 Again, to Astro on Tap, I am so excited for our talks tonight. We have guest speakers here from Lowell Observatory. And so tonight, yeah, that's absolutely, yeah. And so tonight, we have Dr. Jeff Paul, who's going to be talking about the history of Pluto and Dr. Nick Moskowitz, who's going to be talking about NASA's dart mission. And so these talks are going to be fantastic. But before we get to the talks, we need to talk about trivia. Thank you for whoever laughs the one person. So before I get started with the trivia, I have to raise the stakes for you guys. So our regulars that come to Astro on Tap know that the prizes we give out are stickers and pens and keychains from various double AS meetings. But luckily for us tonight, Lowell Observatory brought their own prizes. And so up for grabs tonight, we have a Lowell Observatory hat. Yeah. We have a stress ball, which if nobody wants, I have a couple of grab students in mind who might need it. We have a solar system papercraft model of Pluto. So you build it yourself. It's pretty cool. A set of four coasters, which are pictures taken by the Lowell Discovery Telescope. And happy Jack Arizona. And we also have a mini notebook. Keep clapping. Keep clapping. You guys are two more to go, two more to go. We have a history from the hill, the story of Lowell Observatory. Thank you. And then finally, and perhaps most excitingly, Chasing New Horizons, which is of course the story of Pluto. I said finally, but I actually forgot. We also have stickers, pins, and a key chain up for now. OK, cool. So here's how trivia is going to work. First of all, if you haven't gotten a sheet, please come see Sam, who's right here. And she'll give you a sheet and a golf pencil. So what we're going to do as soon as I put these prizes down and grab the clicker is I'm going to run through the trivia slides up here. I'll leave each one up for about 30 seconds so you can write your answer down. At the end of that, I will run back through all of the trivia slides and leave them up for maybe 10 to 15 seconds. So just run through them a little quicker. And then once that's over, I'll have everybody turn in their trivia sheets to Sam. We'll get started with our first talk, Dr. Jeff Hall. And then in between the talks, I'll announce the winners. Sound good? Yeah. OK, cool, cool. All right, best of luck on the trivia. That's a great, comprehensive thing. Why, if you haven't been here since I've been here, I encourage you to come back out. But thank you for coming out tonight. This is exciting to have to have our own way out tonight. And just because of the great turnout, we're going to throw a gift card in for the number one. Woo! So let them know if you get first place tonight, I'll let them know we need to get part inside. But thank you very much for coming out tonight. Good to have you. Thank you. Thank you so much, Frank. That's fantastic. I didn't know about that until right now either. So I will be playing trivia with you, even though I know all of the answers and wrote the questions. So now it's going to be my absolute pleasure to introduce our first speaker, Dr. Jeff Hall. Jeff came to the Observatory in 1992, is that correct? As a postdoctoral researcher. And just this year in 2022, he was named Executive Director of Lowell Observatory. That was a trivia question, by the way. Jeff has done a lot of really fantastic things for the Observatory. And in the past, his research has been on stellar and solar activity cycles, and particularly how the solar cycles affect terrestrial climate. So today, you're going to be talking about Pluto. And without further ado, I will bring up Dr. Jeff Hall. I'm going to turn mine off first. So I'm going to turn mine off, hold on. All good. OK, thanks, everybody. Thanks for coming out to Astronomy on Tap tonight. Megan, do you have the clicker for me? Yep. Sorry. No problem. OK, and I think I'm glad we're doing things in the order that we are, because I'm pretty sure that answers to some of the questions are actually going to be in my talk. So I'm going to start, since we're pretty far from home here up in Washington instead of Arizona, I've got just a little preface to tell you a bit about Lowell Observatory in general. And then we'll switch to a little bit about one of the questions we get asked pretty much every night I'm on campus for a Meet an Astronomer event, which is, is Pluto a planet? All right, now don't steal my thunder here. OK, so to get started, first a little bit about Lowell and who we are, Lowell Observatory was founded in 1894 by Percival Lowell. He came out to the Arizona territory looking for what he believed was evidence of intelligent life on Mars, as was put in one of the trivia questions. And right there is a picture of the 24 inch Clark refractor that Lowell brought to do some of the initial observations it was installed with Mars in 1896. And that's a picture of Lowell himself there on the right. Now we are located in Flagstaff, Arizona at an elevation of about 7,000 feet, very high airs, thin air, clear sky, beautiful dark skies, thanks to the exemplary dark sky protections we have in place in Flagstaff. Lowell was of the Boston Lowells. Boston is a great town. It's not the perfect town for an observatory. So Lowell came out to the dry air at west. And Lowell Observatory, the main campus is right here on this hill overlooking downtown. And this is a panorama I took just a couple of months ago of the campus. Right here is the Slipher Building. This is the building. My office is right there. Nick Moskovitz's office is right about there. And adjacent to Nick's are the places where Clyde Tombaugh, here's one of the answers, where Clyde Tombaugh worked and lived during the search for Pluto. As Megan noted, the 24 inch Clark refractor was the earliest flagship telescope of the observatory. Our current flagship is the 4.3 meter Lowell Discovery Telescope, because this is a $53 million project that we conceived in the late 1990s and put into full operations in 2015, almost 17, 18 years later. That's sort of the time scale on which these projects unfold. And this was an example of thinking really big. I've said many times, if this project had failed in some fundamental way, I don't think the observatory could have survived financially. The risk exposure was that large. We went into this project with a balance sheet of about $36 million. And this is a $53 million project. That kind of thing transforms any organization that attempts to do it. And now, because we are that special kind of organization for whom $150 million project isn't enough, you got to do two. It's twice as fun. And whoever wins the stress ball, I might take that off your hands at the end of the night. This is the Astronomy Discovery Center. Our vision for this is basically to be the flagship of our outreach mission, as LDT is the flagship of the research mission. And we intend it to be the premier destination for astronomy and formal astronomy education in the world. So we hope you'll come down and see it when it's done in mid-2024. And here is a recent construction cam image. We have a live construction cam. You can go to our website and see it up to the minute status of where it is. As you can see, the visitor experience is not yet ideal. But hopefully, in about two years, it will be. So with that, I'm going to switch a little bit. Megan showed you a picture of the Giovanni Open Deck Observatory. Nick and I and the other astronomers go up there from time to time for meeting astronomer nights. And one of the questions we always get asked is, is Pluto a planet? Because, of course, Pluto was discovered at Lowell Observatory in 1930. The search for Pluto began with Percival Lowell all the way back in 1902. And he started doing calculations based on some supposed anomalies in the motions of Uranus and Neptune that there was a planet X out there, a ninth planet. And Lowell did not live to see the ninth planet discovered. But in 1928, the director at the time, V.M. Slifer, reinitiated the search. And they hired this Kansas farmhand, 22-year-old Clyde Tombaugh, to come carry out the search. And he used the telescope in the Pluto dome, a 13-inch telescope, to expose photographic plates and systematically study the sky for Pluto. And actually, in remarkably short order, Clyde found it. In a pair of images that he took in January of 1930, and what he would do is the technique here was take an image of one portion of the sky, wait six days, take it again, and see if anything's moved. Because over the time scale of a week or so, the stars are so far away, of course, they're moving around quite rapidly, but they don't appear to move, planets closer in will. It's exactly the same effect of driving down the interstate, and the signs are going by you relative to relatively stationary trees far away on a distant hill. And so Clyde found little Pluto right there, and then six days later it had moved over to the other side of this pair of stars. Now, Clyde, of course, did not have benefit of the arrow. So I have always been rather in awe of the diligence and perseverance and attention to detail, scanning hundreds of these pairs of plates. And Clyde, when he found this in double triple and quadruple, checked it, and every time I tell the story, I can feel myself literally getting goosebumps right now. He walked into the very office where I sit every day and said, Dr. Schleifer, I have found your planet X. Now imagine this 22 year old, this is, you know, basically sort of the age of a grad student working on a discovery like that. It must have been an overwhelming experience for Clyde. So here was Pluto in 1930, and that was pretty close to the best image we had of it until very recently when thanks to the perseverance and vision of Alan Stern and a huge team of researchers, we decided to go there and see what it looked like up close. And here was the start of that trip in January of 2006, the New Horizon spacecraft. And the strategy here was build the tiniest, lightest spacecraft you can find that'll do the job and put it right up here at the tip top of the biggest, baddest rocket we've got in Atlas V and put it on steroids with all these solid fuel boosters and flinging out there as fast as you can because one of the mission criteria for New Horizons was the entire project team wanted not to be dead by the time we got to Pluto. So you want to go really fast because Pluto is way out there at three and a half billion miles. So New Horizons went cruising past the moon in about 13 hours. It got to Jupiter in just over a year or maybe it was eight hours to the moon about 13 months to Jupiter and then got a gravity assist from Jupiter and made it to Pluto in the blink of an eye about nine, nine and a half years. And this is what New Horizons looked like about the size of a baby grand piano. You can see the big high gain antenna there. It's bristling with several different types of instruments designed to do imaging spectroscopy so we get those beautiful high resolution pictures see what the surface of Pluto is made of, study its atmosphere, the space environment around it basically learn everything we can as much as we can about the Pluto system during this frenetic fly by when you went zooming right by the planet at about 35,000 miles an hour. And right the back here over here is the power source, the RTGs. So this was the best we had the best image we had of Pluto from the Hubble Space Telescope before New Horizons got there. The problem you have there is resolution a very small object at a very large distance you can't really see too much. And so that was all we had but even there you can tell that Pluto might not be a completely boring object, right? You can see there's spots here that's a little brighter, a little bit fainter. It's not just completely homogeneous maybe boring kind of thing but your problem there is a lack of pixels. So here is an example, a low resolution picture you can't really tell what's going on at all. I can tell you this is a landscape and maybe you'll say okay that's possibly a landscape you can see land, maybe there's sky but the problem there is you just don't have resolution to know what you're looking at but if you have a much better camera and much higher resolution and now we can tell exactly what we're looking at. And so just the same process played out at Pluto. Over the course of several hours New Horizons flew within about 7,000 miles of Pluto three and a half billion miles and it went within, I think they nailed it to within a thousand kilometers of the keyhole where they were trying to get to maximize the science results exquisitely planned to capture images of the planet its moons to fly through the shadow of Pluto so you could get some of those incredible backlit images like the one on my title slide. That's actually I think almost my favorite image of the whole encounter is looking back through this cool atmosphere with all of those layers and so this turned into the iconic heart image after all the big sort of demotion we were on the phone with press all around the world for about 72 hours straight the phones were ringing off the hook and we were trying to take a very nuanced you know it's about science we've got a faculty member who's the surface composition team lead Dr. Will Grundy we're on our way we're interested in the science and tried to really focus it on the science and not the really charged emotions that we're circling, circulating about the change in status and of course then when we get there it's got a heart, I mean good, we're really focused. So, but what we learned from the fly by of Pluto is this is an incredibly interesting dynamic world it's not some boring little cratered happy little ball like Mercury or something it's actually got, I'm sorry, I'm sorry is anybody from Messenger here? So there's this young smooth terrain they're these towering ice mountains there's cryo volcanoes, there's evidence of activity this is far from a dead world out there in the cold distant reaches of the solar system so that brings up the question what actually is a planet? Is Pluto a planet? What should you call a planet? And for the remainder of this little talk I'm just gonna give you some of my own thoughts on this obviously this has been the subject of huge debate over the past, well what is it now? 16 years since the demotion in 2006 at the IAU meeting in Prague. So to start with let's take a very quick census of the planets in our solar system which we're all familiar with here are the so-called terrestrial planets not obviously not spaced to scale but the sizes are roughly to scale Mercury, Venus, Earth, Mars characterized relatively high density, solid surfaces we're very glad they have solid surfaces aren't we? And of course one of our favorite planets at Lowell is Mars showing many of the characteristic markings that Percival Lowell mistook for signs of intelligent life then still to scale we can add the four giant planets Jupiter and Saturn the giants Uranus and Neptune the gas giants you can see vastly larger than the terrestrials also much more widely spaced out and then right here at the bottom there's a little Pluto right there kind of hard to see but drawn scale as you can see considerably smaller than Earth smaller even than our own moon so clearly a different kind of beast now those were the nine known planets and agreed upon as of 2005 but things had started to change in the field of astronomy regarding our understanding of small bodies in the solar system and around other stars and that really began in 1992 with the discovery of the first of what we call the Kuiper Belt objects and there is a Kuiper Belt object like remember those two images from Clyde's work here are three and it's awfully hard to see there's something maybe moving in there but it actually is in there this is the first known Kuiper Belt object out there where Pluto lives have the exciting and romantic name of 1992 QB1 and moving slowly through this star field so there was the first glimmer that there are other things out there in what we would call the trans-Neptunian region of the solar system in the same year the detection of the first planet around another star and this is let me tell you a happening place this is a planet it's orbiting a pulsar a neutron star that dead remnant of a star that has exploded and collapsed spinning several hundred times a second emitting beams of lethal radiation here you are on the planet's surface this is a lovely vacation spot as you can clearly see and then just a few years later we found another spectacular vacation spot the first planet known around a star a little more like the sun and this is just an art these are all artists renderings because of course we can't image things like this here is the star this is the star 51 Pegasi relatively ordinary main sequence star in the constellation Pegasus and this was a planet detected orbiting the star the first known exoplanet now Mercury in its orbit around the sun has a period of about 88 days the period of this planet around its star is four days so you do some basic orbital mechanics and you conclude this thing's got to be extremely close to its star so much so that the atmosphere is probably about a few thousand degrees it's also very large Pegasius it's Jupiter like and so astronomers being the resourceful and incredibly creative sorts of beasts that they are called this a hot Jupiter okay so so this was sort of a new class of planet you know we thought our solar system kind of made sense right you've got the rocky dense stuff sort of sank towards the bottom you've got the big like gas bags farther out that's a solar system architecture that seemed familiar to us and here the first exoplanet detection turned upside down our idea of what the architectures of solar systems might look like and now as we have discovered just a few more we have we have realized there are just any number of different sorts of planetary architectures out there and likely many different kinds of planets so I looked at the exoplanet archive just last week recently it's a little over five thousand planets we've discovered from various means and various missions you know NASA's Kepler mission is a prime example of a groundbreaking mission in helping us understand the population of planets in the galaxy and this plot is basically showing you the orbital period of the planet on a log scale so here is one, ten, a hundred, a thousand days and this is the size of the planet in Jupiter radii so ten to the zero that's one that's the radius of Jupiter so you can see what we tend to find ten to the zero is one, ten to the one is ten this is the orbital period in days we tend to find planets fairly close to their stars because they're easier to find that way particularly if you're doing things by watching for transits we also tend to find really big planets because they're easier to see particularly if you're doing things like radial velocity detections where the reflex motion on the star is greater the earth is over here, this little red dot we're looking for those in fact we've got a program at Lowell Observatory at the Lowell Discovery Telescope specifically targeted at detecting earth-like planets around sun-like stars we have also cataloged just scads of Kuiper Belt objects so it's clear that Pluto is not a loner out there it is a richly populated new frontier of the solar system and many of these objects are fairly substantial in their own right so Pluto is there Pluto's got five satellites we have found a number of other objects in the Kuiper Belt comparable in size they've got their own satellites they may be somewhat misshapen but there's quite a population out there so this calls into question now what's a planet and what's a reasonable way to think about a planet I will tip my hand and say I don't think the current definition of a planet I think it's got some problems and in the last little bit of the talk here we'll go over what those are so first of all let's come a little bit back closer to home and look at this beautiful specimen and how we might classify so this is a giant silkworm moth we were just talking about moths the other night where's Steven I told him that this was gonna be in my talk so this absolutely gorgeous specimen showed up on our door sill about 12 years ago one June and my three little at that point very little sons and I collected it and it's a female which you can tell from the body size and the morphology of the antennae promptly laid about 330 eggs and we spent the summer raising these little caterpillars to see if we could get and it was hard to keep those little buggers alive let me tell you and I think we got about 10 to 12 cocoons out of it and these gorgeous new moths come out and they live about a week because this particular family they have no mouth parts they don't feed they just grow up reproduce and die maybe that doesn't sound so bad actually but so anyway so we all know as we all know in the classic Linnaean taxonomy you know you divide things into this beautiful classification tree you have classes of insects order Lepidoptera meaning scale wing family I love this Seternaeidae named after the big rings that adorn the wings of these species and then you get down to genus and species the oculia silk moth sort of the western relative of the eastern polyphemus moth so this is how we try to understand the patterns in the world around us classification allows us to sort things into things that make sense and how do we do it biologically whilst entomologists will look at things like the structure of the thorax or the patterns of the physical patterns of the veins of the wings which are like the ribs that give the wings the rigidity to function and so we just debase this on physical characteristics so now let's consider go back to the planets in our solar system and start considering physical characteristics and we'll look at how planets were defined in 2006 by the IAU so we have a couple of classes of planets we talked about the terrestrials we've got giants and you might divide those into gas giants and ice giants the planets a little farther away and then you've got little old Pluto which is definitely different it's in an eccentric orbit it's inclined it's very very small it's a different kind of beast maybe than the others that we've seen so far so in 2006 the IAU created a new definition of planet that has three basic components and I think one of them makes a lot of sense and I'm going to take issue with the other two so first of all the planet the the definition puts the definition of the planet specifically in the context of orbiting the sun in the solar system a planet is this so this makes zero scientific sense to me since going back to our example of the silk moth suppose I'm on a road trip and it's here in Seattle and we've decided that species is defined as being in the vicinity of Seattle and it somehow gets stuck in my car and I head back to Arizona and then it gets loose is it the same species yeah of course it is so I think and we know now that there are planets all over the galaxy so constraining a definition to apply only to our solar system is awfully heliocentric if you will then a the component of the definition that I think makes a lot of sense is that the object must exist in what we call hydrostatic equilibrium which is a fancy way of saying big enough to be a ball under its own gravity it shapes itself into a sphere roughly a sphere stars the sun exists in hydrostatic equilibrium when you look up you're seeing giant balls of plasma existing and actually shining because of hydrostatic equilibrium so that makes sense and then there's this third has cleared its orbit and that was in one of the slides right and so we call this big enough to be a bully so it has to have kicked everything out of its orbit and therefore is sort of clear of anything that might be in the way so under this definition I would ask is earth actually a planet because things occasionally hit the earth there's this big impact crater about 35 miles from Flagstaff in fact you can see Flagstaff right in the distance there Lowell Observatory is right at the base right about there the folks of Chelyabinsk, Russia might wonder whether earth has successfully cleared its orbit since they all got their windows blown out in 2013 so I think this again this is this is a very location specific thing if for instance you took earth and teleported it into the middle of the asteroid belt with a Kuiper belt suddenly it wouldn't be a planet anymore if it then eventually cleared the orbit it would become a planet again this sort of location based classification is what bugs me I think the most sensible thing to do is base your definition on the simplest possible physical characteristics then things are going to get more complicated because if you think about the numbers depending on who you talk to there's what two or three hundred billion stars in the Milky Way galaxy alone and we know from missions like Kepler and others that probably the vast majority of those stars have multiple planets so simple math suggests a couple trillion planets in the Milky Way alone in this galaxy we've seen this new image from James Webb Space Telescope all those galaxies in this pinprick on the sky maybe a couple of trillion galaxies in the cosmos now you're up to like a few sextillion planets imagine the richness of the classification scheme that that can be derived from that provided you don't constrain it to one star in one galaxy so I'm going to leave you tonight with just one this is just this is obviously hotly debated just one person's opinion of how you might sensibly define a planet and then it'll get a lot more complicated from there it's big enough to be a ball exists in hydrostatic equilibrium small enough to not be a star here so basically what is what is the definition of a star what is the sun the sun is essentially the mother of all hydrogen bombs it's basically shining by fusing hydrogen to helium in its core thermonuclear fusion is how stars generate their energy some do it more rapidly some do it less rapidly but that's sort of at the heart of what is leading a star to shine so under this definition here are the implications the moon you could call the moon a planet it's it's a ball and it's not shining does that make the earth and the moon a binary planet possibly maybe that's another little thread on the taxonomic tree of planets so in this case we would have terrestrial planets giant planets maybe ice giants and then we've got all of these and I think it is really fair to call them dwarf planets one of the confusing things about the IAU resolution was they decided Pluto was not a planet and then they had to figure out what to call it and what they decided to call it was dwarf planet which is rather confusing and moreover dwarf is a it's a term in use in astronomy right the sun is a dwarf star that has a very specific connotation so I think it is fair to say that Pluto is a dwarf planet it is perhaps the archetype of a very rich class of planets that probably have many different sub-classifications and if we could build a whole fleet of new horizons and go see all of them close up then you'd get close-up views of things like Aracoff this little object that's sort of congealed two little things congealed together what if you could go out and see Hamea up close or Maki Maki this is a plug for supporting your federal agencies that build these wonderful ships which Nick is going to talk about shortly to go out there and explore the cosmos and if we do imagine just the richness go look up at the go look at the taxonomic tree just at the insects with a few million species and then imagine that there's you know not 10 to the 12th but 10 to the 20th planets out there imagine the richness of what's waiting to be discovered when we have the time and the patience to revisit it and think about it carefully so thank you very much oh okay sure sure oh totally totally okay all right so you first then Mike entirely possible yeah um I you know it may well be that it simply hasn't been discovered that it's small it's been too faint to see but you know the the Kuiper Belt has a known extent but I don't see why there couldn't be objects farther out there far quite possibly didn't get anything from New Horizons oh it was like 36 hours so you lost it on time it was it was 10 days yeah and yeah and and that reminded me something I meant to say during my talk whoever wins chasing New Horizons that's that's a really good read and when you get to the end of that book your basic conclusion will be it is an absolute miracle that we got any of the pictures we did because you know just just the the hurdles they had to get past just to get it to the launchpad but then yeah 10 days ago Will would know the specifics 10 days before the encounter they they sent a command and overloaded the computer system and it went into safe mode and they had if I recall they had to re upload everything and you know they're going around the clock and and Alan had you know backups and fail safes and you know that everything was was primed to respond if there had been a disaster but that's particularly gripping moment in the book when you know this is very high profile stuff you know and everybody has spent 25 years of their careers on this and NASA has invested close to a billion dollars and the whole world is watching right because when we went by that image of Pluto was above the fold on practically every paper in the planet and after nine years it goes silent right 10 days before the encounter but you know they're incredibly smart incredibly dedicated people and they were prepared and got it done but yeah it was a heart stopper and and actually just before just before the the show here Nick and I were talking about various missions and and how it is it's a high-risk business yeah way in the back no it's probably not the actual distribution but it's it's we have several different techniques for detecting planets and some of them are optimized for detecting you know big things close in some of them will find or planets that are close to their stars or planets that are large and have a a stronger effect you know and like when you look at the largest scale maps of the universe right you sort of see these fans extending out it's not that the universe exists in fans like that it's just that's where we've observed and where the data are complete and where they're not you'll see the same thing I think you know if you look at maps of the Kuiper Belt there there are weird little things in there that are that are I think functions of where the surveys have been most thorough and where they've not okay maybe one more and yeah go over there what science are we hoping to do with the fancy new telescope so the fancy new telescope is it's optimized to do a wide range of projects one of its unique strengths is what we call the the instrument cube so in the back at the the RC focus the rich equation focus there's this cube and you can put I see Megan is on the ball as usual and it's going to put a picture of it keep on going goodness that's bright all right there we go so the instrument cube right back here at the business end you can mount instruments on all five ports and then switch between them rapidly so you can switch programs from imaging to spectroscopy and so forth very rapidly so some of the projects we've been doing initially involve you know deep imaging of dwarf galaxies really faint surface surface brightness objects you know one of the the most relevant I think to my talk this fabulous new spectrograph that Yale University provided which has exquisite precision we're searching for the reflex motion of earth like planets going around sun like stars and you pencil out the math if an earth is orbiting a star the star should be wobbling at about 10 centimeters per second that's sort of the tug of things like venus and earth on the sun so you're trying to detect those level of motion that level of motion in targets you know trillions of miles away and complicating that fact is and this is where I get really interested in the program the stars themselves are these seething variable balls of plasma and so they're constantly varying and jittering and so for the planet hunters that's noise for me that's signal and so studying these stars and studying the sun our astronomer Joe Lama has this cool little telescope which he calls the Lowell Observatory Solar Telescope or lost and he's observing the sun with it to characterize how the sun varies but what one of the things he's trying to do is discover venus because if you can identify that in your data in sort of a control sample then if you identify comparable signals around other stars you gain some good confidence that you're actually you've got a real detection so those are just a couple of the programs but our former director Bob Millis called it the Swiss army knife of telescopes because we have a a faculty with a very diverse set of interests and we want to be able to accommodate as many programs as possible and make it useful to as many of them as we can okay all right awesome thank you so much Jeff that was a fantastic talk so now we're going to do a quick intermission before Dr. Nick Moskowitz gets up here to tell us about NASA's DART mission and I'm going to tell you guys the trivia answers and I'm going to announce the winners so I need to switch over to the trivia answers can you give me a second didn't think this through swipe this way I don't work oh okay help me okay you can do that so easy okay so we're going to do the trivia answers got to get to the answers all right okay um actually I'll grab those in a second okay the first question low observatory is home to the Clark refractor which is a historically famous telescope question two personal low although he began search for planet nine as Jeff Hall pointed out Clyde Tomba was the one to actually discover Pluto personal low believed he saw canals on Mars which led him to believe that there was intelligent life there and then starting in 1912 observations made of galaxies with the spectrograph at Lowell Observatory helped to prove that the universe is expanding and correct me if I'm wrong here I picked this some rarer galaxy because that was the specific galaxy that was observed yeah see I worked at Lowell okay okay Lowell Observatory assisted with the Apollo moon landing by creating maps of the lunar surface all right Lowell Observatory's flagship research telescope the 4.3 meter Lowell Discovery Telescope is the fifth largest optical telescope in the continental United States the Lowell Observatory Astronomy Discovery Center will be opening by 2024 and it's going to be awesome the aperture of the largest telescope the public can observe with at the Godot is the 32 inch Dobsonian the current executive director of Lowell Observatory is in fact Dr. Jeff Paul okay and then finally Pluto is demoted from planet to dwarf planet because it cannot clear out the debris of its orbital path so thank you so now I'm going to announce the winner all right are you guys ready for what the deal is okay I have thank you I have 12 winners okay but half of them are like the better winners that got one more question right so about yeah four five people got eight questions right and seven people got seven questions right okay so here's how this is going to work I'm going to announce the seven question winners first then the eight question winners the folks that had the eight questions right will get to choose their prizes first luckily I have exactly 12 prizes isn't that crazy I did not plan that up beforehand and once I'm done announcing it maybe I will have somebody randomly choose one of the eight question winners to be the ultimate winner who will also get the Biggerson Brewhouse gift card so good okay it's random we're going random so without further ado the seven question winners and make sure you like raise your hand or like shout some things that I know that you're here and alive oh god I can't I can't read this oh okay I see I see what it says okay first seven question winner is untitled yeah untitled very creative okay the next seven question winner is arian space anybody air oh sorry sorry sorry the next seven question winner is um because we're gonna make these status big vagabonds anybody all right way in the back you gotta be louder than that or you don't get the prize um the next seven question winner is Hermione Texas Granger yes the next one is a hypercubic tesseract a.k.a. Joshua very well very well done Moskovitz-Chan is that Kayla that's Nick's daughter but I swear to god she didn't have any help I was watching I was watching uh the next second seven question winner is Parker P well done okay and that's the last seven question winner so you're ready for the eight the folks that got eight questions right okay so the first one is IPA lot well done you guys okay inner cores yeah uh tennis elbow I'd love to hear the story oh okay I see it all makes sense now it's all clear to me um the next eight question winner is team Cattern nice and then finally the last eight question winner is Grungle Hammer okay okay so now I'm going to randomize these eight question winners does Kayla want to pick the ultimate winner she want to pick okay we're gonna have Kayla pick the ultimate winner you guys want to give her a hand yeah pick one of these this one okay do you want to say who it is it's Grungle Hammer okay so Grungle Hammer we'll make a note of this you guys get the Bigger Sins gift card so for everybody that wants the trivia come see us at the end of Nick's talk don't come to me right now um and so just give me one to two minutes to switch the slides over and I will be back to introduce our final speaker of the night thank you okay make a note okay I'm back did you miss me I absolutely pleasure to introduce our final speaker of the night Dr. Nicholas Moskowitz Nick came to Lowell Observatory in 2014 he is a planetary astronomer he leads the Lowell Observatory cameras for All Sky Meteor surveillance project which observes meteors all over Arizona and other parts of the U.S. in conjunction with different groups he also leads the mission accessible Near Earth Object Survey or MANOS initiative which I think he's going to talk about a little in this talk right no okay never mind never mind forget I said anything and the goal of that and the goal of that survey is to study and characterize Near Earth asteroids and he also heads up the Astor database which is a catalog of all known minor planets and has been run at Lowell Observatory since the 90s so he's got a lot on his plate and today he's going to be telling us about NASA's DART mission which I thought about telling you guys about and then I realized that he's just going to do it so without further ado again I'm going to bring up Dr. Nicholas Moskowitz I think so it's got a little lights on perfect yep all right thank you all right good evening everyone thank you for coming out this evening you can hear me okay yeah all right so we are going to be talking about the NASA DART mission which is a very exciting mission and it's a particularly exciting time on the mission because it's coming to a head in just a couple of weeks or a couple of months and so we're very busy on this mission we put a lot of work into this and I hope by the end of this talk you'll you'll share some of the excitement with me about what is going to be very intense but I think very fruitful fall as the mission comes to a close so I'm going to be talking about DART up here it's an acronym NASA loves acronym as do all astronomers DART stands for the Double Asteroid Redirection Test and so by the end of this talk you will have a better sense of what that actually means but this is important because it's really NASA's and the world's first planetary defense test mission and so we'll talk about that we'll talk about all the prep work that's gone into making this happen and what we'll learn by doing this pretty cool experiment so let's start with a bird's eye view of the solar system so this is if you were floating well above the solar system there are all these planetary things in here the terrestrial planets in the inner part of the solar system Mercury Venus Earth Mars we have Jupiter and then there's stuff out beyond Jupiter that Jeff talked about and then the thing that jumps out here all these little dots those are our current census of the minor planets in the inner solar system there's about 1.3 million dots in this image there's a lot of stuff out there that we now know about and that number is increasing every day every month thousands of new objects are being discovered and that will continue into the future with next generation facilities coming online and we expect within the next 5 to 10 years that number to jump to maybe 10 million bodies that we'll know about in the solar system so there's a lot of stuff out there by number these are by far the most numerous thing in the solar system and these are the objects that I study across various populations but what we're going to be talking about today and this doesn't show up all that well in the image there's a bunch of little red dots in here and they've been color coded as red dots because they're what we call near earth objects and near earth objects are cleverly named as such because they come close to the earth and so those are the ones that we're worried about when we talk about impact hazard to the earth we know that things have hit the earth in the past sometimes very large objects and we'd like to avoid that in the future if something comes along that looks like it's on an impacting trajectory and that's really what dart is all about and Jeff mentioned this in his presentation and I love this video here this is taken in the morning of February 15th 2013 over the city of or within the city of Chelyabinsk, Russia and this driver has a nice dashboard cam that gets this incredibly framed view of this thing coming in and this video is amazing I've watched this many times in the talks I've given over the years the thing that still amazes me is that this driver never slows down it keeps going you can see he just he's taking his morning drive sees this thing flash this thing was brighter than the sun this was early morning for those that can see it was about 9.30 in the morning this was about a 15 or 20 meter body that came in at 15 or 20 meter asteroid that came in over Chelyabinsk, Russia exploded in the atmosphere and delivered a lot of pieces to the ground the largest piece hit a lake and made a really cool crater some divers went down and picked up that thing and brought it up to the surface and it immediately broke after they put it down which is too bad but that piece is still intact there were thousands of other pieces that were just scattered across the snow in the Chelyabinsk region and so it was really easy to collect pieces of these and you can go on eBay now and buy one if you want they're not terribly expensive they're all over the place and they're known as the Chelyabinsk meteorites fortunately nobody died from this event but there were thousands or over a thousand injuries reported and most of those were from people realizing that there was a bright flash of light outside and running up to their windows outdoors or running up to the windows in their house to look outdoors and the shock wave from that blast then hit and shattered the windows so there were over a thousand people that suffered mostly glass injuries or in some cases broken doors and things like that hitting people so a lot of impact and glass shard injuries but fortunately nobody died but these are the kind of events that happened right this is sort of inevitable consequence of living in a solar system that has lots of stuff of it stuff in it and so we would like to do something about these things if we can particularly if we have enough advanced notice ahead of one of these impactors and so that's what Dart is about and to quantify this this is the most technical slide I have and I'm going to walk through it but I get this question typically I'm sitting on a plane and somebody asks what do you do I tell them I'm an astronomer the first thing I get asked is when are we going to get hit by a killer asteroid they don't know that this is what I actually work in and I'm like well let me get on my slide deck and I'll talk you through it I can go through this in explicit detail if you want and there goes four hours of a plane trip so this is frequency ranging from every hour at the top to once in Earth's history so this is how often things hit and this is size from one meter up to 100 kilometers all right so this is a log log plot of time versus size and the answer to how often we get hit is well it depends on what size and the answer looks like that so there you go there's how often we get hit and I'll give a few examples along this plot here we'll start down at the more dramatic end of things and there's no way to be more dramatic than a suffering dinosaur and so we we know there's a large impact feature off the Yucatan coast in Mexico known as the Chicksalub impact feature and we think that that was in part responsible for the demise of the dinosaurs that the ensuing climate change from such a large impact may have had significant climate ramifications that led to the demise of the dinosaurs fortunately for us and one of the reasons we're still here is these impacts of say 10, 20, 50 kilometer bodies are pretty infrequent in the case of Chicksalub we think something like that comes along every 100 million years or so so we're good for a little while the dinosaurs died 65 million years ago so we're good for a while we don't need to worry about that moving up the plot Jeff showed Beringer crater or Meteor crater this is about an hour outside 45 minutes outside of Flagstaff this is about a one kilometer impact feature that was created by something probably in the tens maybe 50 meter size range these are all sort of ballpark numbers here and we think something like this comes along every few centuries every millennium or so it's not terribly frequent but it's frequent enough and if something like this happened over a populated area in modern times that would be pretty bad the largest impact in modern times was Tunguska this was again Russia Russia is just a big country there's nothing about asteroids wanting to hit Russia but this was an impactor that came in about a 50 meter size body that actually blew up in the atmosphere and never made an impact crater to date no convincing meteorites or rocks have been found from this impact there's no impact crater but the explosion was so intense that it leveled hundreds of square miles of forest you can look up Tunguska and Wikipedia the first-hand accounts that are written down there about people that were in the area it's not a terribly populated area sort of Siberia northern Russia but the first-hand accounts are amazing of the people that were there talking about like their clothes feeling like they were on fire from the blast way the heat of the last wave coming and there's a really you know as I say the biggest event in modern history and you know this there's a lot of uncertainty about the size of that object maybe in the sort of 50 meter size range but again this is sort of in every few centuries every millennium type of event and then going down to the smaller end we've got Chelyabinsk about a 20 meter size body there's still debate about how how often we get hit by a Chelyabinsk-like thing it's probably every few decades maybe every century but it's you know that's starting to approach human time scales and so we worry about things on human time scales and so that's definitely something we'd like to consider and in sort of impact hazard mitigation and then lastly Megan mentioned at the top that you know one of the things I'm interested in is meteors and a project that that observes meteors just about every day we get hit by something that's like a meter in size so this would be like a really bright fireball meteor somewhere on the earth we're getting hit by one of those right now and so that's just sort of you know again the consequence of living in a you know cosmic shooting ground so this is the the sort of landscape that we're talking about and this talk is about Dart and Dart fits right here and we'll understand that as I go through the talk why it fits there and in particular the reason for focusing on this sort of size range is that it's that intermediate size range that it's not so infrequent that we don't really need to worry about it and it's not so small that it's not going to do any damage so Dart is focused on understanding these impacts in the sort of Shelly bins Tunguska Beringer crater size where if we found something coming in of that size we want to do something about it or at least give people ample warning time to you know get away from the windows duck and cover kind of kind of approach so that's where Dart fits into all of this so what is Dart I'm going to take half a step back from that and say that Dart is part of an international internationally organized effort referred to as AIDA the asteroid impact and deflection assessment experiment again another acronym AIDA has two parts to it there's the Dart part which is what I'm going to talk about tonight and then the European Space Agency ESA has a follow on mission called Hera and Hera will be going to the same asteroid that Dart will be visiting it launches in 2024 and then rendezvous with the asteroid in 2026 and Hera will sort of view the aftermath of Dart and so what does that aftermath look like one of the great things about being on NASA missions is you get really slick promo stuff and so that you know they do these really you know like teams of people putting these videos together and so this is Dart this is the whole Dart mission the spacecraft slams into an asteroid and then we look at what happens it's a rock hammer and space experiment all right and so for those you know if there's geologists in the in the audience this is you know a cosmic geology experiment here there's not much more to it than that and as I said the Dart mission is coming to ahead in just a couple of months so the spacecraft is not going to see much life after this impact it hits at about 13,000 miles an hour and so our job will transition from spacecraft operations to using telescopes here on the ground to study and characterize the the effects of this impact to understand what the spacecraft did to this asteroid that it's going to hit and that will be the best we have until Hera arrives in 2026 so the Dart experiment starts with the spacecraft it's on its way it's 70 something days away from impact and then it becomes the role of observatories like Lowell and others around the world to characterize the outcome of that impact experiment so as I said Dart is on its way it launched Thanksgiving Eve last year it was a really spectacular event it was on a SpaceX Falcon 9 out of Vandenberg if they ever have a chance to go out there for one of the launches it was fantastic my daughter was there with me and she enjoyed it thoroughly I would show videos but it's videos that include audio of her and my mom squealing and screaming going oh my gosh oh my gosh look at it because it's really spectacular it's hard not to get excited about these things and it's really incredible to see so launch was an incredible success there was almost used up almost none of their margin and fuel which means that they were able to add additional acceleration onto the spacecraft so it's going to hit a little bit higher velocity which is great and more energy involved higher impact speed which is cool so the experiment will be all that more dramatic when it actually hits this is the one slide overview of Dart I don't want to go over all of this in detail other than to say that we had this launch last year Dart's on its way and it's going to impact kind of a special asteroid system this is what we call a binary asteroid which is just two asteroids there's a primary the larger object which we know of as Diddymos and then the secondary the satellite that's orbiting around Diddymos is called Demorphos and so Diddymos is about a 780 meter size body Demorphos is about 160 meters in size so a bit bigger than a say a football stadium and the separation between them is about a kilometer and so Dart is actually going to hit Demorphos and so that's intentional we're not trying to hit the primary we're trying to hit the secondary one of the reasons we're doing that is because this is that interesting size range where these are the types of bodies that hit with enough frequency that we should know about how to deal with them if we find one in the future so this is sort of you know let's get let's get experience on a system that is relatively well understood so the mission objectives we're going to target this Diddymos system we're going to impact Demorphos and that impact is going to essentially change the angular momentum or change the orbit of Dimorphos around Diddymos and we then are going to try to measure that change in orbit from the earth with our telescopes so that's that's the whole mission and as you can see here on the slide and on September 26th the 2314 UTC is impact and so after that it then becomes the role of ground-based observers like myself to follow up and figure out what happened I'll just go through this real briefly because there's a cool movie after this slide so again the top level requirements we first have to impact Dimorphos there won't be much happening if we don't achieve this top level requirement after that we then measure the change in the orbital or we changed its orbital period and then we measure it with telescopes like the Lowell Discovery Telescope and all of this comes down to measuring a quantity known as beta and beta is what we it's it's a bit jargony but it's what's known as the momentum enhancement factor so let's just go to the next movie because that's cool um so what what this is is a laboratory experiment people do these kind of things this is a hyper-velocity impact experiment where you have a one meter granite sphere so a one meter sphere of granite that is being impacted at two kilometers per second by a four centimeter aluminum sphere all right and so that aluminum bullet or the aluminum sphere is coming from left to right and hitting and then the thing that jumps out literally off the sphere is all of this ejecta that's getting kicked off the backside and that is essentially what beta is so beta is if you imagine in space the projectile is coming in hitting this object it's going to impart its momentum onto the the large sphere but then all this ejecta is going to act as additional thrust coming off the back side of that sphere and it's that additional thrust that we get from the ejecta that gets kicked off the surface that we have no idea what it actually is going to look like in space on a real asteroid and that's the point of doing dark beta can be anywhere from one to 10 where one would be essentially no ejecta no momentum enhancement which would be sort of a weak level of orbit deflection and a value of 10 would be you get 10 times more momentum imparted onto the body than you you sent in with the projectile so we've got kind of a graphical depiction of that if beta is one your spacecraft comes in it hits you don't get any ejecta and you get a small change in the orbit of the body if beta is two if it's bigger you get a medium amount of ejecta a medium amount of orbit change and if you get a big value of beta like beta four then you get a big amount of ejecta and a large orbit change and so this is what we're trying to measure with dark we're trying to figure out how effective is this kinetic impactor technology in deflecting an object in its orbit how much deflection or how much orbit change can we get with a basic you know a high impact velocity experiment and this is the I should have said that the impact that we're we're throwing at dimorphos here is about a factor of four five four five six bigger than anything we can do in a laboratory so it's not like we can just hit granite spheres in the lab and scale up to big asteroids we just can't achieve those types of energies in the laboratory so that's why we need to do the experiment in the real world and so that's kind of the point of dark all right so that's great that's the experiment that's what we're going to try to do but we have to understand the system before we change it this is really sort of a before and after experiment let's look at the system beforehand smack it with a spacecraft and then look at the system afterwards and see what what the difference is and so that is where the telescopes have come in and the unique thing or one of the unique things about dimorphos is it's a dimorphos and dinimosis it's not just a binary asteroid but it's an eclipsing binary and so this is an artist's rendition we actually don't have resolved images or very good resolved images of dimorphos and dinimos so this is an artist's rendition of what an eclipsing binary asteroid would look like and what the brightness of that system would look like when observed with a telescope on the earth and so you can see we've got a little satellite here orbiting around the primary and as it passes in front of and behind the primary you get these dips and brightness and those dips and brightness are just because the light from either the primary is being blocked by the secondary or the secondary is being blocked by the primary and the depth and the shape of those dips tell us about the shape and the size ratio of the two astro the two components of the system but more importantly the timing between these dips allow us to use the that measurement as essentially a chronometer of what the orbit of the satellite is around the primary so the orbit of dimorphos around dinimos is equal to the time difference between the dips and so we use those dips as essentially a stopwatch we see a dip we start the clock we see the next dip we stop the clock and that tells us what the orbit period of dimorphos is and so if we change that we can still use that technique to measure the before and after and so we've been using the Lowell Discovery Telescope actually since 2015 to measure the pre-impact orbit period of dimorphos and so this is the LDT here is what one night of data looks like this is from January of 2021 this is essentially a gif of a whole bunch of images from that night where we're essentially just looking at a fixed star field and there are asteroids in this image and there's actually about 10 asteroids in this image and it's really hard to see all of those moving at the sort of frame rate that I'm showing it here but dimorphos or dinimos happens to be the brightest in this field does anybody spot it yet there's probably a few trained astronomers yep he's got it it's right there okay so for those that haven't spotted it it's moving along through the star field here and this sort of you know blinking of images is no different from what Jeff was talking about of how Plotentomba discovered Pluto you know a hundred years ago almost a hundred years ago it's the same exact concept and so we're taking these sequences of images and in each image we measure the brightness of dinimos and are looking for those dips in light that would tell us when a mutual event or one of these eclipse events happens when the primary passes in front of the secondary or the secondary passes in front of the primary now I'm not going to point out the other 10 asteroids I can't actually find them myself but they're in there so you can come up afterwards if you want to see them all right so after 20 years of observations and I've not been at the telescope for 20 years and I'm just getting out this is a sustained effort by myself my colleagues people around the world collecting data in a sustained effort to understand and characterize the system so that the the dart experiment can be successful and so data have been collected in various apparitions throughout the year we started at LDT in 2015 and essentially every opportunity since 2015 we've observed dinimos to measure that pre-impact state of the system and we now know that to ridiculous precision and so I'll just put both of these numbers up here we now know Didimos's spin period so how fast Didimos is spinning around to 40 millisecond precision 0.001 0.001 hours and we know dimorphosis orbit period which is the key for the mission we now know that to 65 millisecond precision which is just incredible that we actually can measure things to that that high of precision and we know dimorphosis position very well to within about 10 degrees at the time of impact which actually exceeds our mission level requirements by a factor of four so we've done a really good job thanks so it's having access to telescopes like LDT and others around the world doing the sort of slow and steady work of making sure every time we get a chance to observe that object and make sure we have good constraints on the orbit period so that dark can be a success and all things are looking good so far so that's great so we think we understand the system now now we actually have to start over we've done all this hard work to prepare for the impact well things are going to change now and so we have to start over and so I'm going to talk through the kind of timeline of the post-impact time period and the hours leading up to the impact and then what happens afterwards so on September 26th dart is no more it hits dimorphosis and the original orbit is going to be something else and we need to figure out what that is with our telescopes again using those mutual events or eclipse events to clock the orbit period of dimorphosis and so let's talk through that impact timeline because this is kind of cool this is you know what is going to be going on as we lead up to this impact and so I'll be stepping through the various key moments in this timeline where 30 days out the camera on board dart detects Diddymos for the first time so Diddymos is so far away even from the spacecraft on route to the asteroid the camera can't even see Diddymos yet it's too faint for the camera system and I should say that the spacecraft has one instrument on board it's a camera and that's it like it doesn't really make sense to put a sophisticated instrument suite like New Horizons had because well there's not going to be much left afterwards so the first time the camera actually sees Diddymos is 30 days out 10 days before impact we start getting continuous coverage through the deep space network the the the array of radio dishes around the earth that are used to communicate with all the spacecraft that are out there being operated by NASA and other space agencies and so 10 days out we essentially have continue continuous contact with the spacecraft eight hours out something called the pre-terminal phase begins and I wish I knew what that meant but I don't it sounds important but we'll be looking at the pre-terminal phase beginning eight hours before impact and it's really at four hours out that things get really exciting because then the spacecraft goes into a fully smart nav or auto nav mode meaning it's hands off it is software that's going to be controlling the spacecraft to first target the Diddymos system and then figure out okay the fainter blob over here on the right is dimorphos and I want to make sure I don't just hit the center of light but I want to hit the center of mass of that body so I get the maximum momentum imparted onto that satellite so it's that from a technological perspective is maybe one of the most challenging things on the mission and the engineers behind that have done an amazing job they're running tests now on binary stars that are of equivalent separation and brightness ratio of the asteroid and so they're going through sort of fake impacts as if the binary star was what they're aiming for and all those tests have been going well and things are looking good so it's looking good so far so four hours out AutoNav begins and then we hold our breath for the next four hours 60 minutes out we get a detection of the first detection of dimorphos so it doesn't even see dimorphos until an hour before impact you're not close enough until 60 minutes out to actually be able to see your target which is kind of crazy you know you have to wait till the last hour after a year long flight to actually see the target that you're going to hit three minutes out the final downlinked images to contain all of dinimos and I should mention that these are just artist mockups these are not the actual asteroids we don't know what the asteroids are going to look like but 60 minutes or three minutes out we get the final download of all of dinimos two minutes out final images that contain dinimos dinimos will pass out of the frame 26 seconds out we're now actually got a big dimorphos in the field of view and we're resolving it with something like 300 pixels so we've got you know sort of a nice image of our target for the first time really only 20 seconds before we hit it it's coming in at something like 13-14,000 miles per hour so this is a high velocity event that's happening here seven seconds out we're now really getting up close 20 centimeter per pixel resolution and then there's one last gasp image and we don't know exactly when this is going to be is it two seconds before impact four seconds it's something like that and we're going to get something like nine centimeter per pixel resolution this is actually a really important image this last one that's going to come in because it will give us some insight into what we hit what the terrain is that we hit because the impact the effectiveness of the impact will be dictated by whether you hit something like a sandy pond of fine-grain material or a large blocky boulder there'll be very different outcome in the impact depending on which of those you hit so we'll be very interested in seeing this last image come in right before we lose contact with the spacecraft and so after this we can go through these sort of mockups of what the timeline looks like after that it kind of becomes you know anybody's guess and so I figured I'd tie things here to a sort of local reference we're here at Bickerson so let's talk about the dart impact of scale and how big the impact will be on the surface so I believe that Bickerson's biggest fermentation tank is a 40 barrel tank I don't know if anybody can confirm or deny that but that's what I saw online so let's go with that a 40 barrel tank something like 15-20 feet high depending on model and all that so let's pretend that dimorphos is the size of one of these large 40 barrel fermentation tanks that would mean then dart with solar panels with the solar panels is the size of a pint can okay the solar panels are actually most of the size of the body the dart spacecraft would be sort of a small cube at the center of this can and so the impact the crater that we expose on the surface would be about the size of a typical half barrel keg so there's your dart experiment that we that's about the extent of our understanding at this point so this is not quite fly on a windshield type of impact but we're not like we're going to catastrophically disrupt our fermentation tank we're just going to put a keg-sized crater on the surface so all right and then you know as I said this is very much planetary defense is a global topic right the things we talk about in the way we deal with some of these problems get very interesting very quickly when we consider some of the political ramifications of how to move an object before impact and how do you deal with that and there are working groups that report all the way up to the UN secretary general before exactly that reason because it is a very complicated political issue and disaster potential disaster management issue but because it's such a global effort there are a lot of people interested in this dark experiment and one of the great things about being involved with this mission is there are telescopes around the world that are already signed up and part of this investigation team and will be contributing observations and data in the period following and leading up to the impact so this really is a global effort yes we've been involved I think that star there is lol we've been involved at lol and helped out over the years but there are many other observatories as well and this is just a list of observatories that I know about that are going to be contributing data there probably are many others and many observers around the world that will be getting their own data so we're looking forward to this opportunity this is you know sort of a pretty unique opportunity to do an experiment like this and be able to use our telescopes for sort of the good of humanity in some sense and with that I'll go ahead and finish I like to show this slide on asteroid related talks you know I think dart is an important step in the right direction for us as a species in some sense you know we are we are taking this first step in sort of planetary defense and it's something we can certainly you know invokes images of Bruce Willis and nuclear you know nuclear bombs and things like that but it's nice to see an agency like NASA and ESA taking this seriously doing something productive and you know providing a little bit more information that will help us you know protect our fragile place in the cosmos here so I'm excited to be a part of the dart mission and I hope you all keep track of what goes on with the dart in the coming weeks and months so with that I'll finish and if people want I'm happy to take any questions thank you we'll start all the way in the back yep I don't know that off the top of my head it's really fast it's really fast the distance to it was one on on one of the early slides the distance to Diddy most at the time of impact is well under an AU it's like a tenth of an AU or even less so it's going to be really fast we're probably talking a minute at most yeah so we'll get that it's not like more just like New Horizons that Jeff talked about where it was just this you know you had to wait and be patient for weeks and months to get the data we'll have the data right away I mean that's a really nice thing and one thing I didn't mention is that there is a an Italian CubeSat that's riding along with Dart right now as an Italian made CubeSat so think you're like a little cereal box with a camera inside it will get released by Dart a few weeks before impact and it will then fly by and catch a few images of the impact cone and impact ejecta and CubeSats are always limited by the amount of data that they can transmit but the fact that we can actually have a CubeSat operational without a mothership just tells you how easy the downlink of data will be for this mission it's it's something that's almost a you know it's a low risk issue for a mission like this on the yes there yeah so the question yeah the question is are you hitting the head on do you hit it from behind do you slap it so there's actually a concerted decision there and you may have seen that the orbit period of dimorphos is 11.92 hours if we increased that and got really unlucky it could get to 12 hours and for people that like to observe things in the night sky a 12 hour alias would be the worst possible thing to deal with because every night you'd begin your telescope to look at the object and you see the exact same thing because every 24 hours you're you're you're opening up your telescope to to observe so it was a concerted decision made to decrease the orbit period so we don't get anywhere near 12 hours but instead go from 11.92 to something less and so that dictated how the actual impact would happen we're going to hit it head on and the intent is to hit it as close to the center of mass as possible and they have an error ellipse of something like 10 or 20 meters which is kind of amazing that you can hit you know that's that's a bull's eye from the distances and speeds that we're talking about so yeah we'll go up front here so the question is when dart enters autonomous mode does it have a lot of fuel on board to to help target there is a fair bit of fuel on board but at that point by the time it goes into autonav like you've got to be pretty close right there's there's not there's moving so fast and you've only got an hour to really make any major corrections that you're not really fuel limited that's the nice thing is there's plenty of fuel on board to make corrections that are needed within the next hour so there'll be a lot of fuel that gets burned up in the impact too I hope not yeah that's in back there near the back heater sure yeah yeah so it's a great question so how do you generalize anything when every asteroid and every body that we visit in the cosmos is a unique entity and it's a totally valid question and I think the simplest answer to that is we have to start somewhere the second order question answer to that is that at the speeds and impact we're talking about it doesn't actually matter too much what the detailed composition like mineral composition is and it's more about the structural properties sand versus boulders and the third level to this is that we think that of order half or so of asteroids in near-earth space have the same composition as dinimos and dimorphos so if we were to pick a representative example to learn something about these systems in this way this is a great one to start with but if NASA wants to fund 10 more dark missions after this we'd be happy to to accommodate and do the experiment more than once yeah here in front the question is what this what is the spacecraft made out of and I just I don't know I honestly don't know there's going to be some hydrazine in there there's going to be some rocket fuel still in there there's going to be probably aluminum and I don't know we're not too worried about yeah the composition of the spacecraft doesn't matter too much it's more just mass and velocity and you know we were limited by how much mass we could launch that was the main constraint we'll take one more question there's one yes the only person with your hand up yeah so the question was about deep impact and whether anything could be learned about beta and impact hazard and impact deflection from from those results for those that don't know deep impact was a mission NASA mission that fired an impacter into a comet and the objective there was to expose sort of pristine material on the subsurface of that comet for study in both in situ and ground based methods the objective there was not so much orbit deflection and the impact there was nowhere near big enough to have any impact or influence on the orbit or trajectory of that comet the scale did not work out the comet was much larger in addition the the beta that you would get from a comet is going to be dramatically different from that of an asteroid and that doesn't mean it's you know we learned valid information about the impact environment of a comet but the thing that's primarily different is so all the volatiles that are present in a comet things like ices and and water ice various primitive ices as those sublimate and were heated in the impact those are going to enhance the thrust coming off of the surface in addition to material that gets kicked off and so you might expect an enhanced beta for comets relative to asteroids and so we have that data point for deep impact and there have been some estimates about beta for that and we'll get a data point for an asteroid now and so we at least have one of each yes yes so there's an online question does the mass of the impact or matter more than the density does the mass of the impact or matter more than the density wow I don't know the answer to that one that's a tricky one that's a really good question yeah I don't know honestly don't know yeah so anyways I'll hang around if any if I didn't get to anybody's question I'm happy to hang out up here if anybody wants to come up and chat but thank you all for coming out again tonight I appreciate it okay I know you just finished clapping but can I get one more round of applause for Dr. Jeff Paul and Dr. Nikolak and I just want to say thank you to Lowell Observatory for helping us put on this fabulous event tonight Astro on top is going to be on August 24th mark your calendars now this is going to be good and I just want to remind everyone that if you want trivia come see us in the front here come see Sam the trivia master the eight aiders get to pick first and then the seveners and with that everybody have a good night and get home safe