:00:18. > :00:23.Hello and welcome back to Jodrell Bank for Back To Earth, where we try
:00:24. > :00:27.to answer as many of your questions as possible, questions from the show
:00:28. > :00:32.we've just done. There were many questions raised. Joining me we have
:00:33. > :00:37.Professor Brian Cox an the head of Europe's space weather forecasting,
:00:38. > :00:46.Richard Horne, solar researcher, Lucie Green, the sky at night's
:00:47. > :00:48.Chris Lintott, and Boulder Colorado 2010 Michael Jackson Costume Contest
:00:49. > :00:53.winner, we have this winner from your Facebook pace, Carolyn Porco.
:00:54. > :00:57.Congratulations. We talk you us up on one side of the show and bring
:00:58. > :01:04.you down in the next. Did you have to dance as well? I did. These are
:01:05. > :01:08.the Aurora cocktails. The colour may dissipate slightly because they're
:01:09. > :01:14.under a UV lamp at the moment which is catching the blue in these. The
:01:15. > :01:20.blue in the quinine in the tonic water. Getting a drink on this show
:01:21. > :01:25.is becoming increasingly tenuous. Any justification. However, you
:01:26. > :01:32.should try the planetary chocolates. You're happy with that. I think you
:01:33. > :01:38.should take Saturn, if you can find it. I'm taking this one. Grab,
:01:39. > :01:43.please take one. This isn't going to explode is it? Take and then I will
:01:44. > :01:47.explain. I'm taking neptune. Still time for you to send in your
:01:48. > :01:59.questions on anything we've talked about on Stargazing Live. Or use #Q
:02:00. > :02:05.Stargazing. Are you finding it difficult to get chocolates? I've
:02:06. > :02:10.just eaten the earth. ? Vment We've had many in, by the way. Quickly, we
:02:11. > :02:14.haven't spoken to either of you, did you enjoy the sights of the Aurora
:02:15. > :02:20.by the way? They were fabulous. It's exactly the sort of thing we've seen
:02:21. > :02:24.in northern Scandinavia before, the beautiful seeing clouds like
:02:25. > :02:28.curtains waving in the night sky, beautiful. It's impressive to see it
:02:29. > :02:34.in real time. Norm lip we see movies of it sped up. But even in real time
:02:35. > :02:39.it has that beautiful motion. We will pick what we left talking on,
:02:40. > :02:43.we give you drink and food and get you to answer questions. With the
:02:44. > :02:54.particularly striking image, obviously an artist's rendition of
:02:55. > :03:01.an astronaut staring at a geyser. That means something else, geezer.
:03:02. > :03:06.Do you enjoy staring at geezers? You do whatever you want, you're on
:03:07. > :03:12.holiday, you're a long way from home. Would it be possible to
:03:13. > :03:15.approach that closely in terms of it? If you were standing there and
:03:16. > :03:17.looking, you had the sun at your back, you wouldn't even know they
:03:18. > :03:21.were there. They're very tenuous. You don't see them until you're
:03:22. > :03:25.looking in the direction of the sun, which is a geometry which highlights
:03:26. > :03:31.small particles. That's why you see them in our images. They are almost
:03:32. > :03:36.powder-sized particles. They're forming one of the rings, aren't
:03:37. > :03:40.they, the E ring? Yeah, but that's very tenuous. Probably if you were
:03:41. > :03:45.there, you'd barely see it. How do you set the exposure? You think it's
:03:46. > :03:50.easy down here on earth with a camera. How difficult is it to get
:03:51. > :03:54.these images? That is a complex answer. We had been to the Saturn
:03:55. > :03:59.system with Voyager that. Was really a reconnaissance mission. It showed
:04:00. > :04:03.us about how bright things were and when you, you know, you can't figure
:04:04. > :04:09.out how long your exposure has to be until you know how much sunlight is
:04:10. > :04:14.hitting the camera. Then you can determine the exlozure time. --
:04:15. > :04:19.exposure time. Over time, as we have orbited Saturn over and over again,
:04:20. > :04:22.our knowledge of just exactly how inherently bright everything is has
:04:23. > :04:26.improved vastly. We know how much sun is getting to the Saturn system
:04:27. > :04:32.to begin with. We know how much is reflected back into the camera.
:04:33. > :04:38.There's a question here, how much longer is Casini expected to
:04:39. > :04:41.operation before its plutonium runs out? You're constantly correcting
:04:42. > :04:46.its path, because you're trying to focus on different things at
:04:47. > :04:53.different times. That's true. But the plutonium we don't correct the
:04:54. > :04:59.orbit using the plutonium. The plutonium supplies reck trace it I
:05:00. > :05:04.to operate the computers an so on. We use Titan as a gravity body. We
:05:05. > :05:09.go by Titan so many times. With ego by to study, but we go by if we want
:05:10. > :05:14.to crank up the inclination to look at the poles of the planet and down
:05:15. > :05:20.on the rings or we want to bring it into the equator plane to visit the
:05:21. > :05:26.moons. We want to crank around the side lines. We use Titan for that.
:05:27. > :05:31.We have a question from Lisa, aged eight. Why is Saturn made of gas?
:05:32. > :05:37.That's a complicated question. But I can make it simple by reversing the
:05:38. > :05:41.question and saying why don't the terrestrial planets have gas. You
:05:42. > :05:43.want me to ask Lisa, aged eight... LAUGHTER
:05:44. > :05:47.You don't need to do that because we're clever enough to figure out
:05:48. > :05:54.how you to spin this. I learned that at NASA, how to spin. You just know
:05:55. > :05:58.that the planets got a lot hotter. It was hotter there. The gas gets
:05:59. > :06:03.warmer, warmer gas, the collisions are more vigorous and so on. The
:06:04. > :06:08.small inner planets weren't large enough to hold onto this very
:06:09. > :06:12.kinetic gas. But the outer planets, because everything was colder there
:06:13. > :06:16.were. They were able to. This made perfect sense until we started
:06:17. > :06:20.looking at other solar systems. When we find planets around other stars,
:06:21. > :06:25.we find all sorts of things, mixed up solar systems with planets like
:06:26. > :06:29.Jupiter and Saturn close to their parent stars. We end up explaining
:06:30. > :06:39.that they formed further out and had to migrate in. Other solar systems
:06:40. > :06:43.seem to have had an exotic path. Those big gassious planets are
:06:44. > :06:48.closer to the star. That's true. But there's still a population we didn't
:06:49. > :06:53.expect. When people started hunting for planets around stars, they got
:06:54. > :06:57.lucky. They weren't expecting the hot Jupiters. I wouldn't be
:06:58. > :07:03.surprised if the atmospheres there have limited lifetimes. This idea of
:07:04. > :07:07.migration is interesting. You threw it away there, the fact that planets
:07:08. > :07:14.move, they did it in the solar system most likely. Planets might
:07:15. > :07:20.have swapped places. One of the best things we have discovered in the
:07:21. > :07:25.ring arena in Saturns's rings is we have found moonlets embedded in the
:07:26. > :07:31.rings. Somewhere between the largest ring particle size and the smallest,
:07:32. > :07:37.you would call a moon. Called shepherd moons? No, They're bona
:07:38. > :07:43.fide moons. They're 100 kilometres across. These things are only a
:07:44. > :07:46.kilometre across or maybe half. That's not what you're talking
:07:47. > :07:50.about. No That's not what I'm talking about. That's a shepherd
:07:51. > :07:54.moon. These moonlets create these wakes that we call propel afeatures.
:07:55. > :08:00.We watch them not only move around like a normal moon, but they drift
:08:01. > :08:04.and they drift because they're interacting with the material. This
:08:05. > :08:08.is giving insight into how planetary migration formed. It formed when
:08:09. > :08:12.there was material around and there was exchange of momentum. Are the
:08:13. > :08:17.discs increasing or decreasing, clumping, not clumping? Saturn's
:08:18. > :08:21.rings are so close to Saturn that you can consider them like a
:08:22. > :08:25.miniature solar I it emin an arrested state of development. --
:08:26. > :08:30.system, in an arrested state of development. So they're trapped? And
:08:31. > :08:34.also the tidal forces from Saturn prevent things from coagulating.
:08:35. > :08:40.That's the beauty of it, it allows us to see processes that happened
:08:41. > :08:43.long ago that are gone. Now, we are going to have a question, if you
:08:44. > :08:49.didn't get your fill of Doctor Who over the Christmas, here is a treat.
:08:50. > :08:53.If you did, humour us for this bit. It's the return of the most
:08:54. > :08:58.intelligent robot dog with more space questions.
:08:59. > :09:10.Greetings master Dara. Commander Hadfield famously created his own
:09:11. > :09:15.version of a hit record in space. But Russian cosmonaut Mikhail Tyurin
:09:16. > :09:20.has a space record of a different kind. What sporting feat did he
:09:21. > :09:28.achieve on the International Space Station in 2006? What was that
:09:29. > :09:39.sporting feat? Send us your answers in the next five minutes, using #K9
:09:40. > :09:44.or e-mail us. Is that Twitter? Yes, Twitter. We'll read the best out
:09:45. > :09:49.later when confer9 will be back to tell -- K 9 will be back to tell
:09:50. > :09:54.all. We discussed the Carrington event. The Carrington flare. As
:09:55. > :10:04.we're fond of calling it, the 70s detective Carrington flare. How do
:10:05. > :10:08.we measure this change? So this is 1859. This is the first time that we
:10:09. > :10:12.had a major event from the sun have a major impact on the earth. Really
:10:13. > :10:16.good question. What are the consequences here on earth? How do
:10:17. > :10:20.scientists measure it? At that time they were developing instruments to
:10:21. > :10:24.measure changes in the earth's magnetic field. What the sun did was
:10:25. > :10:29.produce activity that we'll come to, but the scientists measure the
:10:30. > :10:33.changes in the earth's magnetic field. Here's a piece of kit to
:10:34. > :10:36.demonstrate it. You have a magnet suspended in the jar. That aligns
:10:37. > :10:40.itself with the earth's magnetic field. Let's imagine the sun has
:10:41. > :10:45.done something and it's shaken up the earth's magnetic field, it's
:10:46. > :10:49.changed it. I will represent that by bringing in this magnet. You can see
:10:50. > :10:53.the alignment of this magnet creating a spot on the screen. If I
:10:54. > :10:58.bring this magnet in, it starts to deflect it. That spot goes. I can
:10:59. > :11:03.take it in and out, that's what the scientists saw. They saw something
:11:04. > :11:08.happen to the earth's magnetic field that they hadn't seen before in this
:11:09. > :11:12.strong a way and that's when they realised something big was was
:11:13. > :11:16.happening. Not been taking these readings for very long. No, in the
:11:17. > :11:21.Victorian era, early decades of the 18 hundreds, that's when the
:11:22. > :11:29.sensitive magnetic detectors were being created. Early 18 hundreds or
:11:30. > :11:32.there abouts. Still quite dramatic. We actually have it here. Have you
:11:33. > :11:39.ever seen it before? I haven't. I have been waiting for a long time.
:11:40. > :11:47.These are from the... British geological survey. These are the
:11:48. > :11:50.actual, no we don't have a control view. We had the spot that moved
:11:51. > :11:56.when I brought the magnet being here. You have a trace being made.
:11:57. > :12:00.It gets distorted as a the earth's magnetic field. How quick was that?
:12:01. > :12:05.This scale runs over one day. This is quite a big dip here, but very
:12:06. > :12:11.short. This is over half an hour or so. About ten minutes. That magnet
:12:12. > :12:19.moved quickly and came back again. That happened at 11. 18am, but
:12:20. > :12:22.what's really key, that's the flare. Then what happened 17-and-a-half
:12:23. > :12:27.hours later? If you measure from here going off the page andion to
:12:28. > :12:32.the next page, something like 17-and-a-half hours later we see
:12:33. > :12:36.this huge deviation in the earth's magnet sieve -- magnetic scale. It
:12:37. > :12:41.goes off scale. That 17-and-a-half hours is the transit time for
:12:42. > :12:46.material coming off the sun to actual reach the earth and actually
:12:47. > :12:52.trigger a large magnetic storm. It's one of the fastest times, 17 hours,
:12:53. > :12:57.I think the fastest actually... Maybe 16 hours. This one would have
:12:58. > :13:02.been travelling 2300 kilometres a second. The energy of the particles
:13:03. > :13:08.essentially. This is a very high energy particle. They have a high
:13:09. > :13:14.speed coming towards us, yes. But actually, we get even higher energy
:13:15. > :13:18.particles that this inside the earth's magnetic field. We come to
:13:19. > :13:24.that in a moment. Can you give us a sense of what that would do, if that
:13:25. > :13:28.magnitude hit us today. If a Carrington event occurred tomorrow,
:13:29. > :13:34.it's a very big issue. We know back in, for example, you mentioned
:13:35. > :13:38.yourself, back in 1989, we had a power outage in Quebec earlier, so
:13:39. > :13:44.that was a storm that was a big storm, nothing like as big as the
:13:45. > :13:48.Carrington event. Now we think we may have transformers on the power
:13:49. > :13:55.grid, actually may be damaged. We may have six to 12 transformers in
:13:56. > :13:58.the UK, lets let alone what would -- let alone what would happen in other
:13:59. > :14:02.countries. Satellites would be affected by a large magnetic storm,
:14:03. > :14:10.something like the Carrington storm. We would have satellites going on.
:14:11. > :14:16.In 2003 there was a large magnetic storm. 47 satellites malfunctioned
:14:17. > :14:21.during the storm. We have over a thousand satellites now. We have a
:14:22. > :14:25.question here, could a solar storm be a threat to the International
:14:26. > :14:30.Space Station? The energetic particles are a threat to human
:14:31. > :14:34.health. Whether you're in an aircraft, or that high up on the
:14:35. > :14:39.International Space Station, if you have accelerated particles because
:14:40. > :14:44.of energy from the sup, you have to protect yourself. There is a shelter
:14:45. > :14:47.on the Space Station. The astronauts have to go into the shelter. Cancer
:14:48. > :14:52.damage or the physical damage to them? Because of the possible
:14:53. > :14:58.increased risk of cancer, same happens on aircraft. You get an
:14:59. > :15:03.additional radiation dose to aircrew on polar routes. When you have your
:15:04. > :15:07.astronauts in, ask if they see thousands of -- flashes of lights in
:15:08. > :15:10.their eyes because of the particles coming through their body. That's
:15:11. > :15:21.incredible. Can we build an early warning system? I think we can build
:15:22. > :15:25.one. What we need to know is information about the mass ejection
:15:26. > :15:32.that comes our way and what is the magnetic field. You want our
:15:33. > :15:37.satellites far away from the Earth but they need to measure the mass
:15:38. > :15:43.ejection before it gets to us. At the moment we only have a 40 minute
:15:44. > :15:48.warning. I run an international project called SPACECAST and we try
:15:49. > :15:53.and forecast at this. We try to protect satellites, and we take
:15:54. > :15:59.measurements from between the sun and the Earth. It is where the
:16:00. > :16:03.gravitational pull of the sun balances the Earth. That gives us a
:16:04. > :16:08.40 minute warning. The crucial measurement we make is the direction
:16:09. > :16:16.of the interplanetary field. It is always changing, but when it is
:16:17. > :16:20.facing southwards, it can connect to the Earth's field and you get a
:16:21. > :16:28.tremendous transfer of energy and that gets redistributed back and
:16:29. > :16:37.into the charged particles. There is the son's magnetic field
:16:38. > :16:41.transferring energy. Yes, it is essential because we could have a
:16:42. > :16:46.mass ejection coming towards the Earth but if the magnetic field is
:16:47. > :16:52.facing northwards there will not be much impact. If it is facing
:16:53. > :16:59.southwards, it would be huge. We are threatening an apocalypse! We need
:17:00. > :17:07.to understand it in order to survive! What sporting feat did
:17:08. > :17:28.Mikhail Tyurin set in space? You have sent the answers in. Juggling?
:17:29. > :17:37.No! Tiddlywinks? Sarah says is it a forward roll? I like that! Any
:17:38. > :17:45.guesses? Gymnastics, I think! Weightlifting? No! Baseball? The
:17:46. > :17:53.first person to hit a golf ball? That would be a Scot in one of the
:17:54. > :18:04.Apollo missions. Let's have a look at what canines said. Mikhail Tyurin
:18:05. > :18:08.used the International Space Station as a driving range to hit the
:18:09. > :18:14.longest golf shot in history. With a six iron he hit a golf ball 1
:18:15. > :18:22.million miles before it burned up in the Earth's atmosphere two days
:18:23. > :18:30.later. In the intergalactic rules of golf is a 2-stroke penalty! Until
:18:31. > :18:36.tomorrow, farewell! Yes, it was striking a golf ball. We have some
:18:37. > :18:40.footage here of the record-breaking shot. It may be difficult to see. In
:18:41. > :18:55.fact, it may be impossible! There it is. We can show you it in slow
:18:56. > :19:08.motion. He struck it. I do not think that is entirely responsible! Has he
:19:09. > :19:13.not seen the film Gravity! ? We have had a lot to complain about in terms
:19:14. > :19:19.of weather here which probably Sargent to ask whether it rains on
:19:20. > :19:25.other planets. What substance is the rain made of? You were talking about
:19:26. > :19:39.Titan and on Titan it rains methane. It is orange rain. I do not think it
:19:40. > :19:45.is orange. Methane is very clear. Snow and rivers and lakes are on the
:19:46. > :19:54.surface of Titan. Methane drops will be bigger than raindrop. You have to
:19:55. > :20:05.imagine Christmas baubles. They are like dinosaur raindrop. We also have
:20:06. > :20:10.diamonds. I am told they are representing diamonds! That would be
:20:11. > :20:15.Saturn. I have never heard of that. I you sure it is not a star? There
:20:16. > :20:25.is a hot Jupiter where they detect the diamond. I know they have
:20:26. > :20:37.detected particles of carbon. I know about that. I do not know about
:20:38. > :20:44.Saturn. Hot Jupiter? We have normal Jupiter and other stars have hot
:20:45. > :20:50.Jupiter. It was a Neptune sized thing. I am being careful with this
:20:51. > :20:56.because it is sulphuric acid. I will not go anywhere near this. Where is
:20:57. > :21:04.this question my Venus. I do not think it rains but there are tiny
:21:05. > :21:07.droplets in the cloud. Venus is fascinating because, before the
:21:08. > :21:14.space programme, it was thought it could be a tropical world. I think
:21:15. > :21:17.Sir Patrick Moore wrote that there could be tropical rainforests on
:21:18. > :21:25.Venus. They did think there was something of that ilk on Titan as
:21:26. > :21:28.well. There was a brief period on Venus where they thought it was
:21:29. > :21:36.carbonated water on the surface as well stop a cocktail of ingredients!
:21:37. > :21:47.Sadly, there is this rather hot, unpleasant volcanic world. I think
:21:48. > :21:53.we get the gist of this. I thought you were going to dissolve the
:21:54. > :21:57.glasses in the sulphuric acid! Why are you not wearing gloves? Put on
:21:58. > :22:07.the ridiculous gloves! This is health and safety! Right, I am ready
:22:08. > :22:12.now. I will continue to do the entire show live. I make these
:22:13. > :22:22.glasses look small! Questions on Saturn. How do you get your pictures
:22:23. > :22:29.Back to Earth from Cassini? It is not little green men. The pictures
:22:30. > :22:39.are digital information which are encoded on the telemetry stream. How
:22:40. > :22:45.large are the files? A typical image which is compressed and B four
:22:46. > :22:56.megabytes. Sorry, I mean megabits. I think I have got that right. Not
:22:57. > :23:05.enormous. This mission was designed in the 1980s so by today's
:23:06. > :23:12.standards, they are tiny. You compare that with a spacecraft that
:23:13. > :23:18.has just launched and it has a 1 billion pixel camera in it. It is
:23:19. > :23:24.astronomical! Cassini is an old mission already. Clear skies have
:23:25. > :23:30.been hard to come by recently but when the clouds part here is what
:23:31. > :23:37.Mark Thompson recommends you look at the night. The winter night sky is
:23:38. > :23:41.signposted why Exeter and of stars. Jupiter is a good starting point.
:23:42. > :23:50.Look to the South East and you will see a bright object 45 degrees above
:23:51. > :23:58.the horizon. Directly to the left of Jupiter is the brightest star in the
:23:59. > :24:04.Gemini consolation. To find the next start, go back to Jupiter and look
:24:05. > :24:09.directly upwards. This is the third brightest star in the northern sky.
:24:10. > :24:13.Now find the lowest sky in the Hexagon and look to the right. This
:24:14. > :24:23.is one of the horns of tourists. The two horns lead back to a V shaped
:24:24. > :24:29.cluster of stars. The next star in the Hexagon is in the constellation
:24:30. > :24:39.of Orion. Follow the line down from that and you will see Orion 's belt.
:24:40. > :24:46.Burning white hot and over 130,000 times brighter than the sun. There
:24:47. > :25:00.is another consolation of Canada's major. -- Canis Major. The final
:25:01. > :25:06.start in the Winter Hexagon is the binary star. If you follow a line
:25:07. > :25:16.from serious you will find it passes through the small consolation of
:25:17. > :25:20.Canis Minor. The Winter Hexagon is visible from September to April, and
:25:21. > :25:25.from January it can be seen after sunset. Do not worry if you do not
:25:26. > :25:30.get that because you can find the details on the website. You have
:25:31. > :25:37.been sending in your stargazing photos from across the UK. I really
:25:38. > :25:48.like this first image. He took it with a simple camera and you can see
:25:49. > :25:53.the colour of the stars in Orion. It is wonderful shot. This is the
:25:54. > :26:00.Winter Hexagon as experienced by Gordon. You can see the beautiful
:26:01. > :26:05.lighthouse. Even light pollution can be beautiful if used correctly. I
:26:06. > :26:12.wanted to show this. I like this. This was taken on Saturday on top of
:26:13. > :26:20.the town hall in Newcastle. David does not say what he was doing on
:26:21. > :26:26.top of the town hall? ! There is a sunspot circled here and that is the
:26:27. > :26:29.sunspot we were talking about. We care about sunspot groups because
:26:30. > :26:34.they are exciting for people like Lucie but because they do things
:26:35. > :26:40.like this. This was taken on January the 1st and was uploaded from
:26:41. > :26:50.Scandinavia. The username is mamma Mia! That is why I am guessing it is
:26:51. > :26:55.from Sweden. The Aurora, people were seeing it in Scotland, in Donegal,
:26:56. > :27:00.in the Hebrides. We would be interested in seeing photos from the
:27:01. > :27:07.UK. What with the aim you wanted when you set the challenge? We
:27:08. > :27:24.thought we could do something with half a million clips. The more we
:27:25. > :27:36.get, the more active we are! Two quick questions. How fast does the
:27:37. > :27:39.solar wind go? Voyager one has just passed 15 billion kilometres and it
:27:40. > :27:45.took 30 years to get there. That is where the solar wind ends. That is
:27:46. > :27:57.where we regard the end of the solar system. A question from Hannah.
:27:58. > :28:01.Could there be life on Titan question my personally, I do not
:28:02. > :28:06.think so. It is so cold and there is no liquid water. There is no life
:28:07. > :28:14.that we would even recognise. Titan is still a fascinating targets
:28:15. > :28:17.because it is covered in liquid organic and there is no place else
:28:18. > :28:22.in the solar system where you have seized of liquid organics so it is
:28:23. > :28:25.like a laboratory begging for study. You cannot study natural
:28:26. > :28:37.organics here on the Earth because they are gone. It is the most
:28:38. > :28:42.accessible in the solar system. You very much indeed. Thank you to all
:28:43. > :28:49.of our guests. Carolyn Porco, Lucie Green, and Richard Cox -- Brian Cox.
:28:50. > :28:54.We have two former astronauts on tomorrow, Walter Cunningham and
:28:55. > :28:57.Chris Hadfield. Get your westerns in and we will ask as many as we can.
:28:58. > :29:01.Thank you for joining us, see you tomorrow.