60th Anniversary Special The Sky at Night


60th Anniversary Special

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Welcome to a special Sky at Night.

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This marks our 60th anniversary.

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The first episode of Sky at Night was broadcast live

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on the 24th of April, 1957.

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And we've come a long way since then.

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The programme started before the dawn of the space age,

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when the idea of sending probes to distant planets

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was nothing more than a dream.

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In fact, we knew so little that the idea of advanced life on Mars

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seemed a distinct possibility.

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So we've come here to the Royal Observatory, Greenwich,

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home of British astronomy,

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to look back and see how our understanding of the universe

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has changed over the past six decades.

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Welcome to The Sky at Night.

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The 60th is a diamond anniversary.

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And the Department of Earth Sciences at UCL have been kind enough

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to lend us this.

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It's called carbonado, and it's a black diamond.

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Now if you have a closer look

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it might seem a little disappointing

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because it's not bright and shiny, like your everyday diamond,

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but it has a much more interesting story.

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One that is very relevant to today's programme.

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More about that diamond later,

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but first, back to the progress we've made in the last 60 years.

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We'll be taking a range of subjects

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and with the help of The Sky at Night archive,

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finding out what we've learned during the time we've been on air.

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We'll be going back to 1957,

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to see how we observed the night sky back then.

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Dallas Campbell will be retracing on a bicycle the journeys that have

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taken us from the surface of the Earth to the furthest reaches

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of the solar system.

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And Jim Al-Khalili will be showing us how in just 60 years

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we've created an entirely new history of the universe.

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Using maths and physics,

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we can really understand how the universe was made,

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where it came from, how it works, and how it might possibly end.

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But to start we have to go back to the beginning, to 1957.

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April 1957 was a very different world.

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Our culinary tastes were apparently so unsophisticated

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that Panorama could broadcast an April Fool's report

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into the spaghetti harvest in Switzerland.

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Harold Macmillan had just become Prime Minister.

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And a new series, with a new presenter - Patrick Moore - began.

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Good evening. Tonight, I want to show you a rather unusual film.

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'But at that time our ideas about the solar system

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'were very different from what they are today.'

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The first programme was about the comet Arend-Roland,

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but we don't have a copy.

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It was broadcast live and never recorded,

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but I do have this book, which Patrick wrote about Mars in 1956.

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And after dismissing the idea of Earth-like animal life,

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he goes on to say this.

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"When we turn to plant life the situation is brighter,

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"and as we have seen it is almost certain

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"that extensive vegetation does exist on Mars."

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It seems ridiculous today,

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but 60 years ago it was a widely held belief

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that there were plants on the surface of the red planet.

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And, really, there's no better example

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of how fast our ideas have changed than Mars.

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To guide us through 60 years of astonishing discoveries

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about the Red Planet, Maggie has been talking to Monica Grady.

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Monica, it seems amazing to me

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that just 60 years ago people thought that Mars

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was covered in vegetation. Why was that?

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Well, it's because of pictures like this.

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This was taken in about 1956

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from one of the Earth's biggest telescopes,

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and you can see this big, dark shadow here

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right across the front of the planet,

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and this is interpreted as being a sort of rainforest.

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And at the time, this was the best that the telescope could do.

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Yeah, it's pretty fuzzy, you can't see much here at all.

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No, you can't.

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The problem with looking from Earth

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is that you're looking through the Earth's atmosphere,

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which immediately starts blurring things,

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so what you need to do is get above the Earth's atmosphere.

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In 1964, Nasa launched the probe Mariner 4.

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Eight months later it flew within 10,000km of Mars,

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and pixel by pixel returned 22 images of the planet's surface.

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It seems like a long way to go for 20 photographs.

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Well, I mean these pictures from Mariner 4

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completely changed part of our ideas of Mars.

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What do they show us?

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Well, for a start you've got this hazy bit here and this is...

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Hey, Mars has got an atmosphere,

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so that's something that we didn't know,

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and you can see more structure here.

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You can see that there are these sort of circular patches.

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Now, at the time they were called craters,

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but there are two sorts of craters.

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There's the crater at the top of a volcano

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and there's the crater made by impact from an asteroid,

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and there's lots of discussion as to what sort of craters they were.

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For those who long to find life on Mars,

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the Mariner 4 pictures were a disappointment,

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but they weren't definitive.

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So just four years later Nasa tried again.

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Good evening. We've just had some amazing photographs sent back by the

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American probe to Mars, Mariner 6.

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As Mariner 6 approached in 1969,

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there was much excitement that Mars would finally give up its secrets.

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Mariner 6 came down over this direction,

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over these so-called deserts.

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The question is of course, are these dark areas due to organic matter,

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vegetation, if you like, or are they not?

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But when the pictures came back,

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they revealed a dry and barren surface.

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Now, what about this all important question of life on Mars?

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Primitive life, there may be, I don't even think so.

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Intelligent life? Certainly not.

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So, in other words, you rather think that Mars is a dead planet?

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Absolutely, dead as a dodo.

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Once it was realised there was no complex life on Mars,

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attention turned to the planet's past.

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And here, the story became much more interesting.

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So, this is from one of the Viking orbiters,

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and it's not a single picture.

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It's lots and lots of pictures.

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It's a mosaic that has been put together.

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-But it's glorious.

-It's absolutely fantastic.

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Just looking at these pictures

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started to really capture how close Mars was to Earth

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in many of its features.

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It's got these volcanoes, which are like the volcanoes on Hawaii.

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It's got this rift valley, which is like East Africa,

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and, of course, it's got its icecaps.

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But you've also got the features that on Earth we would interpret

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as being from rivers,

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so you've got something that looks as if

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it's going out into a huge delta.

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You've got other channels, meandering channels,

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and these were formed by flowing water.

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They were formed by rivers.

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So, with the orbiter, we suddenly get evidence

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-for past liquid water on Mars?

-You do.

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So, you get a picture of a planet

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which has had all the ingredients,

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all the things that would allow life to get going.

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So the idea is that, yes, Mars could have harboured life,

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it might still harbour life,

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but if it is, it's not big life.

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We're looking at small life.

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So, if we are still looking for life, how do we find out the detail?

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Well, what you have to do is, you have to get down there,

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so you have to actually land.

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That takes us to these pictures?

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This brings us right up to date

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with the most recent spacecraft to land on Mars,

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which is Curiosity,

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which landed a few years ago and has been trundling across the surface

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near Mount Sharp in the Gale Crater.

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It has been taking the most amazing pictures.

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These are so brilliant. I feel as if I could step inside.

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We've come a long way in 60 years.

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We started off with that fuzzy image 60 years ago. We're now on this,

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where you can actually see the details of single pebbles.

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What are we looking for here?

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Well, we're still looking for life on the planet.

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We still haven't found it.

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So far, a lot of the missions have been following the water.

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Now what we haven't done yet is dug below the surface.

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Below the surface,

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there's a chance that you might find something still living.

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Very difficult to get into those places.

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We need to get more intelligent rovers and eventually,

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we need to get the most intelligent rover of all,

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and that's a person.

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Can it be me?

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I just can't wait to see what the next 60 years bring.

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-It's going to be brilliant.

-Yes. Thank you so much for coming in.

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My pleasure. Thanks a lot.

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Hello, this is Buzz Aldrin, Apollo 11 astronaut,

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first landing on the moon, now working on humans to Mars.

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I do remember Patrick Moore with great respect, great reverence.

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I want to wish The Sky at Night happy birthday,

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60 years of all of that wonderful education

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as to what is going on up there at night. Thanks so much.

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It's been a joy having you with us.

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The Sky at Night isn't the only astronomical institution

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celebrating its 60th birthday this year.

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This is the Lovell Telescope, at Jodrell Bank, in Cheshire.

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It was first switched on in August 1957.

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It's still one of the most sensitive radio telescopes in the world.

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Over the years, we've filmed here on many occasions.

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To mark our shared anniversary, we asked Tim O'Brien,

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one of the astronomers at Jodrell Bank,

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to reveal some of its secrets,

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and to celebrate its most important contributions to astronomy.

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This is the incredible 76-metre wide 3,200 tonne Lovell Telescope,

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the brainchild of Bernard Lovell,

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an astronomer who had an ambitious vision.

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Back in the 1950s,

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Lovell was a pioneer in the relatively untested science

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of radio astronomy.

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They used huge dishes as aerials,

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gathering not light but radio waves from space

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in the hope that this would reveal new information about the universe.

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His revolutionary proposal was to build this telescope,

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ten times larger than any that had gone before.

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But in those early days,

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few believed in radio astronomy as much as Lovell.

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Even as construction began,

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he knew he was taking a high-stakes gamble...

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..as The Sky at Night discovered years later.

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During the building of the telescope,

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were there are any real crises, either with design or with cash?

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Endless crises.

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We started building the telescope in 1952, the foundations,

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and very soon discovered that the cost,

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whilst going to be far greater than the £30 million we got,

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but I didn't tell anybody.

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Then we had, I think, the most colossal stroke of luck,

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that certainly I've ever had in my life.

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The Russians launched the first of the Sputnik.

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After a few days, we got a most magnificent radar echo

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from the carrier rocket of the Sputnik.

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I've still got it, showing it going over the Lake District.

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200 miles above the Earth.

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And it turned out, to my astonishment,

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that this was the only instrument in the world

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capable of detecting this rocket.

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Suddenly, the telescope became world-famous

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and the establishment finally realised its true value.

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Now completely operational,

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the telescope was pulled in two completely different

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and often opposing directions - political and scientific.

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The politicians wanted to use it to monitor our Cold War enemies,

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tracking Russian missiles and space projects.

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But away from the high-profile space tracking work,

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the telescope was actually being used for real science,

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and those early results were breathtaking.

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This is a map of the whole of the sky,

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but seen in radio waves rather than visible light.

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It revealed that space was awash with radio.

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It was a powerful scientific vindication of Lovell's vision.

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And all the more amazing,

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given that some key components of the telescope

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were actually recycled.

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We're here at the top of the towers,

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right on the axis of the tipping of the ball,

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and that tipping of the giant ball is done on these gear racks.

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These are actually from the 15-inch guns of two World War I battleships.

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Once all the engineering challenges had been overcome,

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the new discoveries started to roll in.

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When these first radio astronomers started to scan the skies,

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they spotted intense points of radio light they called the radio stars.

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We used the Lovell Telescope and other radio antennas

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spread across the country to zoom in on these points of light.

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We found they weren't stars at all,

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they were actually distant galaxies

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and they were powered by supermassive black holes.

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These became known as Quasi Stellar Objects.

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The Quasars.

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Hardly noticeable to optical telescopes,

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these objects completely changed the way we thought about the universe.

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Turns out that this new radio sky

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is not full of stars held by nuclear fusion,

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like we see with our eyes,

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it's actually full of supermassive black holes powered by gravity.

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Gathering this kind of data from space is a huge technical challenge.

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So the Lovell is constantly being updated and improved,

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but that leaves it with its own share of quirky idiosyncrasies.

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This is the control room.

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At its heart is the control desk dating from 1957,

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although it is now packed with new electronics.

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Back in the day, the control system

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was an ingenious electromechanical analogue computer.

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There were ten boxes arrayed around the desk here,

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packed with dials and whirring gears,

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and they were used to drive the telescope

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to exactly the position that the astronomers wanted.

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Over its 60 years, the dish itself has undergone some major overhauls.

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In the 1970s, a new surface was built, several metres above the old.

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And this was then replaced again in 2002.

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We've also taken the opportunity to upgrade the electronics,

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networking it to telescopes right across Britain and around the world.

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It gives the Lovell a new and constantly evolving role.

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One of the things we're very interested in at the moment

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is a very weird phenomenon called fast radio bursts.

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These are very brief, fraction of a second,

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strong flashes of radio waves

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that appear to come randomly from across the sky.

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There's about 20 of them known at the moment,

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but we estimate that there's probably as many as 10,000 of them

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every single day and we've no idea what they are.

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Theories range from neutron stars falling into black holes,

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to perhaps rather bizarrely, beams of radio energy

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that are being used to accelerate alien spacecraft.

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Whatever their true origin,

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the fast radio bursts and other similar mysteries will, I'm sure,

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mean that the next 60 years of radio astronomy

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will be just as exciting as the last.

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Happy 60th birthday!

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What a marvellous occasion.

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I think one of my favourite ones was Michael Bentine discussing

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if there were civilisations existing on other planets outside the Earth.

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They both agreed there wasn't any then behind them appeared,

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I think it was a spaceship from another world.

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I thought that was inspirational.

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What do you think of the planet Earth?

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To be frank, old man, not very much.

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Technology has transformed every aspect of life since 1957.

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Take television for instance.

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This is the kind of camera that would have been used

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when The Sky at Night was first broadcast.

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Its four prime lenses on the front here allowed you to select

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between different shot sizes so there's no need for a zoom.

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Compare this magnificent machine to what we use today.

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This camera is not only smaller but it's much more sensitive

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and so we can use it to shoot the night sky.

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If technology has changed television,

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that's doubly true for space exploration.

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To explain how advances in technology have allowed us

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to explore the planet around us,

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we asked Dallas Campbell to take us on a cycling tour

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of the solar system.

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The solar system is a pretty big place.

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This scale model just outside York, that's the sun behind me,

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gives us an idea of some of the challenges faced

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in crossing the huge distances in space

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and how actually reaching the planets

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has stretched our science and our engineering to the limit.

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So I'm setting off to cycle between the planets.

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Retracing the steps of my six favourite spacecraft.

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The pioneering missions that have taken us

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from the surface of the Earth to Pluto and beyond.

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When The Sky at Night first transmitted,

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the space age hadn't even begun.

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The first object that made it into orbit

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was the Soviet satellite Sputnik, and that wasn't launched

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until six months after that first broadcast.

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Sputnik was as simple as a spacecraft can be.

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Really nothing more than a radio transmitter

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that had been strapped to the top of a rocket.

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MAN SPEAKS RUSSIAN

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But it makes my list

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because it showed that space travel was possible.

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Within a matter of months,

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the sights of the world's rocket scientists

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were set on the other worlds of the solar system.

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The first target was obviously the nearest - our own moon -

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and actually from here, it looks really, really close to the Earth,

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but this whole model, and that includes the size of the planets

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and the distance between them,

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is built at the scale of around about 575 million to one,

0:19:520:19:56

so in the real world, that distance is around about 250,000 miles.

0:19:560:20:01

In the 1950s, getting from A to B was a huge technological challenge.

0:20:010:20:07

But within just a couple of years,

0:20:090:20:11

The Sky at Night was able to report on Soviet success.

0:20:110:20:15

In September 1959,

0:20:160:20:18

the Russians landed their Lunik 2 on the moon's surface,

0:20:180:20:21

and then in October 1959, came that great triumph with Lunik 3,

0:20:210:20:27

which actually went round the moon

0:20:270:20:29

and photographed that part of the moon's surface

0:20:290:20:31

which we can never see from the Earth

0:20:310:20:33

because it's always turned away from us.

0:20:330:20:35

Well, I for one certainly won't forget those pictures.

0:20:350:20:37

But the real triumph came ten years later

0:20:400:20:44

with the second mission on our list, Apollo 11.

0:20:440:20:48

That's one small step for man,

0:20:480:20:51

one giant leap for mankind.

0:20:510:20:54

This was one of the defining achievements of the 20th century,

0:20:540:20:59

but in retrospect, what is startling

0:20:590:21:01

is just how simple the technology was.

0:21:010:21:03

The guidance computer on the lunar lander

0:21:060:21:08

had less processing power than a modern toaster.

0:21:080:21:12

When Neil Armstrong returned to Earth,

0:21:120:21:14

he came to The Sky at Night studio.

0:21:140:21:16

When you were actually walking about on the moon's surface

0:21:160:21:19

and kicking about a certain amount of dust,

0:21:190:21:21

did you notice any local colour?

0:21:210:21:23

The colour is a puzzling phenomenon on the moon.

0:21:230:21:27

Aside from the characteristics that I've already mentioned,

0:21:270:21:31

you generally have the impression of being on a desert-like surface

0:21:310:21:36

with rather light coloured hues,

0:21:360:21:39

yet when you look at the material at close range, as if in your hand,

0:21:390:21:45

you find it's a charcoal grey, in fact.

0:21:450:21:47

And we were never able to find any things

0:21:470:21:49

that were very different from that colour.

0:21:490:21:52

Having conquered the moon, it was time to start exploring the planets.

0:21:540:21:59

Mars was the main target.

0:21:590:22:00

A mere 34 million miles from the Earth at its closest approach,

0:22:000:22:05

it's still a long way to go.

0:22:050:22:06

Reaching it is hard enough,

0:22:080:22:09

but putting landers on the surface

0:22:090:22:12

is a feat that has proved consistently difficult.

0:22:120:22:14

All in all, we've tried to land 17 spacecraft on Mars,

0:22:180:22:22

half of which have failed,

0:22:220:22:24

which is understandable when you consider

0:22:240:22:26

you're actually trying to send packages

0:22:260:22:28

of extremely delicate electronic equipment

0:22:280:22:32

across tens of millions of miles of hostile empty space

0:22:320:22:35

and then land very carefully on the surface.

0:22:350:22:39

One of the main difficulties of landing on Mars

0:22:390:22:42

is that the atmosphere is so thin that parachutes are of limited use,

0:22:420:22:46

so more ingenious ways of landing have to be devised.

0:22:460:22:50

Viking, the first craft to successfully land on Mars,

0:22:530:22:56

used a system of retrorockets.

0:22:560:22:58

The Opportunity and Spirit rovers touched down in a bouncing air bag.

0:23:000:23:04

But the next generation of rovers was too heavy for air bags,

0:23:050:23:10

so in 2012 Nasa did this.

0:23:100:23:12

Just for sheer ambition and panache,

0:23:150:23:18

the third of my favourite spacecraft is the Curiosity Sky Crane,

0:23:180:23:22

a triumph of engineering and technological sophistication

0:23:220:23:26

designed to lower the Curiosity rover onto the Martian surface.

0:23:260:23:30

If getting to Mars is hard,

0:23:330:23:34

it's still a lot easier than getting to the outer planets,

0:23:340:23:37

the gas and the ice giants.

0:23:370:23:39

So the next planet out in the solar system, Jupiter,

0:23:390:23:42

is just under a kilometre that way - or, in the real world,

0:23:420:23:46

just over half a billion kilometres.

0:23:460:23:48

And actually getting to it presents a whole new set of challenges.

0:23:480:23:51

And that brings us to the next mission,

0:23:540:23:56

and, really, it's my favourite of them all.

0:23:560:23:58

Though it's actually two spacecraft, Voyager 1 and 2,

0:23:580:24:02

which were both launched in the summer of 1977.

0:24:020:24:05

These plutonium powered emissaries

0:24:070:24:09

were designed to keep functioning for decades in the depths of space.

0:24:090:24:13

They would take advantage of a rare alignment of the planets

0:24:140:24:18

that would see them visit Jupiter, Saturn, Uranus

0:24:180:24:21

and eventually Neptune over the course of 12 years.

0:24:210:24:25

In early 1978, Voyager 1 approached Jupiter.

0:24:270:24:31

The world watched in awe as it returned stunning views

0:24:320:24:35

of the planet's clouds, storm systems and moons.

0:24:350:24:40

It was the first sign of how these two spacecraft

0:24:400:24:43

would go on to transform our concept of the outer solar system.

0:24:430:24:46

Moving on from Jupiter, the Voyagers visited Saturn in 1980 and '81,

0:24:510:24:56

giving us a tantalising glimpse of the magnificent ring systems.

0:24:560:25:00

But to really appreciate the Saturn system,

0:25:030:25:06

we needed a spacecraft and a camera that could study the rings

0:25:060:25:09

in much greater detail.

0:25:090:25:11

For that, we had to wait for another 25 years

0:25:130:25:16

and the fifth spacecraft on our list, Cassini,

0:25:160:25:20

which entered orbit around Saturn in 2004.

0:25:200:25:23

The remarkable thing about Cassini is that it was launched 20 years ago

0:25:260:25:31

with the technology that was around at the time.

0:25:310:25:33

So its cameras, for example, a resolution of about one megapixel,

0:25:330:25:37

a fraction of what's on your smartphone,

0:25:370:25:38

and yet that technology is incredibly reliable.

0:25:380:25:42

It's still sending back the most extraordinary images of Saturn,

0:25:420:25:46

its rings and its moons.

0:25:460:25:47

The Cassini mission is scheduled to end in September this year.

0:25:490:25:52

After a series of closer and closer flybys to the rings,

0:25:520:25:55

it is then going to be crashed into the planet.

0:25:550:25:58

A glorious, a poignant end

0:25:580:26:00

to one of the most transformative missions ever.

0:26:000:26:03

After Saturn, missions get pretty thin on the ground, as do planets.

0:26:090:26:14

So our next planet is Uranus,

0:26:140:26:16

which is twice the distance from the sun as Saturn is.

0:26:160:26:19

Now, for me cycling along here it is about 2.5km,

0:26:190:26:22

in the real world up there it is about 1.5 billion kilometres.

0:26:220:26:26

There's only ever been one spacecraft that's visited it.

0:26:260:26:28

In 1986, Voyager 2 flew within 80,000 miles of Uranus.

0:26:290:26:35

Well, just about two minutes ago...

0:26:350:26:37

..Voyager 2 passed through its closest approach to Uranus.

0:26:380:26:42

And three years later it sailed past Neptune.

0:26:450:26:49

After Neptune, Voyager 2 just kept on going,

0:26:490:26:52

and now both of the Voyager spacecraft are exploring

0:26:520:26:55

the very edges of the outer solar system.

0:26:550:26:57

And since those first two Voyager missions,

0:27:010:27:03

only one other spacecraft has ventured

0:27:030:27:06

into the outer solar system.

0:27:060:27:08

The sixth and final spacecraft on our list is New Horizons,

0:27:080:27:13

the most technologically sophisticated mission

0:27:130:27:16

to visit the outer solar system.

0:27:160:27:18

Half the size of Voyager,

0:27:180:27:19

it made it all the way to Pluto in just nine years.

0:27:190:27:23

In July 2015,

0:27:260:27:28

Chris and Maggie were in mission control

0:27:280:27:30

as New Horizons aimed to pass between Pluto

0:27:300:27:33

and the orbit of its moon, Charon.

0:27:330:27:35

OK, copy that.

0:27:370:27:38

We're in lock with telemetry with...

0:27:380:27:40

Yes!

0:27:400:27:41

We've got data!

0:27:410:27:43

CHEERING AND APPLAUSE

0:27:430:27:44

I told you it would be fine!

0:27:470:27:49

I wasn't worried!

0:27:490:27:50

The jubilation was justified.

0:27:500:27:53

Pluto had been thought to be a frozen and dead world,

0:27:530:27:56

but the data that New Horizons returned showed that,

0:27:560:27:59

against all expectations,

0:27:590:28:01

this tiny world at the edge of the solar system

0:28:010:28:04

was alive with active geology.

0:28:040:28:07

Blimey!

0:28:080:28:09

Here we are. Finally, we make it to Pluto.

0:28:110:28:14

Look how tiny Pluto is. And that's one of its moons, Charon.

0:28:140:28:18

Now, on my scale, Pluto to the Earth, about 10km.

0:28:180:28:22

And in reality it would be round about 6 billion kilometres.

0:28:220:28:26

It's amazing to think in the last 60 years

0:28:260:28:28

we've developed this technology that's allowed us to explore

0:28:280:28:32

pretty much the whole of the solar system,

0:28:320:28:34

from the moment that Sputnik first left the Earth

0:28:340:28:37

all the way to the New Horizons' mission to Pluto and beyond.

0:28:370:28:41

And the extraordinary thing is that every step of the way

0:28:420:28:45

along that history timeline,

0:28:450:28:46

we have been surprised, we have learned something new.

0:28:460:28:49

Nothing is as we thought it would be.

0:28:490:28:52

And who knows what our technology will be like

0:28:520:28:55

in the next 60 years and what we might find out?

0:28:550:28:58

Of course, we've sent many more than six missions into the solar system.

0:29:020:29:06

This graphic represents every single probe

0:29:080:29:11

that we've sent to the planets,

0:29:110:29:13

and between them they have revolutionised our understanding

0:29:130:29:16

of the solar system.

0:29:160:29:18

60 years ago, we thought there were nine planets orbited by 30 moons.

0:29:180:29:24

Now we have just eight planets but over 180 moons.

0:29:240:29:28

And it's the moons that have been the greatest surprise,

0:29:290:29:32

particularly the icy moons of the outer planets.

0:29:320:29:35

Well, I'm joined by Michele Dougherty,

0:29:380:29:39

an explorer of the outer solar system -

0:29:390:29:41

particularly with Cassini, the mission to Saturn.

0:29:410:29:44

I think the thing that strikes me is wherever we've been,

0:29:440:29:47

we've been surprised, and maybe nowhere more so than Saturn.

0:29:470:29:50

Can you tell us about the exploration of Saturn?

0:29:500:29:52

We were launched in 1997, we took a long time to get there,

0:29:520:29:55

got there in July 2004,

0:29:550:29:58

and we've essentially spent the last 13 years orbiting around Saturn.

0:29:580:30:02

The biggest surprise was linked to one of its small moons, Enceladus.

0:30:020:30:07

What are we looking at here?

0:30:070:30:08

It's a very small world, its diameter is 500km.

0:30:080:30:11

We would have long thought if from when it first formed

0:30:110:30:14

there were to be some kind of heat in the interior,

0:30:140:30:16

but over time that dies away, so we thought it was dead.

0:30:160:30:19

But what we are looking at here is a very young surface.

0:30:190:30:23

You can see there are some craters on the surface,

0:30:230:30:25

but there aren't as many as you would expect.

0:30:250:30:28

But I think the most exciting of all are these blue cracks

0:30:280:30:32

at the South Pole.

0:30:320:30:33

The imaging team on Cassini calls them tiger stripes,

0:30:330:30:36

and it was from these cracks

0:30:360:30:38

that we found there was this plume of water vapour

0:30:380:30:41

coming off from the South Pole.

0:30:410:30:42

In fact, we've got an image of the plume.

0:30:420:30:44

You can see it better. This is the night side of Enceladus,

0:30:440:30:47

what we were just looking at is this surface,

0:30:470:30:50

and then there's this jet of material.

0:30:500:30:52

Absolutely. If you look really closely,

0:30:520:30:54

you can see there are individual plumes

0:30:540:30:56

-coming out of the different...

-Separate fountains.

0:30:560:30:58

It's not just water vapour.

0:30:580:30:59

There's organic material, there is dust.

0:30:590:31:03

There's an instrument on board, the Ion Neutral Mass Spectrometer,

0:31:030:31:07

that can actually taste what's in the plume,

0:31:070:31:09

and it found that there was ammonia.

0:31:090:31:11

And we found that out, actually, on one of the really close flybys.

0:31:110:31:14

It was 25km above the surface.

0:31:140:31:16

So you flew straight through the plume?

0:31:160:31:18

We flew straight through the plume.

0:31:180:31:20

We won't do that again,

0:31:200:31:22

because the density of the plume is so strong

0:31:220:31:24

that the spacecraft almost began to actually tumble, and so they said,

0:31:240:31:28

"No, we aren't going to do that again."

0:31:280:31:30

So this is a small moon in the cold outer solar system

0:31:300:31:33

with liquid water?

0:31:330:31:34

Yes. It's weird, isn't it?

0:31:340:31:35

It's very strange. So why is there so much water there?

0:31:350:31:39

How is it liquid?

0:31:390:31:40

What we think is happening is tidal forces,

0:31:400:31:43

as Enceladus is orbiting around Saturn,

0:31:430:31:46

on some parts of the orbit, it's slightly closer to Saturn

0:31:460:31:49

than on others, and so the gravitational force is stronger,

0:31:490:31:52

and so that's where the tidal forces are coming from.

0:31:520:31:54

So it's squeezed and then stretched by its orbit?

0:31:540:31:56

Absolutely.

0:31:560:31:58

I think from my perspective, the most exciting part

0:31:580:32:00

is the fact that, you know, people are very interested

0:32:000:32:02

about potential habitability.

0:32:020:32:03

You know, you need four things for life to be able to form.

0:32:030:32:07

You need liquid water...

0:32:070:32:08

-Got that.

-You need organic material...

0:32:080:32:10

-You've seen that too.

-You need a heat source...

0:32:100:32:13

Something's got to be heating this up.

0:32:130:32:14

And it needs to be stable over a period of time.

0:32:140:32:17

That's what we're not sure about with Enceladus.

0:32:170:32:19

So whether we might have got lucky, maybe we saw something that...

0:32:190:32:22

-This is a recent phenomenon?

-Absolutely.

-And it's not just here,

0:32:220:32:25

we've seen this sort of thing at Jupiter as well?

0:32:250:32:28

There's the Galileo probe to Jupiter.

0:32:280:32:30

Tell us about its explorations of the moons?

0:32:300:32:32

What the Galileo spacecraft did

0:32:320:32:33

is it orbited around Jupiter for four years.

0:32:330:32:36

What they found is on some of the close flybys of the moons,

0:32:360:32:39

in particular Europa...

0:32:390:32:41

-So this is Europa, and it looks kind of similar.

-It does.

0:32:410:32:43

You've got cracks and ice and, I guess, no craters again.

0:32:430:32:48

I think the difference with Europa

0:32:480:32:50

is that they look as if they're icebergs.

0:32:500:32:53

We think that there are some very thin surface regions,

0:32:530:32:58

because if you have a close-up view of Europa, and I think...

0:32:580:33:01

Yes, let's pull one up.

0:33:010:33:02

To me, it looks like it's almost as if you're sitting in an aeroplane,

0:33:020:33:06

flying over Greenland and you look out of the window

0:33:060:33:08

and you see the ice shelf,

0:33:080:33:10

and it's almost as if you can see an iceberg breaking off

0:33:100:33:12

and moving on a slushy surface.

0:33:120:33:16

So we think there might be regions on the Europa surface

0:33:160:33:19

where it's really... The ice crust is very thin.

0:33:190:33:22

And that's one of the reasons we want to go back,

0:33:220:33:25

and so the Juice mission is going to go to Jupiter,

0:33:250:33:28

and there's a Nasa mission called Europa Clipper,

0:33:280:33:30

which is going to go to Europa.

0:33:300:33:33

And thinking back over the 60 years that Sky at Night's been around,

0:33:330:33:36

how big a change has there been?

0:33:360:33:38

It's a huge change.

0:33:380:33:39

No-one thought there would be liquid water oceans

0:33:390:33:41

in the outer solar system. It's too cold.

0:33:410:33:43

And so that's been a sea change

0:33:430:33:45

as far as the search for potential habitability.

0:33:450:33:48

We now know you can get most of the conditions that you need

0:33:480:33:52

in our outer solar system,

0:33:520:33:54

and potentially outside of our solar system.

0:33:540:33:56

There are plenty of other places to look in our solar system as well.

0:33:560:33:59

Absolutely, that's right.

0:33:590:34:00

Hello, and congratulations to the BBC's Sky at Night

0:34:080:34:11

on your 60th birthday.

0:34:110:34:13

Thank you so much for bringing the wonders of the universe

0:34:130:34:15

into our living rooms

0:34:150:34:17

and for inspiring me and so many others to look up to the stars.

0:34:170:34:20

Amateur observing has always been an integral part of the show,

0:34:240:34:28

but even here things have changed.

0:34:280:34:30

So we set Pete Lawrence and a group of amateur observers a challenge -

0:34:300:34:34

to see if they could capture the night sky

0:34:340:34:36

using the technology of the 1950s.

0:34:360:34:39

Although the technology used to view the night sky

0:34:400:34:42

may have changed over the last 60 years,

0:34:420:34:45

amateur astronomers have always had to contend

0:34:450:34:48

with a very British problem.

0:34:480:34:49

..general direction of the moon, frankly,

0:34:490:34:51

I can't see a single star at the moment.

0:34:510:34:53

It's totally obscured.

0:34:530:34:55

We were hoping to see Vega, the star straight above our heads,

0:34:550:34:59

but even that's gone now.

0:34:590:35:01

No, we've got to abandon it for a moment or two.

0:35:010:35:03

We are blacked out.

0:35:030:35:04

These days, we have computer-controlled telescopes

0:35:060:35:09

and high sensitivity cameras to capture images of the sky.

0:35:090:35:14

But have we lost some of the magic of stargazing as a result?

0:35:140:35:18

Tonight I've gathered a group of astronomers

0:35:200:35:22

under the impressive Lovell Telescope at Jodrell Bank,

0:35:220:35:26

and we're going to see what amateur astronomy was like, 1950s style.

0:35:260:35:30

One of the key things I've noticed

0:35:300:35:33

is that there's quite a big difference in type of kit we use.

0:35:330:35:37

So, Richard, I've been admiring this scope from across the field,

0:35:370:35:40

it's beautiful. How old is it?

0:35:400:35:41

This is nearly 50 years old. It's a 1971.

0:35:410:35:44

With an open frame like this you can see everything inside, can't you?

0:35:440:35:47

You can see the primary mirror at the bottom,

0:35:470:35:49

which, actually, looks very clean.

0:35:490:35:51

Light from the object in the sky

0:35:510:35:52

bounces off the primary mirror at the bottom,

0:35:520:35:55

focusing it via the secondary mirror into the eyepiece.

0:35:550:35:59

This kind of telescope works just as well with an open frame.

0:35:590:36:02

And what I've really noticed about it is how heavily engineered it is

0:36:040:36:07

as well, this mount looks...

0:36:070:36:09

It's almost overkill, very heavy and very solid,

0:36:090:36:11

and it gives it perfect balance.

0:36:110:36:14

It does move beautifully.

0:36:140:36:15

That move's so smooth. Isn't that gorgeous?

0:36:150:36:18

Thank you very much for showing me this.

0:36:180:36:20

I wish it was clear, because I'd love to look through it.

0:36:200:36:23

Wait a minute, there's some kind of a break over there.

0:36:230:36:25

Can you see it? Look, over there.

0:36:250:36:28

-Something...

-I can't see anything in it, though.

0:36:280:36:31

No.

0:36:310:36:32

In the '50s, even when you could see something,

0:36:320:36:36

photographing it was complex...

0:36:360:36:38

and expensive.

0:36:380:36:40

So a lot of amateur astronomers turned to sketching.

0:36:400:36:44

Luckily the night before had been beautifully clear

0:36:440:36:47

and some of our amateurs were out looking at the moon.

0:36:470:36:50

So, Paul, you had a beautifully clear night

0:36:500:36:53

and you did some sketching?

0:36:530:36:54

-I did.

-I can recognise that straight away.

0:36:540:36:56

You've three very distinctive craters, that's Theophilus,

0:36:560:37:00

Cyrillus and Catharina.

0:37:000:37:01

-Yes.

-What I love about your sketches

0:37:010:37:04

is the way you've done them on the black paper.

0:37:040:37:06

That's come out so well.

0:37:060:37:07

It's much easier to see as well at night with a little light.

0:37:070:37:11

It took quite a long time to do that, at least an hour.

0:37:110:37:14

If I compare it with a photo I took last night, you can definitely see.

0:37:140:37:17

You've got Theophilus up here

0:37:170:37:18

with its central mountain peak very clearly,

0:37:180:37:21

and you've got Cyrillus underneath

0:37:210:37:23

with the two peaks in the centre, there.

0:37:230:37:25

You've rendered that really well.

0:37:250:37:27

Thank you very much.

0:37:270:37:28

At their very best,

0:37:280:37:29

amateur sketches are every bit as useful as photos.

0:37:290:37:33

These ones from the '30s and '40s

0:37:330:37:36

show a ring plane crossing of Saturn

0:37:360:37:39

and the surface of Mars in incredible detail.

0:37:390:37:43

Just a few minutes to try and get...

0:37:430:37:45

The moon is just being awkward.

0:37:450:37:48

The moon is just being awkward at the moment, I'm afraid.

0:37:480:37:50

Donna, you have performed something of a miracle this evening,

0:37:500:37:54

and you actually managed to get a sketch of the moon.

0:37:540:37:56

Yes. It was very fleeting, but it was there.

0:37:560:37:59

I can recognise that immediately as the Mare Crisium.

0:37:590:38:02

It was very hazy, but I was using binoculars.

0:38:020:38:05

I found myself actually observing as opposed to just looking.

0:38:050:38:09

Do you know, that is really the essence of what you've done here,

0:38:090:38:14

and that's... I think that's something which,

0:38:140:38:17

to a certain degree, we've lost in amateur astronomy.

0:38:170:38:20

Because looking through the eyepiece to sketch something,

0:38:200:38:23

you really do have to look at it.

0:38:230:38:26

It did make me concentrate, I have to say.

0:38:260:38:27

I did actually concentrate.

0:38:270:38:29

-It's a wonderful feeling, isn't it?

-Oh, yes.

0:38:290:38:30

Although tonight the sky might have been typically disappointing,

0:38:330:38:37

I've been powerfully reminded of the romance of sketching

0:38:370:38:40

and how it makes the act of observing

0:38:400:38:43

a more intense and involving experience.

0:38:430:38:45

So if you've got pen and paper at home, why not give it a go yourself?

0:38:490:38:52

Now, to find out what's happening in the April and May night sky,

0:38:520:38:56

why not pop along to our website and look at our latest star guide?

0:38:560:39:00

Also on the website, you can find our viewers' gallery,

0:39:030:39:07

showcasing some of the finest images of the night sky

0:39:070:39:10

captured by Sky at Night viewers using today's technology.

0:39:100:39:14

Happy birthday, Sky at Night!

0:39:210:39:23

I watched you when I was a kid in England,

0:39:230:39:26

all the nice stuff got me into space,

0:39:260:39:29

and then I got involved in Voyager, Galileo, Cassini, and now Juno!

0:39:290:39:34

Over the past 60 years there's been a transformation

0:39:380:39:41

in our understanding of the history of the universe and how it works.

0:39:410:39:45

What we call cosmology.

0:39:450:39:47

We asked Jim Al-Khalili to explain more.

0:39:470:39:49

For thousands of years astronomy was a descriptive science.

0:39:570:40:01

Astronomers made ever more detailed maps of the night sky,

0:40:010:40:06

but they seldom addressed fundamental questions.

0:40:060:40:09

What was a star, a galaxy, a planet?

0:40:100:40:15

How did the universe work?

0:40:150:40:18

But then, unexpectedly, at the beginning of the last century,

0:40:180:40:22

this all changed.

0:40:220:40:24

In the early 20th century,

0:40:260:40:28

the scientific establishment was rocked by the emergence

0:40:280:40:30

of Einstein's theories of relativity

0:40:300:40:33

and the bizarre theories of quantum mechanics.

0:40:330:40:35

And they began to realise that with this new physics,

0:40:350:40:38

not only could they explain phenomena here on Earth,

0:40:380:40:41

but that these theories might apply on an epic scale

0:40:410:40:45

across the universe as a whole.

0:40:450:40:46

And one of the first projects was to try to use this new science

0:40:490:40:53

to explain how the universe actually began.

0:40:530:40:58

By the 1940s, two schools of thought had developed,

0:40:580:41:02

the Big Bang and the Steady State.

0:41:020:41:05

The Big Bang theory said that the entire universe

0:41:050:41:07

was formed at a single moment.

0:41:070:41:09

A cataclysmic explosion from an infinitesimally small point,

0:41:090:41:14

marking the birth of space and time, and it's been expanding ever since.

0:41:140:41:19

Whereas the Steady State theory said that while the universe

0:41:190:41:22

has been constantly expanding,

0:41:220:41:24

new matter is being created all the time, everywhere,

0:41:240:41:28

always the same, nothing changing, no beginning or end.

0:41:280:41:31

In 1957, when The Sky at Night was first broadcast,

0:41:330:41:36

this argument over which theory was right was still raging.

0:41:360:41:40

Patrick Moore returned many times to this theme over the next few years.

0:41:410:41:46

And the one inescapable fact, at least I think it is,

0:41:460:41:49

is that you and me and your television set

0:41:490:41:52

and the kitchen sink and Aunt Emily, they actually exist.

0:41:520:41:55

So the matter making up ourselves must have come from somewhere.

0:41:550:41:59

There are some astronomers who believe

0:41:590:42:01

in what's known as the Steady State theory,

0:42:010:42:03

that the universe has always existed and will exist forever.

0:42:030:42:08

But the problem was the Steady State and the Big Bang theories

0:42:080:42:12

remained pure conjecture,

0:42:120:42:15

because there was no measurable evidence

0:42:150:42:17

that would tell which was right and which was wrong.

0:42:170:42:21

Then in 1964, an accidental discovery changed all that.

0:42:210:42:27

Two young astronomers, Arno Penzias and Robert Wilson,

0:42:280:42:32

had just inherited a strange looking radio telescope, the horn antenna.

0:42:320:42:37

But this unlikely telescope would surprise everyone

0:42:370:42:41

and reveal how the universe actually started.

0:42:410:42:44

The horn antenna was built to look for very specific radio signatures -

0:42:500:42:55

microwaves.

0:42:550:42:57

Penzias and Wilson tweaked it to make it super sensitive

0:42:570:43:01

so they could study the Milky Way.

0:43:010:43:03

But then wherever they looked in the sky,

0:43:030:43:06

they could hear a very annoying hiss

0:43:060:43:08

which they simply couldn't get rid of.

0:43:080:43:11

HISSING

0:43:110:43:15

Eventually, they realised that this hiss

0:43:150:43:17

coming from everywhere in the universe could only be one thing.

0:43:170:43:22

It was actually the faint remnant of the Big Bang itself.

0:43:220:43:27

The discovery of this hiss, the cosmic microwave background,

0:43:330:43:36

by Penzias and Wilson in 1964,

0:43:360:43:39

proved, conclusively, that the Big Bang theory was correct.

0:43:390:43:43

And it told us something else too,

0:43:430:43:45

that astronomy is much more than just a descriptive science.

0:43:450:43:49

What's more, using maths and physics,

0:43:490:43:52

we can really understand how the universe was made -

0:43:520:43:56

where it came from, how it works and how it might possibly end.

0:43:560:44:00

The confirmation of the Big Bang by the cosmic microwave background

0:44:030:44:07

gave astrophysics a massive confidence boost

0:44:070:44:11

and it led to a burst of new and astonishing ideas and discoveries.

0:44:110:44:16

One of the insights of this new science

0:44:190:44:22

was the idea that gravity plays a key role

0:44:220:44:24

in the story of the universe.

0:44:240:44:26

As well as describing the orbits of planets around the sun

0:44:260:44:29

and the motion of stars within galaxies,

0:44:290:44:32

scientists also began to understand that it works within stars,

0:44:320:44:36

crushing them together to create the conditions for nuclear reactions

0:44:360:44:39

that make stars shine so fiercely.

0:44:390:44:42

But their theories also predicted that, on a cosmic scale,

0:44:420:44:46

gravity would produce unexpected and bizarre outcomes.

0:44:460:44:50

For instance, as stars ended their lives,

0:44:550:44:58

the theoreticians suggested they

0:44:580:45:00

would continue to collapse under gravity,

0:45:000:45:02

crushing their cores until they were just a few kilometres across at

0:45:020:45:07

unbelievable densities.

0:45:070:45:08

It seemed the stuff of science fiction.

0:45:110:45:13

Then in November 1967, and using a rather underwhelming radio antenna,

0:45:170:45:22

more like a clothesline than something like this,

0:45:220:45:25

a young research scientist by the name of Jocelyn Bell

0:45:250:45:28

saw something strange.

0:45:280:45:30

In her data was a pulsing radio signal

0:45:300:45:32

incredibly fast and incredibly regular.

0:45:320:45:36

At first it was genuinely thought that this might be a signal from an

0:45:360:45:40

alien world. In fact it was dubbed LGM for little green men.

0:45:400:45:45

But it was soon realised that these so-called pulsars were in fact

0:45:450:45:49

superdense stars or neutron stars

0:45:490:45:51

that physicists had already predicted.

0:45:510:45:54

There was another incredible prediction too,

0:45:580:46:01

perhaps gravity could crush stars so powerfully

0:46:010:46:04

that even light couldn't escape.

0:46:040:46:06

These were called black holes.

0:46:060:46:09

Over the next few years,

0:46:140:46:16

pulsars and black holes shifted from pure speculation

0:46:160:46:20

to astronomical orthodoxy.

0:46:200:46:22

And it seemed as though the universe was finally beginning to

0:46:230:46:27

make some sense.

0:46:270:46:28

But then in the mid-1970s,

0:46:300:46:33

a new series of observations threatened to turn

0:46:330:46:35

everything we thought we knew upside down.

0:46:350:46:39

In the USA, scientists led by astrophysicist Vera Rubin,

0:46:440:46:49

were studying huge spiral galaxies deep in space.

0:46:490:46:52

Rubin had initially thought that

0:46:540:46:56

just like the outer planets of the solar system,

0:46:560:46:59

the outer stars of the galaxy should be orbiting around

0:46:590:47:03

more slowly than the inner stars, but they weren't.

0:47:030:47:07

It was as though they weren't obeying the laws of gravity.

0:47:070:47:10

Her crazy explanation was that the spiral arms of the galaxy contained

0:47:100:47:15

a new kind of material called dark matter.

0:47:150:47:19

This invisible material provided the extra gravity needed

0:47:190:47:24

to control the motion of the stars.

0:47:240:47:26

We just couldn't see it.

0:47:280:47:30

Patrick Moore himself sometimes found dark matter hard to stomach.

0:47:300:47:34

Well, we can see the effect of dark matter where they have a

0:47:340:47:37

gravitational effect and these seem to be definite.

0:47:370:47:39

But what is dark matter?

0:47:390:47:42

Is it something we can't understand?

0:47:420:47:44

More a fudge, isn't it?

0:47:440:47:46

Well, you can call it a fudge but it turns out that it's incredibly

0:47:460:47:50

-consistent with all our observations.

-Really?

0:47:500:47:53

And there was to be more, too.

0:47:530:47:55

In the 1990s, as scientists peered deeper and deeper into space,

0:47:550:47:59

they noticed another inconsistency.

0:47:590:48:02

Sure the universe was expanding but it seemed to be expanding quicker

0:48:030:48:08

and quicker. To explain this, theorists came up with the idea of

0:48:080:48:13

dark energy,

0:48:130:48:14

a mysterious something that pervaded the whole universe and that was

0:48:140:48:19

pushing it apart ever more rapidly.

0:48:190:48:21

As yet, there is no material evidence

0:48:240:48:27

of dark matter or dark energy but if they do exist,

0:48:270:48:31

scientists predict that they make up about 95% of the known universe,

0:48:310:48:37

meaning almost everything out there in space is a mystery.

0:48:370:48:41

As The Sky at Night celebrates its 60th,

0:48:460:48:49

it seems as though the universe is more fascinating and more mysterious

0:48:490:48:54

than ever before and everything we

0:48:540:48:56

thought we knew is still up for grabs.

0:48:560:48:58

And one thing is for sure -

0:48:590:49:01

the next 60 years is likely to be just as interesting.

0:49:010:49:05

Hello, Sky at Night,

0:49:130:49:14

well done on the signals

0:49:140:49:15

from your very first programme

0:49:150:49:17

now having travelled

0:49:170:49:18

60 light years into the universe.

0:49:180:49:20

Congratulations and let's hope you

0:49:200:49:22

haven't started an interplanetary war.

0:49:220:49:25

All that cosmology, the Big Bang,

0:49:280:49:30

the physics of black holes and pulsars.

0:49:300:49:33

It all seems rather distant,

0:49:330:49:36

but sometimes you can find a little bit of a distant universe right here

0:49:360:49:39

on earth which brings us back to the black diamonds, the carbonados.

0:49:390:49:44

To find out more about them, we've been joined by diamond expert,

0:49:450:49:49

Adrian Jones.

0:49:490:49:51

Adrian, let me give this back before I lose it.

0:49:510:49:54

Can you tell me, how does a carbonado differ

0:49:540:49:56

from a standard diamond?

0:49:560:49:58

-They look different.

-They do.

0:49:580:49:59

Especially when you look down a microscope.

0:49:590:50:02

Have a quick look and see what you can see.

0:50:020:50:04

They look quite grey, there's some shiny bits but one of the strange

0:50:040:50:08

things is if they've got lots of holes all over them,

0:50:080:50:10

which is a bit unusual, isn't it? It looks porous.

0:50:100:50:13

They are, exactly. They look a little bit like pumice.

0:50:130:50:15

And the little holes inside them are baffling

0:50:150:50:17

because diamonds are formed at very high

0:50:170:50:20

pressure and high temperature and normally when you make a very high

0:50:200:50:23

pressure, you squeeze things.

0:50:230:50:24

It's very hard to imagine how the

0:50:240:50:26

holes are formed or remain in the diamond.

0:50:260:50:28

Yes. So how do we think they were formed?

0:50:280:50:32

One explanation would be that they have been formed at extremely high

0:50:320:50:35

temperatures, perhaps high enough to melt the diamond,

0:50:350:50:38

so there's a possibility of liquid diamond and there's also the

0:50:380:50:41

possibility of vapour diamond making some little holes.

0:50:410:50:46

You said there liquid diamond. I didn't know that was possible.

0:50:460:50:50

It's certainly extraordinary and not possible on the Earth today.

0:50:500:50:53

-Yes.

-This is one of the main lines of evidence these could be

0:50:530:50:56

-extraterrestrial.

-So, if they weren't formed on Earth,

0:50:560:50:58

where did they originate from?

0:50:580:51:00

So, you need something pretty extraordinary,

0:51:000:51:02

something rich in carbon because diamonds are made from carbon.

0:51:020:51:05

Pressures, perhaps, as great as twice the pressure at the centre of

0:51:050:51:08

the earth, temperatures greater potentially than

0:51:080:51:11

-the surface of the sun.

-Oh, wow!

0:51:110:51:13

One of the few places in the universe where you'd find those

0:51:150:51:18

conditions is in heart of white dwarfs -

0:51:180:51:21

the collapsed remnants of stars like our sun.

0:51:210:51:23

As these stars undergo gravitational collapse at the end of their lives,

0:51:300:51:34

they generate the sort of temperatures and pressures within

0:51:340:51:37

their carbon-rich cores that would be required to

0:51:370:51:40

create carbonado diamonds.

0:51:400:51:42

If that white dwarf was then ruptured,

0:51:440:51:46

it would be broken into diamond-rich asteroids.

0:51:460:51:49

It's thought that all the carbonados on earth may have been delivered by

0:51:500:51:54

just one of those asteroids.

0:51:540:51:57

So, these carbonados from Brazil and

0:51:570:51:59

we know they are found only in Brazil

0:51:590:52:01

and Africa, so they probably arrived as a single asteroid made of

0:52:010:52:06

carbonado which broke up and

0:52:060:52:08

collided with the earth a long time ago.

0:52:080:52:11

In fact before Africa and Brazil

0:52:110:52:12

were separated by the Atlantic Ocean.

0:52:120:52:15

So you find them in both places but they're probably from the same

0:52:150:52:17

-asteroid.

-Probably from the same

0:52:170:52:19

asteroid which broke up and then distributed

0:52:190:52:21

itself over those two continents.

0:52:210:52:22

I see. So this is billions of years old?

0:52:220:52:25

So billions of years old. Three, maybe four billion years old.

0:52:250:52:28

-Or three quarters of the age of the earth.

-Oh, wow!

0:52:280:52:31

Gosh. So, our Sky at Night diamond,

0:52:310:52:34

we think was probably formed in a white dwarf,

0:52:340:52:37

landed on Earth billions of years ago and is now

0:52:370:52:40

sitting in front of us...

0:52:400:52:42

-Yes.

-..for our celebrations.

-That's exactly right, yes.

0:52:420:52:45

Well, that's pretty impressive if you ask me.

0:52:450:52:46

-Thank you so much for bringing them in.

-Thank you. A pleasure.

0:52:460:52:49

Hi, Sky at Night.

0:52:540:52:55

Happy 60th from everyone

0:52:550:52:57

here at the European Space Agency

0:52:570:52:59

and from Rosetta. Nice one, keep up

0:52:590:53:01

the good work.

0:53:010:53:03

One of the other questions that has haunted astronomy, the proverbial

0:53:050:53:08

elephant in the universe is, are we alone?

0:53:080:53:12

Not just within our solar system but throughout the cosmos.

0:53:120:53:15

In 1957,

0:53:150:53:16

nobody knew if there were worlds orbiting other stars.

0:53:160:53:19

The first exoplanet wasn't detected

0:53:200:53:22

until 1995.

0:53:220:53:24

But now we know of over 3,000 planets orbiting distant stars.

0:53:240:53:29

In February this year,

0:53:300:53:32

the most exciting discovery yet was announced.

0:53:320:53:34

A whole system of potentially habitable earth-like planets.

0:53:360:53:40

Orbiting the cold dwarf star, TRAPPIST-1.

0:53:400:53:43

Chris has been talking to one of the lead scientists on the project,

0:53:450:53:48

Amaury Triaud, to find out more.

0:53:480:53:50

I think, one of the most significant

0:53:520:53:53

discoveries in the Sky at Night's 60 years is just last month

0:53:530:53:56

the announcement of planets around

0:53:560:53:58

a star called TRAPPIST-1.

0:53:580:53:59

Can you tell us what you were looking for and what you found?

0:53:590:54:02

What we found is around this small star,

0:54:020:54:05

we have seven planets all turning very close to the star.

0:54:050:54:08

The outermost planet is only 6% of the Earth's sun.

0:54:080:54:12

So all of those will be well within the orbit of Mercury?

0:54:120:54:14

-Completely.

-So it's a very packed system.

0:54:140:54:17

What do we know about those planets?

0:54:170:54:18

All seven planets have sizes and

0:54:180:54:21

they are masses measured to be comparable

0:54:210:54:24

to the Earth. So they have compositions,

0:54:240:54:26

densities comparable to the Earth.

0:54:260:54:29

All seven are far enough from the star that we consider them to be

0:54:290:54:32

temperate, meaning that under certain

0:54:320:54:34

geological and atmospheric conditions,

0:54:340:54:36

water could be liquid if there is water there.

0:54:360:54:38

And that is why we are so excited

0:54:380:54:40

because this is the first system where

0:54:400:54:42

we can test whether liquid water can exist on the surface of a world

0:54:420:54:46

outside the solar system and then hunt for evidence of life.

0:54:460:54:50

A lot of the discussion after the discovery was immediately about the

0:54:500:54:53

star. This is a very different star.

0:54:530:54:56

Stars like TRAPPIST-1 form the majority of stars in our galaxy.

0:54:560:54:59

Most stars are smaller than the sun.

0:54:590:55:01

That's right. Just like TRAPPIST-1 and slightly bigger.

0:55:010:55:04

Most planets similar in size and mass to the Earth

0:55:040:55:07

mostly exist around such stars.

0:55:070:55:09

So looking at TRAPPIST-1 is looking at

0:55:090:55:12

the majority of earth-like planets in the universe.

0:55:120:55:15

But how will new facilities affect this?

0:55:150:55:17

I know people are excited about the James Webb Space Telescope,

0:55:170:55:20

for example.

0:55:200:55:21

The James Webb Space Telescope will be launched in late 2018.

0:55:210:55:25

It has the time to study each of the passages of the planet

0:55:250:55:28

in front of the star and so through those observations

0:55:280:55:32

we will note what type of atmosphere, what climate,

0:55:320:55:36

the level of greenhouse gases,

0:55:360:55:38

so we will infer the conditions on the surface

0:55:380:55:41

in terms of pressure and temperature.

0:55:410:55:43

Well, good luck and come back

0:55:430:55:44

-and tell us as the discovery goes on.

-Thank you very much.

0:55:440:55:48

Well, that's how far we've come in the last 60 years but what about the

0:56:070:56:10

future? What will we be talking about in 60 years' time?

0:56:100:56:14

We've got our experts here.

0:56:140:56:16

Monica, what are you looking forward to?

0:56:160:56:18

Well, I'm looking forward to

0:56:180:56:19

understanding more about Mars because by six

0:56:190:56:21

years' time, we will have found fossilised life on Mars.

0:56:210:56:26

I really don't think I'm afraid that we'll find evidence of current life

0:56:260:56:31

on Mars but we will have found

0:56:310:56:33

evidence that there was life on Mars which

0:56:330:56:35

will link to life on Earth and this is, you know,

0:56:350:56:39

a really interesting question.

0:56:390:56:41

Michelle, what about the outer solar system?

0:56:410:56:43

I'm much more interested in the outer solar system, absolutely.

0:56:430:56:46

But we've got missions going to Europa.

0:56:460:56:48

Where else do you think we will have been?

0:56:480:56:50

Well, there's talk about going to

0:56:500:56:52

Uranus or Neptune because those are the gas giants

0:56:520:56:54

we know the least about in our solar system.

0:56:540:56:57

-We just had one flyby.

-That's right, that's right.

0:56:570:57:00

But from my perspective,

0:57:000:57:01

our understanding of the icy moons of Jupiter and Saturn are making us

0:57:010:57:05

wonder about whether we might find liquid water outside of our

0:57:050:57:10

solar system around some of the exoplanets that have been found.

0:57:100:57:13

So let's have a prediction.

0:57:130:57:15

In 60 years' time, what's the hot topic in exoplanets?

0:57:150:57:18

I think the biggest hot topic is finding out how frequently life can

0:57:180:57:21

emerge. Not just is their life but how frequently can we find life in

0:57:210:57:24

-the universe?

-So you are convinced we will find life out there and

0:57:240:57:27

then we'll just have many examples of it.

0:57:270:57:29

I think there will be a lot of claims.

0:57:290:57:33

The road is really hard but I do hope that before I pass away,

0:57:330:57:37

-we will know.

-But do you think maybe an extraterrestrial intelligence

0:57:370:57:43

will have got in touch with us to put everything into perspective?

0:57:430:57:46

I've got my list of questions.

0:57:460:57:48

They might have the answers, you know?

0:57:500:57:52

It's just like you can speculate.

0:57:520:57:54

If they do, we'll definitely interview them on The Sky at Night.

0:57:540:57:58

That's all we've got time for this month but it's clear there's a lot

0:57:580:58:01

to look forward to and whatever happens and whatever is discovered,

0:58:010:58:04

we'll be here to report it for you.

0:58:040:58:06

We'll be back in June with a special from Rome.

0:58:060:58:09

In the meanwhile, enjoy the spring skies,

0:58:090:58:11

check out this month's Star Guide

0:58:110:58:13

-online and, of course, get outside and get looking up.

-Goodnight.

0:58:130:58:17

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