Us pluto has a haze layer in its atmosphere and mike is going to tell you more about it. Thank you alan. Good afternoon, everyone. Mr. Summers alan. Im going to talk about two new results on the atmosphere that are basically changing the way that we think about the atmosphere. Could i have the first graphic please . This is one of our first images of plutos atmosphere. This was the image that stunned the encounter team. For 25 years, weve known that pluto has an atmosphere, but it has been known by numbers. This is our first picture. This is the first time we have really seen it. This was the image that almost brought tears to the eyes of the atmospheric scientist on the team. What i want to tell you now is what we are seeing here this is the atmosphere. The light, the crescent you are seeing is sunlight scattered by small particles in the atmosphere, and these particles constitute a haze layer. This is a crosssection of that haze layer showing structure. The colors have then enhanced. They are not real colors, just so you can see that there is structure. There is an argument going on if this is dynamics or chemistry. This probably both, but the real answer is this is our first peek at weather in plutos atmosphere. To illustrate that a little bit more, theres a hint that there is either a layer of hayes at 30 miles, 50 miles, or a combination of layers and waves in this region. Those are the kinds of things we will have to sort out the coming weeks, and that will help us sort out how the atmosphere works, but the hayes is extensive, at least 100 miles above the surface. Thats a big surprise, five times further than our models predicted. Pauls predicted models predicted they would form where temperatures are called, but its forming high in the atmosphere where temperatures are hot from plutos specter, which is not hot from our perspective. Its a mystery. Its one of the things we will have to sort out in the coming days. Ok, the hayes haze is pretty. But it is a piece of the big story we are trying to understand, and thats how the atmosphere on the surfaces are connected. This is to illustrate one aspect. Could i have the next timestamp please . This shows how methane in the atmosphere is broken apart by ultraviolet radiation from the sun, and radicals, the small atoms and molecules that react trigger a Chemical Reaction that form complex hydrocarbons like ethylene and acetylene which were detected by new horizons. As time goes on, these buildup. They become supersaturated, and they should nuclease, form haze particles, which then grow and eventually, they will get big enough so you will see a haze layer, and then it will fall to the ground. At some point in this cycle these particles are chemically processed to produce chemically altered hydrocarbons that have a red color. We think that is how plutos surface got its reddish hue. In a minute, kathy will talk about the color and composition but this is just one piece of that story, not a coherent piece. There are some mysteries. As i said, we do not understand why there is a haze layer of the 100 miles altitude. It really is a mystery. The next story regards surface pressure. I will give you a little bit of context here. The surface pressure at any level is a measure of the weight of the air above that level and thats gravity acting on mass. If you know the surface pressure, you think you have a pretty good estimate of the total mass of that atmosphere, and it is important because that is a way of quantifying the global space of an atmosphere. Can i have been next graphic please . Ok this shows surface pressure on pluto as a function of time. The units might be strange to you. They are in micro bars. A micro bar is one million 1 one million of sealevel pressure on earth. What is interesting here is that in 1989, pluto was at its closest distance to the sun and now, pluto was moving away from the sun in its very elliptical orbit. As it moves away, it should be cooling. The nitrogen should be condensing onto the surface, and the mass should be decreasing, but we dont see that. We see the exact opposite. That has been very interesting. Nonetheless, we have been trying to figure this out. What im going to show you now is a new data point, more information that we had to add to this story. It is just one data point, but i do want to say it is significant, and we are going to have to figure it out. This is it. This is what the radio science experiment has contributed to this story a new data point which shows the surface pressure is at most 10 micro bars, so the mass, if you will, of plutos atmosphere has decreased by a factor of two in about two years. That is pretty astonishing, at least to an atmosphere scientists. That is telling you something is happening. It is just one data point. These are early retrievals. We got more data coming, as alan says, and theres more to the story, but its another mystery we will have to deal with over the next few weeks, months years, and so on. Ok, now, im going to turn it over to kathy, who will talk about the color and composition of plutos surface. Ms. Olkin ok. Now what i will tell you now is what we are seeing here this is the atmosphere and the light across as what you are seeing is light scattered. I want to talk about what were seeing scientifically and some of the things we know and understand from looking at this image. You can see the dark region. Remember, the stark regions all around that area. Just above it its a little bit brighter and a little bit less red. Remember, theres dark regions all around that area. If i can have the next graphic. Putting this latitude and longitude grid on this image allows you to help see, draw your eye to that banding pattern. I want to talk a little bit about it because it goes to the complexity mike was just talking about about the atmosphere and the surface and the interaction. Pluto has a very complicated seasonal pattern of transport it takes 248 years for pluto to go around the sun. Pluto has a very eccentric orbit, so sometimes its much closer to the sun than at other times. Also, additionally plutos north pole is tilted over at an angle of about 120 degrees relative to the plane that it orbits in. All of these factors together cause different parts of pluto to get different amounts of sunlight, and the sunlight is powering the sublimation from the surface into the atmosphere. Some parts are kind of eight like new the equator, and other parts received this condensation as you can see on the north here. Weve got a different pattern that you can see manifested on pluto that we understand from modeling of the seasonal transports, but there is one glaring difference in this pattern i just called out, and that is what clearly the reps this pattern of latitudinal variation of colors and brightness is, and one thing i should add is that the darker regions in the story i was telling of the seasonal transport are likely what mike was describing that was raining out from the hazes or falling from the atmosphere and a thesis. What is really special is we are seeing methane, nitrogen, and Carbon Monoxide there telling us something we need to understand. On the northern part, we see methane and nitrogen to jim, but not Carbon Monoxide. Maybe were seeing a source region for some of these. Well be looking at that in the future. As youve heard, we have a small bit of our compositional data down, and will get a lot more information when we get the rest down, but weve got some great images, and Bill Mckinnon is going to tell us about the geology of the region of the nearby vicinity. Mr. Mckinnon thanks, cathy. Ok, could i have my first graphic . Next, please. We will be looking at the fabulous near encounter hemisphere. I know you can see it. You can start the animation. What we have now is the full seven games of what will ultimately be a 12frame mosaic at higher resolution, but not even the highest resolution. That will come down later. This area on the next slide next. Yes. This mosaic covers in its entirety this vast more or less flat icy plain that we have been that we havent formally named. Its pretty big. Its just about the size of the state of texas. All around the periphery and in the interior geological wonders. I would like to share some of those with you. Could i have the next slide please . First, i would like to look at that orange box, the rectangle you see at the upper left of the mosaic. Next slide please. This is the northern boundary. Theres a little scale bar down there, but basically this is about 250 miles across, about the difference between kansas city, missouri, and st. Louis, a city which i picked completely at random. [laughter] mr. Mckinnon ok, next slide. Most of the picture you see is it the famous for having the segmented or cellular structure. You can see this really well a she move to the next side of the image. At the top of the picture, its really different. There is a rugged landscape, a degraded landscape, and something that to the eye of geologists looks like something that has been very deeply and extensively eroded. We can tell its old because you can see with your own eye various impact craters of large size, but what is really interesting to us is the actual interaction between it and this rugged terrain to the top. If you look carefully at the image, you can actually see a pattern that indicates a flow of viscous iced towards the stark or cliff boundary of the terrain. When you look at these streamlines, which ive marked with these curved arrows you see here, they look just like and we interpret them to be just like glacial flow on the earth, but i do not have to remind you that glaciers on the earth are made of ice you know, like in antarctica and greenland but waterice at plutos temperatures will not move anywhere. It is immobile and brittle, but on pluto, the kind of isis we think make up the planet, the kind of ices we think make up the planet are soft and malleable, even at pluto conditions, and they will flow like in the same way that glaciers doing here. Is one thing hiding of the 12 00 decision. We can see a flow of what is probably solid nitrogen ice flowing through a breach partially filling in the interior of the crater. We knew there was nitrogen ice. Weve known this for years. We imagined it was sublimating or evaporating one place and condensing in another place. I want to back up just one little bit and say when i say recent, i do not necessarily mean yesterday. I mean geologically recent, but the appearance of this terrain tells us this is really a young unit. We have models of what these objects would be, and they give various answers, but the best ones would be the ices in the flow we see as you point out that this curved arrows at the upper left there we could see them going around. Its really less conclusive evidence, but to get that to the age, the age is only a fraction of the total age of the solar system. Probably no more than a few tens of millions of years. What we know or can theoretically estimate about the heat flow coming from the interior of pluto, theres no reason why this stuff cannot be going on today. Ok, lets go to the next. Now we go down to the bottom of sputnik planum. This is a very busy scene ok . Its a bit bigger than the one i just showed you. This one is about 400 miles across, like taking a drive from l. A. To phoenix, although its a bit colder than that. Anyway next. Here are some things actually, at the very top of the image, you can still see sputnik planum. You can still see its polygons. At the very bottom is this ancient black, heavily cratered region, which we have been informally calling cthulhu regio. Our group up mountain blocks, which we discovered last week. In this picture, you can see economy the center actually, if you go a little bit above in the center and toward the left another arrangement of mountain blocks. These mountainous regions are actually somewhat similar. You might think the ones on the left are different, but thats just because the sun is higher in the sky when that one was taken, so you do not see the shadow. The arrangement appearance is similar from one region to another. We have given an informal name to this new mountain block after sir edmund hillary, who first summit of everest Summited Everest back in 1953. Most fascinating part to me is that the ice seems to have moved and surrounded the mountain. They cover up not just the mountain blocks, but they extend all the way down, and they just seem to feather out just onto the edge. When you look in detail, theres a lot of fine structure in the ice and a lot of fine structure that is different than the. That tells us the ice is substantially thinner. There are craters that have a sickly basically ponsds of this predominantly nitrogen ice. Lets look from one end of sputnik planum to the other. We start at the north, and were going to careen over the cliffs on to sputnik planum. There are the polygons, well delineated, and as we move into the interior, it seems like they disappear, but they do not. If they look carefully, they are still there. In fact, we basically are approaching the region that is super rich and the Carbon Monoxide ice that cathy was just talking about. Anyway, its a long flight all the way to the south, so we will skip over that part and rejoin our tour here. We are sweeping across them. Big blocks, small blocks, the dark asphalt cone surface, ancient surface on the right and one of those big craters with the big ice pond is coming into view. I crater itself is about the size of the d. C. Metro area that crater itself. The screen has gone dark, but theres a whole lot more we will learn about pluto and its moon. Most of our images, most of our data are still on the spacecraft outbound from pluto. We will be downloading this for months and in fact almost a full year ahead. With that, back to you, dwayne. Mr. Brown thank you. Now we transition into questions and answers. We start here in washington and hit the phone lines and social media and come back. Frank, i will give you the first question because your expression, its pretty cool stuff, right. Aviation week. For dr. Mckinnon i have a couple of questions about things i saw in the new disk image. It looks like a copyright bar just to the west of the plane. Its a big crater with some concentric circles. If you have any idea what that might be. Also, just to continue on the ice flows. Do you have elevation data as to what is making it flow . Dr. Mckinnon thats a couple of great questions. Are some security features i did not particular point there are some circular features i did not particularly point out to the west and north of sputnik planum and those are probably impact craters of some. And so will at least fundamentally ancient, leaving theirough they may be active. That is another crater not really showing on my graphic but another one of these craters that has ice in it, but also a central peak. It is sticking up through a bright ring. Your other question is elevation. We measure the elevation of notice by measuring shadow lengths, and if not, another technique which is determining the relative slip and we integrate, and we get some estimate of harvey. We can see on sputnik planum that the individual cells are by a few meters primary technique we want to use is called stereo imaging, and we do not have data yet to do that analysis. We are going to get more frames of that mosaic, and then legal get a sweet covering the whole of pluto and he will have a beautiful stereo view of on the whole weather sputnik planum is high or low. The one thing we can count is the north, the planum is lower than that close, and in the south, it seems to onramp onto cthulhu regio. Mr. Brown we will go here, and then the phone lines. If i could follow up, you speculate about what could be driving the flows and also how is source region got there to begin with. There has a debates whether these are ices that have accumulated from above or whether something is allowing ices to well up from within. Can you explain how this spot right in the family of the planet got to be there and what is driving it. Mr. Mckinnon if test sort of answered your own question. We have a vast region that is a reservoir. We described it as the beating heart of pluto. Maybe the supply for the entire atmosphere for a lot of geologic activity. How it was formed, you can imagine. You can imagine it was an inpact basin. We see on the south there is highly deformed topography. We know activity beyond the flows talked about at deformed crust. Have deformed the crest. We have only seen these seven images close up. When the rest comes down and we get this uncompressed on the ground, we will get a complete story. You can imagine with any reservoir, it could be filled in from the side by glaciers going into it, from below, you could imagine inside the ic crest of icy crust, nitrogen would be a liquid because it would be warmer and this reservoir of liquid nitrogen could supply the planet. These are interesting ideas, and it is very early days and we are enjoying a great deal of animated discussion. Nothing like these images existed a couple weeks ago. What we are learning and fundamentally is on pluto we have a much more intimate and intricate interaction between geology and the seasonal climate cycle. They are forcing feeding one another, and creating a layered story about planet history. It is rare in the pantheon of objects in the solar system that we have seen this kind of an intricate and complicated story. I am reminded by titan, but few other examples that are so dramatic. It is brandnew. Mr. Mckinnon just you wait until the rest of the images come in because it will be great stuff there. Mr. Brown lets go to the phone lines and then comes back here for social 80. Phone line. Can from the new york times. Remind me of the temperatures. What the temperature of the spirit is the surface and higher up with hazes. The temperature at the services 38 degrees kelvin, 480 degrees below fahrenheit. Mr. Mckinnon even if 30 kelvin solid nitrogen can creep, and below ground nitrogen will warm up and it is very sensitive to temperature. There is nothing physically implausible about the gray shall glacial flow. If there is a modestly deep flow, you get down to that, the pressure from the overburden of ice can change the properties of nitrogen because it is getting warmer because it is less viscous. There may be conditions where you can get liquid digestion flowing below a deep liquid nitrogen flowing below. We have a lot of work to do to say that with any confidence. Mr. Brown next up, wr reuters. I heard you say the surface pressure measurements show that figure atmosphere had increased by a factor of two in two years. Can you tell us what the twoyearold data set is how that is comparativred to what you are getting from new horizons . Mr. Summers it is based on stellar occultations. We have to use these to extrapolate down to the service to get a surface pressure. That is what was done for each of those data points you saw. As far as we can tell, those are accurate measurement of the this fear where the stellar occultations occurs. The thing that is different about rex, you can go down to the surface. And the data looks good. This should be our best measurement of the surface pressure on pluto. This is early our first data, first retrieval. We have more studies to do on this. Taking it at face value, it appears the atmosphere has changed by quite a bit. All those data occultations are dated that is observed from earth. We are detecting what may be a significant shortterm variation in that atmosphere that might be a turnaround. We will have to see. What will help is the most recent observations from sophia, which is one of our 747s, a fabulous telescope, that most recently in june race down to new zealand and chased plutos shadow and got a very beautiful occultation. That is a very recent occultation compared with who dont data for which it might help the interpretation of previous observations. Mr. Brown did you have a followup . As far as the britishreddish hue what would that look like if you are on the surface of pluto particles being big enough to see, like snow ice, fog, and why they universally distributed, or Something Else happened on the surface . This is putting together a puzzle when you do not have pieces but it is curious what your thinking is on that right now. Mr. Summers there are several questions. Were talking about a very thin haze. We only see it when we are looking at long slants through the atmosphere and this is the way he get that image. It is distributed over a very large region. It appears to be 100 miles or so high. In terms of the conversion of those particles to tholins, we do not know the exact details in that. Tholins encompass a range of different Chemical Substances that appear to be altered hydrogen hydrocarbons and compounds, irradiated, so it is not any particular chemical substance. Without having more detail, we cannot test the exact mechanism. We know these substances are around. We see them on titan, and british color is distinctive. The reddish color is distinctive. I can address one part of that question. I believe there is a question about the hazes falling uniformly on the surface, and that probably does happen. We have a lot of work to do to find out the rate of the story of seasonal transport reveals why we see this thing different patterns with these latitudinal bands, and it has to do with those tholins that will absorb more lice. More light. They will be deposited on the poles and cover up the tholines. S. These are pieces of the puzzle that will speak to the production of the tholins and the deposition of it. I have another question which may be too early to answer. Based on the data you have gotten can you say anything about the exact mass of pluto and any changes in the models of what the interior may have . Thanks. Mr. Stern i will ask bill to chip in. We had not been able to attain a new estimate. Before the flyby, data already gave us a very accurate mass. In order to constrain the interior properties, the uncertainty was in knowing the radius so we could get the volume and convert to density. What new horizons was able to contribute west discovered that contribute was to discover was 1187 kilometers. We had uncertainty that ranged over 70 kilometers. Plus or minus 2. Center dot around 1186. It is somewhat bigger than what we had expected. That will lower the density and will have implications to the interior property. Mr. Mckinnon everything alan is pretty much the case. He had good sizes for both pluto and charon. In the years past we thought charon was very icy and please dont have much more r ock. Now they are much more similar. Pluto seems to be a bit rockier. In terms of what the inside of pluto is, without gravity data it is hard to be absolutely definitive. That is one way we test our models of planets when we fly by then. Everything we see, all activity we see is consistent with the idea it has a massive rock core surrounded by huge icy shell, and that shall and that shell is probably figure. It raises test it increases the probability there may be an oce an way down under a single mayor of ice. That is something you keep in mind as pluto. One of the things we learned not just the size of pluto, but it was close to spherical. We cannot detect any old lateness in the body bo oblateness in this body. Pluto probably was spinning very fast after what we believe to be a giant impact that led to the formation of its satellite. After that, pluto and charon are close together and tides have created them to be locked up the way they are. Pluto does not show any evidence from its shape from this fast rotation. We think it must have been warm enough that no residual she could be supported. It is still too early to say exactly how hot, but that is the thing we will be applying our research tools, theoretical models, and going to Scientific Conferences and writing scientific papers and either coming to conclusions or not. That is how it goes in science. Mr. Brown sky and telescope. Mr. Beatty because the atmosphere density is higher you expect it to be, can you tell us about the possibility that are gone playing in the composition argon is playing in the composition . Mr. Summers it has gone the other direction. We believe the atmosphere has shrunk. I am not sure that says anything about argon. I do not believe there is anything we can say about argon. This one goes out to alan. You called pluto a double planet. Considering that pluto is larger than previously thought, what do the findings say in terms of how we define what the kind actually is . There is a bone of contention for those who have followed pluto for a time. Mr. Stern we called the pluto system a double planet for a very specific technical reason, because the two objects are close enough together and their match ratio is sufficient strong balance point between them into free space. That is analogous to the way we define a double sources, when the balance point called Bay Area Center the barycenter, is not within either of the two. I do not think there is controversy about the double planet moniker. There has been this controversy where astronomers and planetary scientists have been on different sides of this. You and the public lightly on the site steam account what we are dealing with. It is hard not to call object like this in this level of complexity with complicated seasonal cycles, and certainly the big complicated system of moons a plan. The way science works is individual scientists make their decisions one time and did eventually consensus reached. Now a new class of plan in our system, we are going three time of transition, and definitions are in transition as well. They will shake themselves up. Mr. Brown leo, you will at the last question. You get to the public also. Leo Bill Mckinnon mentioned a classical ocean. I was trying to understand how to get into what you are seeing. Could you say that nitrogen glaciers could be explained easily without a liquid ocean underneath that other mechanisms could achieve this, or that norgay and hillary could not be explained without that . Mr. Mckinnon we do not have any direct evidence of an interior ocean. What i wanted to imply that pluto is a complex look, plus the fact that any ice mantel increases the radical likelihood that there may be an ocean done it. Mr. Brown lets see what the social Media Questions are. Emily . Emily derek asks what information is used to make these false cover images . Ms. Olkin color images coming from the color camera. We have four filters, and they cover wavelengths where charged coupled devices are typically sensitive. So those images are a combination of those different filters, and sometimes we welcomed by knows to make natural color, and then other false cover images. You can pull the Near Infrared so our i is not to do. We can understand these compositional in a detailed could not with our eye. Emily when images of planets without atmospheres be able to be caught with this . The ring around pluto is from it mr. When images from its atmosphere. We have taken selected images of other objects that do not have missed years do not see the rain. We have a see the ring. We have a nice image where we are talk looking back into the glare of this done that show the crescent of charon, and there is no evidence of it atmosphere. You see a brand new moon. Once we clean it up we will make sure it is released. Mr. Brown two more. Emily simon asks is there a theory of what is driving the nitrogen ice flow . Mr. Mckinnon i guess that is for me. It is not sunlight. It is internal heat. If you have a sick enough, a massive enough mayor of these kinds of cases nitrogen, Carbon Monoxide, or methane, it will move if there is sufficient flow. We have done calculations which we need to do better ones, but we believe our leading model for the formation of the polygon at this moment is internal convective motion rising and falling at a slow rate of the nitrogen ice within sputnik planum. It is driven from the heat that is leaking the interior of pluto. Mr. Brown the final one. Emily when will we see the relatively High Resolution of the service . Mr. Stern in the nature of new horizons, it demanded that it was a consequence that we were going to observe one hemisphere in exquisite detail and the other side in much less detail. That is a combination of the fast speed combined with the slow rotation rate. The last time we saw far hemisphere we were 3. 2 days out, and that corresponded to millions of miles away. As opposed to the image you are seeing, it was taken 10 times we have a dichotomy and our maps. The far side, we can detect the largest craters on the surface and the largest units, but not nearly as well as in the close approach hemisphere. We have a good bit of imagery still in the spacecraft that will help improve the maps more, and in the fall when the data starts coming in, we will produce a better map of the far side than we have now. Eric i have a question for alan or mike. This shrinking atmosphere, the plummeting pressure, assuming it got to zero, that means the atmosphere froze out. Does this mean you got there in the nick of time and that is what pluto that is where it was heading, and how can you reconcile a changing atmosphere with detecting haze higher than was expected. It seems contradictory to me, a shrinking atmosphere with a hza aze. Mr. Summers the haze particles are very small. You could have the atmosphere decreased by factor of 10 and can still have a haze present. It could still be there. If you want to take the other part mr. Stern for a long time there have been models and climate models for pluto that suggested as it draws the sunday pressure could precipitously drop. In fact, during a time when the National Academy and committees were looking at a Pluto Mission and its priority, there was an interest in trying to get pluto while it had a substantial atmosphere. That helped motivate the case to get a Mission Launched in the 200s0s. Eventually there came to be a believe that it has been 25 or more years since its closest approach to the sun, maybe there is not going to be any atmosphere to collapse. What rex has detected is the first stage of the collapse just as it arrives. We will see if this is in fact it is complicated, not related to atmospheric collapse, and we have several more rex data sets that will help inform the question because we got data from two different stations at ingress and two sets at egress. Mr. Brown that will do it here. Pluto is very complex, and as dr. Stern mentioned, the data is raining down and we will be bringing you more in the future. Stay tuned for updates on how we will share that with the public and the world, and follow us on the National Social media accounts twitter, facebook youtube. Keep the questions coming in. Follow the conversations which will go on for a long time at plutoflyby. And updates cutting down in the future at 2 www. Nasa. Gov newhorizons. This theme is not