0:00:02 > 0:00:05MUSIC: Little Green Bag by George Baker Selection
0:00:12 > 0:00:13# Yeah...
0:00:17 > 0:00:19# Lookin' back... #
0:00:24 > 0:00:26Just after 11 o'clock tonight,
0:00:26 > 0:00:30a rare event is going to take place in our solar system
0:00:30 > 0:00:36and it won't happen again in our lifetime or that of our children or even our grandchildren.
0:00:36 > 0:00:40In fact, it won't happen again for over a century.
0:00:46 > 0:00:48In just a few hours' time,
0:00:48 > 0:00:52Venus will begin its journey across the face of our sun,
0:00:55 > 0:01:01giving us the opportunity to watch its transit for the very last time.
0:01:01 > 0:01:04This is going to be a truly beautiful spectacle,
0:01:04 > 0:01:08but it is far more than just that.
0:01:08 > 0:01:12It's helping us answer some of the most profound questions we can ask
0:01:12 > 0:01:15about life in our own solar system.
0:01:15 > 0:01:22And it's helping astronomers explore the realms of much more distant stars in the search for life
0:01:22 > 0:01:26- on planets hundreds of light years away.- You need to keep watching
0:01:26 > 0:01:32because tonight is your very last chance to witness the transit of Venus.
0:02:03 > 0:02:09This is the Observatory Science Centre, for decades the home of British astronomy.
0:02:15 > 0:02:18And in just two hours it will all begin.
0:02:18 > 0:02:24Across the globe right now, telescopes are being aligned and focused on Venus
0:02:24 > 0:02:29so that we can better understand the secrets of our universe.
0:02:33 > 0:02:37Transits represent some of our greatest scientific achievements
0:02:37 > 0:02:44and to me they stand for our insatiable desire to constantly push the boundaries of our knowledge
0:02:44 > 0:02:46and to explore the unknown.
0:02:46 > 0:02:51So tonight it feels like I'm part of a very special moment in history
0:02:51 > 0:02:55and it's a moment that you can be part of, too.
0:03:00 > 0:03:03'As stargazers across the world are getting ready,
0:03:03 > 0:03:07'we'll be showing you why this event is so important.'
0:03:07 > 0:03:09You're sure that's Venus?
0:03:09 > 0:03:13'From the first transits that are the basis of all modern astronomy
0:03:13 > 0:03:18'to the one tonight that's helping us search for alien life.
0:03:23 > 0:03:28'And if you want a piece of the action for yourself, we'll be showing you how.'
0:03:31 > 0:03:36The reason the transit of Venus is so rare is that you need an unlikely set of events
0:03:36 > 0:03:43to all come together. So this is Venus and the Earth in orbit around the sun.
0:03:47 > 0:03:50Now Venus travels faster than the Earth.
0:03:51 > 0:03:54And its orbit is shorter.
0:03:54 > 0:04:01For a transit to happen, it has to overtake us, but that only happens once every 1.6 years.
0:04:06 > 0:04:11Not only that, but Venus's orbit is tilted compared to the Earth's
0:04:11 > 0:04:13at an angle
0:04:13 > 0:04:15of 3.4 degrees.
0:04:15 > 0:04:21And that means that Venus's and Earth's orbits will only ever cross at two points.
0:04:26 > 0:04:30But because of the relative speeds of Earth's and Venus's orbits
0:04:30 > 0:04:34and because of their position relative to the sun,
0:04:34 > 0:04:39only two transits, separated by eight years, will happen every 100 years or more
0:04:39 > 0:04:43and one of them is happening tonight.
0:04:47 > 0:04:54'All astronomy today is built on one particular transit that happened over two centuries ago
0:04:54 > 0:04:58'and observing it led to one of the most epic voyages in history.'
0:05:09 > 0:05:12On August 26th, 1768,
0:05:12 > 0:05:19Captain James Cook, then a young lieutenant, embarked on one of the greatest ever voyages of discovery.
0:05:24 > 0:05:28It was a journey that was fraught with danger. The men on board knew
0:05:28 > 0:05:32that half of them probably wouldn't make it home alive.
0:05:34 > 0:05:38But it was all for one magnificent goal,
0:05:38 > 0:05:42to reach Tahiti in time to observe the transit of Venus.
0:05:52 > 0:05:56For me, Cook's voyage was like a modern space mission,
0:05:56 > 0:06:00a voyage of discovery, a testing ground for the latest technologies,
0:06:00 > 0:06:07but above all a test of human endurance. Just like astronauts voyaging into space.
0:06:12 > 0:06:18'And in 1768, they believe the transit was a risk worth taking
0:06:18 > 0:06:22'because it held the key to a great mystery.
0:06:22 > 0:06:27'It promised to reveal nothing less than the size of the solar system.'
0:06:32 > 0:06:38As a scientist today, I feel humbled by the lengths people went to in those days to discover new things.
0:06:38 > 0:06:42I can't imagine putting myself through that ordeal.
0:06:42 > 0:06:47But finding the size of the solar system was the great mystery of the time,
0:06:47 > 0:06:51like understanding dark matter or detecting the Higgs-Boson is today.
0:06:51 > 0:06:56Observing the transit of Venus was the key to unravelling it.
0:06:59 > 0:07:05Without leaving the planet, how could you measure distances out in space?
0:07:07 > 0:07:12It had baffled the greatest minds for thousands of years.
0:07:15 > 0:07:20Astronomers at the time knew the relative distances of the planets from the sun,
0:07:20 > 0:07:25but they didn't know what this distance was in miles.
0:07:29 > 0:07:33It was like having a map without a scale.
0:07:36 > 0:07:42It was my all-time favourite hero, Edmond Halley, who realised that Venus held the key.
0:07:42 > 0:07:47He worked out that if you were in the right place at the right time during the transit,
0:07:47 > 0:07:51you could work out the distance between the sun and the Earth
0:07:51 > 0:07:55and he did it by using the most beautifully simple solution,
0:07:55 > 0:08:00a phenomenon you can observe by holding up one thumb and closing one eye.
0:08:01 > 0:08:04The principle is called parallax.
0:08:04 > 0:08:09It's the shift you see when you hold up your thumb and look at it first through one eye,
0:08:09 > 0:08:11and then through the other.
0:08:11 > 0:08:17You can measure the shift in position of your thumb, with the distance between your eyes
0:08:17 > 0:08:21and actually work out how far away your thumb is from you.
0:08:21 > 0:08:28In a stroke of genius, Halley saw that this simple technique can understand the solar system's size.
0:08:30 > 0:08:33He worked out that the problem could be solved
0:08:33 > 0:08:37by timing the transit from two very distant points on Earth.
0:08:39 > 0:08:43Effectively, it's like drawing the largest triangles ever in space.
0:08:43 > 0:08:50To do this, you need widely separated observers on Earth, for example in Canada and Tahiti.
0:08:50 > 0:08:56From those two different locations, they see Venus transiting the sun along two different tracks.
0:08:56 > 0:09:02And they can work out those tracks very precisely if they time the transits.
0:09:02 > 0:09:06That information, along with the distance between your two observers,
0:09:06 > 0:09:12allows you to build up the triangles that you need to work out the distance between the Earth and sun.
0:09:23 > 0:09:29'And this is why Cook made the 12,000-mile voyage to Tahiti.
0:09:32 > 0:09:35'And he wasn't alone.
0:09:35 > 0:09:41'Observers were sent to the four corners of the known world in the name of science.
0:09:44 > 0:09:48'And after eight months battling stormy seas,
0:09:48 > 0:09:52'desertion and even suicide,
0:09:52 > 0:09:58'Cook finally reached his destination, just in time to observe the transit.'
0:10:03 > 0:10:09When the time came, Cook and the other two observers set up their stations.
0:10:09 > 0:10:15They would have had a tent to keep them out of the heat of the sun and, of course, their telescopes
0:10:15 > 0:10:21with an all-important filter to block the glaring light of the sun and view the transit directly.
0:10:22 > 0:10:27'After the transit passed, Cook and his fellow astronomers compared notes.
0:10:27 > 0:10:32'But they found something they weren't expecting.
0:10:32 > 0:10:36'There was a difference between their timings.'
0:10:37 > 0:10:42What Cook noticed was something called the Black Drop Effect.
0:10:42 > 0:10:46I have a copy here of Cook's drawings and you can see
0:10:46 > 0:10:49the edge of the sun and then the disc of Venus.
0:10:49 > 0:10:53And, literally, a black drop appears between the two.
0:10:53 > 0:10:59This mean that getting those crucial timings, the contact times when Venus is at the edge of the sun,
0:10:59 > 0:11:01became incredibly difficult.
0:11:07 > 0:11:09'But it was a long journey home.
0:11:13 > 0:11:17'After the transit, Cook opened his sealed orders.
0:11:17 > 0:11:21'They told him to set off in search of unknown lands,
0:11:21 > 0:11:26'ones we now know as Australia and New Zealand.
0:11:26 > 0:11:32'So it was another two years before they eventually returned with their precious data.'
0:11:39 > 0:11:44Finally, back in London, it was down to the mathematicians to crunch the numbers.
0:11:44 > 0:11:50They collected data from expedition sites at over 40 locations around the globe
0:11:50 > 0:11:52and they came up with a number.
0:11:52 > 0:11:56They came up with 93 million, 726 thousand
0:11:56 > 0:12:01and 900 miles as the distance between the sun and the Earth.
0:12:01 > 0:12:04Now today we know, using modern radar equipment,
0:12:04 > 0:12:09that the distance between sun and Earth is just under 93 million miles,
0:12:09 > 0:12:15which means, incredibly, in the 1700s they were accurate to within 1%.
0:12:18 > 0:12:25'It was a real triumph for science and one that marked the birth of modern astronomy as we know it.'
0:12:31 > 0:12:35I find it simply amazing that in 1769 they could work out
0:12:35 > 0:12:37the size of the solar system.
0:12:38 > 0:12:43And this number, the astronomical unit, couldn't be more important today.
0:12:43 > 0:12:49It's the foundation of modern astronomy and without it, my job simply wouldn't exist.
0:12:49 > 0:12:54And just to think, they did all this using only the sun and Venus.
0:12:54 > 0:12:56It still blows my mind.
0:13:03 > 0:13:08In the early hours of tomorrow morning, you, like Captain Cook,
0:13:08 > 0:13:10will be able to view the transit.
0:13:10 > 0:13:16All around the world, scientists will also be observing and studying it,
0:13:16 > 0:13:20but this time they'll be looking for answers to new mysteries.
0:13:27 > 0:13:29This is a truly global event
0:13:29 > 0:13:33and your view depends on where in the world you're going to be.
0:13:33 > 0:13:37Not everyone is going to see the same bit of the transit.
0:13:37 > 0:13:45The first contact between Venus and the sun will occur at precisely 23:03:47 our time.
0:13:47 > 0:13:51So obviously the first places to see that will be those in daylight,
0:13:51 > 0:13:57so we're talking North America, East Asia and most of Australia and New Zealand.
0:13:57 > 0:14:03And then for the next six and a half hours, Venus will journey across the sun.
0:14:07 > 0:14:12Until, eventually, as the sun rises in the UK
0:14:12 > 0:14:15at precisely 05:37:20,
0:14:15 > 0:14:21if the skies are clear enough we should be able to spot the third contact
0:14:21 > 0:14:28as Venus touches the inner edge of the sun's disc before leaving it for the last time this century.
0:14:35 > 0:14:40For hundreds of years, Venus was shrouded in mystery.
0:14:43 > 0:14:48Because it's a comparable size to Earth and a similar distance from the sun,
0:14:48 > 0:14:52many thought that Venus was just like our own planet.
0:14:54 > 0:15:00But there was no real way to know because it lay hidden beneath a thick layer of cloud.
0:15:01 > 0:15:07'When they say, "Take me to your leader," and they take them to a creature like this,
0:15:07 > 0:15:09'you know they're on planet Venus.'
0:15:11 > 0:15:17Because we couldn't see its surface, we could only really hazard a guess at the planet's true identity
0:15:17 > 0:15:20and Venus has certainly fired our imagination over the years.
0:15:20 > 0:15:23# I'm your Venus, I'm your fire... #
0:15:25 > 0:15:29From poptastic tunes to great works of art,
0:15:29 > 0:15:32it's even seen highly unscientific attempts at matchmaking.
0:15:32 > 0:15:38'The most talked about woman in the world knows what she wants on Venus, too.'
0:15:38 > 0:15:44But as for the true Venus, it took us quite some time before we really got to know her.
0:15:49 > 0:15:53'Eventually, the Soviets sent a probe to have a look.
0:16:00 > 0:16:03'After 16 failed attempts,
0:16:03 > 0:16:07'one eventually managed to land on Venus's surface.
0:16:08 > 0:16:13'But these first pictures revealed something no one was expecting.'
0:16:14 > 0:16:20It soon became clear that our planetary neighbour had a very different temperament to ours
0:16:20 > 0:16:25and was nothing like the calm, tropical world we'd imagined.
0:16:25 > 0:16:29Venus was, in fact, a hostile, raging inferno,
0:16:29 > 0:16:33our polar opposite, our evil twin.
0:16:37 > 0:16:41Something had happened to Venus to change its fate,
0:16:41 > 0:16:43making it very different to Earth.
0:16:43 > 0:16:49And it's a mystery that has led scientists to search for answers here on our own planet.
0:16:57 > 0:17:02'If you want to understand Venus, you need to go somewhere a bit like it.
0:17:02 > 0:17:05'Somewhere like this.
0:17:05 > 0:17:10'Kilauea Iki crater on the big island of Hawaii.'
0:17:15 > 0:17:19This may seem pretty nasty, but this is mild compared with Venus
0:17:19 > 0:17:24because, for a start, I couldn't be standing on the surface there.
0:17:24 > 0:17:28The temperature is 460 degrees Celsius.
0:17:28 > 0:17:32That's hot enough to melt lead and certainly too hot for me.
0:17:38 > 0:17:44But even if I survived the temperature, the weight of the atmosphere would be crushing me
0:17:44 > 0:17:49because the atmospheric pressure on Venus is 92 times that on Earth.
0:17:49 > 0:17:53And that is like being squashed by a kilometre of ocean.
0:18:00 > 0:18:03'But what I really want to know
0:18:03 > 0:18:07'is what happened to Venus to turn it into such a hostile place.
0:18:08 > 0:18:12'How did Venus and Earth turn out so differently?
0:18:12 > 0:18:18'I spend my life studying the forces that shape our planet
0:18:18 > 0:18:23'and I know that the answer to this question lies deep in the heart of these two worlds.
0:18:28 > 0:18:33'And that's what scientists are studying here on Hawaii.'
0:18:33 > 0:18:37So why, apart from the amazing weather, work in Hawaii?
0:18:37 > 0:18:41There are many volcanoes just like Hawaii on Venus.
0:18:41 > 0:18:43I've been studying those
0:18:43 > 0:18:47for almost 20 years now and Hawaii is a great place to come and see
0:18:47 > 0:18:51the volcanoes we can't see directly on the surface of Venus.
0:18:51 > 0:18:56I mean, the thing that I really like about volcanoes is that they link
0:18:56 > 0:19:03the interior, which is the part that I study most, to the surface, which we can see on other planets.
0:19:03 > 0:19:08It feels like we're... I don't want to say like we're on a different planet,
0:19:08 > 0:19:12- but that's what I want to say! - I'm sure it looks a lot like this on Venus.
0:19:15 > 0:19:19I think we've reached the end of the road here!
0:19:19 > 0:19:23- Wow! Look at that. - Yeah, geology in action, huh?
0:19:23 > 0:19:28- How long has this been here?- This is less than 10 years old. 2003.
0:19:28 > 0:19:34- It just swept over the road. You used to be able to drive all the way across...- But not any more.
0:19:38 > 0:19:43'Sue has been piecing together a picture of what's happening on the surface of Venus
0:19:43 > 0:19:47'in an attempt to understand what's going on inside it.'
0:19:53 > 0:19:58No humans have ever visited Venus and it's such a long way away,
0:19:58 > 0:20:02- how do we know there are volcanoes there?- Well, in the '90s,
0:20:02 > 0:20:06there was a mission that mapped the surface of the planet using radar
0:20:06 > 0:20:12so we have these radar images that show us there are these huge volcanoes. This is Maat Mons.
0:20:12 > 0:20:14It's about 9km high.
0:20:14 > 0:20:19Hawaii, if we measured from the ocean floor, is similarly about 11km high.
0:20:19 > 0:20:23- So we're sitting on top of Earth's version of that.- We're about here!
0:20:27 > 0:20:33'The surface of Venus is littered with volcanoes, but the key to understanding its fate
0:20:33 > 0:20:37'is not how many there are, but where they're located.
0:20:38 > 0:20:42'On Earth, volcanoes sit along the edges of tectonic plates,
0:20:42 > 0:20:47'the vast slabs of rock that drift across the surface of our planet.
0:20:48 > 0:20:52'But on Venus things are very different.'
0:20:52 > 0:20:58- So this is a map of the volcanoes on Venus.- Well, you can see the little volcanoes poking out,
0:20:58 > 0:21:02almost evenly distributed around the planet. On Venus they're everywhere.
0:21:02 > 0:21:07Some of them are on these big hot spot areas, some out on the plains.
0:21:07 > 0:21:12There are hundreds and hundreds evenly distributed around the planet.
0:21:12 > 0:21:16So because there's no pattern of lines, we think Venus doesn't have plate tectonics?
0:21:16 > 0:21:19There are big tectonic features, but no plates.
0:21:23 > 0:21:29And it's this lack of tectonic plates on Venus that makes Earth and Venus so different.
0:21:32 > 0:21:38On Earth, the moving plates are driven by currents of molten rock beneath the surface
0:21:38 > 0:21:42making our world a dynamic and changing place.
0:21:46 > 0:21:51But Venus has no plates and no dynamic core
0:21:51 > 0:21:55and this one difference can mean life or death for a planet.
0:22:00 > 0:22:04And it's most obvious with one vital substance.
0:22:10 > 0:22:17Water makes our planet what it is - a place teeming with life in all its diversity.
0:22:22 > 0:22:26But because of the different way Venus works on the inside,
0:22:26 > 0:22:29water is one thing it couldn't keep.
0:22:35 > 0:22:38Venus used to be a much more comfortable place to live
0:22:38 > 0:22:42because billions of years ago it had liquid oceans.
0:22:42 > 0:22:48But it's 30% closer to the sun than we are and that made a crucial difference.
0:22:48 > 0:22:54Being that little bit warmer meant that a little bit more water evaporated from the ocean
0:22:54 > 0:22:58and that went into the atmosphere as water vapour.
0:23:00 > 0:23:05On its own, this wouldn't necessarily have spelt disaster for Venus,
0:23:05 > 0:23:09but this is where the two planets took different paths.
0:23:13 > 0:23:18The dynamic nature of the Earth's core helps generate a vital magnetic field.
0:23:18 > 0:23:23It's this field that shields us from the devastating solar wind
0:23:23 > 0:23:27that would otherwise strip our planet of its water.
0:23:27 > 0:23:30And this is what happened to Venus.
0:23:34 > 0:23:40With no magnetic field to protect it, its water was simply carried off into space.
0:23:44 > 0:23:51What I find amazing is that these two planets that had such similar beginnings, Earth and Venus,
0:23:51 > 0:23:54have ended up so differently.
0:23:54 > 0:23:59Earth has become this beautiful, diverse, living planet
0:23:59 > 0:24:05and Venus has become this horrible place, the evil twin.
0:24:12 > 0:24:16The surface of Venus is such an extreme environment
0:24:16 > 0:24:20that it's impossible to imagine any life forms surviving on it,
0:24:20 > 0:24:24but we also know that Venus wasn't always like this.
0:24:24 > 0:24:28It once had a much more temperate climate and it had oceans.
0:24:28 > 0:24:32So just like Earth it had all the vital ingredients for life
0:24:32 > 0:24:36and when life takes hold, it tends to hold on pretty tightly.
0:24:40 > 0:24:47So if life did once exist on Venus, is there a remote chance that it's still there today,
0:24:47 > 0:24:51hidden somewhere we just haven't thought to look?
0:25:00 > 0:25:06'This frozen, icy cave couldn't be more different to fiery, volcanic Venus.'
0:25:08 > 0:25:09Wow.
0:25:10 > 0:25:16'But hidden in this ice are clues that are challenging our most fundamental assumptions
0:25:16 > 0:25:18'about our evil twin.'
0:25:19 > 0:25:22The main reason I became a biologist
0:25:22 > 0:25:30is because I am constantly amazed by the beautiful, almost unbelievable complexity of life.
0:25:32 > 0:25:36And how it manages to find a foothold in the most improbable,
0:25:36 > 0:25:39challenging environments.
0:25:40 > 0:25:47And it's by studying these hidden oases at the outermost edges of our living world
0:25:47 > 0:25:51that we can understand more about how life persists,
0:25:51 > 0:25:55both on this planet but also throughout the universe.
0:25:59 > 0:26:04And it's by studying extreme environments like this
0:26:04 > 0:26:09that scientists like Birgit Sattler are rewriting the story of where life can be found,
0:26:09 > 0:26:12even on places like Venus.
0:26:12 > 0:26:18Birgit, what are we looking for down here, 30 metres below the surface?
0:26:18 > 0:26:23It's dark, it's cold, just frozen, but if you melt this ice up
0:26:23 > 0:26:28you will see millions of bacteria just dwelling in this environment.
0:26:28 > 0:26:33You can even shine them up. If we do a digital evaluation,
0:26:33 > 0:26:37we can actually detect the photosynthetic active pigments.
0:26:37 > 0:26:42It's pitch dark normally without the lights and there is still photosynthesis possible.
0:26:46 > 0:26:52The microbes thriving here show how life can survive in extreme conditions.
0:26:53 > 0:27:00'But to understand Venus we have to hunt for life in an even more distant part of our planet.
0:27:02 > 0:27:06'And to find it, we have to go up there.
0:27:06 > 0:27:08'In one of these.'
0:27:17 > 0:27:20That's as secure as it gets.
0:27:21 > 0:27:24Oh, sweet Jesus! Butterflies!
0:27:25 > 0:27:28- It's quite speedy.- Mm-hm.
0:27:28 > 0:27:30And windy!
0:27:34 > 0:27:39I was told it was a cable car. It's more like a crate,
0:27:39 > 0:27:42- supported by metal bars.- Yeah.
0:27:42 > 0:27:46- Has this ever had an MOT? - What is an MOT?
0:27:52 > 0:27:57Ooh. The angle's changing. Is this the 45 angle...? Oh!
0:27:57 > 0:27:59Ooh! I didn't like that.
0:28:14 > 0:28:17Wow. That's... That was amazing!
0:28:19 > 0:28:25'We've come to the top of one of Austria's highest peaks to look for life.
0:28:26 > 0:28:31'We're not looking on the ground, but high up in the clouds.'
0:28:31 > 0:28:34Some nice clouds surrounding us.
0:28:34 > 0:28:40Yeah, even if we don't see here obvious clouds, there are lots of microbes, viruses, algae spores,
0:28:40 > 0:28:46fungi floating around. So anything that is floating in the atmosphere we want to catch.
0:28:47 > 0:28:51'We've known for a while that microbes exist in the Earth's clouds
0:28:51 > 0:28:58'but we thought they were just blown up there. We didn't think clouds could permanently sustain life.'
0:28:58 > 0:29:00We attach it to here.
0:29:00 > 0:29:03'But we're here to prove otherwise.'
0:29:03 > 0:29:07This lovely cloud right there is perfect.
0:29:07 > 0:29:09- All right?- Oh!
0:29:12 > 0:29:18So this machine is going to be collecting microbes for a couple of hours now. It's straightforward.
0:29:18 > 0:29:24But the key thing here is to be able to prove that the microbes can actively reproduce
0:29:24 > 0:29:29and survive up there without the need to get back down to Earth.
0:29:32 > 0:29:37And if we can find evidence that life is replicating in these clouds,
0:29:37 > 0:29:41it doesn't only tell us something about life here on Earth,
0:29:41 > 0:29:45it may also have implications for Venus.
0:29:47 > 0:29:51Birgit, Venus is a super-hot, choked greenhouse planet.
0:29:51 > 0:29:53We've sent probes there, they've burnt to a crisp.
0:29:53 > 0:29:57We concluded there could not be life on that planet.
0:29:57 > 0:30:01What does your research here have to do with Venus?
0:30:01 > 0:30:06You can actually find one layer in the atmosphere where it's actually habitable
0:30:06 > 0:30:09with warm temperatures, but not too hot. We have moisture.
0:30:09 > 0:30:14So if you're able to prove that life can reproduce and live happily in the clouds up there,
0:30:14 > 0:30:20we can dare to think that it might be possible in this particular cloud layer of Venus? Is it that simple?
0:30:20 > 0:30:25It's not that simple, but why not? We have to go step by step.
0:30:25 > 0:30:30If we see life is possible here, why shouldn't it be possible in a warmer environment?
0:30:34 > 0:30:38Life in Venus's clouds might seem inconceivable.
0:30:38 > 0:30:42As well as being very hot, they are also very acidic.
0:30:42 > 0:30:48But evidence here on Earth has shown us that life can adapt to highly toxic conditions,
0:30:48 > 0:30:53so if Birgit can prove life can live in Earth's clouds,
0:30:53 > 0:30:57maybe we were wrong to write Venus off so quickly.
0:31:05 > 0:31:11In the lab, the cloud samples are offered DNA which carries a radioactive marker.
0:31:11 > 0:31:16If the DNA is taken up, it's proof replication is taking place.
0:31:19 > 0:31:24Well, I'm looking here at a sample from the cloud layer which we brought to the lab
0:31:24 > 0:31:30and we fixed the sample to get a snapshot of the condition of the cells,
0:31:30 > 0:31:34and this is very surprising, but I can see one dividing cell.
0:31:34 > 0:31:37- OK, where am I looking? - If you go to the right side,
0:31:37 > 0:31:41so approximately to five o'clock on this slide, you can see it -
0:31:41 > 0:31:45- two tiny cells being very tightly together.- My gosh! Yeah, yeah, yeah.
0:31:45 > 0:31:50- Right?- Oh, yeah. - Two tiny cells.- It's tiny. - Very tightly together.
0:31:50 > 0:31:55- Yeah, it's really tiny. - That is cell replication? - That's replication, yes.
0:31:55 > 0:31:58- That's incredible.- Yeah.
0:31:58 > 0:32:03What about the radioactive basis, the new DNA strands? Have you got any results for that?
0:32:03 > 0:32:06This is the outcome of the reaction 24 hours later.
0:32:06 > 0:32:13What just looks like dry numbers is actually the proof that the radioactivity is inside the cells,
0:32:13 > 0:32:16so it must have been taken up actively.
0:32:16 > 0:32:23Absolute proof that replication is going on in the micro-organisms that we sampled from that cloud?
0:32:23 > 0:32:27- Right.- That's huge, Birgit. - That's the proof, yeah.
0:32:27 > 0:32:33So when you first saw this data being crunched up by your computer, how did you feel?
0:32:33 > 0:32:39I was just sitting in front of the machine, praying, "Please spit i out, please spit out higher numbers.
0:32:39 > 0:32:46- And it did and it was so exciting. I just ran over and said, "I got it! - To your colleagues?- Yeah.
0:32:50 > 0:32:56It's a wonderful thought that the clouds we thought were hiding Venus's true identity
0:32:56 > 0:32:59may be the one place where life exists.
0:33:03 > 0:33:07We already know that life on Earth can survive in hot, acidic conditions.
0:33:08 > 0:33:13And now we know it can also survive in our clouds.
0:33:20 > 0:33:25It's just incredible to think that life has managed to carve a niche out for itself
0:33:25 > 0:33:31and thrive up there in the clouds and that we've only just found out about it.
0:33:35 > 0:33:41But for me what's most fascinating is what this means for Venus.
0:33:41 > 0:33:45We had completely written off the possibility that it could harbour life,
0:33:45 > 0:33:49but all this latest evidence makes for a pretty compelling case.
0:33:55 > 0:34:01Right now, Venus is hurtling through space at over 78,000 miles per hour,
0:34:01 > 0:34:05nearing the perfect position for its transit with our sun.
0:34:05 > 0:34:11And it's already incredible how much we've learnt about our solar system from this one planet,
0:34:11 > 0:34:17but this year, scientists are hoping that the transit will do even more.
0:34:19 > 0:34:23As well as hunting for life in our own planetary neighbourhood,
0:34:23 > 0:34:27they will also be turning their attention to the realm of much more distant stars...
0:34:28 > 0:34:32..using the transit to hunt for alien life
0:34:32 > 0:34:35and possibly even intelligent life.
0:34:35 > 0:34:40But what hampers this search is the sheer vastness of space.
0:34:40 > 0:34:42To understand the problem,
0:34:42 > 0:34:45we need to get a sense of scale,
0:34:45 > 0:34:49so there's our sun, the Earth and Venus,
0:34:49 > 0:34:51and as we now know thanks to the transit,
0:34:51 > 0:34:56the distance between us and the sun is 93 million miles.
0:35:01 > 0:35:03Now, that might seem like a lot,
0:35:03 > 0:35:07but the distance to the outermost regions of our solar system
0:35:07 > 0:35:10is something like a thousand times that.
0:35:10 > 0:35:14It took the spacecraft Voyager 34 years to even get close to it.
0:35:23 > 0:35:29But then, the distance to our nearest star, Proxima Centauri, is over four light years away.
0:35:29 > 0:35:33It would take Voyager 70,000 years to reach it.
0:35:41 > 0:35:48And it's just the first of the 200 billion stars that make up our own galaxy, the Milky Way...
0:35:51 > 0:35:57..which is just one of billions of galaxies that are millions of light years apart.
0:36:02 > 0:36:08So how do you go about hunting for life on planets hundreds of light years away?
0:36:08 > 0:36:12Once again, the transit is showing us the way.
0:36:12 > 0:36:14FAINT WHIZZING SOUNDS
0:36:32 > 0:36:35When I come to a place like this,
0:36:35 > 0:36:40I get a sense of how small I am against the vastness of this landscape.
0:36:44 > 0:36:48But it all pales into insignificance when I look up into space.
0:36:48 > 0:36:53I'm utterly overwhelmed by the magnitude of the universe out there.
0:36:53 > 0:36:55And I don't know about you,
0:36:55 > 0:36:59but a little part of me always wonders, "Are we really alone?"
0:37:04 > 0:37:07It's one of the most important questions to ask,
0:37:07 > 0:37:09but one of the hardest to answer.
0:37:11 > 0:37:17In recent years, we really seem to be coming to one of those points in history where things are changing
0:37:17 > 0:37:22just like when Kepler and Halley worked out the size of the solar system.
0:37:23 > 0:37:28But I really think we're closer than ever before to finding some answers.
0:37:34 > 0:37:38I've come to Nevada far away from the bright lights.
0:37:38 > 0:37:41It's the stargazing capital of the world.
0:37:47 > 0:37:50You can't come to a place like this
0:37:50 > 0:37:53and not be bowled over by the stars.
0:37:53 > 0:37:56They are simply breathtaking.
0:37:57 > 0:38:01And look, there's Venus, the brightest light in the sky,
0:38:01 > 0:38:05and for me, a shining example of how far we've come in everything we've achieved.
0:38:10 > 0:38:14But Venus is just a small planet that's relatively close to us.
0:38:14 > 0:38:19In this patch of sky alone, there ar literally millions of stars.
0:38:22 > 0:38:27So when it comes to looking for life out there, just where do we look?
0:38:32 > 0:38:34Searching for stars is all very well
0:38:34 > 0:38:38In the right conditions, they're easy to find.
0:38:38 > 0:38:42But if we want to look for life, we have to search for planets.
0:38:42 > 0:38:46And not just any planets. The right kind of planets.
0:38:46 > 0:38:52Probably a planet very much like Earth - rocky, rather than a gas giant like Jupiter
0:38:52 > 0:38:57But not only that, the planet has to be just the right distance from the star.
0:38:57 > 0:38:59Not too far away...
0:39:01 > 0:39:05..and also not too close to the parent star.
0:39:05 > 0:39:11It needs to be just the right distance, so that liquid water can exist on the surface,
0:39:11 > 0:39:13a habitable exoplanet.
0:39:16 > 0:39:23The problem with finding these exoplanets is they are lost in the glare of the stars they orbit
0:39:28 > 0:39:33So finding them is like looking for a flea crawling across a car headlight...
0:39:34 > 0:39:37..from a mile away.
0:39:40 > 0:39:43'Five, four,
0:39:43 > 0:39:45'three, two...
0:39:45 > 0:39:50'Engine start, one, zero, and lift-off for the Delta II rocket with Kepler
0:39:50 > 0:39:52'on a search for planets.'
0:39:53 > 0:39:58But recently, we've had a new tool to help us, a telescope in space - Kepler.
0:40:01 > 0:40:04When a planet crosses between us and its star,
0:40:04 > 0:40:08the light from the star dips by a fraction of a percent.
0:40:12 > 0:40:17And it's by measuring this dimming that Kepler tracks down planets.
0:40:19 > 0:40:22Kepler carries a photometer on board
0:40:22 > 0:40:27that measures this tiny dip in light and it sends back a signal.
0:40:27 > 0:40:31Now, it's not a picture or a message from the aliens.
0:40:31 > 0:40:33It's this - a light curve.
0:40:34 > 0:40:37And this may not look like very much
0:40:37 > 0:40:42but this dip can tell us a lot about the planet that is in orbit around the star,
0:40:42 > 0:40:46for example, how long it takes to orbit and what size the planet is
0:40:46 > 0:40:51And using data like this, we can even work out the key question -
0:40:51 > 0:40:54is the planet in the star's habitable zone?
0:40:56 > 0:41:02In the last four years alone, Kepler has discovered 61 new planets
0:41:02 > 0:41:08and there are more than 2,000 others awaiting confirmation.
0:41:10 > 0:41:17Such a rapid rate of discovery makes this one of the most exciting fields of exploration today.
0:41:20 > 0:41:25And these new techniques are not onl helping our search for planets.
0:41:26 > 0:41:29They are also helping us hunt for ET
0:41:54 > 0:41:58I've always wanted to come here to this eerie place.
0:41:58 > 0:42:03These telescopes are very famous, but they're not telescopes that are looking.
0:42:03 > 0:42:09They're telescopes that are listenin and they're listening out for any sign at all of a message from ET
0:42:09 > 0:42:13a bit like an interplanetary telephone exchange.
0:42:23 > 0:42:28This is the Allen Telescope Array, home to the SETI Institute,
0:42:28 > 0:42:35a group of scientists who have dedicated their careers to searching for extra-terrestrial intelligence.
0:42:39 > 0:42:43And leading the search is Dr Seth Shostak.
0:42:45 > 0:42:49How do these telescopes actually go about getting data for you?
0:42:49 > 0:42:53In principle, all you do is aim all these antennas in the direction
0:42:53 > 0:42:56of some star system that, for one reason or another,
0:42:56 > 0:43:00maybe just because it's a close star or a star known to have planets,
0:43:00 > 0:43:02you think, "That might be a habitat for ET,"
0:43:02 > 0:43:09then you just search over a wide range of the radio dial, looking for a signal at one spot on the dial.
0:43:09 > 0:43:13It is a big universe out there. In our galaxy alone, there's 100 billion stars.
0:43:13 > 0:43:19- How do you focus your search? - We tend to look at star systems that are like the sun
0:43:19 > 0:43:24because we know that a star system like the sun can have planets where you get intelligent life.
0:43:24 > 0:43:30- We're here.- We're here. We also tend to pick nearby star systems if we can as the signals would be stronger
0:43:30 > 0:43:33and if you found something, it would be more interesting
0:43:33 > 0:43:37to find nearby neighbours than somebody 5,000 light years away.
0:43:37 > 0:43:43NASA's Kepler mission is now studying 150,000 stars, looking for planetary transits.
0:43:43 > 0:43:46How has that technique helped your search?
0:43:46 > 0:43:50One of the problems we had was that we're aiming these antennas towards the south
0:43:50 > 0:43:55on the assumption that whatever star we're aimed at has a signal coming our way
0:43:55 > 0:43:58that's arriving just at the right time, so it gets picked up.
0:43:58 > 0:44:03It's like two cowboys aiming their pistols at one another and having the bullets meet in the middle.
0:44:03 > 0:44:07- Across the vastness of the sky. - I mean, it's not very likely.
0:44:07 > 0:44:11But transits, the transit of the Earth in front of the sun,
0:44:11 > 0:44:16as seen by ET, gives them a clock and they might be clever enough to say,
0:44:16 > 0:44:21"Wait, what we'll do is broadcast a signal that gets to Earth just as it's transiting the sun."
0:44:21 > 0:44:27OK? That way, they'll know where to look when, so the bullets have a chance of meeting.
0:44:39 > 0:44:45This is where all the action happens, there is where the signals from the telescopes are brought in,
0:44:45 > 0:44:4920 million channels a second being analysed. Tell me what happens here.
0:44:49 > 0:44:54There's a whole room full of electronics and fibre optics and other hi-tech stuff.
0:44:54 > 0:44:57And all the signals from all the antennas go in there.
0:44:57 > 0:45:00They're sliced and diced and sampled
0:45:00 > 0:45:05and, you know, some part of them is then sent to be analysed for signals.
0:45:05 > 0:45:09What would the signal have to be lik to get you out of bed at three in the morning?
0:45:09 > 0:45:14Nobody would call me unless the signal had the characteristics required to get me out of bed,
0:45:14 > 0:45:17but it would have to be a very clean-looking signal,
0:45:17 > 0:45:22a very narrow band and drifting at a rate that looks like it's not a transmitter here on Earth.
0:45:22 > 0:45:25ET, yeah, I'll get out of bed!
0:45:25 > 0:45:28It's utterly incredible to think that these images,
0:45:28 > 0:45:33which amount to really nothing more than noise and fluff on the screen,
0:45:33 > 0:45:38could ultimately be the first tantalising glimpse that we get of life elsewhere?
0:45:38 > 0:45:44Yes, it doesn't look very dramatic, but that's the nature of discovery science and that's what we're doing.
0:45:44 > 0:45:49A little plot like this with just a little wiggly, scraggly bit of brightening across it,
0:45:49 > 0:45:54that's the clue that would tell us that there's somebody out there.
0:46:02 > 0:46:06Seth's pretty bullish about his chances of finding ET
0:46:06 > 0:46:10and actually, I think he's got reall good reason to think that way.
0:46:10 > 0:46:14Kepler and the science that's coming out of the planetary transits
0:46:14 > 0:46:17is really reviving and giving focus to his search.
0:46:17 > 0:46:22If I was new to science today, I would very much want to go into this area.
0:46:22 > 0:46:25There's so much data being collected about these planets
0:46:25 > 0:46:30and we're learning so much about their size and suitability for life.
0:46:30 > 0:46:34And I think that in the coming years we will find what we're looking for.
0:46:39 > 0:46:45Transits have been crucial in helping us track down Earth-like planets.
0:46:47 > 0:46:51But to find out if they sustain life,
0:46:51 > 0:46:53we need to take the next step.
0:46:54 > 0:46:58We need to get closer to these planets than ever before.
0:46:59 > 0:47:03Close enough to peer inside their atmospheres.
0:47:10 > 0:47:14To get a peek at the atmospheres of these distant planets,
0:47:14 > 0:47:18I'm travelling as far out of our own atmosphere as I can get.
0:47:21 > 0:47:23This is a bit of a bumpy drive,
0:47:23 > 0:47:27but we're on the way to a really exciting place.
0:47:27 > 0:47:29We're going to Mauna Kea,
0:47:29 > 0:47:32one of the most famous observatories in the world.
0:47:32 > 0:47:35It's also very, very remote.
0:47:59 > 0:48:01I feel like I'm on top of the world
0:48:01 > 0:48:04and I'm not far off.
0:48:05 > 0:48:09There's very little air up here, compared with down on the ground.
0:48:10 > 0:48:13I can feel it's quite hard to breathe.
0:48:18 > 0:48:22All the weather, the turbulence down there,
0:48:22 > 0:48:25all of that is underneath,
0:48:25 > 0:48:28and that's why all these telescopes are here.
0:48:29 > 0:48:34So this is an amazing place to come to get away from the Earth.
0:48:34 > 0:48:37It's like a step on the way to the sky.
0:48:55 > 0:49:01It's getting really cold here. The sun has just gone down.
0:49:01 > 0:49:03But the telescopes are waking up.
0:49:03 > 0:49:10There's a stunning sunset and we can still just see all the telescope flaps opening.
0:49:15 > 0:49:18So as the view of the land fades away,
0:49:18 > 0:49:22the sky is opening up and I can see Venus up there with my eyes.
0:49:27 > 0:49:32But beyond Venus are billions of planets we can't even see,
0:49:32 > 0:49:37and yet using these telescopes, scientists have developed an exciting new technique
0:49:37 > 0:49:41to find planets with atmospheres that could support life.
0:49:41 > 0:49:48And the most recent focus of their search is a new class of planets only slightly larger than our own -
0:49:48 > 0:49:50super-Earths.
0:49:50 > 0:49:56Now, all of these planets are just so far away. How do you study an atmosphere that's that far away?
0:49:56 > 0:49:58When they pass in front of the star,
0:49:58 > 0:50:00something very special happens.
0:50:00 > 0:50:05The light from the star shines through the planet's atmosphere.
0:50:05 > 0:50:11And as it does so, the light is absorbed at different colours by molecules
0:50:11 > 0:50:14and each molecule has a unique fingerprint.
0:50:14 > 0:50:17What are the chemicals that you're looking for?
0:50:17 > 0:50:21The one that we're using as a key diagnostic right now is methane.
0:50:21 > 0:50:25Here on Earth, of course, methane is connected to life processes.
0:50:25 > 0:50:29We're really looking for life changing the atmosphere
0:50:29 > 0:50:33in a way which can't be explained by any other process.
0:50:33 > 0:50:38So you collect this data using this enormous thing here. How does that work?
0:50:38 > 0:50:43This is the NASA Infrared Telescope Facility, a really marvellous telescope.
0:50:43 > 0:50:49And the instrument my team uses a lo is the SPECS instrument back here, this blue one.
0:50:49 > 0:50:55It works just like a prism. It break light apart into all these different colours, but mainly in the infrared.
0:50:55 > 0:50:59And what's the most recent thing you've been working on?
0:50:59 > 0:51:02This is a well-known super-Earth, GJ 1214b,
0:51:02 > 0:51:06and what you're seeing right here is a preliminary spectrum
0:51:06 > 0:51:09that our team obtained here at the IRTF with SPECS.
0:51:09 > 0:51:13This is the feature we're out to try to confirm.
0:51:13 > 0:51:18But how long are we going to have to wait until we can really look inside a planet's atmosphere
0:51:18 > 0:51:22and answer the question about whether there's life there?
0:51:22 > 0:51:27That's a question I think we will get to over probably the next 10 to 15 years.
0:51:27 > 0:51:32Within my professional life, I expec we will have answered it, but there is still a lot of work to do.
0:51:43 > 0:51:47I find the measurements that they're making here absolutely astonishing.
0:51:47 > 0:51:54The subtlety required to detect an atmosphere from this far away is just amazing.
0:51:55 > 0:52:00Science fiction writers have been inventing crazy planets for decades
0:52:00 > 0:52:03and now we know they really exist.
0:52:03 > 0:52:07And it makes the sky for me a completely different place.
0:52:14 > 0:52:18Studying the atmospheres of distant, transiting planets
0:52:18 > 0:52:22is some of the most exciting science happening today.
0:52:22 > 0:52:26But precision is everything and to be as accurate as possible,
0:52:26 > 0:52:29we need to know if we're doing things right.
0:52:31 > 0:52:38And that's what's happening tonight with one very special telescope 350 miles above us -
0:52:38 > 0:52:39Hubble.
0:52:41 > 0:52:47So what are you hoping to achieve with tonight's transit and Hubble's observation of it?
0:52:47 > 0:52:51We hope to retrieve the atmospheric signal from Venus
0:52:51 > 0:52:56and to do that, we will observe the transit of Venus with a spectrograph
0:52:56 > 0:52:59So a spectrum looks something like this.
0:52:59 > 0:53:05It basically tells you what's inside the atmosphere of the object you are studying.
0:53:05 > 0:53:10But we already know the atmospheric composition of Venus, so why are you doing this?
0:53:10 > 0:53:18Well, the idea is really to be able to test our technique to study the atmosphere of exoplanets.
0:53:18 > 0:53:22We want to use Venus as a template, as a model.
0:53:22 > 0:53:26So, basically, you're testing that your method is correct
0:53:26 > 0:53:30and if it correctly splits up all the components of Venus's atmosphere,
0:53:30 > 0:53:35you can then apply it to exoplanets far away that we haven't analysed yet?
0:53:35 > 0:53:41Yeah, with much more confidence than we would have without doing this experiment.
0:53:41 > 0:53:46But it's not quite as simple as just focusing the Hubble telescope on the transit, is it?
0:53:46 > 0:53:53No, actually, it's forbidden to point Hubble to the sun because it could damage the instruments,
0:53:53 > 0:53:57so we are going to use a trick which is pointing at the moon.
0:53:57 > 0:54:01In other words, we are going to use the moon as a giant mirror.
0:54:01 > 0:54:04It just seems like such a huge undertaking
0:54:04 > 0:54:08and there's only one chance in your lifetime to get it right.
0:54:08 > 0:54:14This is a unique opportunity to record the transit of Venus with Hubble.
0:54:14 > 0:54:19- Does that make you a little bit nervous about getting it right? - More than a little bit.- Really?
0:54:22 > 0:54:26From the first transits we witnessed
0:54:26 > 0:54:28to the one that's happening tonight,
0:54:28 > 0:54:33the transit of Venus has transformed our understanding
0:54:33 > 0:54:36of the vast universe we belong to.
0:54:38 > 0:54:42It's given us the size of our own solar system
0:54:42 > 0:54:47and now it's helping us to take giant leaps into distant space
0:54:47 > 0:54:50in our search for life.
0:54:52 > 0:54:56It's meant so much to so many people
0:54:56 > 0:54:59and tonight is no exception.
0:54:59 > 0:55:01I'm going to watch it with my kids.
0:55:01 > 0:55:08This is kind of a way I get to share with them a little bit of what I do and the excitement of astronomy.
0:55:08 > 0:55:10I'm excited to be going to Svalbard.
0:55:10 > 0:55:14I'll meet the Venus Express team there and we'll see the transit together.
0:55:14 > 0:55:17Hopefully, somewhere up on the mountains for the best view.
0:55:17 > 0:55:22During the transit, I might actually be in bed trying to get some sleep
0:55:22 > 0:55:26because the real work for me starts after it.
0:55:26 > 0:55:31During the next transit of Venus, I'll get some of my colleagues together, we'll have a big party,
0:55:31 > 0:55:36haul out our telescope, put a solar filter on it and watch Venus pass across the sun.
0:55:36 > 0:55:39After all, we won't be around the next time this happens.
0:55:43 > 0:55:47And if you want to enjoy this spectacle safely,
0:55:47 > 0:55:51you don't even need a telescope. It's something everyone can share.
0:55:51 > 0:55:55Now, there are lots of ways in which you can take part,
0:55:55 > 0:56:01but there's one thing that you must keep in mind and that's never look at the sun directly.
0:56:01 > 0:56:06It gives out a lot of light and heat that would damage your eyes without you even realising.
0:56:09 > 0:56:14By far the simplest way to view the transit is by using a filter,
0:56:14 > 0:56:19so, for example, one of these, and they're extremely easy to use.
0:56:19 > 0:56:26All you have to do is put them up in front of your eyes and then turn to look at the sun. Let's give it a go.
0:56:28 > 0:56:30Wow! What does it look like to you?
0:56:30 > 0:56:32Green.
0:56:32 > 0:56:34Green?
0:56:34 > 0:56:39Now, Venus is only one-thirtieth of the size of the sun,
0:56:39 > 0:56:42so you'll have to have pretty keen eyes to see the transit.
0:56:42 > 0:56:46- Do you think you'll be able to see Venus?- Yeah.- You'll give it a go?
0:56:48 > 0:56:53If you want to project an image of the sun that's bigger, you can us a telescope like this one
0:56:53 > 0:56:56and you should never look through the eyepiece.
0:56:56 > 0:57:01Instead, project the image of the su on to the card like we have here.
0:57:01 > 0:57:05Hold it just underneath the telescop and what can you see on here?
0:57:05 > 0:57:08I can see quite a lot of sunspots and there's quite a large one.
0:57:08 > 0:57:14- This one is massive.- Yes. - Using this kind of technique makes the sun much, much bigger.
0:57:14 > 0:57:19- Do you think you'll be viewing the transit?- Yeah. It's going to be exciting.
0:57:31 > 0:57:33- SHE LAUGHS - Yeah.
0:57:33 > 0:57:36- Absolutely beautiful.- Yeah.
0:57:37 > 0:57:40I look at the moon quite a lot through binoculars.
0:57:40 > 0:57:43You're a bit of a pro at this, aren't you?
0:57:44 > 0:57:46Wherever you're watching it,
0:57:46 > 0:57:49this is going to be a spectacular event.
0:57:49 > 0:57:55There's just over an hour to go before Venus makes its first contact with the outer edge of our star.
0:57:55 > 0:58:02And I absolutely cannot wait to find out what this transit teaches us about our incredible universe.
0:58:02 > 0:58:07And since this is the last transit of Venus until 2117, make the most of it.
0:58:07 > 0:58:11Be a part of this rare moment in history.
0:58:11 > 0:58:15And remember, the next time you look up at the morning star,
0:58:15 > 0:58:20just take a moment to consider how remarkable it is.
0:58:29 > 0:58:33# I'm wishing on a star
0:58:33 > 0:58:37# To follow where you are
0:58:40 > 0:58:44# I'm wishing on a dream
0:58:45 > 0:58:49# To follow what it means
0:58:51 > 0:58:53# To follow where you are... #
0:58:53 > 0:58:56Subtitles by Red Bee Media Ltd