Horizon

'Emergency, which service?'

'Police. My husband's been attacked.'

'There's still deadlock tonight between the United States and Iran

'over the 60 American hostages held in their embassy in Tehran.

'But the Muslim students did...'

For decades, some have suspected there might be others out there.

Beings capable of communicating with us,

even visiting our world.

It might sound like science fiction,

but today, scientists from across the globe are scouring the universe

for signs of extraterrestrial intelligence.

My students showed me this signal that was so bright

and apparently so far away

that it was unlike anything we've ever seen before.

Then we realised this is just impossible,

unless a civilisation is way more advanced than we are.

A Kardashev Type II civilisation

would need to build a massive network of solar collectors

that would orbit their star in space.

Something we call a Dyson sphere or a Dyson structure.

Some scientists believe advanced aliens really could exist.

About 10,000 detectable civilisations

at present in our galaxy, the Milky Way.

And yet, no solid evidence has ever been found.

But recent discoveries mean that could all be about to change.

The data for the star looked nothing like any other star

that we know of today.

And so at last we might be close to answering the question

of whether we are alone in the universe.

One day my father happened to tell me, there are other worlds in space.

And, to an eight-year-old kid,

I thought that meant worlds just like mine.

Just like the Earth, creatures just like myself and I wondered,

what are they like? Are they really like that, or are they different?

And I've wondered those same questions my whole life.

The universe is thought to contain 700 million trillion rocky planets

like our own.

Countless worlds other intelligent beings might call home.

And yet, in more than 50 years of searching,

we're yet to find them.

The deafening lack of any communication from extraterrestrials

has become known as "the great silence".

Oh, I believe very strongly that they're out there.

The numbers support that.

There's so many stars in the universe,

numbers that are so large they make no sense to us.

We can be very, very wrong and yet there will be

many, many detectable civilisations.

We met in Arecibo in Puerto Rico.

There's a large radio telescope there.

I used to work at the observatory as a staff scientist

and you were a grad student at Cornell,

and they used to send their students down from Cornell.

We met at the observatory in the control room.

Husband and wife Duncan Lorimer and Maura McLaughlin

share a passion for astronomy.

Boys, it's breakfast time!

I was never, you know, the type of kid, when I was really young,

that was super into astronomy.

I still don't know, like, a single constellation.

But when I was sort of 10, 11, 12, I started reading science fiction.

So when I went to college I decided to take astronomy classes.

I still wasn't sure what I wanted to do,

but then I did research with a professor at Penn State

that took me down to Arecibo and I observed pulsars.

I was just so excited,

and I just really enjoyed doing that and I thought,

"OK, I think this is what I want to do",

and I've just stuck with it ever since.

Nice day! Yeah.

What do you have today?

Gym. Gym.

I got into astronomy in a different way to Maura, I guess.

I've always been fascinated with the night sky.

When I was about 16, taking my A-levels,

my physics teacher saw that myself and a few other students

were interested in astronomy and said,

"Here's the key to the school telescope. Go and fix it up."

And it was this old telescope, this early 1900s telescope,

and it had lots of things,

lots of moving parts that were fascinating to us

and we got the telescope going

and we took a picture of a lunar eclipse,

and we started a little astronomy club at school

and I went to college after that and heard about neutron stars,

and once I found out about those, I knew that's what I wanted to study.

I would have had nothing to do with him

if I'd met him like 30 years ago.

Yes. That would have been it.

Oh!

We work here in the Department of Physics and Astronomy.

We're next-door neighbours, aren't we?

Yeah, our offices are right next door

and it's typically really useful.

We can just, you know, pop in and out, so it saves us a lot of time.

See you. All right, then. Have a good day. You, too.

Occasionally we have disputes.

I'm in control of the temperature in both offices,

and so I like it really warm, and Duncan likes it a lot colder.

So we have occasional arguments, but generally it's really useful

being right next to each other.

Sometimes you bang your feet on the wall

and I have to tell you to stop.

But generally it's really nice.

It's good. We like it.

In the summer of 2006,

Duncan and Maura began a project searching historical data

for the Park's radio telescope.

So we'd just arrived at West Virginia University.

We wanted to find some data that already existed to get working

on a project straightaway.

So we kind of like bandied around some ideas for good projects,

and one of the things we thought of was re-analysing the data

from an old survey taken, like, in the late 1990s,

of the small Magellanic cloud and this large Magellanic cloud,

to look for pulsars that had been missed before.

The project involved painstakingly searching hundreds of data plots,

work Duncan delegated to student.

Every week my student would come to me with the results of his analysis

from the previous week,

and sometimes those would be known pulsars,

sometimes we would see sources of interference or just noise.

But one week, I remember it very clearly,

he came to me and showed me this plot with a signal

that was so bright and apparently so far away

that it was completely unlike anything we'd ever seen before.

So this is the plot that my student David brought to me,

and you can see straightaway this is the pulse that he found.

This big dark feature here.

This is a graph of telescope time along the horizontal axis,

so this is almost two hours of observation here.

And on the vertical axis is basically distance.

You can see the background of noise from the telescope and the sky,

these little dots here.

So this feature really stands out

because it's so bright and so far up the plot here,

which indicates that it's a bright source that's very, very far away.

Quite frankly, it was unlike anything I'd ever seen before.

Yet, it had all the hallmarks of a signal

that was coming from deep space.

The signal, or "fast radio burst" Duncan had discovered

became affectionately known as the "Lorimer Burst".

When people started calling it the Lorimer Burst,

at first I just chuckled.

Because it seemed just so funny

to have something actually named after Dunc,

and it was even funnier when people didn't realise I was married to him,

we have different last names, so I got lots of questions,

like, "What do you think about the Lorimer Burst, is it real or not?"

So I kind of got a good chuckle out of it for a little bit,

but then that kind of stuck and so we started using the name

in proposals and things, which was kind of fun.

To have something named after me like this was really a great honour.

Yeah, not something I was expecting, but yeah, really nice.

But the Lorimer Burst was so distant and yet so bright

it didn't appear to have been produced

by any naturally occurring phenomenon.

I did think that it could be a signal from an extraterrestrial

civilisation - we create signals like that on Earth,

so it's not crazy to think that radio bursts

could be created on another planet.

Once we actually thought about it, and looked at the energetics,

you'd need to harness almost a whole solar system's worth of energy

to create something this bright.

Then we realised this is just impossible

unless the civilisation is way more advanced than we are.

We couldn't think of how to make something this energetic.

Scientists have been searching the cosmos for strange signals

like the Lorimer Burst for more than 50 years.

Ever since a secretive meeting took place

in the foothills of the Appalachian Mountains.

There have been, over the years,

a lot of claims, of sightings of extraterrestrials,

colonies on the moon.

The subject had gotten to be treated with contempt, really.

It was considered almost taboo.

But, in 1961,

Frank Drake held a conference behind closed doors in this room

at the Green Bank Observatory.

The National Academy of Sciences of the United States,

a very eminent body,

asked me to convene a meeting of all the people I knew in the world

who were actually serious thinkers on the subject

and I invited them all.

All 12 of them.

The group called themselves the Order of the Dolphin.

I could talk about all of them at length but let me just mention a few

just to give you a feel for who they were.

There was Otto Stuber,

director of the observatory here at Green Bank,

and considered perhaps the most important astronomer

of the 20th century.

Besides being a great astronomer

he was a very strong proponent of the idea that intelligent life,

and life in general, was very common in the universe.

And there was Carl Sagan, a familiar name,

who was a great proponent of extraterrestrial intelligent life.

He had popularised it, gotten support for it,

both with the general public and the scientific world.

Then there was John Lilly, not an astronomer,