Back to Earth 2 Stargazing Live


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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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issues of cosmology and space science that we want to discuss

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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happening in one place and everything expanding from that

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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lots of energy conditions which are usually assumed with general

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

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

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

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

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programmes we talked about this idea where the universe falls to

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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has a protection conjecture. cannot go backwards. You may

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

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

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

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

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

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

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

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

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following creatures were among the very first travellers to voyage

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

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

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

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

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

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

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

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

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

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tortoise! Until tomorrow, master. Farewell.

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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more detailed and accurate measurements but our knowledge

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

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insanely catchy songs. # Our galaxy itself contains 100

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

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

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

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

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galactic central point. # We go round every 200 million

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years. # And our galaxy is only one of

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millions of billions. # In this amazing and expanding

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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mentioned inflation briefly and we think that has expanded way faster

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

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

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in between rather than be galaxies themselves physically or any other

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

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

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that is expanding his our observable universe. That is what

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

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

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

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

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I think the most accurate measurement needed is one that

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

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

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

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

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

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

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

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the Andromeda. It can be difficult to locate at

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

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

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

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

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constellation of Andromeda. Then imagine an elongated and quite

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

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

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

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

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

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

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across, more than double the size It contains approximately one

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

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

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

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

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Back to Dara. He will probably talk over me

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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you prefer we collided with Andromeda, that space itself is

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