realised that this burst

could not have come from our galaxy,
and also not from the SMC... Mm.

..but way beyond that.

And the reason
that they could figure this out

was because of something called
the dispersion of radio waves.

So, as you know, there's
a lot of stuff between pulsars

in our galaxy and us, right?
Mm-hm.

There are these electrons
and plasma that's floating around.

And so this plasma actually
acts like a prism. Mm.

And so, which means that the radio
waves that are at lower frequencies

are reaching us much later than
the radio waves at higher frequency.

Oh, just like... Cos a prism
would bend blue light differently

from red light, because of the
difference in wavelength? Exactly.

Which is the same as difference
in frequency. Exactly. OK.

We now know these objects as FRBs,
or fast radio bursts.

A blast of radiation that,
for a few milliseconds,

can outshine an entire galaxy.

What do they tell us about
the universe and the galaxy

to which their light travels?
Yeah, I'm glad you asked that,

because we can use them
as independent probes of cosmology.

And one of the key aspects
in which FRBs can help

is this so-called
missing baryons problem.

Baryons, is this just normal matter?

Electrons, protons, oxygen,
hydrogen, helium,

all the rest of it? Exactly, yeah.
Yeah, yeah, yeah.

Some of it, we can see.

Light is our only source
of actually detecting and seeing

these baryons in the universe,
but a lot of it is so diffuse

that we just cannot see it
at any wavelength,

like, they're not emitting
any radiation.

But, because FRBs are so fast,
and only last for millisecond,

which means that you can see
dispersion in them,

and then you know that
the total delay that you see

in your radio band,
because of the dispersion,

has contributions from your galaxy,

has contributions
from the host galaxy,

but it also has contribution
from the diffuse baryons

in the cosmic web.

It's really rather lovely that
the light from something like an FRB

tells us about everything
it's passed through. Exactly.

And you're literally
weighing up the universe. Yeah.

So if you have enough FRBs
that are well-localised

with well-known distances,
all across the sky,

you could map out the cosmic web.
Oh, so you just...?

And that's just,
I think that that thought,

like, really, you know,
gives me, like, shivers.

With the work of physicists
like Vanessa and Kaustubh,

Jocelyn's legacy is strong today.

But, in the wake of her discovery,
she endured shocking discrimination.

So journalists would interview
Tony and I together, ultimately,

and they'd ask Tony about
the scientific significance

of this experience.

And then they'd turn to me
for the sexual content.

How many boyfriends did I have?

What were my bust, waist,
and hip measurements?

Really important questions
like that.

And the photographer, similarly,

"Could I undo
some shirt buttons, please?"

It was thoroughly degrading.

Young women were sex objects,
full stop.

Never mind if you'd made
a major scientific discovery,

you're a sex object.

Tony did nothing...

..absolutely nothing to stop it.

Jocelyn's treatment would extend

to the most prestigious accolade
in all of academia.

It was 1974, and I remember
the day very well.

I was working in X-ray astronomy
by then.

This particular day, our satellite
has launched 8am in the morning.

And, about two minutes past midday,

a colleague comes bursting
into my office.

"Have you heard the news?
Have you heard the news?"

I thought, "Oh, my God.

"The satellite's gone in the drink."

But it wasn't.

It was the announcement of
the Nobel Prize award

to Tony Hewish and Martin Ryle,

my former supervisor
and the head of the group.

Well, in essence, it's...

Cambridge's Martin Ryle and
Tony Hewish had won the Nobel Prize

for their pioneering research
in radio astrophysics -

Ryle for his observations
and inventions,

and Hewish for his decisive role
in the discovery of pulsars...

..while Jocelyn, despite being
integral to that work,

missed out on the acclaim.

At the time of the Nobel Prize,

women still weren't regarded
as serious in the male world.

It's really only in more recent
years that women are recognised

in their own right
for their own abilities.

Thank goodness.

If you have a group of people
that all think the same,

it's great fun for them,
and they do good work.

But they fail to see
anything out in the wings.

Whereas, if you have
a diverse group,

you're more likely
to pick up on the new threads.

APPLAUSE

Jocelyn has since won
numerous awards for her work,

donating prize money to fund
the Bell Burnell Scholarship.

PhD student Aida Seye,

from the Mullard Space
Science Laboratory,

is a current recipient.

Hello, Aida. Hi. Great to meet you.
So nice to meet you. Same.

I gather you're at MSSL?
Yes, I am, yeah.

Yeah. Wonderful place.
Yeah, thank you.

I worked there for a while.

Yeah, I've heard
we're on the same office.

Really? On the first floor, yeah.
That's right. Yeah.

I had the desk in the window,
looking out over the front door.

Yeah. Could see all
the comings and goings.

Yeah. So, exactly what are
you working on, Aida?

What's your thesis
going to be about?

So just trying to make
the most out of the data

from the Gaia satellite... Right.

..which was launched
a few years back... Yes.

..and has been quite remarkable
with galactic astronomy. Yeah.

So just trying to use that data

to understand
the structure of the Milky Way,

understanding where
the spiral arms are,

the different populations... Yeah.
..and the bulge and kinematics,

and, yeah, just trying to understand
the history of our galaxy.

It's quite complicated to do that,
because we live inside it. Yeah.

If it was another galaxy
that you could look at...

Yeah. ..it'd be a lot simpler.
It would be simpler, yeah.

So have you always wanted
to do astrophysics?

Or has it been
quite a journey for you?

It has been a journey, I feel
almost like a serendipity thing.

I liked maths in primary school
and secondary school. Good.

I liked solving equations
and doing algebra,

and astrophysics
just sounded cool to me,

and I just wanted to try it. Yeah.

And I tried it, and I fell in love.
And here we are.

Yeah, that's fantastic.

Well, thanks, also,
thanks for the scholarship.

So, what prompted you to do that?

Well, I was awarded $3 million US
by the Breakthrough Foundation,

and had to think rather rapidly
what to do with that money.

Because, if it's announced,
you've got that kind of thing,

the phone keeps ringing.
THEY CHUCKLE

So that's when I decided
to give the money

to the Institute of Physics
to set up these scholarships -

you've got one, congratulations -

to enable people
from minority groups,

minority in physics groups -
which includes all women -

to do PhDs.

Yeah. It has helped me, so... Good.
THEY CHUCKLE

I did my PhD in Cambridge.

I'd never been
that far south before,

and it was really scary.

There was all these young men
walking in the streets,

talking in terribly loud voices
about what Hegel said,

and what Hegel didn't say.

I thought, "Oh, my God.

"They've made a mistake
admitting me."

And there were very few women
in Cambridge at that time, as well.

I really suffered
what's known as impostor syndrome.

I don't know,
has that ever affected you?

Because you're also
a minority person in another way.

I also went to University
of Cambridge for... Right.

And definitely,
the impostor syndrome was,

yeah, it was off the charts.

Because there's not many women
doing physics.

There's also not many people
of colour doing physics.

I feel like I'm representing,

so, like, every person of colour,
or every woman,

that I have to do it so well,
because if I, you know...

If I don't do well, then it's going
to reflect badly on them. Yes.

So, it...
Yeah, it doesn't feel nice.

But, at the same time, it is a...

It's a great source of motivation,

to try and, you know,
be as good as possible.

I always felt that,
if I did something stupid,

they'd say, "Oh, trust a woman.
No more women," you know? Yeah.

I guess any minority
is under pressure. Yeah.

Yeah. Pressure not to
let the side down.

The more of us there are,
the easier it gets.

So, please, hang in there.
Don't give up.

Yeah, I won't. Yeah. Good.

MAGGIE: If you're feeling inspired

to do some of your own
astronomical exploring this month,

then Pete has got you covered.

Over the coming months, there are
three phenomena which give us

a perfect opportunity
to do a refresher on terminology

which astronomers
may meet quite often -

occultations, conjunctions,
and eclipses.

A conjunction is a term which
describes when two or more objects,

which are normally
vast distances apart,

appear in the same area
of sky together.

Or, if you want to get technical,
it's when those objects share

the same set of
celestial coordinates.

To see Venus and Jupiter
at conjunction,

look towards the north-east
horizon around 02:40am

on the morning of
the 12th of August.

While the two planets
are really located

hundreds of millions of miles apart,

their positioning makes them
appear close together,

about two full moon's widths
from each other in the night sky.

You can spot them again at the
same time on subsequent mornings,

with the gap between them
increasing.

Next, we have occultations,

and these occur when one object
moves in front of another,

hiding all or part of
the more distant object from view.

The upcoming occultation of Venus

will take place during the day
on Friday, the 19th of September.

You can find Venus
low above the eastern horizon,

with the moon in brightening
dawn twilight around 06:30.

The occultation will take place
between 12:45 and 14:10,

so early afternoon.

Please take care and use
the correct protection

when viewing through binoculars
or a telescope,

as you can cause permanent damage
to your eyes

if you look at the sun
through a lens.

Finally, in our trio of terminology,
we have eclipses.

The term eclipse means
"to obscure" -

so, like occultations,
it's one object hiding another.

But typically with eclipses,

we talk about one body
casting its shadow onto another.

A UK lunar eclipse is coming up
on the 7th of September,

but it will be a tricky one to spot.

As the moon rises above
the eastern horizon

around 8pm,
it will be coming out

of its total eclipse -

so look out
for a dark moon

as it starts to appear.

Once it has reached
a few degrees

above the horizon,

you'll see it
forming an odd shape

as it exits totality.

The main part of
the eclipse

ends around 9pm.

As the summer comes to an end,

and the longer and darker nights
come in,

there are plenty more events
involving the planets and stars

to look out for.

And you can find out more
in our detailed star guides

available on our website at...

You can also find out details
of our Flickr account there.

And if you take any photographs,
you can upload them,

and you never know -
they might appear on the programme.

Here are some of
our recent favourites.

One of the things
I have learnt is,

if you don't get a Nobel Prize,

you get every other prize
that moves.

Whereas if you do get a Nobel Prize,
nobody feels they can match it,

so you don't get anything else.

So I've had parties almost
every year for different prizes.

Fantastic.

It's amazing to think that

what started as nothing more than
a blip on chart paper

became the constellation
of exotic objects

that astronomers study today -

all thanks to the fabulous,
indefatigable, marvellous

Professor Jocelyn Bell Burnell.

Before we go, we're excited to
announce that we're joining forces

with the hit Radio 4 series
Curious Cases

in a special programme solving
space mysteries sent in by you.

Submit your space mystery
questions to...

Goodnight.