All language subtitles for BBC.The.Sky.at.Night.2024.Space.Rock.Return.1080p.HDTV.x264.AAC.MVGroup.org

It's time to get ready...

And liftoff.

..to blast off into space,

as The Sky At Night is back,

bringing you the very latest

in celestial news
and cosmic engineering.

A lot has been happening
since we've been off the air.

The Juno spacecraft made its closest
approach to Io, Jupiter's moon,

bringing spectacular images
of its volcanically active surface.

Incredible images also continue
to come from JWST

and the data it's sending back.

2024 is proving to be a wobbly year
for moon exploration.

Japan's SLIM mission landed
on target despite being nose down,

while the Odysseus robot also
had a fall after landing,

but marks the first private company
to land on the moon.

Nasa also launched its Deep Space
Optical Communications experiment,

successfully sending back to Earth

this recording of a cat
chasing a laser.

Its aim wasn't to share a cute
cat video with passing aliens,

but to test out the potential

of faster and further communications
by laser,

instead of the traditional
radio waves.

But the big news this month
is that scientists have been sharing

their initial findings from Nasa's
first asteroid sample return.

So, tonight, we're looking at Bennu,
an asteroid that could, one day,

hit our planet.

If Bennu were to hit Earth,
and that's a big if,

it won't be for another
150 years or so.

So, relax for now.

But just last year, Nasa's
OSIRIS-REx spacecraft returned

to Earth with a piece of Bennu.

Scientists from all over the world
have been prodding and poking it,

and now they're ready
to announce their findings.

The Sky At Night team has been
finding out what's been discovered

now that the space rock
has returned.

ALL: Welcome to The Sky At Night.

In 2016, Nasa's OSIRIS-REx
spacecraft started

its 1.2 billion-mile journey
to the near-Earth asteroid, Bennu.

Its aim? To extract some
of the asteroid's material,

which was then carefully sealed
and returned to Earth.

With two samples already obtained
by the Japanese space agency,

why is there so much interest
in asteroids?

If you know one thing
about asteroids,

it's probably
that dinosaurs didn't like them.

When an asteroid hit our Earth
65 million years ago,

just off the coast of what is now
modern-day Mexico,

it caused our
planet's last great extinction.

Good news, in the long run, for us
descendants of scurrying mammals

that survived the impact,

but definitely bad news
if you're a dinosaur.

Astronomers weren't keen
on asteroids for many years either.

Sure, when they discovered the first
few in the early 19th century,

they celebrated them as new planets.

But as the number mounted,
they were quickly downgraded.

Nowadays, we know of more
than half a million of the things,

so let's get to know them
a little bit.

First of all, asteroids are small,

no more than a few hundred metres
across, and they're rocky.

Now, it is true that most
of the asteroids

that we've visited with spacecraft

look more like potatoes than
planets.

But these are no small potatoes,

because the asteroids have been
more or less unchanged

since they formed
billions of years ago.

Look at this - tiny Dinkinesh,
visited by the Lucy spacecraft

just at the end of last year.

This is the place we went
by accident,

the equivalent of a cosmic
motorway service station.

We can learn more from larger worlds
like Ceres and Vesta,

both visited by the Dawn spacecraft.

These are round.

They're more planet than potato.

And you can think of them
as small protoplanets.

They grew this big,
and then things stopped.

But where you're sitting,
5 billion years ago,

would likely have looked very much
like the asteroid belt does today -

rubble all over the place
and 20 to 30 worlds

the size of Ceres or Vesta
careening about, causing chaos.

And it's from that chaos
that our planet was formed.

And even once the Earth
was assembled,

the asteroids were not done
with us yet.

Yes, they did for the dinosaurs.

But billions of years earlier,
they may have been beneficial.

Could they have brought water
to the parched surface

of a dry early Earth?

And who knows? They may have had
a role in the origins of life.

With the potential to explain
those big questions,

like, "How did life begin?",

Chris is heading to a place

with samples that could
reveal the answers.

The Natural History Museum in London

is home to an incredible collection
of rocks,

from precious gems
to unusual asteroids

and even samples brought back
to Earth by the Apollo astronauts.

But it's not just the displays
that are fascinating.

I'm off to meet two
museum scientists

who've been working
on the Bennu sample return.

Hello. Oh, hello.
Nice to see you both,

and wonderful to be talking
about the OSIRIS-REx mission,

which sounds like a dinosaur
in the collection,

but it's, of course, Nasa's asteroid
mission. Yep.

What was the mission trying to do?

Yes, so OSIRIS-REx was Nasa's
first attempt to go to an asteroid,

collect a piece of an asteroid,
bring it back to Earth

so we can study it here in the labs.

So, Sara, you've been involved
in this mission for a long time.

What was launch like?
Launch was amazing.

Yes, absolutely incredible.

Cape Canaveral, everything went
to plan, an incredible experience.

And everything worked.
Everything worked.

Then you had this long,
two-year journey to get

to the asteroid Bennu.

What happened when the spacecraft
arrived?

When they got there, you know,

I think they were kind of expecting

something a bit
like a beach, you know? Right.

Lots of fine-grain material
all over the surface.

It turns out Bennu's surface
was covered in these huge boulders,

tens of metres in size.

Really interesting. Really exciting.

Also a bit dangerous when you want
to try and grab a sample

off the surface.

So, the plan was to go and scoop up
some of the asteroid

and bring it back, but the pictures
of that happening

look quite dramatic and exciting.

Were you expecting this sort of
reaction from the surface

when you hit it?

As the sampling happened,
the arm went down,

and we were kind of expecting it
would hit a kind of solid surface,

but it just kept on going down
and through,

as if it was just going
into a ball pit.

And all of this dust came up.
All of this dust suddenly flew up.

And it was only because
of the thrust backwards

that it actually managed
to escape from Bennu,

otherwise it may have sunk
all the way through.

So, this was designed as a sort
of touch-and-go mission,

but you disappeared
into the asteroid. Yeah.

SHE LAUGHS
Good job the spacecraft survived.

Yeah. Something like that. Yeah.
No more to say to that.

You're like, "Yes! It was good."

After a seven-year round trip,

the spacecraft returned
with over 120 grams of Bennu...

..the largest asteroid sample
ever collected,

with more than half of that trapped
outside the container.

OSIRIS-REx came back to Earth,
sample landed, and, Ashley,

you were one of the first people
to...to see it.

Yeah, I had an amazing experience.

I actually was one of a handful
of scientists who were there

when that sample
made it back to Earth.

The Quick Look team is what we were
called, or the Tiger team,

waiting to get our hands
on that sample and do exactly that,

have a really quick look
at what that material was.

And so what did you see? So you
were in a clean room, presumably.

So the clean lab's really noisy.

It's actually quite difficult
to communicate,

and so they want to keep it
very calm, very quiet

for all of the...all the curators
to work.

And the rest of us were just
in a room next door to that,

watching everything
that was going on in that clean lab.

And it was incredible.

They took the lid off -
we all jumped up.

We did exactly that. We started
pointing at things and going,

"That one's sparkly, that one's
black," and we're all geologists,

so we immediately start thinking

about what that could be telling us
about the rocks.

But in the meantime,
you had another challenge,

which was getting into
the sample collection jar itself,

which...which proved a bit
of a problem. Yes.

So...so they...what
the curation team did,

they turned their attention

to the actual sample collection,

the thing where all the material
from the surface was going to be,

and, you know, it's got 36 screws
around it,

and, unfortunately, two of those
just wouldn't budge for them.

So they couldn't immediately
get all the material out

of the sample collector.

It does sound frustrating
that you've gone all the way

to an asteroid and back, and you
can't get the jam jar open...

Yeah. ..essentially.
Was it a big problem?

Because it's in this curation
facility,

so you can't just
put any spanner in there. Right.

You have to have something

that's been approved by Nasa
and is curation-clean.

It's not going to contaminate
the sample.

This is the stuff that hasn't
been touched. Exactly. Yeah, yeah.

So they had to go away, think about
how they were going to do this.

And they came up with a new type
of spanner that they could use.

And so they actually got it open
about a month or so ago.

So all the material is now
out of the collector head.

THEY CHEER
Let's go!

Bennu samples have now
been distributed

to about 200
scientists around the world.

And Sara has a piece
right here at the museum.

So are these the samples?
Yes, they are. They are.

I know they look like really boring
black spots, but...

Can I hold it? Yes, you can.

This is a bit of Bennu?
That is a bit of Bennu.

Yes, brought back by OSIRIS-REx.

That's not boring at all. No.

That's really exciting.

So it's this tiny grain here.

It looks almost like a sand grain.

Yes. Yes.

So we received about a teaspoonful
that was just grains,

about that size or even smaller. OK.

So we've picked up...
I'm going to give this back to you.

Yes? I actually feel quite nervous
holding that. Yeah.

So you picked that out
of your teaspoon?

We've picked... Yeah. So we've
picked out these individual grains

and CT-scanned many of them,

and then we've put them in epoxy
and polished them like this.

OK. But then you can place them
in...in a microscope, can you?

Yes, exactly.

So this is the microscope
I'm using today.

So it's firing electrons
down a gun here

to the sample that's inside there.

And this is an image of the sample
of Bennu that I'm looking at.

So what can we see on the screen?

So what we can see on the screen

is that most of the rock is really,
really fine-grained,

all the stuff around the outside.

It's got bright bits here,
which are an iron oxide, magnetite.

But most of the screen here
is dominated

by this sort of skeletal-looking
grain,

which is a mineral called olivine.

Which we see on Earth. Exactly.

It's a really common mineral
on Earth.

And where would that have come from?
Would it have formed with Bennu?

So it's formed before Bennu
was around, in fact,

before any asteroids
or planets were around.

And they give us a glimpse back

into what the composition
of our solar system was

in those pre-planetary times.

So you expected olivine, but there
have been some surprises as well.

Yes. So one of the surprises,

we saw as soon as we opened
the sample return capsule.

Most of it was a black rock,

which is what we were expecting,

but there were little flecks
of white stuff in there.

And it turned out the white stuff
was mostly a mineral

called magnesium phosphate.

Each element in this map
has been given a different colour,

with the compound
magnesium phosphate shown here

as green.

So why is the magnesium phosphate
important?

It's important because it's so
abundant in Bennu,

but it's not really abundant at all
in any meteorites in our collection.

It's an incredibly rare mineral.

We don't really see it
in Earth rocks at all.

So it's just...it was just
a complete surprise to see it.

But we think it probably formed
by the action of water.

So it probably formed...

..it's probably telling us
that in its early history,

Bennu had loads of water

that was creating all of these
watery minerals.

Well, that's surprising, right?

Yeah. Bennu is dry now.
It's made of rock. Yeah.

It's not an icy comet
or something like that. No.

So where's the water come from?

Yeah, so it probably means that
Bennu formed

in the outermost part
of the solar system,

and it formed
with bits of ice grains

incorporated into it that heated up
and then became liquid.

So it's quite a complicated story?

It's an incredibly complicated
story,

and we're just at the beginning

of starting to understand what it's
telling us

about the whole history
of our solar system,

from pre-planetary times

to...to the origin of water

and...and how that got potentially
to the Earth.

I know you're a proper geologist

because at the moment you say
it's complicated,

you light up, you get excited.

Yeah. The more complicated,
the better.

There's so much in it, and each
little grain

is a little bit
different from the others.

So it's going to keep us busy
for years and years.

Sara, thank you very much
for showing us.

It's genuinely exciting
to be in the lab with Bennu,

so thank you again. Well,
I'm really pleased

to be able to show you, Chris.

Such small grains
can tell us so much,

but they're a challenge to analyse.

How can it be done?

Maggie is on the case to find out.

Today, I'm at one of the UK's most
impressive science facilities,

the Diamond Light Source
in Oxfordshire.

Right now, I'm standing
above their x-ray synchrotron.

Now, this huge machine is designed

to look at some of the smallest
objects in the world.

It's effectively a high-tech,
giant microscope.

Scientists use the Diamond
synchrotron

for a huge variety of things,

from looking at how viruses like
Covid-19 work

to figuring out which specific
pigments were used

to paint some of the most famous
artworks in the world.

This machine is also critical
for analysing artefacts from space,

including those new samples
from the OSIRIS-REx mission.

So I'm going to find out
how it all works.

I'm meeting Dr Sharif Ahmed,

one of Diamond's
principal beamline scientists.

Sharif, thank you so much
for having us here.

Welcome. Welcome to Diamond, Maggie.

I really want to get an
understanding of how it all works,

and I think this model can show us.

You're right.
You're absolutely right.

So essentially, the synchrotron
starts with electrons.

Electrons are released
by heating up a metal.

These are then sped up
inside two machines,

the first a linear accelerator

and then a booster ring.

And in the booster ring,

the electrons will go up

to really...really up to about 98%
of the speed of light.

So 98% of the speed of light?

So how do you accelerate
the electrons to get

to that sort of speed?

We use radio waves in a particular
frequency,

and as the electrons
pass through them,

they essentially
are pushed by these waves.

And we keep doing that in a circle,
again and again and again.

The electrons are then injected
into a larger storage ring.

Once they have reached
their optimum speeds,

they move so quickly that they could
travel around the entire world

seven and a half times
in just one second.

And it's these high speeds that
allow the ground-breaking science

to happen at Diamond.

The storage ring is a multi-sided
polygon,

ie. it's got
lots of straight sections.

So it's shown as a circle here,
but it's actually a series of flats?

Exactly. Straight edges,
with something called

a "bending magnet" that connects
these straight edges.

Every time we turn the electrons,
we decelerate them... OK, yes.

..because they have to slow...

So it's very similar to how when
you decelerate or brake your car,

motion energy is converted
into heat.

So these electrons are very
energetic, and as you bend them,

they slow down.

And that causes the emission
of x-rays, ultraviolet rays,

infrared and even visible light.

You work on one of the beam lines.
Indeed.

And it's an x-ray beam line. It is.

Can we see it an action?
Of course. Come with me.

We can obviously go and have
a look at it. Fantastic.

Thank you. Excellent.

So all the x-rays are obviously
coming through the ratchet wall.

The first room that the beam
of x-rays enter

is called the optics lab.

Here, carefully aligned mirrors
and precise filters allow Sharif

to tailor the incredible, powerful
x-ray beam to the specific needs

of each scientist.

After that,
it's on to the experimental hutch

where the x-rays meet the sample
being analysed.

And that's where the magic happens.

Now, when we talk about x-rays here,

are we talking about the sort of
x-rays

we get at the dentist or in
the hospital?

Or are these different?

They are similar, but different.

They are much more energetic
and powerful.

A good comparison would be
a laser pointer that you'd use

for doing a presentation,
for example,

compared to a laser that's used
for, say, melting or cutting metal.

The x-rays used by Sharif

are 10 billion times brighter
than the sun,

and he's been using
these to analyse the Bennu samples

with Ashley
from the Natural History Museum.

And there's something special
about this DIAD beamline

that takes their analysis
to the next level.

So, what's DIAD?

The most unique thing about
this instrument is the fact

that we have two x-ray beams,

and it's done
by these two detectors.

So you have a very simple detector
here,

which is essentially
an x-ray microscope.

On the robot arm, we have something
a lot more special.

It's a...what's called

a cadmium telluride direct detection
system.

Using these two detectors, Sharif
is able to combine images

of the sample with data
about the different atoms

and molecules inside it

to give insight that no other
instrument can.

So what does the data look like?

So I've got an example
to show you very quickly.

So what you're looking at here
is...it's like a CT

that you'd get at a hospital,
so you can see a cross-section,

or as if to cut an object.

And over here, what you're looking
at is all the different materials

in that particle.

So that is from using x-ray imaging
or x-ray CT... Yes.

..and this, the colour image
is an overlay over that.

So suddenly, you can actually see
the internal structure...

Yes. ..but also the material
it's made up of.

And so you have been doing
sort of samples from Bennu?

We have. We've had the pleasure
of being the first synchrotron

in the world, I believe,
to have a Bennu sample.

And hopefully, at some point,

we'll be able to show you images
like this,

once we've gone through
the process of reconstructing it.

Well, thank you so much.
That's amazing.

Just hearing the capabilities
of this beamline

is quite mind-boggling, and I can't
wait to see the results from Bennu.

DR CHRIS LINTOTT: And
The Sky At Night will no doubt

be reporting on these results
once they are released.

Another scientist trying to uncover
Bennu's secrets is Dr Queenie Chan

at Royal Holloway University.

Queenie is remotely collaborating
with a team in America and Japan,

where the sample is held.

They're looking for small pockets
of water trapped

within the asteroid.

George Dransfield went
to talk to her

about what this water can tell us,

and why learning what is contained
within it is so important.

In your analysis, then, what is it
that you're actually looking for?

We are looking for tiny little bits
of fluid inclusion

within the samples.

Fluid inclusions?
What are they, then?

Well, fluid inclusions are little
pockets of water,

trapped in a mineral as the mineral
grows on the asteroid.

To find these pockets of water,
Queenie looks at the minerals

inside the asteroid sample
under a microscope.

The Bennu sample Queenie
is working with is in Japan,

and the images aren't ready
to be released to the public yet.

But she does have a meteorite sample
in her lab

that perfectly
illustrates her work on Bennu.

We do have a salt crystal
that is now sitting

under that microscope... Amazing.
..and this salt crystal is coming in

from another sample,
extraterrestrial sample

from a meteorite.

It's alien salt? It's alien salt.
Yes. Yeah. Really?

That's a mineral that's capable
of trapping fluids as it grows.

So imagine a glass, you know,
in your home,

that you put lots of salt, like,
really salty water in it.

Yeah. And if you let it sit
for a while, you start to see

the little crystals start to grow...
Yeah.

..little salt crystals,
baby crystals start to grow,

and they get bigger and bigger.

As it grows, it's capable
of trapping fluid within them.

And this is exactly what's happening
on an asteroid,

and it's probably
what's happening on Bennu as well.

OK, so I can see the alien salt
over here.

Where's the liquid?

So you can see that alien salt,
staring at you now,

with those little black dots
over there. Yeah.

Those are the fluid inclusions.

The next stage is to analyse
the water trapped inside the mineral

in order to understand
what's contained within it,

because not all water is the same.

Let's think about if you
go in...take a glass,

go into the river, get a scoop,
and compare that glass of water

to another glass of water
that you take from the ocean. Yeah.

The content is going
to be completely different.

You've got different kinds
of salinity in different water.

The iron that's dissolved
into the water is going

to be completely different.

The amount of organic constituents,
for example,

will be different, as well.

Some scientists believe
that the organic materials needed

to start life could have been
brought to Earth by asteroids.

Queenie searches for these
organic molecules using a process

called spectroscopy.

So how are we actually going
to be looking for organic molecules,

then, in this sample?

With the Raman Spectroscopy
technique,

we're capable of telling
the kinds of organic molecules

we have in the sample,

roughly tells us about the
structure of the organics.

We use other techniques
subsequently,

for example, another technique
called ToF-Sims -

Secondary Ion Mass Spectrometry.

It's capable of telling us
even more details

as to the chemistry of it.

We're looking at the little
fragments

that form those larger molecules.

Amazing. So you're looking
for the building blocks

of the building blocks
of, potentially, life.

Exactly - building blocks
of the building blocks. Nice. Yes.

Queenie and the international team
hope

that by analysing any tiny
pockets of water

trapped
within the minerals on Bennu,

they'll identify different molecules
and discover if they are the ones

that could have been key
to starting life on Earth.

Today, I've had my mind absolutely
blown by alien salt

and its ability to tell us something
about the origins of life.

Now, she does have quite a long way
to go with this research,

but I cannot wait to hear
about the results as they come in.

The work scientists are doing
on the Bennu sample

could answer some big questions
in the future.

But in the meantime, our resident
stargazer, Pete Lawrence,

is looking up to the skies to tell
us what can be seen this month.

Comets and asteroids can be fun
to track and are a great target

for amateur astronomers,
but the first challenge

is to identify them.

And there's a quick and clever way
to do this,

which is known as the blink test.

I did one recently for the bright
asteroid Vesta, and the principles

are quite simple.

You record the stars
in the field of view

you believe the object
to be in, like this one.

And then, over subsequent nights,
if you take another image

and then you align the stars
between those images

and flick backwards and forwards
between them,

if you spot a moving object,
that should be the comet or asteroid

that you're after.

If you head outside this month,
there are two interesting comets

which are relatively easy to locate.

The first is C/2021 S3 PanSTARRS,

which is an early morning object

best seen from around 1am, BST.

To find it,
locate the Northern Cross asterism

in Cygnus, the swan.

At the start of the month,

it's located near
the Coat Hanger Cluster,

Collinder 399, slowly tracking up

the vertical of the cross

to end the month not far

from the brightest star, Deneb,

at the top of the cross.

It may be a bit tricky to spot

due to the myriad of faint
background stars

in the dense
section of Milky Way found here.

The BLINK technique

will certainly
help show its motion.

If you're not a morning person,

there's comet 12P/Pons-Brooks,

which could get bright enough

to be seen with the naked eye.

It has a 71-year orbit
and will be closest to the sun

on 21st April.

The evening twilight will make
seeing the comet tricky

towards the second half
of the month.

So probably, the first half of
April is the best time to catch it.

To stand a chance of seeing it,

you'll need a low, clear
west-northwest to northwest horizon,

and the use of binoculars

is also recommended.

Wait for the sky to darken

sufficiently for mid-brightness
stars to appear.

The key markers for finding
the comet

are Hamal,

the brightest star in Aries,

Jupiter, the Pleiades,

the star Aldebaran,

and the Hyades open cluster.

Aside from the comets, as ever,
there's still plenty to see

in the night sky, although it has
to be said that the planets

are rather sparse at the moment -

too close to the sun
and lost in its glare.

But there are still two
which are worth looking out for.

Jupiter is still there,

low above the west-northwest
horizon after sunset.

It's been gradually catching up
with Uranus over the past months,

finally reaching conjunction
when the pair appear closest

on 20th April.

They will be separated
by just half a degree.

That's the apparent size
of the moon.

But the evening twilight will
make the view harder to see.

Meanwhile, this month, the moon
will be showing some interesting

clair-obscure effects,
or tricks of the light,

on the morning of 16th April.

As it approaches setting,

you should be able to see
the popular Lunar X and V,

effects which make the letters
X and V appear on the terminator -

that's the line dividing
lunar night from day.

On the evening of the 18th,
the easy-to-see Jewelled Handle

will be visible, an effect caused

when the peaks of the curved
Montes Jura mountain range

catches the light of the lunar dawn.

That's the viewing highlights
for the UK.

But the biggest event this month in
North America happens not at night,

but rather during the day -

a total eclipse of the sun.

These rare occurrences are always
a treat,

so long as the weather is on your
side,

as we've found out throughout
the years.

FOG HORN BLASTS

The Monte Umbe sailed from Liverpool
a week before the eclipse

with 300 members of the British
Astronomical Association on board.

It's something I've wanted to see
all my life, and all we can do now

is wait and hope the weather holds.

We were all rather worried
by the hazy conditions.

Oh, clouds, keep away, please.

I haven't given up hope yet.

The moon has started to pulse
under the sun,

and the great eclipse has started.

And sadly, at the moment,
from here, on St Anthony Head,

we can't see it because the sky
is totally overcast.

It can clear dramatically
at the last moment,

and you never know. There we go.

Look at that. There's the diamond
ring and the corona reaching out

as the shadow hits us.

There's a break. Look there,
there's a break in the cloud

and there is the crescent sun.

That is the most incredible sight.

It really is.

This is incredible. The best corona
I think I've ever seen in my life.

I can't believe
this is over already.

So, diamond ring.
Get the glasses on.

By Jove, was it worth seeing!
APPLAUSE

CHEERING

Now, if you were lucky enough
to see this month's eclipse

in North America,
and if the skies were clear,

then do share your photos with us.

You can do so
via our Flickr account.

Details on the website at:

We'll show a few of the best
on next month's programme.

But until next month, goodnight.