Original subtitles

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

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.

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.

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.