0:00:35 > 0:00:38Hello! Welcome to The Sky at Night.
0:00:38 > 0:00:41This month's programme is coming from Stonehenge,
0:00:41 > 0:00:44where we've joined the crowds to celebrate the summer solstice.
0:00:44 > 0:00:46In just a few hours' time,
0:00:46 > 0:00:48the sun will rise in a very special location
0:00:48 > 0:00:50over the heel stone.
0:00:50 > 0:00:53People have argued about the significance of this place
0:00:53 > 0:00:56and its connection to astronomy for more than 100 years.
0:00:56 > 0:00:59We've looked at the connection between these magnificent stones
0:00:59 > 0:01:01and the skies above our heads,
0:01:01 > 0:01:03particularly at the moon.
0:01:07 > 0:01:11The creation of Stonehenge by our Neolithic ancestors
0:01:11 > 0:01:14still inspires us, thousands of years later.
0:01:16 > 0:01:18Why was it built? What was it for?
0:01:18 > 0:01:23And is the controversial link with the moon real or imaginary?
0:01:24 > 0:01:27Stonehenge still perplexes us today.
0:01:29 > 0:01:31It was around 5,000 years ago
0:01:31 > 0:01:35that the first architects on this site built the grass bank and the ditch
0:01:35 > 0:01:38with 56 post holes around the inner ring.
0:01:40 > 0:01:41Then came the stones.
0:01:41 > 0:01:45The blue stones are thought to have come from west Wales,
0:01:45 > 0:01:47a feat that still impresses.
0:01:48 > 0:01:50These stones have been rearranged many times
0:01:50 > 0:01:53in what some speculate was an attempt
0:01:53 > 0:01:55to chart the celestial calendar.
0:01:57 > 0:02:00The striking Sarsen stones are from closer to home.
0:02:00 > 0:02:03They're from Marlborough, just 20 miles away.
0:02:04 > 0:02:08But this is our idea of how Stonehenge would have looked
0:02:08 > 0:02:09in its prime.
0:02:12 > 0:02:18Professor Clive Ruggles is a world expert in the study of astronomy in ancient civilisations.
0:02:18 > 0:02:24Clive is going to help The Sky at Night pin down the link between Stonehenge, astronomy,
0:02:24 > 0:02:26and in particular, the moon.
0:02:26 > 0:02:29The first mystery to solve is that of The Avenue,
0:02:29 > 0:02:31a track in the landscape
0:02:31 > 0:02:34which lines up on its approach to Stonehenge
0:02:34 > 0:02:36with the solstice sun.
0:02:36 > 0:02:42Clive, you've brought us to a field, which I'm assured is very important for Stonehenge.
0:02:42 > 0:02:44There's a feature here called The Avenue.
0:02:44 > 0:02:47But I'm finding it hard to sense this feature. Tell me about it.
0:02:47 > 0:02:50You don't see a lot in the long grass. You're standing in it.
0:02:50 > 0:02:52Chris is standing in a ditch on one side of it,
0:02:52 > 0:02:54the other ditch is over there.
0:02:54 > 0:02:58So it's a long avenue that led straight up to Stonehenge in this direction.
0:02:58 > 0:03:01This clearly was the way you'd come on important occasions.
0:03:01 > 0:03:03I should say you don't see much here,
0:03:03 > 0:03:06but if you look at it from an aerial photo, you see it very clearly.
0:03:07 > 0:03:10The Avenue, far from being created just anywhere,
0:03:10 > 0:03:12is based on a natural feature.
0:03:12 > 0:03:15Recent excavations have shown it to follow
0:03:15 > 0:03:18the line of a channel carved by glaciers.
0:03:20 > 0:03:24It's this natural alignment that first connected this landscape
0:03:24 > 0:03:26with the summer and winter solstice suns
0:03:26 > 0:03:31and it might even be the reason that Stonehenge was here in the first place.
0:03:32 > 0:03:36If you're somewhere in this landscape, hundreds of years before there's anything here,
0:03:36 > 0:03:41and you see these striations and you see the sun on the shortest day of the year setting in line with them,
0:03:41 > 0:03:47surely that to you is going to make it a special place. It's going to be a sacred place.
0:03:47 > 0:03:50Because it's already lined up to this feature that we care about.
0:03:50 > 0:03:51To us, it's a coincidence of nature,
0:03:51 > 0:03:54but to them, what more can you ask for,
0:03:54 > 0:03:57to show that this is a really special place.
0:03:57 > 0:04:00Perhaps that's why Stonehenge is where it is,
0:04:00 > 0:04:03because this is a place that acquires that significance
0:04:03 > 0:04:06to do with the sunset all through.
0:04:06 > 0:04:09And then gradually people build things. A ditch, a bank, some timber things,
0:04:09 > 0:04:13and then eventually it gets enhanced and turns into what we now see.
0:04:15 > 0:04:18The Sky at Night has been to Stonehenge before.
0:04:19 > 0:04:22Hello to the first ever Sky at Night from Stonehenge.
0:04:22 > 0:04:24It is, in fact, midsummer morning.
0:04:24 > 0:04:26There are a great many people here
0:04:26 > 0:04:30and in a few moments, the druids will begin their main procession.
0:04:30 > 0:04:32SINGLE DEEP HORN NOTE
0:04:32 > 0:04:36In 1972, Sir Patrick Moore investigated the link
0:04:36 > 0:04:38between Stonehenge and the moon.
0:04:38 > 0:04:41Patrick wanted to know if the monument could be used
0:04:41 > 0:04:43to chart the lunar calendar.
0:04:43 > 0:04:49Patrick also saw a magnificent sunrise the day before the summer solstice.
0:04:49 > 0:04:53Through that great arch, the heel stone in the distance,
0:04:53 > 0:04:55the alignment absolutely perfect
0:04:55 > 0:04:58as the sun comes up to its rising point over the top of the stone.
0:04:58 > 0:05:04And there it is. There are very many people who've never actually seen this.
0:05:04 > 0:05:08I've never myself seen it before. It really is a superb sight.
0:05:09 > 0:05:16In fact, the sunrise over the heel stone can be seen for a couple of days either side of the solstice.
0:05:16 > 0:05:19So you don't have to join the druids on the day itself!
0:05:23 > 0:05:26Radio astronomer Professor Gerald Hawkins
0:05:26 > 0:05:32was one of the advocates of the idea that Stonehenge could be used to chart eclipses
0:05:32 > 0:05:34and the movements of the moon.
0:05:35 > 0:05:39The Aubrey Holes. 56 of them. A significant number?
0:05:39 > 0:05:41Very, very, of course.
0:05:41 > 0:05:43The most critical number for the moon.
0:05:43 > 0:05:47It's three nodal revolutions of the moon's orbit.
0:05:47 > 0:05:50When the Stonehenge people came here,
0:05:50 > 0:05:54they started with these holes, the ditch of the bank and this circle.
0:05:54 > 0:05:57Because of the 56 Aubrey holes
0:05:57 > 0:05:59and because of the alignments here at Stonehenge,
0:05:59 > 0:06:02it could be said to be more a moon observatory
0:06:02 > 0:06:04than an observatory for the sun.
0:06:04 > 0:06:08And just as the sun rises over the heel stone at midsummer,
0:06:08 > 0:06:12the moon rises over the heel stone at midwinter.
0:06:13 > 0:06:15If this theory is true,
0:06:15 > 0:06:17then the builders of Stonehenge
0:06:17 > 0:06:21would have achieved a remarkable degree of astronomical sophistication.
0:06:21 > 0:06:24After all, the moon's hard to pin down.
0:06:24 > 0:06:27Its movements seem to have a touch of lunacy about them
0:06:27 > 0:06:29and that's because of its orbit.
0:06:29 > 0:06:34Well, if bits of Stonehenge really are aligned with the movements of the moon,
0:06:34 > 0:06:38then the builders must have understood some quite complex geometry.
0:06:38 > 0:06:40Let's see if we're as good as they were!
0:06:40 > 0:06:43I've got here the Earth. We'll need the orbit of the moon.
0:06:43 > 0:06:45Here's the orbit of the moon.
0:06:45 > 0:06:48It's slightly tilted in respect of the Earth's orbit around the sun,
0:06:48 > 0:06:51which is very ably held by Clive over there.
0:06:51 > 0:06:54We'll exaggerate that tilt for the purposes of this demonstration.
0:06:54 > 0:06:58I'm going to bring in the moon and put it directly opposite the sun
0:06:58 > 0:07:00so that it's in the full moon phase.
0:07:00 > 0:07:04Now, the moon takes 27 days to do one complete lap of the Earth
0:07:04 > 0:07:07and ends up where it started, back at full moon.
0:07:07 > 0:07:11But, of course, while the moon's been doing that, we've all moved relative to the sun.
0:07:11 > 0:07:13So we're over here by now.
0:07:13 > 0:07:17And that means that the moon is no longer in the full moon phase
0:07:17 > 0:07:19when it's at this point. It has to move on a couple of days
0:07:19 > 0:07:21to be aligned with the sun.
0:07:21 > 0:07:25If that was all that was going on, building Moon-henge would be easy,
0:07:25 > 0:07:30because the moon would rise and set at the same points on the horizon every single month.
0:07:30 > 0:07:33So you'd only need a couple of stones and the job would be done.
0:07:33 > 0:07:35But things are more complicated than that.
0:07:35 > 0:07:37The complication is something called procession,
0:07:37 > 0:07:40and that makes this experiment a little more cumbersome!
0:07:40 > 0:07:42So I'm going to get out the way
0:07:42 > 0:07:44and hold the Earth from down here.
0:07:44 > 0:07:46All procession is is a wobble.
0:07:46 > 0:07:50That means that the moon's orbit, which is tilted, moves around,
0:07:50 > 0:07:54and the position of full moon gradually sinks lower.
0:07:54 > 0:07:57It takes years for this to take place.
0:07:57 > 0:08:02But then it gets to its lowest point and then gets higher again and eventually returns to there.
0:08:02 > 0:08:05That's why it takes almost 19 years
0:08:05 > 0:08:10for the full moon to appear in our sky in the position where it started.
0:08:13 > 0:08:15The rising and setting of the moon
0:08:15 > 0:08:19seems to be unpredictable and unintuitive.
0:08:19 > 0:08:21It pops up all over the place!
0:08:21 > 0:08:23And that's because of its complex orbit.
0:08:25 > 0:08:28But we can chart the moon's movements
0:08:28 > 0:08:32and it seems there might just be a connection to Stonehenge.
0:08:33 > 0:08:36Clive is going to help us map out what the moon is doing
0:08:36 > 0:08:39over the course of its 19-year cycle.
0:08:39 > 0:08:42But to set the scene, we first have to explain
0:08:42 > 0:08:44what the sun is doing.
0:08:44 > 0:08:47Clive, we're on the most important part of Stonehenge,
0:08:47 > 0:08:49- at least...- On the axis.- Exactly.
0:08:49 > 0:08:52So why is this axis important? Why is this line important?
0:08:52 > 0:08:54Because when you look along the axis,
0:08:54 > 0:08:56that's where the sun is rising on midsummer's day.
0:08:56 > 0:08:58Just over this heel stone.
0:08:58 > 0:09:01And that happens around midsummer, it'll happen tomorrow.
0:09:01 > 0:09:05- It happens around the summer solstice, exactly.- What about the rest of the year?
0:09:05 > 0:09:08Well, if you were to come here every morning and look,
0:09:08 > 0:09:13you'd start to see the sun rising just a little to the south every morning.
0:09:13 > 0:09:15And then further and further to the south.
0:09:15 > 0:09:18And then it starts to get going faster!
0:09:18 > 0:09:21- So by the time you get towards the equinox...- Mid-September.
0:09:21 > 0:09:23It's rattling along the horizon day by day.
0:09:23 > 0:09:26As we approach December, we slow down again
0:09:26 > 0:09:29- and we're right here.- And we meet the mid-winter sun.
0:09:29 > 0:09:32Thank you, Paul. If you were here any midwinter,
0:09:32 > 0:09:34you'd see sunrise in this position.
0:09:34 > 0:09:39Yes. Any time in the year, you'll see sunrise somewhere on this arc of the horizon.
0:09:40 > 0:09:42So in any given year,
0:09:42 > 0:09:44the sun has two extreme positions.
0:09:44 > 0:09:47Its summer sunrise and its winter sunrise.
0:09:47 > 0:09:49The moon does something similar,
0:09:49 > 0:09:53but it takes 27 days, the lunar monthly cycle.
0:09:58 > 0:10:02We're going to mark out the extremes of moonrise over the course of a month.
0:10:02 > 0:10:06Pete is holding one lunar position, and Chris is holding the other.
0:10:07 > 0:10:12But the complexities of the lunar orbit means these points change position
0:10:12 > 0:10:15over the course of that 19-year cycle.
0:10:16 > 0:10:18OK, so that's moonrise now,
0:10:18 > 0:10:21but over the course of a month, the moon rises at different positions.
0:10:21 > 0:10:25Exactly. You'd see it moving up and down an arc on the horizon,
0:10:25 > 0:10:29just like the sun, but doing it up and down in 27 days.
0:10:29 > 0:10:32And it would reach all the way to Pete,
0:10:32 > 0:10:34the most northerly extent of moonrise up there.
0:10:34 > 0:10:36But that's true now,
0:10:36 > 0:10:39but of course because of the complexities of the moon's orbit,
0:10:39 > 0:10:42we need to move Chris and Pete again.
0:10:42 > 0:10:46Yes, because with the moon, these limit positions every month
0:10:46 > 0:10:47change gradually.
0:10:47 > 0:10:50So if we now roll the time forward
0:10:50 > 0:10:53to eventually 2015, that's enough,
0:10:53 > 0:10:56then we're going to reach a position here
0:10:56 > 0:11:02and so by 2015, you'll find the moon is only going up and down between these upper limits.
0:11:02 > 0:11:04But then it starts to come back again
0:11:04 > 0:11:08and if you both move out, and we go over another almost ten years...
0:11:08 > 0:11:11Past the point of midwinter sun...
0:11:11 > 0:11:14..right out the same distance in the other direction,
0:11:14 > 0:11:18this is where the moon is going up and down in 2025.
0:11:18 > 0:11:19It's called a major standstill year.
0:11:19 > 0:11:23And in that time, there are certain times every month
0:11:23 > 0:11:26when the moon is going to be rising extremely far south,
0:11:26 > 0:11:30much further south than the sun ever rises, and also much further north.
0:11:30 > 0:11:34And those are the things that we think there might be alignments from Stonehenge.
0:11:34 > 0:11:37That's where some things do appear to be aligned at Stonehenge.
0:11:37 > 0:11:40Let's go into the centre of the circle and look at those alignments.
0:11:43 > 0:11:45Once every 19 years,
0:11:45 > 0:11:48the moon will rise at its most southerly position.
0:11:52 > 0:11:53Just over nine years later,
0:11:53 > 0:11:57the moon will set at its most northerly position,
0:11:57 > 0:11:59in exactly the opposite direction.
0:12:00 > 0:12:04The question is, did Neolithic Man use Stonehenge
0:12:04 > 0:12:06to mark these points?
0:12:07 > 0:12:09This reconstruction of Stonehenge
0:12:09 > 0:12:11shows four stones around the edge.
0:12:11 > 0:12:13Called the station stones,
0:12:13 > 0:12:17these seem to mark the limits where the most southerly moonrise
0:12:17 > 0:12:20and the most northerly moon set occur.
0:12:20 > 0:12:23Today, two of those stones are missing,
0:12:23 > 0:12:27so we've sent The Sky at Night team to mark the places where they once stood.
0:12:27 > 0:12:33So those are the station stones. What exactly are they lined up with?
0:12:33 > 0:12:36Most importantly, they're lined up with the axis of the monument.
0:12:36 > 0:12:39That makes us think generally - we don't know exactly -
0:12:39 > 0:12:43it makes us think they're put there much the same time as the big stones.
0:12:43 > 0:12:45So how does that get us to the moon?
0:12:45 > 0:12:50The other way, they're pointing in two of these lunar directions,
0:12:50 > 0:12:52give or take a degree or two.
0:12:52 > 0:12:58So to the north-west, they're pointing very closely to where the moon theoretically would set
0:12:58 > 0:12:59as far north as it ever sets.
0:12:59 > 0:13:04To the south, a bit closer to where the moon rises at its furthest south.
0:13:04 > 0:13:07The station stones do stand out.
0:13:07 > 0:13:11It's intriguing that they do have this lunar direction to them.
0:13:11 > 0:13:14- People talk about a Neolithic observatory.- Right.
0:13:14 > 0:13:16Is that justified? Can we go that far?
0:13:16 > 0:13:18I don't like the word observatory
0:13:18 > 0:13:20because that implies that people built this for astronomy,
0:13:20 > 0:13:23and that that was its exclusive or main purpose.
0:13:23 > 0:13:27I'm sure that wasn't the case. But neither did it have nothing to do with astronomy.
0:13:27 > 0:13:29Clearly this solsticial axis meant something.
0:13:29 > 0:13:34I don't think they were using it to time the longest and shortest day accurately in our terms at all.
0:13:34 > 0:13:40But I do think they were timing seasonal ceremonies, festivities, other activities,
0:13:40 > 0:13:42which in their way of thinking of things
0:13:42 > 0:13:46would have been absolutely essential to keep all the seasonal things functioning.
0:13:46 > 0:13:50Ancestral spirits could be used to help regenerate crops
0:13:50 > 0:13:52or whatever needed to be done to bring things about
0:13:52 > 0:13:54successfully in the next year.
0:14:08 > 0:14:11It's seven o'clock now, and they've just opened up the site
0:14:11 > 0:14:13to all the excited visitors.
0:14:13 > 0:14:17And also, the sun's come out, and the moon is rising behind us.
0:14:17 > 0:14:18When you're in a landscape like this,
0:14:18 > 0:14:23it's hard not to think about what's happening in the sky relates to us here on Earth.
0:14:26 > 0:14:30For some, the moon rising or setting over the station stones
0:14:30 > 0:14:33is just an intriguing coincidence.
0:14:35 > 0:14:37Simon Banton is a keen amateur astronomer
0:14:37 > 0:14:41who dresses as a druid, but only to impart cosmic wisdom.
0:14:41 > 0:14:45..the centre of The Avenue is looking to the north-east in that direction...
0:14:45 > 0:14:50Simon has studied the moon's movements at Stonehenge
0:14:50 > 0:14:53and for him, the coincidences add up to something more.
0:14:53 > 0:14:57But he's still got to convince Pete and Paul, who are a little sceptical.
0:14:57 > 0:15:01You believe there's an association with lunar astronomy,
0:15:01 > 0:15:03you're not quite convinced.
0:15:03 > 0:15:06I'll tell you why I'm not convinced. Because...
0:15:06 > 0:15:11the way the sun comes up every day, and the way it moves across the horizon, is intuitive.
0:15:11 > 0:15:15- But the moon isn't. The moon is a tricky devil to predict. - It hops about.
0:15:15 > 0:15:19It hops about a lot. So I have a great deal of difficulty
0:15:19 > 0:15:23with a culture that is trying to get all the details of the moon
0:15:23 > 0:15:26- and they can't write anything down. It's all by word of mouth!- Yes.
0:15:26 > 0:15:30Firstly, I think you underestimate the capability of oral tradition
0:15:30 > 0:15:32to transmit knowledge effectively.
0:15:32 > 0:15:36And I did stand here on the north barrow in 2006
0:15:36 > 0:15:39at the greatest southerly moonrise
0:15:39 > 0:15:44and watched the moon rise over the station stone that Hawkins identified
0:15:44 > 0:15:47as being a marker for that event.
0:15:47 > 0:15:51The problem is the markers are marking the positions
0:15:51 > 0:15:54where the moon goes to its maximum extent and then back again.
0:15:54 > 0:15:56It's important to say "roughly".
0:15:56 > 0:16:00The precision aspect of it may sometimes get overburnt.
0:16:00 > 0:16:03So that's a watch for at least 18.6 years
0:16:03 > 0:16:05and probably for several of those cycles.
0:16:05 > 0:16:07It is important to note, though,
0:16:07 > 0:16:10that if you do watch the moon rise over the hills there,
0:16:10 > 0:16:14it can rise in a range that's to the right of it and to the left of it.
0:16:14 > 0:16:17And when it rises over the heel stone in the same way that the sun does,
0:16:17 > 0:16:22then there will be an eclipse either of the moon that night, the full moon,
0:16:22 > 0:16:24or two weeks later of the sun.
0:16:24 > 0:16:27- It's quite incredible, really.- Now, I don't say that it's planned,
0:16:27 > 0:16:29but to notice that.
0:16:29 > 0:16:33To notice it and then go, "That's interesting! Let's count."
0:16:33 > 0:16:36Because these people have got counting. They're not idiots.
0:16:42 > 0:16:45There are no written records from the people who built Stonehenge
0:16:45 > 0:16:47and who worshipped here.
0:16:47 > 0:16:50But they did leave behind their burial mounds, called barrows,
0:16:50 > 0:16:54which contain some of the objects they treasured.
0:16:54 > 0:16:59At Stonehenge, Bush Barrow contained a truly amazing find
0:16:59 > 0:17:02which shows that when Stonehenge was less than 1,000 years old,
0:17:02 > 0:17:07the people who lived here understood mathematics and geometry.
0:17:07 > 0:17:10Chris North has gone to the Wiltshire Museum in Devizes
0:17:10 > 0:17:13in search of the gold lozenge.
0:17:19 > 0:17:24The Wiltshire Museum is full of artefacts found in ancient barrows.
0:17:25 > 0:17:28200 years ago, well-meaning amateur archaeologists
0:17:28 > 0:17:30dug into the Bush Barrow,
0:17:30 > 0:17:32just half a mile from Stonehenge.
0:17:32 > 0:17:35Inside, they found some remarkable objects
0:17:35 > 0:17:39which have challenged our perception of early Bronze Age people.
0:17:39 > 0:17:43Museum curator David Dawson looks after the objects
0:17:43 > 0:17:45and has a new exhibition opening this October.
0:17:45 > 0:17:48They've carefully recreated the grave site,
0:17:48 > 0:17:50showing how all the objects were laid out.
0:17:51 > 0:17:54This is the centrepiece of our display.
0:17:54 > 0:17:57This is a reconstruction of a burial at Bush Barrow.
0:17:57 > 0:17:59He was a man who was stout and tall.
0:17:59 > 0:18:03He's buried with an axe at the top, two daggers,
0:18:03 > 0:18:08a dagger fitting, and most important, the gold lozenge
0:18:08 > 0:18:10that was on his chest.
0:18:10 > 0:18:14The fact that he was buried with such artefacts
0:18:14 > 0:18:16and the daggers and axes and so on,
0:18:16 > 0:18:20he was an important chap in their society.
0:18:20 > 0:18:23Absolutely. He must have been the top of the tree
0:18:23 > 0:18:26as a chieftain, a warrior. We call him the Bush Barrow Chieftain.
0:18:26 > 0:18:29And he was buried in this prominent place
0:18:29 > 0:18:31so that when they returned to Stonehenge
0:18:31 > 0:18:35for hundreds or thousands of years afterwards, they'd still see his...
0:18:35 > 0:18:39His descendants would see him and say, "On the hillside, that's where our ancestors are buried."
0:18:39 > 0:18:42Upstairs, David has a special treat for us.
0:18:42 > 0:18:46The real 4,000-year-old gold lozenge.
0:18:46 > 0:18:48This is rather special!
0:18:51 > 0:18:53That is...absolutely astonishing!
0:18:53 > 0:18:56This is 4,000 years old?
0:18:56 > 0:19:00- Right.- Thereabouts. This looks like a solid piece of gold.
0:19:00 > 0:19:04Actually, it's not. It's less than a millimetre thick.
0:19:04 > 0:19:07It's been very carefully smoothed and thinned out.
0:19:07 > 0:19:10It was mounted on a wooden backing plate.
0:19:10 > 0:19:14Today it's perspex. But see that tiny piece of gold there?
0:19:14 > 0:19:18See the way the edges are lapped over?
0:19:18 > 0:19:20It's just like wrapping a Christmas present.
0:19:20 > 0:19:23But much more expensive!
0:19:23 > 0:19:26- Much more expensive, and rather better than I can manage!- Yes!
0:19:26 > 0:19:29But the amazing thing is you can see the lines.
0:19:29 > 0:19:31- Look how straight they are. - Dead straight.
0:19:31 > 0:19:33And the zig-zags in between.
0:19:33 > 0:19:37Clearly whoever laid the design out knew about geometry.
0:19:37 > 0:19:41It had to be made out using three concentric circles.
0:19:41 > 0:19:43Then the straight lines are tangents.
0:19:43 > 0:19:46A bit like a Venn diagram.
0:19:46 > 0:19:50So to get those triangles, the four zigs along one straight line,
0:19:50 > 0:19:55- you'd need an understanding of geometry.- Geometry and mathematics.
0:19:55 > 0:19:57And the fact that this is so intricate
0:19:57 > 0:19:59it says it was far more...
0:19:59 > 0:20:03Far more sophisticated. It seems a very peaceful society,
0:20:03 > 0:20:05very stratified. Everyone knew their place.
0:20:07 > 0:20:10These precious clues from objects thousands of years old,
0:20:10 > 0:20:13paint a picture of a long-dead society
0:20:13 > 0:20:17which was sophisticated, orderly and intelligent.
0:20:17 > 0:20:21And capable of feats which are still impressive today.
0:20:21 > 0:20:24CHANTING
0:20:29 > 0:20:32We're just having the opening ceremony right now.
0:20:32 > 0:20:36One of the leading druids has started the celebrations, as you can hear.
0:20:36 > 0:20:38It's a bit like church service I went to as a kid.
0:20:38 > 0:20:41We've had communal singing, a bit of a sermon,
0:20:41 > 0:20:42and everyone's happy to be here.
0:20:42 > 0:20:45And it's not raining, so maybe there's something in it.
0:20:50 > 0:20:54Every aspect of Stonehenge has attracted attention over the years.
0:20:54 > 0:20:56And that includes its sound.
0:20:56 > 0:21:00Dr Rupert Till has created a model of Stonehenge
0:21:00 > 0:21:02as it was when it was complete.
0:21:02 > 0:21:04CHANTING CONTINUES
0:21:04 > 0:21:09He says the sound inside the circle would have reverberated and echoed,
0:21:09 > 0:21:13being amplified by the stones and drawing everyone in.
0:21:15 > 0:21:18Paul is finding out how noisy Stonehenge can get.
0:21:18 > 0:21:22Rupert, here we are on a lovely summer solstice evening, outside Stonehenge.
0:21:22 > 0:21:24And the one thing that strikes you
0:21:24 > 0:21:27is the beats coming out of there. The acoustics are good.
0:21:27 > 0:21:29This is what you've been investigating, isn't it?
0:21:29 > 0:21:31My background is sound,
0:21:31 > 0:21:34so what struck me immediately about this space was how it sounded inside.
0:21:34 > 0:21:39We wanted to model that sound to hear what it might have sounded like 5,000 years ago.
0:21:39 > 0:21:42So you've developed a time machine, if you like,
0:21:42 > 0:21:44that allows people to go back what, 5,000 years or so?
0:21:44 > 0:21:47About then, to when Stonehenge was first built.
0:21:47 > 0:21:50And possibly to look at how it changed over time
0:21:50 > 0:21:55and also where the sun rose might change slightly in terms of where the stones are.
0:21:55 > 0:21:57So we can see that with our model.
0:21:57 > 0:22:00Presumably, sound was quite different if there were many more stones?
0:22:00 > 0:22:03Yes, it really encloses you.
0:22:03 > 0:22:06When you go inside, you can't really see out. You can't see in.
0:22:06 > 0:22:08And the sound is the same.
0:22:08 > 0:22:09It's kept inside the space.
0:22:14 > 0:22:16Sound would have been part of the ritual
0:22:16 > 0:22:18in the way it is in most cultures.
0:22:19 > 0:22:22It's not all about sound. It's one piece of a jigsaw.
0:22:22 > 0:22:24PEOPLE CHEER AND SHOUT
0:22:40 > 0:22:43Some of the revellers are settling down for the night,
0:22:43 > 0:22:46but all the time, people are streaming into the site.
0:22:46 > 0:22:50The estimate is that more than 20,000 people will be here for sunrise.
0:22:52 > 0:22:55It's very lively, but it's friendly
0:22:55 > 0:23:00and I think it's not too far from how our ancestors would have celebrated their solstice.
0:23:02 > 0:23:04Right now, the sky is looking good.
0:23:04 > 0:23:08The moon is out and it's only a few days away from being full.
0:23:09 > 0:23:12Pete, Lucie and I find a quiet spot away from the crowds.
0:23:12 > 0:23:16This month, we're launching our latest observing challenge.
0:23:16 > 0:23:19And it's all about Sir Patrick Moore's favourite object -
0:23:19 > 0:23:21the moon.
0:23:23 > 0:23:25Called The Moore Moon Marathon,
0:23:25 > 0:23:28we want it to be something everyone can take part in.
0:23:29 > 0:23:33Pete, you've devised some real treats for us. What's in store?
0:23:33 > 0:23:37The moon is one of the loveliest things we can see in the night sky.
0:23:37 > 0:23:41I hope I've put together something which makes it very accessible for people.
0:23:41 > 0:23:44This is the nice thing about looking at the moon.
0:23:44 > 0:23:47- Finding the moon is the easiest astronomical task!- Absolutely.
0:23:47 > 0:23:49There are things you can notice even with the naked eye.
0:23:49 > 0:23:54So we start off in the first of the sections with the lunar seas.
0:23:54 > 0:23:55You can see them just with the naked eye.
0:23:55 > 0:23:58That's right. The lunar seas are easy to pick out.
0:23:58 > 0:24:01Then we progressively move on.
0:24:01 > 0:24:03We move into crater territory on the next section.
0:24:03 > 0:24:06And then into what I call shaded craters.
0:24:06 > 0:24:09The ones you can see close to the terminators.
0:24:09 > 0:24:12The first ones are easy. You can pick the first ones out on a full moon.
0:24:12 > 0:24:16Give us a flavour. What are some of your favourite objects in there?
0:24:16 > 0:24:19I've had a bit of fun at the end of the marathon.
0:24:19 > 0:24:21I've got what I call lunar specials.
0:24:21 > 0:24:24Things like the basketball player in the moon.
0:24:24 > 0:24:28I've never seen the basketball player!
0:24:28 > 0:24:31The lunar seas, when you look at them, you can make shapes out of them.
0:24:31 > 0:24:34- It's like seeing faces in clouds. - Like the man in the moon?- Right.
0:24:34 > 0:24:36Basketball player is there,
0:24:36 > 0:24:39and he's throwing a ball - that's the Mare Crisium.
0:24:39 > 0:24:41Oh, off on its own? OK.
0:24:41 > 0:24:45Once you've seen these things, you can't stop seeing them.
0:24:45 > 0:24:47If you'd like to get involved, just go to our website:
0:24:51 > 0:24:54Download the forms, give it a go, and see how far you get!
0:25:03 > 0:25:05Already the night is almost over.
0:25:05 > 0:25:08We're joining the throng back at Stonehenge
0:25:08 > 0:25:10for sunrise.
0:25:10 > 0:25:12I'm going to try and get inside the circle
0:25:12 > 0:25:14with the drumming druids!
0:25:14 > 0:25:16RHYTHMIC DRUMMING AND CLAPPING
0:25:16 > 0:25:19From out here, we can't even see the heel stone.
0:25:19 > 0:25:23The sun will rise over there in about 20 minutes.
0:25:23 > 0:25:27But it's only people on the axis, the very middle of the monument,
0:25:27 > 0:25:28that actually get a good look.
0:25:34 > 0:25:38Lucie and the rest of the team have bagged a safer spot,
0:25:38 > 0:25:41away from the more "enthusiastic" celebrants!
0:25:41 > 0:25:44So we're here, waiting for the sunrise.
0:25:44 > 0:25:46Only about 20 minutes to go, now,
0:25:46 > 0:25:49and the excitement in this area is really picking up!
0:25:49 > 0:25:51It's heaving, isn't it?
0:25:51 > 0:25:55It's remarkable how quickly the sky has brightened in the last ten minutes.
0:25:55 > 0:26:00Yeah. You did wonder if the sun was going to appear! I still wonder that!
0:26:00 > 0:26:02It's so murky!
0:26:02 > 0:26:05- It's very cloudy. - It's been a good evening.
0:26:05 > 0:26:06On the whole, a good session here.
0:26:06 > 0:26:10- The whole atmosphere is really most interesting.- It really was.
0:26:13 > 0:26:15It's just a couple of minutes before sunrise.
0:26:15 > 0:26:17The focus is still on the circle.
0:26:17 > 0:26:20But we're where the action is, with the heel stone right behind us.
0:26:36 > 0:26:39Well, I'm afraid there are no breaks in the cloud.
0:26:39 > 0:26:43It's another damp, drizzly, summer solstice sunrise!
0:26:43 > 0:26:48- Now, Clive, I think you know what I'm going to say, don't you?- I do know what you're going to say!
0:26:48 > 0:26:54So the sun has risen, but there was almost no response from the crowd. Why is that?
0:26:54 > 0:26:57Well, does it surprise you? There was no sun!
0:26:57 > 0:26:59People are looking to actually see the sun
0:26:59 > 0:27:01and if you don't see the sun, they don't cheer!
0:27:01 > 0:27:04People in the Neolithic, I'm sure, were the same.
0:27:04 > 0:27:07This is why Stonehenge wasn't a calendar, in our sense,
0:27:07 > 0:27:11because any day around what we know to be the solstice would have done.
0:27:11 > 0:27:14When they actually saw the sun, when the weather was good,
0:27:14 > 0:27:16that would be the day of celebration.
0:27:16 > 0:27:18So it really is just about the celebration.
0:27:18 > 0:27:21In fact, it feels to me a bit like an endurance event.
0:27:21 > 0:27:23It's about staying up all night!
0:27:23 > 0:27:27Are you dedicated enough to stay up all night and stay there for the sunrise,
0:27:27 > 0:27:32and if you are, you've done your celebration and you've paid your respects to the rising sun?
0:27:32 > 0:27:34I think you're too negative.
0:27:34 > 0:27:37I think it's enjoyment! It's about enjoyment!
0:27:42 > 0:27:46Sharing this often absurd, but still entrancing event
0:27:46 > 0:27:49with 20,000 people has been quite an experience.
0:27:49 > 0:27:51It's one I will not forget.
0:27:51 > 0:27:53And I might well come back.
0:27:57 > 0:28:01The moon's role at Stonehenge will always provoke debate
0:28:01 > 0:28:03and speculation.
0:28:03 > 0:28:06After all, we'll never really know whether the position of the stones
0:28:06 > 0:28:09was deliberate or just a coincidence.
0:28:09 > 0:28:12But I hope whoever put them there
0:28:12 > 0:28:15would at least be pleased that we're still arguing about them
0:28:15 > 0:28:17all these thousands of years later.
0:28:20 > 0:28:24In next month's programme, we celebrate a very special birthday
0:28:24 > 0:28:29as NASA's Curiosity Rover reaches its first anniversary on Mars.
0:28:29 > 0:28:33- And so, until next month, from The Sky at Night, goodbye.- Goodbye!
0:28:51 > 0:28:55Subtitles by Red Bee Media Ltd