Back to Earth 2 Stargazing Live

and we might even get a proper Welcome to Back to Earth. Luckily,

we have an extra half-hour to contemplate 13.7 billion years of

the universe! 13.75. Not 15. We want you to join in, too. If you

have a cosmic query, send it in at [email protected]. We have

Professor Brian Cox, Dr Joanna Dunkley, Dr Tim O'Brien, Professor

Ed Copeland and Phill Jupitus. Where did you learn your cosmology?

Episode of Futurama. It was a very good one. Really? There was a Big

Bang and every particle fades to dark matter and then it starts all

over again. Have Futurama done what we wanted to do in 24 minutes?

little less detail. OK. That is shattering(!) Can I give you all a

drink? We always do. You have yours. This is excitingly a space beer.

Space stout! When you are in space, your tastebuds don't work as well.

It should taste quite strong. what I did there? Space stout!

have tested it. They have gone on to one of the planes? People

drinking weightlessly! LAUGHTER They are very happy. How does it

taste? It doesn't taste of anything at all! They have said, "You are in

space, you can't taste anything!" It is very nice. We also have

coming down the line from NASA's Jet Propulsion Laboratory Eric Idle.

How are you? I'm very well, thank you. Can you hear me? We can. You...

I want... No, this will go on for a while now! LAUGHTER What? Yeah.

What? Yeah. OK. My name is on the Curiosity Rover. My name is on

there. It certainly is. Very good. We will come back to you. We have

issues of cosmology and space science that we want to discuss

with you later on. Is that all right? I'm the natural expert to

ask(!) LAUGHTER By the way, you have a beer as well, don't you?

do! Thank you very much. Thank you. They call it "the vomit comet" I

think. We will be back with Eric later. Can I come to you? Why was

that number that you got 15 rather than 13.7? Anyone who tweeted 13.75

billion cheated and looked it up on Wikipedia. Oh! Some of them might

have made a genuine mistake. If you take the Hubble constant as 70

kilometres km/s/Mpc. If you did the sums, you would get 15 billion. It

wasn't a trick question. It was can you follow instructions? It's lucky

it was a good approximation. Are we blaming dark energy for this?

There is another aspect to this which is important in cosmology.

You are dealing with such huge numbers. How have you got any idea

whether you are right or wrong? That ability to make a quick

estimate of things is a useful tool to have at hand. It is a remarkable

thing. By doing some simple maths, based on simple observations, you

can get an estimate for the age of the universe. If we said, "Work out

how old everything is." It is a difficult problem. It is quite easy

to solve in a sense. If I went back to my Mum and said, "The universe

is 15 billion "she would go, "Excellent." It was formed on what

day? LAUGHTER That is what she would want to know. Was it

Wednesday? Was it Wednesday? long is it till we have that level

of precision? I don't think we will have that level of precision!

Planck will help us more. You would turn up on the wrong week! Loads of

questions coming in. Many are asking this. What is the universe

expanding into? This is a great question. It is not expanding into

anything. When you think of that, you maybe think of the Big Bang as

happening in one place and everything expanding from that

point. Then it has an edge and you say, "What happens beyond that

edge?" That is not how space is. We think it is expanding everywhere.

It has no edges. One of the big problems - I shouldn't blame TV for

things - we see these pictures... Not on TV! We see these pictures of

the Big Bang as an explosion. that one. Like the left-hand edge

of that where there is a flash of light. In a sense, that is telling

us we are looking at this explosion from the outside. In fact, we are

inside the explosion. So it is not possible to have that God's eye

view of the Big Bang. It's unsatisfactory. I get asked that

question a lot. Space, time began at that point, you are not allowed

to ask questions like what happened before? Are we to really believe or

do we really believe that is the situation? There is no cause for

this thing. Could it be there is a cause for the Big Bang? You are not

being very fair. Every question you are giving me, I don't know the

answer! Phill?! LAUGHTER One thing you can say - this issue over the

singularty at the beginning is a real e-- singularity at the

beginning is a real effect. The hot Big Bang Model had to end up with a

singular point at what you would think of as the star. Hawking did

this when he was 21. Don't hate the player! LAUGHTER Of course, we also

know that our mathematics breaks down. We can't trust what is going

on there. So it could be that something else, some quantum effect,

some quantum gravity-type effect has come into play at that point

and maybe the universe has indeed popped out in a very natural way

from some process. We don't yet know what it is. There are models

out there that people have put forward. Hawking got one. There are

other models which are cyclical. Lots of people love that. It breaks

lots of energy conditions which are usually assumed with general

relativity. I don't know your wife. Is it important that that is her

favourite? How many of you like that idea? One! LAUGHTER I like the

idea. There are big problems with this initial moment. One of them is

the old nature of the thing. In many of my most miserable

programmes we talked about this idea where the universe falls to

bits so it gets more and more disordered. More disordered set-ups.

This is quite a disordered thing we have now. More disordered set-ups

are more likely. People have said to me, "That means, if you wanted

to have some random thing, it is more likely the universe began now

than it is at any time in the past?" It was more ordered in the

past. So you are not allowed to give these random ideas. That means

it was more likely it popped into existence now and now and now!

Every moment it gets more likely it popped into existence. All my

memories are at random. We popped into existence now. There is no

past. It is pretty unlikely. Those are big problems. How did it get

into that ordered state? We are not going to answer that question! Dara

has some fluff. Fluff?! We are going to go to some photographs.

Mark, we have been inundated, haven't we? We are looking at stars

so it is lovely to see this picture of the Sun taken by Robert Arnold

yesterday. It was taken with a particular filter and it shows a

fine level of detail. We have the Sun just there. The second picture

was taken by Alan in October last year. It shows the star trails and

a beautiful Aurora display. That was taken towards the end of last

year. A beautiful picture of the Greater Orion Nebula. It is easily

visible tonight. Keep them coming in. All the details on the website.

A question from Logan. Do you think we will ever be able to warp space

and travel faster than light? It will probably take too much

energy to warp the space? Being lazy! No, a lot of energy. It is

this whole idea that you have got to get from here to here and it is

too far to go. The speed of light would take you forever. So you

curve space and make those two points next to each other and jump

through that gap. The amount of energy is extreme to do that.

theoretically possible? What kind of energy are you talking about?

Any mass in space bends it a bit. By being here, we are bending space

a bit. And time. We don't weigh that much to make it really super-

warped. There are solutions where you can connect these two regions

with worm holes. As far as I can tell, as soon as you decide to go

through it, the worm holes go unstable. They just disappear on

you. How can a seven-year-old ask that question?! His parents would

have been thrilled - "Don't ask me, ask Uncle Brian!" Ask Dara, you

will get fluff! If you can do that, you will be

able to build a Time Machine. It would be illogical. Stephen Hawking

has a protection conjecture. cannot go backwards. You may

possibly be able to go forwards in time. We travel in time. Every day.

No, further than that. I want to travel in time. "You are right

now!" LAUGHTER You can travel as far as you want into the future

relative to other people. You could get into the 10,000 years, 50,000

years into the future of Earth by getting on a spaceship and flying

around very quickly. Yeah. If you could manage it! It is time for the

Back to Earth brain-teaser brought Hello, I am K9. I am not the first

non-human intelligence to have journeyed into space. Which of the

following creatures were among the very first travellers to voyage

around your moon? Monkeys, dogs, catalogues, Rack's or tortoises or

So which one of those was the first to pass over the dark Side Of the

Moon? Dog, cat, monkey, taught us? I would go cat. Monkey. Dog. I have

no idea! That is the way guesses work, Brian! Scientists don't

guess! Let's find out the answer from K9.

Here is the answer. Two of the first Earth creatures to travel

beyond the dockside of your moon were a pair of Russian steppe

tortoises. They made the journey on 18th September 1968. As you might

say, that is one a small step for mankind, one giant leap for a

tortoise! Until tomorrow, master. Farewell.

Thank you, K9. Always a treat to see him back. Would you want to go

into space? I shouldn't mind a go at it, it has to be said, but you

either go up and its -- and pay millions and millions or you become

a cosmonaut. You do the one that goes up, the parabolic flights.

They are quite manageable. Yeah, they just give you a sheet saying,

this is a Russian for "excuse me". Because that is all... You have to

leave now! Most of the space tourism flight some very short hops

essentially into... Just at the very top of the atmosphere. 45

minutes. You would need a playlist, I would presume. You mustn't forget

to swipe your oyster card. That is so 4! Space oddity is the space pop

tune. It has got to be. Would everyone pick that? It is either

that or we are all made of stars. If you've got to go with David

Bowie because it was his birthday yesterday. Yes, we already

mentioned that. The one I haven't been able to get out of my head is

Eric Idle's one. Hello, Eric, how are you? You have probably

contributed the primary space song at the end of the -- at the end of

The Meaning Of Life. Yes, that is right. But since we have ensured

more detailed and accurate measurements but our knowledge

keeps expanding. Let's have a reminder of one of the most

insanely catchy songs. # Our galaxy itself contains 100

billion stars. # It's 100,000 light years side to

side. # It bulges in the middle, 16,000

light years thick. # But out by us, it's just 3,000

light years wide. # We're 30,000 light years from

galactic central point. # We go round every 200 million

years. # And our galaxy is only one of

millions of billions. # In this amazing and expanding

Brian how -- Brian, how much of that would you like to correct?

Well, we did actually correct it together and we have written the

song, which will be in my new series! Genuine a 27th of BBC Two

at 8pm. -- 27th January. There is a wonderful list of things that you

got wrong or has actually changed. One thing you admitted is that the

sun is the source of all-out power. And he admitted to that? Well, that

is because you gave me a lot of criticism for it because we wrote

the song entirely with Brian and the entirely new lyrics are about

the origins of life, not about biology, and also about the width

and size and dimension of the universe as opposed to the galaxy

because we now have some insight. And Brian would sit in a corner

with a pencil saying, that is problematic, but is not enough

stars! He would say, I think it is more like a million, billion stars.

And then you have said it is only 30 billion light years from side to

side yet some people say because of the time it has taken Hayes like to

get here, the universe is now 190 billion light years! -- it has

taken my ears. So he is not the easiest to write his song with!

you tell us why you wrote the song? Were you out of France gazing at

the sky and it inspired you to musical heights? -- out in France?

Yes, I became obsessed with reality after working on Monty Python soil

used to look at the Galaxy and the stars at night in France and a few

glasses of pink wine and it makes you very cosmic! He Eric, was there

any time in the process when you write in with Brian that you wanted

to shake him and say, it is only a joke!? Are but he is always smiling

so it is a joke anyway! Thank you for joining us. I know you are

going to enjoy having a look around NASA there. Thank you so much. One

of the most popular questions, and we are running out of time, from

London, how cantinas expend -- how can the universe expand faster than

the speed of light? You can't have any signals travelling faster than

the speed of light so you can't travel and you can't communicate.

You cannot tell one part to the other party has compost.

mentioned inflation briefly and we think that has expanded way faster

than the speed of light. These things you see in the Hubble Deep

Field are moving faster than the speed of light but it is the space

in between rather than be galaxies themselves physically or any other

significant information. Chris and David say, how can the universe be

both expanding and infinite? How can it start infinite? So the bit

that is expanding his our observable universe. That is what

is still expanding. And it is a very difficult concept, this idea

of a spatially flat universe which is formally infinite, but we have

our own horizon, are observable bit, which can expand beyond that.

we have a suspicion because we know it goes way beyond that horizon and

I think the most accurate measurement needed is one that

implies it is spatially infinite. We can only measure that from the

bit of the universe we can observe. It is hard to imagine an infinite

universe but it is also hard to imagine a finite universe because

then you have to imagine it is curved back on itself and there is

an outside somewhere. Well, those doughnuts are there to demonstrate

a very important cosmological point! So just eat them! I am

talking! Here's Mark and his Starcast to show you how they found

the Andromeda. It can be difficult to locate at

first but it becomes easier with practice. Niqab the area about a

third of the way up from the horizon to the point directly

overhead. Start looking for the great Square of Pegasus. Despite

being in the Great Square, this star is the brightest in the

constellation of Andromeda. Then imagine an elongated and quite

faint the letter pattern of stars. It is about halfway up the woman's

body. It does take some practice to see but it is like a faint smudge.

You can also moved up from If you can imagine the lower half

is an arrowhead it points to the rough location of the Andromeda

Galaxy. When you find it, you will be looking at a spiral galaxy like

our own Milky Way. It is estimated to be around 260,000 light years

across, more than double the size It contains approximately one

trillion stars and it is heading our way on a collision course at

about 70 miles per second but no need to panic because it won't hit

us for another 4 billion years! If you want to get hold of one of

Lucy's excellent Star Guide, go to the website.

Back to Dara. He will probably talk over me

anyway! We will be unveiling the model of the William Herschel

telescope tomorrow. It is a real model. Yes. We will have more

information on Mars. By the way, talking about Andromeda, and if you

worried about whether it is going to collide with us, you can keep an

eye on it. It is right there. So, we are OK! Gets and a live shot of

Orion. We couldn't do this last night because we were draped in

cloud. And that is the telescope we used last night to see the water.

What's the other shot you had of the top? With the supernova?

Betelgeuse. Top left. The top left corner. If we go out again for a

wide shot. There it is. That is the one we hope will explode sometime

on the show! It is looking brighter It is not... Vibrating or changing

its colourful stop who he -- its colour. Her we know the type.

will explode in the next few hundred, 1,000 years, but you

cannot predict it or pin it down to the day. But when it goes it is

minutes. Yes, the central core of the star collapses in seconds and

the rest of the stars are flung out into space. Why can Andromeda be on

course for us if the universe is expanding? Well, it is bound

towards the Milky Way. There is a local group of galaxies bound

together so it is only on the very large scales, but on smaller scales

you can have objects that were bound together by gravity. Would

you prefer we collided with Andromeda, that space itself is