Episode 2 Stargazing Live

Last night we spoke to the last man on the moon. Tonight we are heading

to the centre of our galaxy. I am Brian Cox, he is Dara O'Briain, and

Welcome back to Jodrell Bank for the second night of Stargazing Live.

Yesterday, we concentrated on the moon, which is a bit unfair because

it did not rise for a couple of hours after we went off air. We

were relying on people staying up late or getting up early, and

people sent us a number of photographs. This is a beautiful

picture of the Moon which was taken by James West. We have another one,

it taken by James Dyson. I am fond of this picture. It is a beautiful

picture of a cluster of young stars which were formed together. Most

people can see about six or seven of them with the naked eye but you

can see tens of them through a telescope. That transient. It will

drift apart and will not be a cluster anymore. We have had the

most incredible response so far. A lot of you have contacted us about

Captain Cerna. Some of you wanted to know why the Stars and Stripes

flag looked like it was flapping in the wind when there is no

atmosphere in the -- on the moon. It sounds like a conspiracy

question. The answer is there is a piece of metal in it because they

would knew it would flatten if there was no atmosphere. If you

think we did not land on the moon, turn over to ITV, I did not -- I do

not want to! You can keep questions coming into us, or you can tweet us.

You can join the online chatroom, Talk Stargazing, at

bbc.co.uk/stargazing. To see what is in the skies over Macclesfield

tonight, are there to mark and friends, and a very special guest

astronomer. Good evening, I am joined not only

by a veritable army of astronomers from the Liverpool and Macclesfield

astronomy society, how are you doing? They sound like they're

having some fun. They have joined us for our special star party at

Jodrell Bank. You can find out details of the events around the

country near where you are, at our website, bbc.co.uk/stargazing.

Standing relatively close to this new telescope is Impressionist and

space, Jon Culshaw. Well come. What is it about astronomy? I remember

receiving a book by Patrick Moore when I was nine and I read it to

cover to cover, and I was hooked. Any time there was a -- the Moon

was out, I could not resist having a look. Do you use these binoculars

often? Yes. I have not got a stand for them yet. You do need at quite

an impressive stand. The sky is looking incredibly Claire so come

back to us later on. -- incredibly clear.

Ironically, the thing we are going to talk about is not actually

visible. We are going to talk about black holes. The truth is that from

a physicist's perspective, we do not really understand them. Here is

an introduction to the enigmatic inhabitants of the cosmos.

Black holes are some of the strangest, most mysterious and

destructive things that exist in the universe. There is one here.

And there is probably another one here. But you can't see them. And

they can't be photographed. So we have to use computer graphics to

try to explain what they are and how they are formed. Black holes

are cosmic bodies with such immense gravity, nothing can escape them.

For their lives to start, a star has to die. Stars are effectively

huge nuclear reactors, fuelled by hydrogen. At the end of their lives,

when the fuel runs out, they dive. When this happens, stars the size

of our sun with the, to become much smaller bodies, known as white

dwarfs. When bigger stars die, they destroy themselves in explosions

known as supernovas. If the explosion is 30 times the mass of

the Sun, black holes can be formed. As the outer layers of the star

blow off into space, the core of the Star, which can be as big as a

planet, is crushed down to almost nothing. The whole process can

taste -- tastes -- take less than a second. What is left is an object

that has the same mass as the core of the star, but is packed into a

much less -- much smaller space. Despite being significantly smaller,

it still exerts the same gravitational pull. This incredibly

powerful entity, which is small but massive at the same time, is what

we have come to know as a black hole. From the moment of their

creation, some black holes begin firing out great jets of radiation.

The immense gravitational pull from the holes means that anything that

strays too close to them is powerless to escape. Even a nearby

star would be torn apart, the matter from its surface being

pulled into orbit around the hole. That poll from the black hole is so

strong that eventually, it is eventually -- it is impossible to

escape -- that poll. This terrifying point of no return is

known as the event horizon. Everything in its path is sucked in,

and the more -- the more it swallows, the bigger the black hole

becomes. Beyond the event horizon, not even light can travel fast

enough to escape. That is why you can't see them, and how they get

their name. They are quite literally black holes in space. If,

by some miracle, you were to survive the tidal forces at the

Event Horizon and fell into a black hole, you would be ripped apart.

But nobody knows how long that would take.

We are going to go to the age of physics and also the heart of our

Garroch -- galaxy. It is a journey we should start right here. Let's

take a look at where we are in our galaxy. This is the Milky Way,

taken from outside it, so it is a taken from outside it, so it is a

graphic. That is the location of earth. We had this as a question

from Gary in Belfast, how do we know where the earth is and how can

we know what it looks like? There is something like between 200 and

400 billion stars in the Milky Way. It from there, you can't see it all,

we use telescopes like the Lovell, radio astronomy. Looking at the

radio emission, you can see how bright the universe is. Also, by

looking at how that shifts, you can see how fast it is moving. So you

can work out precisely the structure and speed of rotation of

our galaxy. When we look into the sky, every star we see is part of

the Milky Way. Everything you can see with the naked eye apart from

one thing. We have a life picture of that one thing. This is from

Macclesfield now. Where are we? This is a picture of the Andromeda

galaxy. This is the nearest neighbouring galaxy, about 2

million light years away. There is something like a trillion stars in

that galaxy. That is a live picture now of Andromeda. The Galaxy is

basically a collection of stars? They are. That is the nearest

neighbour, so there are two of them. This is one of the most famous

pictures in astronomy. It is a picture of the piece of sky you

would cover, if you took a five pence piece and held it about 25

metres away, cover a little piece of sky. It was a piece of sky that

is anti from the surface of the Earth as far as we could tell, but

the Hubble take -- telescope took this picture and it is far from

empty. There are over 10,000 galaxies in this image, the most

distant his 13 billion light years away. If you extend that over the

entire sky, there are around 350 billion galaxies. Although we can

see the Andromeda galaxy in the night sky, that is pretty much the

only visible to the naked eye in this hemisphere, but there is

plenty more visible in the southern Welcome to the southern African

large telescope in the middle of the Karoo desert. The weather has

been rubbish again, but it looks like it might be clearing up, which

is why the SALT telescope is moving into position. There are two

galaxies visible to the naked eye, closer than Andromeda. A couple of

nights ago I went galaxy gazing with budding astronomers from the

nearby town. In the middle of the Karoo desert,

about 200 miles north-east of Cape Town, lies the tiny town of

Sutherland. Before the South African astronomical observatory

relocated here in the mid-70s, this was just a small farming community

with a few hundred people. But now, Sutherland is home to one of the

largest telescopes in the world, and that has made it something of a

tourist destination. Astronomers are also keen that the whole

community understands just what a special star-gazing spot this is.

Anthony runs the Observer drew's outreach programme. -- the

observatory's outreach programme. Why are they flying kites? You have

to look up, it is a way of exposing them to the night sky. As the stars

come out, they will change their attention... To what is happening.

Sometimes before a lucky, we get a shooting star, and somebody will

ask, what just happened? One of the astronomers down here, at David

Gilbank, will be talking to the kids about galaxies later on.

good way to describe a galaxy is as a city of stars. Our Milky Way is

all the stars that belong to the Star City. If we can see our galaxy

from the outside, we would see something that looks like the East

shape of a dinner plate. We live about two-thirds of the way out

from the centre. When we look at the night sky, we are actually

looking into the thickest part of the stars, as if we are looking

through the edge of the plate. many stars are in the Milky Way?

good question. They are about 100 billion within our own galaxy.

is the closest galaxy to our own Milky Way? The nearest galaxy is

called the Andromeda galaxy, but there are lots of much that smaller

galaxies in between. -- the mirrors that is the same size. This misty

patch looks like a small version of the Milky Way.

This is called the Large Magellanic Cloud. This is the satellite galaxy

of the Milky Way. The Large Magellanic Cloud is the satellite

galaxy of the Milky Way that orbits around us. What you are looking at

through the telescope, it looks like a bright patch, this is called

the tarantula nebula. It looks like little legs of the Spider. It is a

cloud of gas in which stars are being born. You can see there are

new starts by looking around, we can see bright blue luminous stars.

Why are the new stars blue? If you think about the taps on the sink,

blue is cold, bread is hot, it is the opposite in astronomy. -- red

is hot. Imagine taking a piece of iron into a fire, it will start of

glowing red hot, that is the coolest you can get. If you heat it

further, it will glow white hot. If you could eat it furthered without

the metal Motty, it would be blew hot. Blue is the hottest iPod star

-- without the metal nothing. Back These very bright stars do not live

very long. If you see these hot blue stars in the galaxy, you know

they have been put there recently. If there is no new star formation

going on, you will only see these older stars, which will appear red.

They are red because they are older? That is right. What stops

star formation in galaxy? To form stars we need these nebula, these

clouds of gas. We know something must be removing the gas and

preventing it from forming stars, but we don't know what that is,

this is one of the things I am trying to answer in the work I am

doing with SALT. There is also a Small Magellanic

Cloud in the southern hemisphere. In fact, SALT altered its viewing

window in order to observe it in its entirety. It has about a 10th

of the stars of the large cloud, and it is more elongated and the

large one, but we look at it head on from Earth. The magellanic

clouds are part of this local group of galaxies, what is the local

group? It is the name we give to the collection of nearby galaxies

bound together by gravity. It consists of three big galaxies

including the Milky Way and Andromeda, and debris several dozen

smaller galaxies. -- may be several dozen. You have been attempting to

find out how many galaxies there are in the universe, you have

looked at 3% of the sky, what have We are mainly looking for galaxy

clusters and we have found 38,000, which amounts to 3 million galaxies

in one tiny speck of the sky. Galaxies are everywhere you look.

They are distributed across the universe in a cosmic web of

filaments and astronomers are only just beginning to understand what

that might look like. Join me later when I find out how galaxies growth.

Apparently the Milky Way is in for a bumpy ride.

Here is a positive message for those people needing more exercise.

You cannot be at rest. We travel around the sun but also around the

Milky Way. Of course we travel round the Sun every year. But the

sun is one of 200 billion stars in the Milky Way galaxy. Our whole

solar system is travelling around the galactic centre. We think it

takes about 225 million years to make one orbit. If you think about

that, that means that since this formation of the solar system we

have made 20 orbits, which is 20 galactic years, if you like. The

most remarkable thing about that is if you think that humans have been

around for a long time, we have been around for 11 thousandth of a

single galactic year, which is like a afternoon. We will get an

explanation of how that formation happens but first let's go into the

field. This guy's a miraculously clear for us. -- the sky is run

Cristie Kerr for us and we have found the Andromeda galaxy. For you

are not mood to astronomy. -- you are not new to astronomy. That is

right. A bit of cloud has gone across and it can be quite helpful

if it takes away some of the glare. But not too much. Oh exactly.

was the first time that you have seen galaxies? The first time I saw

Andromeda was in the 80s. I think my favourite view of our galaxy,

the Milky Way, was in Kenya a few years ago. Far away from any kind

of light pollution. We have a wonderful, polished sky tonight so

we can make out the stars. It is beautiful. It seems that two thirds

of Western Europe cannot see our galaxy because of light pollution.

That is basically excess and intrusive light that Brighton's the

night sky. On your screens is Europe, and it looks spectacular

but that is basically the glare from streetlights, offices and

houses. The effects of excess lighting are plentiful. It affects

the environment, wasting vast amounts of money, and it can

disturb wildlife. It can even affect your own body clock. More

crucially it is disastrous for I have come to the Royal

Observatory in Greenwich, one of my favourite places and a real

landmark of British astronomy. I am here to meet a group of stargazers

who all live nearby in London. I want to know about their experience

of astronomy in the city and find out how they are affected by light

pollution. So what is it that you find frustrating about light

pollution? It is just the glowing in the sky that prevents me from

seeing what I want to see. Especially when I am with my

children. I see the images in books and on television and they always

ask why they cannot see things like that. Clearly the answer is light

pollution. It is constant, really. Your eyes never adapt fully to the

night sky. Security lights at debating where animals in gardens,

constantly flashing. -- activating by animals. Some of the brighter

stars we cannot even say because of the constant orange glowing that is

there all the time. When Greenwich Observatory was first founded in

the 1600's, it was a long way outside the centre of London. Now

it looks straight out over the city. And all of these lights from the

Millennium Dome to the individual street lights have blocked the sky

it from view. As London astronomers, these people rarely get to

experience proper darkness. I am taking them somewhere to experience

stars without the glowing. I am taking you to a proper dark sky.

What would you like to see? naked eye view of the Andromeda

galaxy which people say is possible. That would make my day. I am

longing to see the Milky Way. I just love seeing it in photographs

because it is beautiful. Just to see that with my own eyes would be

a dream, really. How about yourself? I am dying to see a

galaxy, any galaxy will do! Just to see it with my own eyes, in real

time, something that is so far away, that would be amazing. So to fulfil

the wishes of the city astronomers, we are leaving the bright lights

behind and heading somewhere really, really dark. Now we have come all

the way from London. We have diligently kept our heads down.

Three, two, one. Take a look. How is that? Beautiful. Amazing. There

is just so much to see. Just so many stars. It is overwhelming and

disorientating. Beautiful. This is the stone circle in the Cotswolds.

It is so dark here that we have to use a special light intensifying

camera that is thousands of times more sensitive than any normal

camera. Can I tell you away for just a moment? I know it looks

impressive. I know you want to make the most of it but we have got a

challenge for you. You have to work for this. If I use my laser pointer,

can you see the consolation of Pegasus? The winged horse. It is

the square that we are interested in. I am guessing that you can pick

out those stars back in London, just about. You challenge is to

count how many you can see within the Square of Pegasus. Really?

I can't normally count any inside it. So from London you can't see

any? 1, two, three... 10. Nine. There leaven. I have got 12.

have 12. I have one that might be a discrepancy because it is on the

line. Borderline! Let's say that it is. You can see 12 stars within the

Square of Pegasus. That is a fantastic measure of how dark the

sky is. To see 12 is incredible. And zero in London. It makes you

realise the beauty of what you get. I have a treat for you. If we take

the top corner stark of the Square of Pegasus, -- corner star, and we

hop further to the North, there is one there and a faint one there.

You can make out that fuzzy blob just there. That is the Andromeda

galaxy. Mind-blowing, isn't it? Truly amazing. We have seen some

pretty incredible things are so far but the crowning glory, the thing I

am pretty sure you could not normally see from your houses in

London, is that overhead, running all the way from the horizon over

there. The Milky Way. Fantastic. That is actually the combined light

from all the stars in our galaxy. As you can see, there are thousands

and thousands of them. Even our specialist cameras are not

sensitive enough to pick up the Milky Way. But here it is in all

its glory. It was taken on a long exposure from exactly where we are

standing. It is incredible. takes a moment to take it all in.

So overwhelming. I have seen it in pictures. All this time, there it

is. I am awestruck because I have never seen so many stars in such

clarity. It is just awesome. It really is. My have just never seen

it before. -- I have just never seen it before. It goes to show

that the beauty of the night sky is taken from us by pollution.

It is incredible how much more you can see in the correct conditions.

Dark Sky Discovery is a network of groups that puts together of dark

areas in the country near you. don't have to be in the middle of

nowhere. We have some images of some of the areas. This one, for

example, is a science centre in Winchester in Hampshire. That

stunning picture was taken from there. Then we have this

observatory in Northumberland. Again a beautiful scene of the

North Star with the start trials rotating around it. -- star trails.

Actually we are the ones rotating. And this one near London. And now

this car-park on the Isle of Skye. The sun is very active at the

moment. If you are in the North of the UK, you can see quite a lot.

All of the information is on our website, as always. You will find

details of how to find an area of darkness. It just needs to be far

away from light pollution and with a clear horizon. Light pollution is

not just from office blocks. We are all guilty of it because even the

smallest communities create a lot of light. Tomorrow we are going to

ask a small town to switch off all of their lives simultaneously on

air. Here is the low-down on what we are trying to pull off. This

rural town may not be the kind of place you would associate with

light pollution. Only 1600 people live here and it is near to an area

of Exmoor which has the darkest skies in Britain. That is precisely

why we have chosen this town for the challenge. Even a town this

small generates a lot of excess light. As the sun sets, the lights

go up and a familiar orange glow descends on Dulverton. We should be

able to see the Milky Way from here, but like 90% of the UK, we can't.

We decided to give every single person the challenge of turning off

every single light. Last week we cent mark down there to help to

make it happen. With 40 shops and cafes, three pubs, a sports ground

and all those houses, there was plenty to do. There are literally

thousands of lives here and it will take some serious powers of

persuasion to get everybody on board. There are also some

technical hurdles. As it turns out, most of the street lights are

controlled individually by automatic light sensors, so there

is no big button that we can use to turn them all off. This challenge

will not be easy but if it works, it will really bring this community

together. We might even get to see the night sky as nature intended.

The last couple of weeks, Mark has been trying to spread the word

among the inhabitants of Dulverton. How is that going? It has been a

challenge, I will say that, but the people in Dulverton seem to be

getting on board with it. I have had posters, fly is a letter boxes,

and even shops putting up special displays, including a space cake. -

- flyers in letterboxes. They probably think you are weird. What

is the chance of success? We have to rely on everybody. Not just the

council, the shops, but on everyone doing their thing. Until tomorrow

night, we just don't know. Mark will be going down to Somerset to

persuade the town before coming live from doll that in itself for

the big switch off tomorrow night. If you are from there, he is

legitimate! It is not just a massive burglary heist. Don't take

him out of town! Aside from the amazing array of planets, stars and

galaxies, occasionally things crop up that do not make sense. Look at

his picture. If you think it is a UFO, you should have already turned

over to Celebrity Big Brother! Having said that, why she is -- my

machine is not working. It is not too bad. Apart from the faeces that

the seagull is dropping behind him. That is the giveaway. UFOs

generally do not drop faeces. How come so many people are seeing

There are some things that just seemed to belong in Hollywood movie.

And not on roads in Wiltshire. But this is a surprising statistic. One

in five people in Britain are convinced that aliens have visited

In fact, the government took sightings of UFOs sufficiently

seriously that until 2009, the MoD had a department investigating them.

Over 11,000 cases were examined by MoD staff. David Clark has been

studying them, and he wins a prize for best job title of the show.

have got reports from police officers, coastguards, military air

crew. And some quite silly reports from people who have seen things

whilst leaving the pub and that kind of thing. A couple of sighting

stand out. In 1996, a strange light was spotted in the sky above

Skegness in Lincolnshire. It was made all the more credible by the

fact that the key witnesses in this case were police officers. In the

end, one of the police officers went on to the top of the police

headquarters in Boston and started making a film. The police alerted

the RAF, who saw an odd blip on their radar which stayed there for

hours. The UFO caused such a step, the newspapers had a field day.

Another strange case was that of Alex Bird, who took this photograph

in Sheffield. It was examined by intelligence officers, there was a

full report produced. Quite something for a 14-year-old lad in

the 1960s. By an eerie coincidence, Alex was privy to another UFO

sighting when he took this photograph, more than 40 years

later, of Retford Town Hall in Nottinghamshire. When he got home,

he was looking at the negatives and he could not believe it, on one of

the images, there is a classic flying saucer, by the side of the

town hall. It is clear that many perfectly normal members of the

public are spotting UFOs all over the place, but not everybody is

convinced they have everything -- anything to do with aliens visiting

Earth. There are many things we don't fully understand about the

atmosphere. Just because you don't know what something is, doesn't

mean it is a flying saucer, or an alien spacecraft. It may simply be

something we don't understand. to expect aliens to even reach

Earth is asking quite a lot. Most people have very little idea of the

enormous distances between the stars. We are talking like Cheers.

At our current rocket speed, it would take tens of thousands of

years for our own spacecraft to go outside of our solar system and

reach another star system. We have no reason to believe there would be

any other civilisation with many, many light years of Earth. If we

are not seeing aliens, what are we seeing? In the case of the Boston,

it is rather embarrassing. They consulted the Greenwich Observatory

and their opinion was from the directions and times, what the

police had not -- observed was the bright planet, Venus, which was

really prominent in the sky at the time. This is quite a common

mistake. Venus is known as the Queen of the LSO's -- de UFOs,

because it is often mistaken for something mysterious. It was

concluded that Alex Birch's UFOs were most likely ice crystals, and

the one in Red that was most likely caused by a more Strood drop it on

his camera lens -- Moorish Je drop it. Some are also as a result of

the latest military hide where. Their forces are often

experimenting with new technologies and they can be 10 or 20 years

ahead of what you see on the news. I favour it was this one by NASA,

launched in 1961 -- my favourite. It was a vast spherical metal

balloon which was launched into the upper atmosphere, used to bounce

communications from one part of the world to another. For decades, the

military have been flying exotic objects around the site, and they

are still doing it. By the 1980s, much of the US Air Force's

technological research was going into stealth aircraft, and the

enormous Stealth bomber. By the time the Stealth aircraft had been

publicly revealed, it is probably no coincidence that the general

trend in UFO sightings was moving away from the circular disc,

towards something that was more triangular in shape. And a lot of

UFO reports are down to people simply not knowing what is in the

night sky. Satellites for example. There is a group of satellites,

they are communication satellites in very high orbits. Most of the

time you don't see them but often - - every so often they catch the

light of the Sun for 10 or 15 seconds. Anyone looking at that,

seeing it get brighter, might think it is something coming straight

towards them, and then as it faded they might think it had turned

around and whizzed away, but it is the satellite going across the sky

and catching the light of the Sun for 10 or 15 seconds. Satellites,

water drops, planets, secret military planes, that is that

settled, then, hey? No matter how many cases you explain, people will

always be seen something new and asking for an explanation. I don't

think UFOs will ever really die. We may mention more about UFOs and

aliens tomorrow. An apology on behalf of my colleague, Celebrity

Big Brother does not start until nine. He is not the professor of

everything! Liz Bonnin got an amazing view of the closest port

galaxy to earth and now she has moved to a larger telescope to get

a more detailed look -- closest dwarf galaxy.

We are in the control room of SALT with ape Peter who we met last

night. -- with Petri Vaisanen. Tell us what that SALT image is there.

We were looking at this contracting colliding galaxy about 400 million

light years away. It is a major galaxy, smaller than the Milky Way

but bigger than the magellanic clouds. How do galaxies get that

big? They grow by accumulating smaller galaxies around them,

eating up other galaxies. The bigger the galaxy, the faster it

will grow. Little galaxies are coming up to bigger ones but bigger

ones interact and merge. This is of colliding galaxies? That is right.

They are two major galaxies, and a small reward in interaction and

basically a collision. -- smaller one. The individual stars did

actually collide, they are too far apart from each other, they are

very small -- don't actually collide. The gas and dusts collides

and when that compresses, new stars are born. The more violent the

interaction is, the more spectacular starburst you get.

is a beautiful image but you are interested in more? Yes, we take

spectra and from that a lot of the science comes. We can measure

masses and their star formation history is, and try to piece

together where they came from, where they went, how they changed.

Fascinating, thank you very much. Another SALT astronomer is Steve

Crawford. I believe the Milky Way is on a collision course with

Andromeda, is that right? That is true. They are expected to merge

together in about four and a half billion years. Not too soon, what

is going to happen? If we look at the simulation, we can see the two

spiral galaxies merging together for top they are literally going to

pass through each other? What is going to happen to our solar system

and Planet Earth? It depends on where in the Milky Way It -- where

in the solar system the Milky Way is, it could be floating out into

deep space. What will the resulting galaxy look like? They will form

together to make a new elliptical galaxy. What are we going to call

it? Milkdromeda? What do you reckon? I might go with Andromeda's

milkshake! It is a really good name! I don't think we have to

worry about it quite yet. Coming up tomorrow, or we are going to go

right across the plateau to check out this, it is called Superwasp,

super wide angle search for planets. It has found 75 exo planets and is

looking for more as we speak. I will be finding out how that works

tomorrow. See you then. Thank you. We will also find out

how our search for a planet has gone. Let's go back to see how Mark

and the observers are getting on. John has had a great time but he

has had to head back into the studio. The skies are still clear

for the second night running, which is remarkable. The guys have been

taking some beautiful images and joining me is Steve from the Mac

has filled astronomers society, he has taken a beautiful image -- the

Macclesfield. It is an assembly of 109 of the 110 Messier 83 objects

because one of them is never visible from my back garden. As the

seasons have rolled by, I have made a conscious effort to try to

capture the more obscure ones in a digital camera, attached to a

telescope. Whilst my sky conditions are orange and challenging, overall

I am plight -- quite pleased with the result. From the back garden,

it is incredible. Stay tuned for Back To Earth, where I have a guide

to find what -- to show what you can find in the night sky. But with

Thank you, the cleverness of the skies has been a real treat but

things are different tonight -- clear theirs. Thicker cloud has

spread in. ICloud dulling the sky in one or two spots, you will have

to get out quickly -- high cloud, dulling the sky. We are going to

see those cloud layers spread southwards and eastwards, bringing

mist and rain for the most part. By the end of the night, before the

sun gets up, you might get clear skies into the north-west of

Scotland. It is a case of getting out early if you can for tonight.

Tomorrow we split the country into two. Southern parts of England and

Wales, a lot of cloud with outbreaks of rain. North Wales,

Midlands, East Anglia, you might One of the biggest questions is how

the Milky Way was formed. We asked Oxford University to do something

they have never done on this scale before, to run a computer

simulation to show how it started from the beginning of time from the

Big Bang, how our galaxy formed. Fiat to show us the result is Dr

Andrew Pontzen, this is not a simple task -- here to showers were

that it is not. We started with programming a computer with simple

physics. We then set up the computer with what we think the

universe look like near the big bang. So you say the basic laws and

you press go? That is basically it. So the earlier slide we can see in

years after the Big Bang. Yes, it had tiny ripples in it which we

think came from quantum processes at the start. This is the beginning

Talk us through what we are seeing now. You are seeing the matter that

started out being quite uniformly spread out, it is starting to clump.

As well as the whole universe expanding, it is forming comes out

of what was originally quite smooth. What is the green? I have coloured

it green because it is dark matter so normally would not be able to

see it at all. But we can pick out anything in the virtual universe.

We have picked it out in green. have frozen 1.7 billion years after

the Big Bang. Dark matter, we should talk about that a bid. The

universe is dominated by staff that is not this. Yes, something like

four fifths of the stuff, we think, is not like the stuff that you and

I are made out of. We can infer its presence, we are fairly certain how

much there is. We can measure it through the cosmic microwave

background. What we are seeing is the visible matter. That is right.

We have switched and the faint blue stuff is gas, the white stuff is

stars. If he did not run this would be dark matter in the simulation,

would it work -- you did not? you would not see this. There would

not be a big enough gravitational pull. We need the dark matter to

create the galaxies. Yes. We can roll the clock on again. I think we

keep it frozen for a moment. We are zooming in. The blobs might have

looked like single stars, they are many galaxies, they have up to 100

million stars in their -- meanie galaxies. We can see that all of

these are surrounded, we call them halos of dark matter. We have these

irregular shaped things that have already formed, the real matter is

Yes, when we see what happens next, the dark matter controls it. The

little galaxies all merged together. What is notable about this process

is that it carries ongoing. It is not just that a few little galaxies

come together and that is a galaxy, it carries on happening. This is

the history of our galaxy through time. We started as a small clump,

then we mashed with other ones, spinning around to create larger

galleries. -- galaxies. Yes. And if we skip to the present day, we can

see enormous spiral galaxy and fly in to see what it looks like from

inside. This is a simulation of the creation of the universe. You have

put in some basic physics, basic data about the distribution of dark

matter and you have pressed go. You sit there and this galaxy emerges,

looking like the Milky Way. This is a picture of the real Milky Way,

and if we cross fade them, you can see how similar it is. It is a

testament to the power of what we know from basic physics that we can

do this. That is the simulated Milky Way and that is the real one.

Are we leaving anything out of this model? Yes, there are certainly

things that we do not fully understand at the moment. We have

black holes in there. We don't really understand fully what we are

doing with those black holes. are one of the big unknowns in the

galaxy formation. That is because nobody has ever seen one. How do we

know for sure that they definitely exist?

Ask any physicist about black holes and they will tell you that they

exist. But I could say there is the Unicorn in these would lens, and

you would rightly say that there is not because you cannot see it. --

this woodland. I could say that it is there but it is invisible and

you would probably think I was daft at best. But what is the difference

between my imaginary Unicorn and a black hole? But goals by definition

are invisible. You cannot see them so how do we know they exist? --

black holes are by definition invisible. The first clue that

black holes are real came from here, in the Cambridgeshire countryside.

It was in the 1950s. While the rest of the country was this thing into

wireless radio at home, out here they were listing into a different

radio signal. Radio signals from outer space. This is the mallard

Radio Observatory. Back in the 1950s some of the first radio

telescopes in the world were built here. When they turned them to the

Nobody could work out what it was and what it was coming from.

Imagine that this thought is a beam of radio waves. Telescopes in the

1950s could detect radio sources in the sky. They could tell roughly

where the beams were coming from. Somewhere over there. But they

could not tell precisely. Then an of astronomer at the very clever

idea indeed. -- had a very clever idea indeed. He knew that on 25th

August, 1962, the Moon would be in the same patch of sky as the radio

source. So he watched and he waited and he saw that as the moon

travelled across the sky, it went in between the Earth and the radio

source, and carted off. Then as it continued its journey across the

sky, the radio source reappeared. By measuring precisely when the

been disappeared and appeared, the astronomer was able to pinpoint

precisely the source of the beam. It was tracked to what looked like

a faint star in the constellation Virgo. One tiny dots of light among

the millions of others in the sky. This is an image of that piece of

sky. That point of light just there is the source of the radio signal.

Pretty much every point of light that you can see in this image is a

star inside our galaxy, inside the Milky Way. But this point of light,

the origin of that radio signal, is 3 billion light years away. And yet

it can still be seen. No star could shine that brightly. So what could

that possibly be? The astronomers called it acquired the stellar

object, quasar for short. -- Scientists could only think of one

way that stars could appear that bright, and that is if they were

falling into a black hole. Stars falling into a black hole would be

completely ripped apart. Gas and dust would be torn from their

services as they spiral inwards at tremendous speeds. They would in it

so much radiation that it could be seen right across the universe and

that would mean we could detect it on earth. -- they would emit

radiation. The astronomers in Cambridge realised that the quasar

that they were seeing was actually a black hole, a giant black hole,

and the light and radio waves were coming from entire stars having

light and dust ripped off them and spiralling to destruction inside

the black hole. Over 100,000 quasars have now been discovered.

All are thought to be super massive black holes, actively feeding on

stars. And all of them are found in exactly the same place, right in

the centre of galaxies. So does that mean there is a black hole at

the centre of every galaxy? Our galaxy, the Milky Way, could not

have a quasar like the one discovered in Cambridge because we

would see it. It would shine as brightly as the full moon, visible

in the daytime. But imagine a black hole that had eaten all the nearby

star systems, so there is no gas and dust to spiral own and no

radiation to make it bright. So it could still be that there is a

super massive black hole at the heart of the Milky Way. One group

of scientists spent 16 years painstakingly searching for it.

This is what they found. I think this is one of the most remarkable

graphics in recent scientific history. It is a picture of the

centre of our galaxy and the stars that orbit around it. In a two

stars that you can see are orbiting very fast around some central

object. They reach speeds of around 11 million mph. When you plot the

orbits out precisely, you can calculate the mass of the object

that they are orbiting around. It turns out that the mass of that

object is 4 million times the mass of the sun. But it is more than

that, because you can also work out the maximum size that it can be. In

a star get close to that central object, as close as Neptune gets to

the sun. We have an object 4 million times the mass of our son,

compressed into a space smaller than our solar system. And it is

invisible. The only thing that could be is a black hole. The

centre of our galaxy. Black holes started out in the imagination of

physicists. But we now have evidence to prove that they are

real. Not only do black holes exist, but we now suspect that they formed

the heart of nearly every galaxy in the universe. Including arrow. --

including our own. Someone up there we know there is a super massive

black hole at the centre of our galaxy and the solar system is

orbiting around it. Why do we orbit around a black hole? We need to

explain how gravity works. This is the theory of relativity and it

showed us this. It was the interaction of a planet and how we

twisted the space around it. This is traditionally shown by

physicists by using spandex. wondered where my trousers had

gone! It is a large mass and it twists the space around it.

Something going past it is sent off course. Einstein said that things

follow a straight line through space and time. Mass is curved

space and time, so if you do not know that the space and time is

curved and you are travelling through it, then it will look to

you that you have curved around the mass. If you enter the density at

the right speed, you will be spinning round and round, and that

is what an orbit is. You can think of Einstein's gravity as a

fictitious force, at the space and time be incurred by massive -- be

incurred by massive objects. This is the curve that you get from a

black hole. The black hole curves the space so far, that when

something approaches bit... This could be a photon, a particle of

light. What happens in a black hole is that the photon approaches and

it cannot escape when it crosses the boundary, which is called the

event horizon. Eyes and's theory predicts that if you get close to

the centre of the black hole, which is caused the singularity,

infinitely dense, infinitely small, space and time are infinitely

curved, and the theory itself breaks down. This is probably the

most fascinating thing about black holes on the physicist's

perspective. The best theory we have, the theory of relativity,

predicts its own demise somewhere down there. Spandex cannot read as

much as space can, of course. -- cannot stretch. There is literally

no way out for anything. Yes. Tim O'Brien, associate director here,

has been telling us that that holes a one of the specialist subjects

here. -- black holes of one of the specialist subjects. Yes. This is

the Hubble telescope. And some other telescopes. This is a radio

image of the sky. We can see through the dust cloud that block

our view of the centre of the galaxy. In the middle, that is

Sagittarius, the black hole. This is new research, essentially.

just last week. The quasar is in the middle and this is the optical

view, the black dot in the middle. We can zoom in and look at the

radio image. Where the black hole is the bright spot in the middle.

The thing that shoots off to the left is a jet of particles we think

out from the black hole, almost at the speed of light. -- rushing out

from the black hole. The shape of it is like a corkscrew. It is

spinning like that. One way in which that might happen would be if

this were the result of a merger between two galaxies. When the

galaxies merge, the two black holes end up whipping around each other

and that causes this. Do they fall into each other over time? Yes.

They will. They spiral closer together. They create ripples in

space and time, predicted by Einstein. Not yet directly detected

but we are working on that with this telescope across Europe.

of the most remarkable things about these images, these experiments, is

that we are trying to look for a breakdown in relativity. The

breakdown in Einstein's theory. For me this is what science is all

about. We are trying to test our theory to destruction. We have

discussed this for a long time. The show carries on for another half an

hour in this very room and you can ask more questions. We need help to

fight our own exo-planet. 60,000 of you have taken part so far and the

more of you that take part, the more likely it is that we will find

one. You can download your star guide from the website. We are

going off and now here but we are coming back on in 10 seconds to go

and sit over there. -- going off- air. We will be talking about black

holes and you can send in your questions for us to answer. Jon