 Y priwethaf, o'r cwm田 Llywodraeth yma, pe fwrdd mwy hi wedi lawer iawn i weld y ffantastrodd gyda eu gwirio sy'n dyfanydd. Ond roedd yr unrhyw ffas fflower yn bleibai sydd wedi ei ddim yn hynny yn gallu y twfynfaen ysgol o'r fwyaf o'r gwyl. A llwyddo'n gweithio roedd ei wneud y Gymru yw'r cwmwysau dyma yna chi'n gweithio'r ffilm yma a llwyddo'i'r mwyaf ar ei sysinsau. Felly, mae'n gweithio defnyddio fel argymysg iddyn nhw i ydych chi'w prif i roi ni i gael y cyffredin. Felly, mae'n gweithio eich rhywbeth o'r ei bethau roedd. Mae'n gweithio i'r cyffredin a phrygau. Mae yn hanffwylu cyfreiddol, a'r tymnu hwn yn ei gweithio eich gweithi yn eich gweithio eich cyffredin, i'n gweithio i chi'n gweithio i'r cyffredin. Mae'n gweithio i'ch gweithio i'r cyffredin. ynghylch chi'n wneud y gynllun oedd y cyflawn ni'n byddgol ddal 80% yn iawn. Dyna llawer o'r adres o cwestiynaw'r credu o amgylch yn y credu o amgylch y mhwy, ac ydych chi i meddwl am eto'n rhan o'r cyflawn. Wrth gwrs, mae'r greu cyffredinol y peth, mae'n cyfrifes i'r credu cyfechennid, ac mae'n edrych i fod y ddynski yn bach i mlyneddiaeth. Mae'r dynsi gynllun yn ddefnyddio unrhyw phobl, bod y gallwch ar ystafell panesydd yma ar y gwaith yma ar gyfer y parys Allysmoedd Hyde a ein bod e'n meddwl i wedi'i gwneud i ni eisiau gŵr a muudu'r hyffordd arweinlu o'i gan y dyfodol yn rydyn ni i'w bwysig yw a chwyfynu ar gyfer y bod yn ei gwneud i ni i gŵr. Mae'r bwysig yw'r cyfle yw gwneud i ni i gŵr. Fe yna ychydig yn y gyfosig ar y gwaith. Os y cwestiynau, mae'r ffordd arno a'r hyffordd? McFarland yn ddatgani'r cychynol sefydliadol, oherwydd mae'n ddysgu ei bod yn ei ddysgu. Felly mae'r ddysgu ei thas yn fapiradol. A os yna bod y cychwyn gwych mewn niechys? Is mae'r ddysgu ddysgu hwn yn ddysgu pob ar gyfer yr eich ddysgu yn fapiradol i gynnigau'n gweithredu gan rhannogau'r duwungen pwynt. Oais mae efallai gynnig ym oed i ddysgu sy'n bobl ac yn ychydig ar y penderfyniad iawn yn ochr o'r fawr. O'r rhan o unrhyw bwysigol o'r bwysigol, a hwnna cyflywch ar munsio. Wrth yr awr o adegau, dwi'n dechrau bod dystwynt, ac ydy'n oed agor来w. Yn chi'n gyd o'r ddylch. Mae'r potodol o'r twrnod o holl ar gyfer ddwyng Fyr簷, a y dystiad gyda'r gwrs, yn ni fawr yn mynd i gael i eu cynnyddio, a'r gwleidiau yn y maesiau yr oedd yn yr holl. A chi'n rhan o'r tîm fydd y gallwn gweithio, ac mae bod yn codi'r gwahwn o'r oedden nhw, y gwahau i'r gwahau ymwynt iawn. Felly mae ydych yn un o beth hyn o'r canu i gyfl Özellion i mor gweithio sydd rydych chi'n ffrin o'r gwahiau ag i rhaid o'i cyhoeddeth ymlaen arfer o'r cyforce systemu sy'n gweithio i'r llai'r haf. O 넣wch y rhai eich cwestiwn yn ynghylch yn cymhreithi'u clwymau mae'n gwneud ymlaen i'r rhannu a sy'n gwneud yr olygu cymryd mewn. Mae'r rhannu a gallai cyfryd yn meddwl. Ond ar ôl y space ac yn ymlaen i'r cyfrifodau wedi gwleidio, mae'n ddu Llywodraeth yn gwneud y bobl yn gweithio y rhesaith gyfly固, As the dust grains actually enter the instruments like a box, they pass through a laser curtain, cause a flash which you detect, and then the particle hits the target underneath and you measure the momentum, and from the timing between the two you can get the speed, you can get the size from the light flash and you get the mass from the momentum transfer when you hit the target, and that means you can work out the density of the dust grains. On the right hand side you can see the red dots are where we've detected dust grains around the green orbits around the comet, the comet's the blue bit in the centre, and you can see we're detecting dust particles all around, this is just the very very first few detections, we've got many hundreds now but I can't talk about all those. But what we've found already is that there are both classes of particles are present, so we've seen high density compact grains but we've also seen very very fluffy low density grains and they arrive in clusters probably broken up by some interaction with the spacecraft. The other interesting thing we've found is that actually there's far more dust than there is gas, so this classical picture of a comet as being a sort of dirty snowball is actually the wrong way round, it's mostly dirt with a bit of snow. And these observations have been confirmed by an instrument called cosima, it's probably quite difficult for you to see there but inside the red square there are two little dots and they're magnified a bit on the right hand side, the before and after pictures so you know that they weren't there when the mission started and these are compact grains. In the bottom there are about a tenth of a millimetre in size at the bottom comparable to what we're detecting with Jarder, at the bottom you're seeing these larger fluffy grains and in fact these are so structurally weak that they basically collapse when they hit the target. This instrument is now making measurements of the composition of these grains but I can't tell you what that is because it's data's embargo I'm afraid. Now these are measurements made in the coma of the comet but they don't allow you to study what's actually happening at the surface and what you really want to do is get down at the surface and find out what's really going on. And of course that's the other unique part of the Rosetta mission, it had the Philly lander and you can see here a sequence of images which actually show the lander in its transfer down to the surface and you can see there were several images which actually captured the lander in the foreground. Up near the top of the image is the landing site where the lander very briefly arrived within a few metres of its targeted position but unfortunately it didn't stay there. It bounced off in the incredibly low gravity of this object and then headed off to the right and right in the top right hand corner you can see it silhouetted above a dark region, flying off to the right hand side. And so here's X marks the spot where we were supposed to be and the arrow shows the direction it went in disappearing over the horizon again inside the little markers on the right hand side you probably can't see the little white dot which is Philly disappearing over the horizon. But we know of course it did land again, we just don't know precisely where. The red ellipse there shows you the region where we think it is and this has been derived from another instrument called Concert which measures radio signals transmitted through the comet. So using the shape model of the comet from the images and the signal making an assumption that the comet is uniform in density allows you to work out the length of the signal through the comet and therefore as the spacecrafts are on the main spacecraft as it moves behind you can then work out the track. And so you can then predict where you think the lander has arrived and that's inside that little blue area there. So that gives us a search region in which to look for the spacecraft. Once we find it we can then work backwards and say now we know precisely where it went we can then look in those signals for deviations from a uniform density to try and figure out what the internal structure of the comet is. So that's a sort of wait for event. Of course the first view from the surface already told us something fantastic that we didn't see this crust of what we are expecting to see a sort of smooth dusty layer. We saw something that looks very much like rock. In fact it's almost certainly ice, a solid ice with very little material on it. But it came apparent almost straight away from the position of the foot in the bottom left hand corner there that the spacecraft wasn't orientated correctly standing on its feet. And we can see how the spacecraft is orientated by using the six cameras on different sides of the lander looking out and you realise one of those cameras is pointing up at the sky, that's the one at the top. The one on the right and the one on the far left were clearly looking at rocky surfaces but one of them is in shadow. And then below you're looking at surfaces much closer to the spacecraft and so the base of the spacecraft is pointing to the one that's at about eight o'clock. And that is the direction in which the samplers that were going to make measurements on the surface would be taking their measurements. And that brings me to the second experiment that we've been involved with at the Open University and this is called MUPUS which is measuring physical properties of the surface and it has three sensors in it, three systems in it. The first of those are temperature sensors which were on the harpoons and many of you may remember that these harpoons which were supposed to anchor the comet, the spacecraft to the comet didn't work, they didn't fire. They probably wouldn't have worked anyway as it turns out if the comet is as hard as we think it is but unfortunately it means the temperature sensors that they were carrying couldn't work either. Fortunately we also had a thermal imager on the base of the spacecraft which took an image of that region and it measured a temperature of minus 160 degrees C. So this is much much colder than the temperature which I sublimates in a vacuum which is about minus 90. So that wall could be solid ice, it's just at the moment too cold to vaporize. It may well be doing now or in the future as the comet comes close to the sun and that will get very exciting. The third system is on an arm and it has a little hammer which hammers its way into the surface and as it does so it measures the strength of the material and then it deploys temperature sensors to measure the temperature profile down into the body to see whether you can vaporize ice below the surface. We wasn't sure whether this would actually reach the surface or not because we didn't know how far away it was from the base but it did. It reached something that was relatively soft, it went in about 20 centimeters and we sort of interpret that as being a dusty insulating layer and then it hit something hard which again we assume is ice much like the wall on the right hand side. That was so hard that the hammer couldn't penetrate it and so we don't have any measurements from inside but that's a useful piece of information because it tells us there's a limit on how hard the surface is and the experiments now are going on to see how hard ice has to be for that hammer not to get through it. That will help us understand what structure is on the surface. We've been doing experiments to understand how ice is vaporized and complex mixtures of ice is in dust and if you put them together and expose them to the sort of conditions you have on a comet to see if you can make that kind of insulating crust and you can make a hard layer that we see on the comet now. Initially when we did this we collected our snow very kindly donated by a snow zone and then mixed it up with other stuff. You wonder actually be surprised whether there could be terrestrial applications from this kind of blue skies research but strangely enough the sensors that we designed to make the measurements of the structure of the materials that we were making are of great interest to people who make snow and companies who make snow such as the one in Italy shown with their snow making instrument on the right hand side are very interested in how they can control the snow they make and this company who produces systems to make snow for a lot of the risky results in Europe are very interested in our techniques. We've had our first meeting with them to discuss it but later on you'll hear a bit more about many applications that have come from the work we've done on comets.