 I'd like to start by talking a little bit about why we are interested in comets in the first place. And this is because comets are leftover bodies from the time that our planets formed, from the time of our solar system formed. This is an artist impression of what this might have looked a little bit like. In the centre of the young sun, they're surrounded by a disc of gas and dust. In the inner parts of this disc, there is where rocky planets like the earth form. And in the outer parts, ice and gas forms the giant planets and also small bodies like comets. And comets are particularly interesting not only because they are some bits that are left over from this time, but also because the comets are possibly what brought ice and water and many of the chemicals needed for life on earth from the outer regions of this disc into the inner regions and brought them to earth. Now comets are something that we've known and have seen since ancient times when there's a truly great comet which happens once a decade or so, it can fill half the sky. The image here shows the comet North, which lit up the skies in the southern hemisphere in 2007. This is its tail silhouetted behind one of the telescopes at the European Southern Observatory in Chile. And this is a huge structure. It's tails are many millions of kilometres. At the time it's the biggest thing in the solar system. A normal sized comet and not such a spectacular one as this, this is an image of Chiromoff-Jerasimenko, the comet that Rosetta is now in orbit around, taken in 2003 when it was last close to, when it was on a previous close approach to the sun and at its most active. And what you can see is that it again stretches over a huge area. There's a long tail of dust stretching off into the top right of your image there and the coma of dust surrounding the comet there. This is again a very large structure. This is it on the same scale as Planet Jupiter, largest planet in our solar system. If it was at the same distance, it would be this sort of size. A comet is a very large object. This is how big the earth is on the same scale. A comet is much bigger than the earth, but a comet is very tenuous. It is nearly all of this coma is dust and gas that you could fly right through without even noticing it was there. It all comes from a very small central nucleus. And this is the nucleus. This is the nucleus of Churnoff-Jasimenko and images returned from Rosetta. The top right you see an animation of images, the first sort of images we got of resolving it when it got given this rubber duck nickname because you can see the shape of it. It's this very unexpected two lobed shape with a smaller head sitting on a larger body. And then on the right you see the details on this when we got closer and the structure on it. This is the source of this gigantic comet. This thing that produces a cloud of dust and gas bigger than Planet Saturn comes from this thing which is only a few kilometres across. To give you an idea of this scale, I don't need to compare it to Planet Earth. I can compare it to Milton Keynes. If we put the back end of it out behind the Open University, it would stretch up to the top of Willan Lake and across to about the train station in the other direction. This is a pretty small lump of ice and rock that evaporates to produce a gigantic comet. But now I want to show you more details about this nucleus, because the real point of Rosetta is getting close to this nucleus and returning really detailed images, the likes of which we've never seen before in comments. The first thing we discover is that this comet has a very low density. So although this looks like a really rocky structure and the images you'll see look like cliffs and rocks, you'll find that actually this thing is very under dense. It would float in water. We don't see any ice on the surface. We know that there is ice in here producing this submate to produce the coma, but the surface looks remarkably grey and dust covered, but there's a great variation in textures. So some areas are smooth and some are pitted, and there are a lot of changes from one side to the other. I'll now show you some sort of zooms in on some of these areas. So starting up at the top left there, this is a view across the back of the back of the duck looking at the back of the head. What you see is a large cliff. This is a kilometre-high cliff that forms the back of the head of the duck, which again looks like a great big cliff in the mountain areas of earth. This thing is kilometre-high, looks like rocky. Remember this is very under dense. This is a thing that is lighter than ice. The other structures, the middle image at the top there, shows an area where these pits that seem to have the walls collapsing. There's scree slopes at the bottom. This appears this cliff that's collapsing into small rocks. Whereas the bottom images show smooth areas. One on the left-hand side there shows an area where we think there's a crater that's been covered over by sand-like material, really smooth material. The big image here on the right shows that although this thing is very under dense and there's this light material, as we look across the horizon here, we see structures that look like the rocks you see in Arizona, these carved messes and so on. These are things 100 metres high that are clearly supported themselves, aren't falling down, so they are made of a strong material, but a very light one. Another area this is looking, zooming in on the neck of the duck. An interesting thing we see here is there appears to be a crack that runs around a lot of this neck. So there's interesting speculation as to whether the head is going to fall off of this duck at some point in the near future, or whether this is left over from the time that the comet formed when these two parts came together and weakened this area. A very unexpected feature was that we see evidence of wind blowing across the surface of the comet. Now, we know that they have to have dust and gas coming out of comets to produce this big coma, but what we see here on the left look like dunes, and on the right appear to be things like snow drifts, or as you'd see on Earth, where you've got the wind blowing snow or sand behind rocks. You see a tail behind it, you see a material stretching behind, and this is what you see. So it seems that there's material blowing across the surface as well as out from it, which is a very unexpected thing. And then possibly the most fascinating feature that we've identified are what we've been calling goose bumps. And in a cliff on the right-hand side here, or in the walls of one of these pits on the left, what you see is that the vertical structures here seem to be made of lots of little balls. We think that this is... One interpretation is that this is really looking at the fundamental building blocks that built up this comet. And that's interesting because if you imagine that this whole comet is made of these sort of few-metre-sized balls stacked together to produce 10-metre-things, 100-metre-things up to the size of this comet, these are the things that went on to build the planets. So the idea is this comet is a leftover bit from planet formation. It is one of the ones that escaped. Other things the same size, these little balls combined to build bigger and bigger things, and eventually would build up all the way to build planets like Earth. In Earth, more rocky things, in the outer solar system, more icy things. But that's one interpretation that you're really looking here at building blocks that have built up this comet. So those are... That's a quick tour of some of the features on the nucleus. The other thing that we see with the Osiris cameras is we can also look at the sources of the activity that make this comet. As I said, the whole comet is a huge thing that comes from this tiny centre. This image from Osiris is an overexposed one where you can see the nucleus kind of saturated and you see jets of material coming from it. This is the material leaving and producing the big comet. Thank you very much.