Original subtitles

Tonight, in a special programme,

The Sky At Night takes to the air

in a converted jumbo jet.

On board is one of the most amazing telescopes ever built,

and we're going to see it in action.

So, welcome to The Sky At Night at 40,000 feet.

We're on our way to NASA's Armstrong Flight Research Center,

a couple of hours' drive from Los Angeles, because tonight,

we're flying with SOFIA, the world's only airborne observatory.

It may look like an ordinary Boeing 747,

but this ex-passenger aircraft has been specially converted to

carry a 17-tonne telescope that sees the universe not in visible light

but in the infrared part of the spectrum.

Visible light, the light that we can see with our eyes,

only reveals part of the universe around us.

In fact, over half the radiated light comes in the form of infrared,

which tells us about the formation of galaxies,

of stars and of planets,

and the orbit of black holes.

It tells us the secrets of our cosmic origins.

You can record infrared light with a thermal camera like this one,

or with the vastly more sophisticated SOFIA,

the Stratospheric Observatory

For Infrared Astronomy.

Before we took off, I caught up with the man who pioneered the

observation of infrared radiation

from the centre of our Milky Way galaxy way back in 1966.

He could also be said to be the father of SOFIA - Eric Becklin.

So, we're here with this noisy aircraft behind us, because we want

to fly in it to go and look at the infrared, but what is the infrared?

The infrared is the wavelengths of light

that are beyond the red.

It's a very important extension of the optical spectrum,

and it's basically heat waves,

so we are detecting heat waves out in space.

So why do we need a plane to get to these wavelengths? OK.

Because it's like it's cloudy all the time down here on Earth

in the infrared, so we want to get up into the stratosphere,

get into the stratosphere

above most of the water vapour and it clears up,

especially out into what we call a mid- and far-infrared,

where most of the radiation from our galaxy and other galaxies

is coming out.

I want to imagine what it would be like to be able to see

the far-infrared with my eyes, so let's pick something from here.

Let's say I look towards the constellation of Orion,

but in the far-infrared, what would I see?

The picture you get of what's out there, in a region like Orion,

where stars are forming,

is completely different when you look in the infrared.

There are some things that are completely invisible,

that you only see in the infrared.

There's a bar, a mission, you see in the optical,

but in the infrared, it comes out really bright.

And one of the things that you see in the infrared is something called

the BN Object. You discovered that when you were a graduate student?

That's right. And that's the brightest source there.

That is... No, it's not the brightest, actually.

There are some things that are brighter,

but it was the first one found.

There are believed to be forming stars, and they're in the

youngest stages of formation,

so this is the closest region where massive stars are forming

The BN - or Becklin Neugebauer - Object

is 1,400 light years away in the Orion Nebula.

It was discovered by Eric in 1967,

the first protostar ever seen,

and since the launch of SOFIA in 2010,

Eric and his team have been able to explore

the infrared universe in even more detail.

You've looked, I know, at the centre of our galaxy,

at the centre of the Milky Way,

where there's this super-massive black hole.

What does the infrared tell us about the galactic centre?

Well, first of all, the infrared

is what allowed us to see that

there was a black hole there, because there's so much dust

between us and the galactic centre

the light is completely extinguished by a factor of a billion.

Wow! So you can't see anything.

You don't see anything, so you have to go into the infrared,

and you can see through the dust, just like you can a fire,

when it's smoky.

They have infrared-view cameras and can see right down to the fire.

We do the same to the galactic centre,

so that's how we actually saw there was the black hole.

But now, in addition to that,

with SOFIA and the mid- and far-infrared,

we can actually see the dust orbiting around the black hole,

so it's very much like the fact that planets orbit around the sun...

Yeah, yeah, yeah.

..but now we're talking about Yeah, yeah, yeah.

..but now we're talking about material and stars

orbiting around the black hole. Well, it's a pleasure to be here.

I'm looking forward to getting on board. Thank you very much.

Yeah, have a good flight. And thank you for SOFIA!

I hope you enjoy it. I'm sure I will. Thanks.

Back on board, the mission is about to get under way.

Ready for takeoff, and for the next ten hours, we're travelling to

the cutting edge of infrared astronomy.

We'll be finding out how this magnificent,

slightly odd machine operates, and why it's so important

for astronomers to view the universe with infrared eyes.

By climbing 40,000 feet into the stratosphere,

SOFIA rises above 99% of our infrared-blocking atmosphere.

And now we're up here, the first job is to uncover the telescope

and calibrate the instruments.

Training the telescope on an object of known brightness like Mars lets

the team calibrate the instruments and tune out the background noise.

For the first two decades of its life, SOFIA was a passenger jet,

but it was acquired by NASA in 1997 and extensively modified.

Where once rows of passengers sat,

now a 17-tonne, 2.7-metre reflecting telescope resides.

To limit the impact of having a huge open door in flight,

the fuselage was also modified to avoid turbulence.

As the science team settle into the ten-hour flight,

Pilot Dean Neeley has time to take a break from the cockpit

and tell me what it's like to fly.

So, how's your evening going?

It's great, this flight's gone really well.

A lot of work from a lot of people leading up to it

really made this happen,

so made it fairly easy and smooth to execute.

And so how does flying a plane like this compare to a normal aircraft?

It's very unique for several reasons.

One, it's huge, as you can see.

One thing that reminded me, as we started the engines

and began to taxi out tonight,

I always feel like I'm driving a stadium around.

You know? You're so high in the air, and steering this thing is

unlike anything else, so it's a very large aircraft.

And then you take on top of that the special design and the

modifications putting this incredible telescope in the back.

I mean, there's nothing like it anywhere in the world.

Because of those modifications, if you took, say, a commercial pilot

who'd spent their life flying 747s, and you put them here

and you didn't tell them about the back end,

do you think they'd notice, just from the way it handles?

Honestly? No, they wouldn't, because of the amazing way

that they did the aerodynamic modelling and designing

with the structure in the back for the telescope assembly.

In fact, when the whole back side of the aircraft opens up

for the telescope to look out - in the front,

I would never even know it except there's a little light on the panel

that says it's open or closed.

So, in preparing for an evening like tonight,

how much back and forth is there with the science team?

How much negotiation about what's possible

and what the ideal situation would be?

What you see going on here is only a small part of it.

So the planning for this started many months ago. The astronomers

and the science planners putting together a rough plan, and then

they pass that to an aircraft planner -

typically somebody who's a former navigator,

who understands the flying, so as you lead up to the day of the flight

they go a few rounds starting 36 hours prior to the flight,

and then the last round to finalise the details

of the timing and everything is 12 hours prior to the flight.

What about when we're flying along?

We're at 43,000 feet right now in the middle of an observation.

Are you having to do things to try and keep the flight

as steady as possible, or does the telescope take care of that for you?

No, the telescope does most of the precise hard work,

and what we've got to do is just keep the aircraft

as steady as possible, cos it's very sensitive,

so when we make turns, we make very small turns -

one degree at a time -

maybe one degree every 20 or 30 minutes typically,

and we make sure when we do those turns,

we only use one or two degrees of bank.

We have to think ahead, because we can't just manoeuvre like a

normal aircraft would, including climbs and descents

to different altitudes, things like that.

Yeah I'd noticed this evening there's some negotiation,

or at least chatter amongst the team,

about when to climb and how fast to climb and so on.

It seems collaborative. Yeah.

Very much so. The people driving the airplane up in the front

have to work through the mission director,

who is kind of like the orchestra conductor,

working with everybody else down here,

including the telescope operator.

The one thing you have to get used to, as a NASA research pilot,

is when you get in a group like this,

I have to be humble enough to understand that I'm the dumbest guy

in the room, and just drive the plane the way I'm supposed to.

Rather important, though. We should let you get back to it.

Thanks for your time and enjoy the rest of the flight.

Sure. It was great talking with you. Thanks.

SOFIA's focus is the far-infrared, which makes it ideal for

astronomers who want to peer through gas and dust.

One of the biggest mysteries in astronomy today

is how dense clumps of gas form into stars.

SOFIA's High-resolution Airborne Wideband Camera +,

or HAWC+,

is used to investigate just that.

I caught up with project scientist Kimberly Ennico Smith

on the much quieter upper deck.

So, one of the reasons we're here on this marvellous aircraft is

to learn about star formation.

What do we know and what are the mysteries of star formation?

Big questions, Chris, and questions that we've been asking

for a long time,

and learning as we go, but if you think about it,

some of the big questions about stars and how they formed are still

unanswered. There's a mystery out there. Why, when we look at

our Milky Way, when we look at other galaxies,

why are stars forming in certain regions

and stars are not forming in other regions?

What makes those places special? What makes them different?

And it's infrared that matters because that's where the action is?

These wavelengths of light longer than our eyes can see allows us

to peer deep into clouds that we wouldn't see in the visible,

and that means we can get at the heart of, you know,

where stars are forming.

A lot of the images that we are taking in the infrared

don't show the stars at all.

They're showing the dust from which stars are forming,

or into which stars are going after they head at the end of their lives.

So the study of dust is equally important to the study of stars.

What does HAWC actually see?

HAWC's an infrared camera, so it's taking pictures and it works

the far-infrared, and we're looking at the far-infrared and so we're

going to be measuring cold things, as dust being emitted, cold dust.

I know there are results already, so can you

say something about what HAWC's found so far?

Yeah. So it's not published yet. Even better.

I know, but it's just really exciting.

So one of the new developments in star formation theory

is the observations that there are these structures called filaments.

So, you've got some images here. So this is optical, I guess.

That's in the optical, and you see this filament?

It's this long string-like snake-like cloud.

They could be several degrees on the night sky.

And in the longer wavelengths here, you're seeing the gas along

the filaments glowing, the re-emitting of the light.

It's the opposite, right? In the optical, the filament's dark,

but here it's the thing that's glowing brightly.

And then you see the hot spots, those eyes? Oh, yeah, yeah.

Those are where stars are forming or they've just formed.

When Herschel did this all-sky survey and found these

filaments are everywhere in the Milky Way, some of the filaments

have stars and some of them don't, so there's a mystery.

We're thinking this is how stars are forming along these filaments,

but, you know, what can create the stars from forming?

What might stop them?

Might speed them up? A lot of mysteries.

So stars are forming in these filaments,

but it's not that the whole filament suddenly lights up?

Bits of the filament... No, little bits.

Sort of like on your Christmas tree with your fairy lights, right?

Fairy lights on your tree.

By looking at the light from the filaments in detail,

HAWC+ can detect magnetic fields within them -

perhaps a clue to how and why the stars are forming.

So, what's interesting with the new data from HAWC+ on SOFIA

is measuring the magnetic fields on filament scales -

actually looking at the shape, the orientation of the field -

and we're finding they're perpendicular

to the direction of the filament.

So the filament goes across like this...?

And the magnetic field is going down like that. Or like this.

Material would tend to flow along the magnetic fields, presumably?

One could guess, or it could be a barrier.

It's unclear, so one idea is just like, you know,

a hedgerow on the countryside and it's a windy day and you have...

You know, this time of year, we have lots of leaves falling down.

Yeah, yeah, yeah.

If you have that wind blowing perpendicular to the hedgerow...

Yeah, yeah, yeah.

..the leaves start accumulating.

Yeah. Could the magnetic fields...

If they're perpendicular, there'll be a channel to, you know,

add material or create instabilities

for which, chaotically, things will collapse and form stars.

So those are then the places where stars will form? Could be.

And the critical thing here is that the instrument HAWC+

allows you to look at what's going on in the filament.

Previously, we've only had a really broad-brush look. That's right.

Now we can zoom in and see where the action's happening.

It's clear we're just at the beginning of what HAWC+ will do,

so I'm looking forward to seeing the rest. Thank you very much.

Thank you. And it's a pleasure to host BBC Sky At Night... Thank you.

..on the world's premiere flying observatory.

We're well into the flight now,

we're about 1,000 miles off the coast of California.

The telescope is looking at its science targets.

The plane is moving around a bit, even though we're up at 40,000 feet,

which begs the question, why would you put a telescope

on a vibrating platform like an aeroplane at all?

Making sure SOFIA's telescope stays trained on its targets

is Emily Bevins

Tonight, the team are using the telescope to investigate

how stars evolve, but the ability to continually swap out and

customise different instruments for different tasks means that

SOFIA has been able to investigate many different phenomena,

from dust circling around black holes

to the activity of passing comets,

and it will soon have another string to its bow -

it will be able to probe how planets form...

..because NASA's currently building the next generation instrument,

the High Resolution MidInfrarEd Spectrometer,

or HIRMES.

Before taking off, I met with Sam Richards,

who's one of the team designing and building the instrument.

So, Sam, thanks for talking to us.

You're working on the next generation of instrument for SOFIA,

something called HIRMES. What is HIRMES and what's it going to do?

HIRMES is looking primarily at protoplanetary discs,

and these are discs

around other stars where once,

a long time ago in our solar system,

it was just a disc of material, you know, dust and ice.

This is the leftovers from star formations.

Exactly, yeah.

So it accumulates around in a disc around a star,

and then those discs, those particles, can join together

and they build up small little pebbles,

and then the pebbles become rocks,

and rocks become asteroids and comets and things like this,

and, eventually, you get planets.

It's always amazed me that we don't really understand that process,

how the dust sticks together. Exactly.

So we have our own solar system,

which is one data point,

and we know it fairly well but we still don't know

why it's in the order that it is,

and where all this material and chemicals came from,

so this is one of the key reasons why HIRMES is being made,

so with the high-resolution aspects of it,

we can understand how this material is moving around other stars,

and then how the different components, like the water

and the ice and the oxygen and all these kind of

key life-building components,

how they come together and then they evolve over time

to eventually create what would be a solar system like the Earth

and with gas giants like Jupiters and Saturns and things like this.

Why is it important to look at the water and the oxygen?

What stories do those tell us?

One of the big questions about how Earth got its water

and why it has so much water is, how did we get here?

Because we think the early Earth was dry.

Yes. It lost all its water and we've got to get it back somehow.

We need the high-resolution science to be able to figure out

exactly how all this chemistry moves around in a disc.

Yeah, so that's the point, isn't it?

It's telling you what's happened to this material over time. Yeah.

So we're on this long journey to figure out

where our solar system fits into the story of all the other

potential solar systems out there,

and then we can figure out which family tree that we came from,

and then kind of backdate the models that way.

So, this is exciting stuff and this will depend on HIRMES,

which I think will start flying, what, next year?

Something like that. Yeah. HIRMES is currently in the kind of

building phase, so we're currently putting the components together,

and to achieve this type of science you really need

a high level of complexity,

which you can't really do from space,

and SOFIA's the perfect platform for this type of instrument.

You're fairly new to the project.

You've flown on SOFIA before, so what was the first flight like?

I'm a total fan boy, so when it comes to NASA

and this type of mission, you know, you get to don the flight suit,

all the patches, and you really get to enjoy

being in the moment there

and something that's very different to ground-based observatories.

Well, good luck. I hope all goes well and I look forward to seeing

the results from HIRMES. It's really exciting.

Yes, thank you. We're excited too.

Back on the plane, operations are in full swing.

Although SOFIA is based in California,

it's actually a joint venture between NASA

and the German space agency, the DLR.

And on board tonight, the instrument

is the German REceiver for Astronomy

at Terahertz frequencies,

or GREAT for short.

GREAT looks at the extreme end of the infrared,

searching for atoms and molecules amongst interstellar gas clouds,

because by looking at them, we can work out how stars evolve

in the crucial first few million years of their lives.

Instrument Scientist Karl Jacobs

tells me more about what they're trying to find.

By expanding our view into the infrared,

SOFIA shows us snapshots of stars and planetary systems of all ages,

of our own solar system, and build a clearer picture of the universe.

It's about 3.30 in the morning. We've just landed.

I'm pretty tired and so are the crew.

It'll take them weeks and months to analyse all the data that they got

just from this evening's flight.

One thing's for sure, though.

This is a marvellous way to fly and to see the universe.

When come back next month, we'll be on the edge of the solar system.

Until then, good night.