Episode 3 Stargazing Live

Over 100,000 of you have been working hard scouring an unexplored

area of Mars. Your efforts have paid off. You have made an

incredible discovery on the surface of the Red Planet. We will be

revealing all tonight. I'm Brian Cox. He is Dara O Briain. This is

Welcome back to a very foggy Jodrell Bank Observatory. So foggy

we can hardly see the big dish. Not a great night for stargazing. It is

the third and final night of this year's Stargazing Live. Thank you

for your questions. We have some remarkable viewer photographs that

I want to show you. This is the Orion Nebula. We saw it on the

first night. This is a picture - it is taken with a 4.5 inch reflector.

26 30-second exposures. This was taken last night. This one,

California Nebula. Is it because it's the shape of California?

It was taken on the 9th. This one is the jewel in the crown in many

ways. It may not look like it. It's - we now know - a comet. It was

discovered, or the photograph was taken by Nick Howes in the States.

On Monday night, the stargazers at the school - this is now a comet.

That is a genuine discovery. As we mentioned, we have made some

interesting discoveries on the surface of Mars. Chris Lintott will

be back later in the programme to reveal all. There is much more to

stargazing than these TV shows. There are over 500 events taking

place up-and-down the country for you to get some hands-on with

astronomy. I have some pictures. I want to show you what everybody has

been doing. Here is one. This is the Canterbury Star Party. 1,200

guests turned up to Canterbury on Tuesday 8th. This is them showing

how to make rockets with a vitamin tablet. This is the Eden Project.

1,500 guests on 8th January. Finally, this one - that is nice.

Where was that? Birmingham. This is people from Birmingham University

explaining how gravity works. One last picture. This one was sent in

by Private Eye. There is Dara O Briain looking very handsome and

Buzz Lightyear! To find an event near you, go to

bbc.co.uk/stargazing. We will be going to see how Mark got on with

the Herschel Telescope. Among his many claims to fame, Herschel

coined the term "asteroid". It means star-like in Greek. In five

weeks' time an asteroid 45 metres wide is going to pass between us

and the Moon, coming closer to Earth than some of our satellites.

In March, the comet Panstarrs will streak by in the sky followed by

Ison. This was taken on 9th. Ison will pass very close to the Sun. If

it survives that encounter with the Sun, it could break up, it will

sweep out in January 2014 - it could be one of those comets that

you see in a tapestry! Fantastic. We are going to pass through the

tail of that later in March. It may give us a meteor shower. Fantastic.

We have had lots of questions. "What is the difference between

asteroids, comets and meteors?" We have to keep on explaining this.

Comets are large dirty snowballs. Yes. They are icy with some rock

mixed in. They come from distant regions of the Solar System. We

will see that later on in regions called the Kuiper belt and the Oort

Cloud. The comets are spectacular. We have some fantastic footage.

This is a beautiful shot from the International Space Station. Looks

like some kind of computer graphic. That is Comet Lovejoy. Lovejoy was

discovered in December 2011 by Terry Lovejoy in Australia. Here it

is passing behind the Sun. Remarkable piece of footage. Here

is another video. This is from the Solar Observatory. The thing about

comets - you tend to think of them streaking along. The tail is blown

by the solar wind. The Sun is heating the comet up. You are

getting gas and dust erupting. it is moving away from the Sun, it

follows its own tail? Yes. Asteroids are more like rocky

fragments of planets. Yes, this is the first asteroid we encountered

in space. This is not a video. This is Eros. It's about 34 kilometres

long, which is about the size of the thing that - if it hit us, it

would be the size that killed all the dinosaurs. It doesn't cross the

Earth's orbit at the moment. It crosses Mars' orbit, though.

Because it continually crosses the orbit of Mars, it could be

perturbed by Mars. We landed on the surface of that asteroid. When we

talk about meteors and meteoroids, they interact with our atmosphere.

Meteors are when they burn up. Meteor showers. What are they?

is a meteor shower in December. The reason for that is that they were

created by a comet. They are the remains of the tail of a comet.

you think about what a comet does. It orbits the Sun. So they leave an

ellipse of debris and that will sit there in orbit around the Sun in

the place where the comet tracks around. The Earth passes through it

at the same point in its orbit every year. And that is why you

always see them coming from the same place. That is how meteor

showers are named. So one of the things we want to

talk about is the big asteroid coming our way very soon. It is

called Asteroid 2012 DA14. On Friday February 15th it will pass...

Here it is. That is how close it is going to come! These are our

satellites. The green blobs are the satellites. It will come well

within the orbit of the station. will pass on 15th February. This is

going to be more pressurised Valentine's Day so do something

good on the 14th February! It will miss us by a mile! How can we be so

sure that this trajectory is so right? Liz Bonnin is standing by

for us at the Goldstone Observatory. Welcome to Goldstone in the Mojave

Desert. This is the Mars Antenna, part of NASA's Deep Space Network.

Now, I'm inside the base of the antenna and presently, it's

tracking the New Horizon's Mission to Pluto. Marina, you are one of

the scientists that does that work. How does tracking an asteroid work?

It is simple. You point it to the asteroid and you bounce on some

mike waves. This allows you to get its location very precisely --

microwaves. This allows you to get its location very precisely.

were tracking Apophis last night. Scientists thought it was going to

hit us. What is the latest? Well, we have been tracking it since late

December and what you are seeing here are the images from this

morning. Is that Apophis? What you are looking at, this is a 300 metre

diameter object that is 14.5 million kilometres away and we have

the detection. Radar data that we have collected have completely

excluded any chance of impact. We are safe. That is good news.

Furthermore, we can now precisely predict its trajectory decades into

the future. Fantastic work. As well as tracking, you get a good

resolution from these orbits. This is Toutatis. This is a prime

example of what radar can do. This is 4.6 kilometre-long asteroid. It

was 7.5 million kilometres away from Earth. We are getting

resolution to resolve surface boulders. Wonderful technology.

Scientists are also getting a better idea of the composition of

asteroids with their latest work. What is clear is that there are

many more different types than previously thought. Amy Mainzer,

another NASA scientist, taught me how to make my own.

We have asteroids that are solid lumps of metal. Take some of this

dirt and spoon it in. Step one - all asteroid also have some type of

dirt? That's right. You have silicon in here, all kinds of

heavier elements and that's going to be the basic constituent of most

asteroids. We will pour some of that water in and make a big mess.

One theory about why there's so much water on Earth is that some

arrived here aboard comets and asteroids. That's not the only

familiar substance found in them. Let's take some of this molasses.

How much? That's pretty good. This one is carbon-rich! Now we need a

squirt of another ingredient that has been found in the remains of

asteroids that have landed on Earth, ammonia. Then we add our final

ingredient - dry ice. At minus 78 centigrade, it will mimic the

freezing conditions of the Solar System. Sprinkle that in there. We

will freeze it up good. Let's take a look and see what we have ended

up with. Amazing! That is what we got. In true asteroid-style, it is

beautifully irregular. It is not completely round. Oh my goodness!

This asteroid is a very particular kind, a randomly active main belt

object. A Rambo, would you believe?! It is special. We have

discovered in the last ten years or so this very unusual class of

asteroid that becomes active. Active in what way? These things

exhibit huge clouds of gas and dust coming off the surface. What

happens is when the Sun hits the objects, we use this bright lamp to

represent the Sun, what we think happens is that a smaller asteroid

may strike the surface and scrape off some of this dirty outer layer

and it may expose some of the ice. Look at that jet coming out from a

tiny little hole and you can't see any of the ice exposed? That's

right. This is a really good example of what we think happens.

If we were orbiting the Sun, this object would have a big tail around

it. And a big halo following it. Almost two years ago, the Hubble

Space Telescope photographed a Rambo which grew a tail when it was

heated by the Sun and just there is its X-shaped impact scar. Closer to

home, what is the worst that could happen to the Rambo we have made?

This is a good sized lump of rock. How can this really cause that much

damage? Well, something this small obviously can't. If something were

the size of a building, like 30 or 40 metres in diameter, it would be

large enough to make it through the Earth's atmosphere. Now you have

something that can cause a great deal of damage because if it is

travelling at 10 kilometres a second or more, it packs an

enormous punch. Amy has now joined us at Goldstone. You use Space

Telescopes to find out potentially dangerous asteroids. Tell me about

the project? It's a Space Telescope that used infrared light to

discover and track near Earth asteroids. Infrared is heat. We are

sensing heat. It gives us an idea of the size of the object. We can

tell the difference between something that is really large but

dark, like a piece of coal, or something that is much smaller, but

highly reflective. OK. Getting the size is important for understanding

We sampled some of the population and used it to look at what is out

there. What have you come up with? For objects that are larger than a

kilometre, like the dinosaur killing object, 90% of these have

been found. What about the other 10%? We don't know where they are

yet. There's another piece of not so good news which is that for

objects larger than 100 metres, we've only discovered 25% of those.

They can cause great damage. Absolutely. You need to continue

this surveying work. We have a lot more work to do. What happens if a

big one is coming at us? Ideally we will find an object 20 to 30 years

before it will happen. If we have time like that, we can design

strategies that would use explosives to push the asteroid

aside or break it into pieces or maybe even devised technology to

target out the way. How? A either gravitationally or attaching solar

sails. Astonishing. Thank you. Come back to us when we talk about

emissions and more about asteroids and comets. Standing by it on our

live block is Don. He is head of NASA's near earth objects

department. He will be informed if an asteroid is heading our way for

a start -- he will have to inform the President. He can take your

questions at bbc.co.uk/stargazing. A lot of people are asking where

these objects originate from. We have a model for you. All of the

asteroids we ever encountered... Everything comes from three places.

We have an animation that shows just the asteroid belt ter, between

Mars and Jupiter and it is the Mars and Jupiter and it is the

green area. Every point is a map position of an asteroid. This is

what it looks like. It is a bit of a mess, which is why we get impact.

The asteroid belt is packed with Rocky objects, including this one.

This is called Vesta. I have an image of it. It is quite a big rock.

It is about 350 kilometres in diameter. The remarkable thing

about Vester is I have a piece of it here. This came from there. The

mystery will be revealed later. It mystery will be revealed later. It

is beautiful. This is the Kuiper belt. Faces a region of IAC, rocky

object. This is where Pluto lives. It was demoted because it turn

Celtic is one week -- one of many objects of a large size in the

Kuiper belt. We are on our way to Pluto at the moment. This is a

picture of a spacecraft on its way. It left in January 2006. When it

left Pluto was a planet. When it got to about there, Pluto was

demoted, but by that time it was too late to stop. It makes no

too late to stop. It makes no difference to the mission. These

are the best images we have of Pluto now. They are from the Hubble

Space Telescope. It is extremely cold. We don't know a lot about

Pluto other than these images. is ice. For is an ice, about -200

Celsius. Finally you step into this region, the far reaches of the

solar system, the Kuiper belt. This is a picture of the Oort cloud, a

spherical cloud. This is a disc of the solar system? Yes. This is more

spherical. It is a vast collection of large and small lumps of ice and

rock. It stretches out about a light year, we think. A quarter of

the way to the nearest star. Nearly all of the Committee's wheezy come

from either the Kuiper belt or the Oort cloud. -- comets we see.

wanted to work out what things were in danger of hitting. We need to

know where the Earth is at any time. How do we were kicked out? The

How do we were kicked out? The answer lies in the southern

hemisphere's guy. -- southern- hemisphere sky. This is an iconic

constellation. It even features on the Australian national flag. It

was by interpreting patterns have stars in the sky that we began to

make sense of our cosmic surroundings. On Earth, it is easy

for me to work out my position relative to the object I can say. I

can understand my place in this world. If you're an astronomer, you

have a problem because all you can see on little points of light in

the sky and for the early astronomers, they knew nothing more

than that. To make progress, people began to make maps of the night sky

end as much detail as possible. He this is an early start shot of the

southern sky from 1801. It is a two dimensional representation of the

position of the stars. This is the Southern Cross. When you follow

what you get to the bright southern star. 200 years ago, the way these

maps were made meant their accuracy was limited. When he made this map,

he did it by hand. He looked at this guy and transcribed the

positions of the stars on to this piece of paper. A huge opportunity

for human error in that process. But in the late 19th century, a new

technique allowed astronomers to achieve real precision. Photography.

If you have a photograph, a plate and a telescope, the marks on a

plate are not made by the human hand, they are made by photons of

light that have travelled from the stars themselves, hundreds or even

thousands of light-years to register their position on the map.

By fitting a camera to a telescope, the accurate positions of thousands

of stars could be recorded in a single exposure. Something

astronomers hoped would help them determine our place in the universe.

In 1887, a decision was taken to map the position of every star that

can be seen in this guide with high precision. That was a project that

An incredible commitment, like building a cathedral. Much of the

southern sky was mapped here, at Sydney Observatory, and this is one

of the photographic plate that was used Clinton's -- to construct the

used Clinton's -- to construct the Astra graphic catalogue. An

exposure, just over six hours, and you can see very faint black dots

on the plate. Each one of these black dots is a star and the

positions were measured and transcribed into here. The Astra

graphic catalogue. This is 1893, John Reid 20th. Documenting the

positions of the stars in this photograph. What we have here is a

perfect representation of the positions of the stars in the sky

from Sydney on January 20th, 1893. 750,000 stars were recorded at

Sydney Observatory and the results were combined with surveys made at

19 other observatories around the world, creating a single, huge

catalogue of the stars across both hemispheres. For the very first

time, astronomers had an accurate record of our position relative to

4.5 million stars. That has helped us to make another intriguing

characteristic of the stars with great precision. In the 1990s,

these measurements were repeated, this time by a satellite the

European Space Agency Bill. What was found was that for at least

some of the stars, their positions had changed an appreciable amount.

For his slow drift is unique to each star and because it takes

years to become apparent, comparing recent satellite data with this

catalogue has given us the most accurate ever record of this

phenomenon. He the reason for this movement is that all of the stars

in the Milky Way are a orbiting around the centre of the galaxy,

but each at its own particular speed. Today, even deeper in the

universe, it is not just stars fat have their own unique motion. -- of

that have. By looking out beyond the stars in the Milky Way, we

found that all the galaxies in the universe on moving relative to each

other as well. We are part of a group loan -- known as a local

group. 43 galaxies bound together in the same way the stars are bound

together in the Milky Way. That group itself is moving roughly in

that direction to something called the Super cluster, a group of 5,000

galaxies or more, about half a billion light years in that

direction. And we are travelling towards this enormous cluster of

galaxies that is over 500 -- at over 500 kilometres per second.

What we discovered over hundreds of years of astronomy, making

precision measurements of the sky, is that everything in the universe

is moving relative to everything else. We've learned that the stars

and galaxies are all taking part in a vast cosmic doused which we --

dance which we can now plot with We have all of these objects in an

Orbit around the sun. Why are some of them suddenly lurching out on

these crazy journeys? The answer, as with every answer, lies with

mathematics. We've got Tim O'Brien to explain. The mathematics of

this? You remember that all these objects orbiting around the Sun a

doing it under Newton's law of gravity. It turns out that there's

only four possible shapes of orbits they can have. They are really --

the really neat bit of mascot those shapes are defined by slices

through a core. Depending on what angle you slice through, you get a

circular Orbit, and elliptical Orbit, a Parabolica or Orbit or a

hyperbolical bit. Fees are in her elliptical orbits, some of them a

more secular. But in general, everything... They go round and

back. A most common or bits of the elliptical and hyperbolic her.

Hyperbolic Orbit is open. If something gets bumped into a

hyperbolic Orbit, that will go around the same place as before,

but it will shoot off. Yes, and it never comes back. It goes out into

interstellar space. The difference is essentially to do with energy

and angular momentum. Let's say we are in the Kuiper belt and

something has a gravitational interaction. It interacts with lets

a Pluto. It will change the energy of that object. It will change the

Orbit because these shapes are defined partly by the energy. One

of these things can be perturbed spirit begins a journey into the

inner solar system. Halley's Comet, which came from the Oort cloud,

that comes in. It is still an ellipse. It is. A period of 76

years, it comes back every 76 years. It could have jumped from a

circular Orbit into an elliptical Orbit. Because of an interaction.

The Oort cloud is interesting because it is so far out. Many of

the perturbations come from passing stars. They are very weakly bound.

The false drops away. -- force. bombed sit by passing and Zenit

heads off on a new journey. These hyperbolical orbits are interesting.

You don't see them coming because they come in and they have such an

Orbit that they go round once and disappear. Something perturb them

and dumps them. It is gone and we Bonevacia him again! Maybe some

time he will pass you. Let's find out if there are clear skies where

you are tonight. Let's go to Susan We are up against it this evening

thanks to a lot of cloud piling into the UK. To the east of the UK,

we have had a weather front that has hung around for much of the day

today. So that will obscure the skies here. Further west, another

front that's fizzling out. We will lose the rain but the cloud is

going to stick around. Between the two, a few clearer spells across

the North West and for Northern Scotland. My top picks for the

clearest skies - it will be in the west. And give it a couple of hours

and Northern Ireland will be looking almost crystal clear.

More information as ever on the BBC More information as ever on the BBC

Weather website. Thanks. Mark Thompson has been

building a modern interpretation of William Herschel's 20-foot

telescope. Anyway, in a tribute to his work,

Mark has been trying to re-create that telescope.

Over the past three weeks, I have been working with the local

community in Derby and a crack team of experts. We have had to make

changes to Herschel's plans to keep everyone safe, but we have remained

true to his principles. So far, we have built the supporting structure.

Big, isn't it? Now we have the small matter of making the

telescope. In Herschel's Telescope, right at the bottom of the tube was

a piece of polished metal to reflect the light from the stars.

It was shaped and positioned to focus the light towards the top of

the tube and here, Herschel would have stood on this viewing platform

and looked down the barrel through an eye-piece. This is our telescope

tube. We will put a mirror up this far end. So light comes down the

tube, hits the mirror, bounces back up the tube and then all the way up

to the top into this special adjustment we have made. We have

had to cut some of the tube out where the eye-piece is going to go

and hopefully, we will see some stunning views of the sky through

it? Want me to push? Not too much! Now we need to get it up into the

cradle. Chris Hill is on hand to supervise. That will do. That's it.

It is finally starting to look like a telescope. Inside the university

workshop, Chris is putting the final touches to the mount for the

mirror. An instrumentation expert is here with the missing piece.

It's arrived! We are using a modern glass mirror in our telescope.

Herschel would have used a piece of metal and that would have easily

tarnished. Even though he polished it for hours, it still wouldn't

have been very reflective. Herschel would have been blown away by this.

Yes, this would have been his Christmases! The mount has a set of

screws on the back, so that the angle can be adjusted. Now, we can

align the mirror. So the light from the stars is reflected through the

eye-piece. Shall we put it in then? Let's try it. The time has come.

Yeah. You got the screws? Back a bit. There! The first step is to

cover the opening with a large sheet of paper. For the next bit,

Herschel would have probably used a candle but we are going to use a

laser pointer. The light travels through a small hole in the paper,

down the tube and hits the mirror at the bottom. It is reflected back

at an angle to hit the paper again. I need to guide Chris to adjust the

mirror. Until the reflected laser light moves into position where the

eye-piece will be. Chris, if you can tilt the bottom towards me so

bring that away from you? Got you! Can you see it moving? Yes, keep

going. Woah! Spot on! How is that looking? Perfect. Excellent. That

is perfect, mate. Well done. This laser beam is simulating star light

and it is bouncing back out of the tube which is where I need to look.

If I spray this, you can see where the beam is coming out the tube. It

shows that we are ready for some clear skies!

After all that work, the time has come to reveal the telescope. Let's

cross live to Mark at the University of Derby.

There is a fantastic atmosphere. We have our own Herschel quintet. We

have the children from the school here. CHEERING We have also got the

members of the Derby Astronomical Society. Hello, guys. Now it's

taken us five weeks and hundreds of man hour. It weighs in at just

under half a tonne. It is Stargazing Live's Herschel

Telescope. CHEERING Now, it is the most amazing piece of kit. It has a

crank to turn the whole telescope. The whole structure moves around so

that you can access any part of the sky that you want to. It is the

most amazing piece of kit. Hopefully, we might get a chance to

look through the telescope. With me is Professor Alan Chapman. Alan,

what do you make of it? It is absolutely remarkable. It is a

tremendous realisation of Herschel's Telescope, using

scaffolding and modern equipment. I have never seen anything like it

before. Me neither! Even to the chaps pushing it around. Herschel

probably used sailors! We have used the same tube dimensions, the same

mirror diameter. We only had a drawing to work from. It took him a

year. We did it in five weeks. That is incredible? To him it was

entirely experimental and a brilliant piece of inspired

engineering. Herschel was a skilled worker with his hands. He employed

carpenters to do the heavy work for him. Yet, Herschel was a skilled

musician. A string player, a keyboard player and I think all of

those skills were necessary to the manipulation and adjustment of that

instrument. I will have to stop you there. Thanks to the guys from the

Derby Rugby Team. I'm really looking forward to looking through

the telescope. It is still cloudy here. It is foggy in Derby. With a

bit of luck, it may clear up. Do come back to us later on tonight

and we will see if we can re-create the images that Herschel saw.

Hopefully we will. We have been talking about asteroids and comets.

Of course, we will be struck by large objects from space. It's

happened all through history. It isn't necessarily a bad thing.

Without these impacts, our world might not be the place that we know

today. If you want to see one of the best

preserved meteor impact sites on Earth, you need to travel to the

Barringer crater in Arizona. Craters can be found all over the

Solar System like this. The battle scars of a long history of impacts.

Most are the result of one period, around 3.6 billion years ago, when

the whole Solar System was turned upside-down. It was all to do with

the combined gravitational force of our two biggest planets, Jupiter

and Saturn. We now believe that the giant planets formed much closer to

the Sun than they are today. Their orbits drifted hundreds of millions

of years until Jupiter and Saturn fell into a regular pattern. Once

every cycle the two planets aligned creating a gravitational surge that

played havoc with the orbits of all the planets. Neptune was catapulted

outwards and smashed into the ring of comets surrounding the Solar

of comets surrounding the Solar System with dramatic consequences.

For 100 million years, the Solar System turned into a shooting

gallery as the comets ploughed through it. Millions of comets were

scattered in all directions peppering the planets. It was

called the Late Heavy Bombardment. It created many of the craters we

see throughout the Solar System today. It left scars all over our

Moon. And it had a lasting impact on the Earth as well. The only

impact craters we see on Earth today, like this one in Arizona,

were made much more recently, but they reveal the scale of these

impacts. Today, impacts like this are relatively rare. They will

happen again. But during the late Late Heavy Bombardment, the

environment was changed radically and dramatically. Those changes

weren't necessarily catastrophic. It's now thought that a significant

amount of the water in the Earth's oceans was delivered by the impacts

of water-rich comets and other objects during the Late Heavy

Bombardment. That means that impacts could have played a key

role in the development of life on Earth. Before the Late Heavy

Bombardment, the Earth was a barren rock. Afterwards, it supported the

oceans that would become the Crucible for life. Without the

water delivered in the Late Heavy Bombardment life on Earth may never

have evolved. All this may have been caused by the violent

gravitational pull generated by two Joining us now is Dr Richard

Greenwood. We have seen one of your fantastic samples already.

talked about Vesta. It is from Australia. It has a special

composition that we know matches Vesta. One billion years ago, a

meteorite smashed into the southern hemisphere of Vesta. They drifted

into the three to one resonance with Jupiter and it is a real

conveyer belt. We have ten times as many meteorites coming from Vesta

as we have from the Moon, or Mars. That is remarkable. It is to do

with this gravitational interaction with Jupiter throwing these things

our way. Absolutely. This is iron? That is. If we pick it up, you will

see it is three times denser than a rock that you find in your garden.

It is pure metal. It is the core of an asteroid that melted. When it

melted, the metal sank and formed a core. We used to think these were

quite young. That is one of the oldest objects in the Solar System.

The reason for that is - at that time, they had a short

concentration of Aluminium 26. That would have been formed in a

supernova. Yes. It's probably the shockwave from the supernova that

triggered the collapse which formed Within two million years, which is

a small length of time, it would have gone. These are relatively

unstable and made in a supernova explosion? Exactly. Heated the

asteroids up. That is why you get the iron sinking? That's right.

is not the oldest thing? This fell in Tanzania, it is called Ivuna.

That is some of them there. In there, there are diamonds, graphite

and they came from some of the stars that pre-dated... This is

older than the Solar System? Yes. 4,567 million years. That is older.

That is older. The story of the origin of the Solar System is a

supernova went off, a shockwave came through this gas and dust,

that caused it to collapse and pieces of that shockwave - this is

from outside the Solar System? Exactly. And got trapped? Yes.

Startling. Technology now allows us to get up close and personal with

asteroids and comets whilst they are still in orbit. Let's go back

to Liz in the Goldstone Observatory to hear more. Thank you very much.

Goldstone and the rest of the Deep Space Network have communicated

with some truly remarkable missions getting us very close to asteroids

and comets that are speeding through space. Amy, if we can talk

about a few of them? Stardust? Stardust Mission flew through the

comet and it collected tiny pieces of the comet and it brought them

back to Earth. It has given us a new window into the Solar System.

None of that material has changed for 4.5 billion years? Exactly.

Deep Impact Mission does what it says on the tin? Exactly. It was

two spacecraft in one. An impacter spacecraft and an observer. They

separated when they got close to a comet. The observer watched and

allowed us to see the inside of the comet. What have we learned from

that material? It was a really surprising result. It turns out

that this particular comet was more dust than water-ice. Also, the

They have a lot more in common than we thought. And then for Dawn

Mission which sent an order to do my to it -- mighty fester. It has

been orbiting Vesta and it has returned spectacular images that

have allowed us to see the turbulent history that has happened

to this asteroid. Two giant impact craters on the South poll of the

asteroid and joy and scrapes that I even larger than the Grand Canyon.

Thank you for joining us. Dawn is on its way to Ceres, the biggest

rock in the asteroid belt, 950 kilometres in diameter and it has

been declassified as a dwarf planet. It will reach it in 2015 and will

begin its exploration then. That space around our planet is not

just filled with natural objects, it is also filled with staff and we

put up there. So much stuff that there's a pilot waiting to happen.

He in a quiet corner of Hertfordshire is a radar tracking

station that is used to monitor the movement of objects 2000 kilometres

above the earth. There are lots of things we got up

there. 1,000 satellites, nearly 20 telescopes and one space station.

But there's also a lot of junk, affectionately known as space

debris. So space debris is effectively all of the stuff in

space we know longer use or need. It could be dead satellites, did

rockets, fragments, pieces of electronic circuits, pieces of

paint from the outside of the spacecraft. They are floating

around. The Final Frontier is packed with rubbish, litter.

There's everything from an astronauts glove, that one stage in

Orbit for a month, to particles of you're in, flushed from early space

craft. There are bits of rock left by the Apollo missions. Even 32

nuclear reactors that used to power satellites. This shows you a

simulation of what we can see in Orbit. It ranges from debris close

to the Earth to places where TV satellites up operating. Fees range

in size from some things are size of a mobile phone up to a space

station. Her these objects mean we are getting tight for space in

space. We've realised over many years that although the universe is

potentially infinite, the space around the Earth is very finite.

But the problem isn't just that it is crowded up there, it is also

dangerous. All these objects are hurtling about at over 25,000

kilometres per hour. It is like a cloud of flying pockets. It has a

high energy moving at that speed. A pound coin in Orbit around the

earth has the same energy as a minibus travelling at 1,000

kilometres an hour. If that hit a spacecraft, it would destroy it.

1983, a chip of paint collided with the Space Shuttle. The impact was

enough to crack its 1.5 centimetre thick windscreen. In 2009 a US and

Russian satellite hit each other. Both were completely destroyed and

created up to 1,500 new bits of junk. It can only get worse. In 60

years we've gone from no man-made objects in Orbit to an estimated 35

million. And the worry is that areas of space we rely on to send

satellites for navigation, weather forecasting and TV will soon become

no-go areas. Currently there's no working answer, but all sorts of

plans are being hatched. From sales that would slow an object down so

they fell back to earth to giant balloons that would inflate to help

put the brakes on. But the UK's largest space company has come up

Astrium in Stevenage is better known for building satellites that

get sent to space. But engineer Jamie's job is to use his harpoon

to drag them back to work. We've got a harpoon we are going to fire.

It goes into the barrel inside a protective chamber. I will put some

goggles on. For harpoon uses compressed air rather than

explosives to fire. It is safer for space. We are ready to fire now.

Turn the firing switched on. Sadly At the moment, Jamie is test firing

his harpoon into pieces of actual satellite. It's early days, but

when complete the harpoons will have a spring loaded barrel and her

capers. If the system works, the harpoon will be mounted on a

satellite that will Chasetown space junk, harpoon it and tow it back

towards earth where we it will burn up socially in the atmosphere. --

safely. This only works with large objects. In Orbit, pig objects are

just thousands of small objects waiting to happen. -- big object.

Something has to be done and this could be the big thing -- best

thing. But until somebody can enforce an intergalactic litter

campaign, the research has to continue.

This is a vivid demonstration of the problem. This is lent was by

the National Space Centre a, a panel from a satellite. That is a

great picture with us shuttle underneath. The office was in Orbit

for six years. They saw this Goring. These are impact of micro meteors.

Invisible to the human eye. They are travelling between 8 and 9

kilometres per second and up to 30 kilometres per second. A tremendous

amount of energy. The plasma Burns. If you lift it up, you can see...

This is the spacecraft... That is a whole and that is a whole. You can

see the Dent. Minuscule pieces of dust. Back over to mark in Dobbie.

Last time we saw him he had unveiled our version of Herschel's

telescope. Have they observed anything with it?

Unfortunately not. It is amazing standing on this platform like

Herschel did all those years ago. Herschel did it in the damp English

weather. I'm safer than he is because I have harnessed to make

sure I don't fall off. There have been times observers have fallen

off those platforms. We can't show you any pictures, but it is

incredible to think that Herschel spent many years observing the

British night sky with the weather to contend with. We did get some

clear skies a few nights ago. We managed to record some images of

managed to record some images of things in the sky. The first

things in the sky. The first picture we got was Jupiter. Moving

very gracefully across the screen, caused by the rotation of the Earth.

The telescope doesn't have the The telescope doesn't have the

drive system so you can't see the object being tracked. A picture of

a beautiful Binary Star system in Cygnus. We have the picture of a

star cluster inside the Orion nebula. We have a final image of

Uranus which Herschel discovered with a slightly smaller telescope.

There's a very slight distortion which is caused by the orientation

of the optics in a telescope. He will have had to have contended

with these poor images. We can't show you anything live tonight, but

it is great to follow in Herschel's footsteps. Without greater

astronomers like him, we would not have learned as much about the

universe as we can see now. It is great that we can leave his

telescope to the residents of Derby so hopefully in the years to come

they can enjoy the night sky like Herschel did all those years ago.

Back to the studio. They are beautiful images and that

talent the scope will be in Derby for the next three years. --

telescope. This week you have been doing your own pioneering

scientific work thanks to our online experiment. We asked you to

study Mars's surface looking for unusual features. I spend a lot of

time looking at this guy thinking it is amazing. In this case, the

hyperbolic and third -- adjectives are appropriate. This is wonderful

and amazing. Real science in two days. More than 100,000 people have

helped us explore an area about the size of Holland. It was

Switzerland! We are working our way up. We found some great stuff. We

were looking at the Antarctic region of Mars and these strange

France which we think on from material suddenly erupting

material suddenly erupting underneath the surface of Mars. We

had this idea that it has to do with ice under the surface that was

being heated up. It is the time lapse. Yes. It was a year on Mars

has put together by users. At some point in the year, in the Martian

spring, these things erupt as the planet heats up? That is what we

now know. I can tell you for sure because we only find these around

March in the Marshin calendar. They happen close to the equator and

then they head closer to the polls and we thought they were rare, but

look at this. This whole region of ground would have erupted

underneath your feet. Don't go there in the spring! What about

this are titters -- artistic impression. We discovered that. Our

viewers discovered that is what is happening. We know when and where

it happens and we now know it is much more common than we thought.

That is because people used pattern recognition skills. More than that.

A good scientific experiment always leaves you with more questions.

We've no idea what this is. This is a type of terrain I'd never seen

before. It has angular features. These moved from year to year. No

idea what this is. It is something to do with ice escaping from

underneath and going into the Martian atmosphere. People will be

working on this the years. Wonderful. We have more time in the

show afterwards. I pledged applied to somebody. -- a pint. Tell us

what to think that is. The best week, I will buy you another pint.

I'm very excited. What is that? other guy is still waiting for his

plight. Before we go, just time to say goodbye to Liz and NASA. How

has it been? 30 seconds. Thanks. It's been such a privilege to meet

all of the people behind so many or inspiring endeavours. What struck

inspiring endeavours. What struck me most is how every single mission

seems impossible on paper. I'm not sure what impresses any more, for

fact they are able to dream up crazy schemes like lowering a road

on to Mars using as Guy Cramer and sampling, it as they hurtle through

space or the fact they are able to make those ideas a reality. They

are always thinking ahead. By the mid- 2020s, there's talk of putting

a man on an asteroid, and a few decades after that a man on another

planet. It is an exciting time. Sadly, it is time for us to say

goodbye to everybody at NASA and you at home. At night from NASA.

Thank you for wearing your telescope hat especially! Don't

forget there are hundreds of stargazing events happening up and

down the country. Details are on the website, bbc.co.uk/stargazing.

Don't forget about our Star Guide. We're going to be back in a second,

but do you want to wrap up? discoveries on Mars are real

scientific discoveries. Chris was telling me there's going to be a

paper written. There's a scientific paper written and everybody