How I Killed Pluto and Why It Had it Coming

it’s a great pleasure for me to introduce our next speaker dr. Michael Brown of the story and he’s going to tell you is one of the most exciting stories in modern planetary astronomy dr. Brown is the discoverer of many of the worlds beyond Pluto beyond Neptune indeed and it is his discoveries that have caused a lot of the trouble about Pluto that you’ve heard so much about in the news media dr. Brown is professor of planetary science at the California Institute of Technology in Southern California because of his troublemaking work he was named by time magazine the year of his most important discovery one of the hundred most influential people in the world and so we’re delighted that he’s brought that influence to pair for good rather than evil he has continued to search the skies for other interesting worlds to make us think about the solar system so here to tell you about how i killed kudo and why it had it coming also the title of his forthcoming book i should say it’s a pleasure and privilege to present like the Michael Brown who are survived the weekend and made it to the end here I only barely be up to the end here I just just flew in from Argentina yesterday so I’m only barely awake if I fall over any point in the talk and it’s not because I trip on this so I just waking up I’ll be right back so let’s say I’m feeling like I tend to wander during my talks and so I’m feeling constrained miles here but I want to try to keep myself in this little triangle just like this so indeed i’m gonna talk today about about Pluto and and how pluto was killed and i know by now most of you are over feeling unhappy bums anybody i’m still actually still likes Pluto by the end of the talk you’re still mad at me you can find me on Mykelti I can drink there so the story of a really wide Pluto had it coming started with the discovery of Pluto itself in fact that started even before the discovery include of itself when astronomers in the the early part of the 1900s started looking for this mythical planet x i’m sure most of you know the story that this planet x was out there and was thought to be out there because it was influencing the orbit of Neptune cult tugging along with neptune and so astronomers could use all those new fancy physics that they had figured out to learn where Planet X was and so did calculations to try to figure out exactly was went to the sky went to the telescope took a picture looking for Planet X and sure enough there it is do you guys see it I minute so if you can’t sell get something I feel bad for you guys right around here so I’m going to stand right about here the entire time so if I mean your way the entire time please feel free to get up and move somewhere where I’m not quite so irritated so so yeah so it’s actually not really right there this just looks like the sky and the reason that his drivers thought they would find Planet X by simply looking at a picture in space because they thought it was big the thought was the size of Neptune or larger if it was tugging captain web and if Neptune were on this picture it’d be sort of this big would be this huge thing in there and you would know it you would know it just like those initial discovers of Neptune they didn’t have to do anything fancy to find it once they knew where to look they looked at the sky and sure enough there there Neptune was and on this one it wasn’t the case of course all of you know the story now that by about 1930 clyde tombaugh had been hired to come work at Lowell Observatory down in Flagstaff to find this mythical planet x and he figured out that he was he was smart enough to know they didn’t know how to find it how to just know what it was when he looked and he realized the only way to find Planet X was going to be to take a picture of a sky and come back a day later and take another picture this guy and watch it move you guys saw it already kind of Trigon here’s the night one night to anybody sick yeah miners there we go together 91 92 I don’t know why but for some reason the the fourth

time everybody was that is your appearance without the arrows these these are the actual discovery images in 1930 of Pluto you know I look three time to give you four does also so there it is that’s the even calling talk about though we’re surprised with this you know it looks really small it’s so small that I or get torrent is always it is this someone of the tailor their right that’s it right okay so it says well it looks just like a star it doesn’t look like anything big and phantom like and I in many ways i wish i were astronomer back in nineteen thirty because they got to be a little more crazy than we are today we’re pretty crazy stuff but they got to feel less constrained by physics because physics was listen les old at that time and so they came up with a lot of theories on why even though they knew fluto was big because it was tugging neptune one why it looks so small how could it possibly be so mess and even though they look so small and there were some theory some semi Blackie ideas but my favorite mechanism that i read which was that it actually has a core of solid green so this is nineteen thirty so they didn’t realize that that’s actually really bad idea solid you’re eating a liquid oxygen ocean surrounding that core of solid uranium so it looks small because you’re only seeing that horror of uranium which is actually can be pretty small because it’s pretty dense but actually the liquid oxygen ocean actually functions like a lens to it makes look even smaller so what I let you know what to do is to go home tonight thinking that maybe Pluto is made out of uranium with the liquid oxygen ocean it’s not actually true in fact it’s not very massive at all and these days we actually know pretty good reason to there’s a really good reason why my Pluto looks so small anybody and it took a long time to figure that out and this is one of the reasons why worse it was a planet back because was Madison we knew it was massive even though it wasn’t it’s so strong that i’m going to show you this picture a lot of different times i’m going to put this is showing a real picture of the solar system it is impossible you can’t both show how far apart planets are and how big they are you can do one or the other so as a compromise most pictures you ever see the solar system do neither and they make these horrible pictures like my daughter has a lunch box of the planets and in a mercury and Pluto or the same size and Jupiter’s about that much bigger in the earth is a little bit between the two and they’re all crammed in together and there’s aliens flying around and it’s a these things give you an incredibly bad impression its solar system so bad that most people really don’t have a very good feel for how big things really are so I like this one doesn’t show you the sizes of things so I’ve had to cram them all onto one page but it does okay okay so we have working at the top Venus Earth Mars I actually have the asteroid belt here and these are all everything is real sizes you can see series there’s the biggest one there and these ones that i have shown only things on the slide in the solar system that are big enough to appear as one have a point fixing that’s the criterion for inclusion and so there are edict n asteroids that are a powerful pixel size Jupiter really big Saturday thought the Rings till the Uranus Neptune Pluto Pluto are there it’s really really really kind of small so small that if you’re sitting in the bag but you don’t notice it’s that little insignificant thing over here in the corner it’s it’s really tiny and if you look at that compared to the other two the planets in the solar system you start to wonder what the heck is going on it really doesn’t hit the pattern nice going out of the solar system it also doesn’t fit the pattern of the orbits of the solar system the planets are all of these very beautiful circular orbits in a single disc going around the Sun and Pluto this was known very early on Pluto is in a very crazy orbit it kisses the orbit of Neptune in here goes out further he’d left to go ahead if I had been able to turn this screen on its edge you would see the Pluto was tilted by about 20 degrees it makes no sense whatsoever as part of the system planets but in 1930 the really warning on the other option was to call it there was nothing else out there there’s this they’re over you know there’s an asteroid belt that’s interior but then there’s Jupiter Saturn Uranus and Neptune empty space and then this little thing it didn’t make any sense to call it anything else and so planet was the most natural thing that you could possibly call alright so we’re going to fast forward before we fast forward i’m going to imagine it to the clyde tombaugh even quite amo if you read his writings about so he was a little bit unsure about this day in fact he was not convinced that Pluto even when he first discovered it he wasn’t convinced it was the thing that was tugging up to the reason why he wasn’t

convinces because you look at it was so small i thought this it’s harder to imagine this thing thing so so dense to talk on epic so he spent the next 10-15 years surveying the entire or at least as much of the skies he can see it this is this is how much he did this is a map of the sky with the years old the North Star will be up here Southern Cross and being out here the ecliptic along with all the planets goes in three rd servings yellow region through there a tremendous area Scott they serve a night after night after night by taking these photographic plates on his telescope and developing looking to buy I just an amazing job he felt many things in the survey but he didn’t find anything else any any other planets out there and he was left concluded that that was it Pluto really is this lonely oddball out at the edge of the solar system and as far as anybody knew it really was that was it was the only thing out there and a strange thing out there all that changed in 1992 when the very first other object out beyond Neptune was discovered and by today there are something like 1,200 known objects in this region beyond that too here’s plants can Jupiter Saturn or is that too each one of these little diamonds is an object in what is now called the Kuiper belt in this region outside of metric in fact some of them you see are actually inside of them children even all the way over here these are objects that used to be out in the Kuiper belt and have gotten a little bit too close to the Neptune at one point that flung inward just like when we set a spacecraft out and we gravitationally system out work day but had a nice little gravitational assist in word they didn’t fly anywhere to mention become comments it’s one of the sources of the comments that we see that comes by self so these these 1,200 objects that are known today we’re all found the same way the clyde tombaugh take effect to the sky come back and ours who later take another christian sky find something that moves and you know you’re on to something up and pluto in fact is this little blue one right here if you look at actually Pluto does a very nice job of defining both the inner and the outer part of the main region of the Kuiper belt as soon as you see this about Pluto and if enough oh but I can’t show you the orbits of all these little diamonds because if you look into confusing but if you looked at the orbits all those diamond shape things they would all look like Pluto they’re not all exactly the same elliptical or tilted exactly the same way but it’s just a big mess and you can see that Pluto very naturally fits amongst this mess as opposed to fitting in the nice orderliness of the planets even back in the days when we were crazy enough for something call include a planet it was very clear that you had to say the Pluto was both a planet and part of this Kuiper belt would be crazy to say it’s not part of this kind of crazy so it’s plenty to but there is a big one so let’s put all the rest of pegram going on here and talk about this these early days in the Kuiper belt that is sort of two thousand two ish you can see there’s kudo is still there and then there’s all the other Kuiper belt objects have been found and the biggest ones are the ones i can put on the screen they are there’s there’s one that’s about a third the size and pluto that was known my mouth this is this about eight years ago there’s one that’s about a quarter of the size and the argument that was made then this is bob 2002 the arguments made that instead then shirt Pluto is part of this paper house but it’s bigger than everything else in the Kuiper pebble still has a special place amongst the Kuiper belt so so we ought to do anything with it we can we can leave it where it is this is this is about where I came in Missouri and I started I hadn’t looked at all these objects in the Kuiper belt had thought about the kind of belton realized that then one of the main reasons that we didn’t know if there were any other larger objects like Pluto out the Kuiper belt was not because they not because astronomers had serving the whole sky and realized it was nothing else out there was because of strana murs had done something that initially seems a little strange clyde tombaugh looked at this much scott and up to two thousand two astronomers had looked at about this much guy this seems a little funny right but i gave this talk to to second grade class once in this second grader was just happy he said well how come astronomers are so stupid and that’s the pale that’s next hear the answer but if in fact astronomers are stupid it’s very it’s very obvious when you when you realize what’s going on is that this is this was just at the time when when ccd cameras were getting to be big in astronomy and it’s the same time than ccd cameras and digital cameras we’re getting to be big and everything at this point i am sure that there is nobody in this room that does not have a digital cameras there anybody would claim and not have digital camera in this entire room Wow nice so this is interesti– this is actually the first time the penny I’ve ever been able to have talking and no one’s like me sometimes in the last couple years people say I don’t have one and then I asked my family so give a cell phone

that has them yes or no no let’s see no cell phone no camera we’ll talk later so here’s the out then the laptop get this laptop ever camera as caroline give a webcam we may win I’ll have about thirty must-have everybody hasn’t that people don’t even know they have camera time John does have a camera well here’s why you’re Becky because every time you guys have gotten caught on your camera what happened 12 Jake if you’re like me so I might buy a new camera about once a year only because I lose my camera once a year and when you do you spend like 300 bucks on your new camera and every time you get a new camera it has i started i remember the first one that had like half of a megapixel and i thought that was the coolest in the world and now there i had actually lost if i spent 300 bucks on camera how many megapixels when i get these days and what would he do with them all does anybody know okay so but astronomers at this point still had those tiny little camera is the typical astronomical camera covered about as much sky as you could as you can see if you if you take your fingers squish them together as sure as you can and hold about an arm’s like food that’s about how much sky these initial astronomical cameras cover now imagine trying to cover the whole sky by doing this it would take you very long hi Tom bow in contrast when he wanted to cover big chunks of the sky he was using the still primitive but but but fabulous technology of photographic plates photographic plate is literally a piece of glass with photographic emulsion painted on the back of it and it can come pretty big piece of glass and slide out on the back of your telescope and he would cover about this much Scott once so that was pretty good but in 2002 we finally realized that the technology was getting better enough of you have on cameras not all of you enough the technology medical crisis were going down we could finally put together this thing at the time was the biggest astronomical ccd camera in the world and in 2002 those are very impressive though it’s you know and by next year you’re going to have this in your pocket it was a 182 megapixels all sort of held together with bubble gum and baling wire and and and you have to kick it every once a while to make it work but it worked and so we actually we got that camera we put it down at my favorite little telescope down at Palomar Observatory is not I’m sure some of you have been out and see the 200 telescope battle cowboy this is the one you don’t get to see all the tourists which is to that is it’s so much better this is the 48-inch telescope it’s the one that that back in the 1950s and then again in the 80s and 90s did the big Palomar sky surveys the big photographic Palomar sky serpents we ripped out all those photographic handling systems that are slapped on this this crummy little ccd it was the biggest in the world and did one other thing that really made my life much better put this thing this thing is a microwave link that goes down to a site in the middle of the forest and then reflects over to San Diego supercomputer center where then my internet up to my office and Pasadena the fabulous thing about this for me is that from from 2002 in 2009 when we were running this survey night after night after night after night almost every single night I think I went down to telescope three times and I never stayed awake because it was all done robotically and I did things that normal people too during that time like get married and have kids and stuff like that so I like to think this as the only reason that this project was really possible so what do we do about all the astronomers up to 2,000 T we can come from this much guy and since from two thousand to two thousand nine actually finally finish this part we covered this much guy which yeah try this again they have covered this week on with this you guys are not impressed I it does oh yeah we found sorry yeah well so the Milky Way goes here as you point out here to milk when we avoided it because the first time we didn’t avoid it we realize is a complete waste of time there’s so many stars and and everything else within the Milky Way that you’re looking for these little Kuiper belt objects there it just is jump we also missed this little section of the sky which is the far northern sky in January and it was for five or six years in a row we just got no clear nights in January so so never there’s probably like the biggest type of object in the world that’s gonna really irritate me when somebody finds a putz up but most of the ones week by the time we got this far off of the ecliptic you weren’t finding that many more so we were willing to finally give up so let me let me show you I’m gonna tell you a

little bit about exactly what we do show you some of the stuff that we found then talk about something every so so what really happens well the telescope gets a list of places in skiatook oh bookings like and then it takes three pictures of this guy takes three pictures about an hour and a half apart and in the morning all those pictures are transmitted back to capacity and a single image so i told you before that these routers before it could cover about this much Scott and Clyde time I’ll cover about this much guy we cover about this much guy all it was it’s not bad it’s still it’s still not as good as if you were applied talking about but you can imagine if you’ve been doing this for seven years like we have that you could you can actually cover a significant chunk of the sky and see what you see so we get these images back in pasadena the computer does most of the processing again this is i am continually what every time I think about this guy are continuing of clyde tombaugh having founded oh my he stayed up all night taking pictures on with these photographic plates that he then had developed that he then had to look at in a day then he didn’t had to go observe the next night again it’s amazing that he actually lived for more than about five years trying to do this much less action fountain things we do this all mostly by computer computer takes the images sends them down does the analysis looking for little things that move and all that I do at the end other than writing all the software that makes it happen is is look at those last little images that the picture the computers picked out and decide the real number the computer I have carefully tuned to be not very good because I much rather have the computer show me a lot of junk and get to pick it out myself then they have the computer sighs oh no that’s that’s not real I’m going to throw it out and then find it much later actually that happened but we’ll talk about that so what does something look like well when the computer gives me a little snap a little postage stamp in the morning of an area where things have found something and look something like this here is three images in a row and your stars that are all in the same place over the course of the three members in rank the middle you can see this little thing moving one two three you can immediately tell a lot of things about an object that you find it by looking at just two things we’re looking at how fast it moves and how bright it is how fast it moves is is a direct function of how far away those things are really close to us very quickly it’s all just its parallax just like you’re you’re looking out the window is the car going by so the mailboxes are moved by really quickly the mountains are barely moving same thing here the asteroids the meteorites the airplanes that fly over have all the time in San Diego are moving very quickly the things that are near Jupiter are moving still pretty fast and finally the things that are out the Kuiper belt by removing very slow and this is one of those it’s out of the Kuiper belt this is one of these it’s out the Kuiper belt is moving at a typical Kuiper belt space so I can tell you just looking at that picture right there that it’s that it’s sort of the middle of that region between the orbit of the inner and outer edge of Pluto sort of thing I can also tell based on how bright it is about how big I can’t tell exactly how big it is and we’ll talk about that later Joe I can tell about writing is this one’s pretty faint compared to most the things we see this is this one’s probably i’m going to guess about twenty first magnitude and that something is 21st 92 @ about the distance of pluto in a little further away it’s not a particularly big object it’s probably this was probably two three hundred kilometers ten fifteen percent of the of the size of Pluto so it’s you know it’s probably the top hundred of the Kuiper belt objects out but it’s a typical one that we found of the hundreds of these things just going to flip sure review of these for you just to give you an appeal from what it’s like this one a little brighter so about the same species to go with this be fun we made about the same speed which means in about the same distance and it’s bright brighter weeks it’s bigger this one is actually turns out to be about a third the size of Pluto here’s another one this one is going a little bit more slowly and I don’t know if you can tell people or so it was a little assistance if it was a little bit more slowly and it’s about as bright as the last one that’s kind of interesting because a little bit more slowly means that it is further away but it’s as bright so if it’s further away and as bright it must be a good bit bigger because all of this is just reflected sunlight from the Sun so I’m going to be bigger to be a little bit brighter so this one is this one is getting to be almost half the size of Pluto this is a pretty big substantial object this is this is this is maybe in the tub when they’re yes this is maybe in the top 10 of the Kuiper belt objects that we know out there what’s the testament the fast early when I was about to say if you look very carefully here’s another one one one two three any guesses it’s fast right that’s so as I said the closer you are the faster you move that’s about the typical speed of

an asteroid out there it’s very convenient for us because they very easily sort themselves out so we see probably tens tens of thousands of asteroids in these data and if we had to track down every single one of those asteroids and asked what it was we would be spending a lot of time but we just ignore all those ones out there there and only look at the interesting stuff I’ll feel really bad I admit when one of the ones in ignore ends up hitting us but okay so let me get let me show you one more and this one more I will tell you this is one more than I found on the morning of January fifth 2005 and as soon as I flip that on to my screen I did two things three things first thing I did is wouldn’t double gypped because every time you find something exciting in anywhere in science chances are you did something and so and you know you do it all the time I figured this can’t be real I’m gonna go check it out again and the second thing i did itself none really this is stupid i couldn’t build this and I the third thing I did is almost fell out of my chair and I almost fell out of my chair why slow so it’s really really far away not one is so it’s so far away that it’s beyond that outer edge of the Kuiper belt by about a factor of two and it’s the brightest thing we’ve ever seen so if it was the brightest thing we’d ever seen it be really exciting if it was the furthest thing we’d ever seen it be really exciting if it’s the brightest and the purpose of it that we never seen it is the technical term is very very very very exciting I think that if you cue the exciting’s or something it’s it’s a this thing was it was clear from the first moment this thing was the biggest thing we’ve ever found the most distant thing we’d ever sound and it took me about 15 seconds to get out my pencil and calculate how big it should be if we’re going to see it this variety missed our way and it was very obvious to me that this thing was at least as big as Pluto and likely much much bigger than Pluto does the point though where I have to admit that we went all these times when I’ve been telling you about how big things are I’ve been I’ve been cheating a little bit the reason I’ve been cheating a little bit is because we don’t know instantly how big things are going to see him out there there he says is because again as I said they’re reflected sunlight and all you see is how much sunlight is being reflected from them you don’t really trinsic li see how big their and you can imagine that that something that is huge but covered in dirt will reflect a lot of life back to you and something that’s kind of small and covered in snow will also reflect a lot of light back to you and those two things like exactly the same thing what I knew though is even if it was small and covered in snow it was still bigger than Pluto but I didn’t know is what it was actually heaven how big really was and I remember say the email to the two guys or work with on this project chatra he go out of the Gemini Observatory and david rabinowitz at Yale and I said email telling them that we had just found this thing and giving them the table with how big it would be if it had these different things on the surface and the the one at the bottom was if it was covered in dirt basically that it was the size of mercury which was going to be very exciting we didn’t know and so we were we were interested to go see how big this thing before I can see how big the thing was though we had to figure out where what’s what kind of morbid had what i was doing around the Sun and usually for these things when you discovered them it takes a couple of years to figure out what kind of bourbon they have you can imagine how irritating I would find that if I had to wait a couple of years to figure out how how how what kind of work and had one son the nice thing is as an astronomer you can do one other thing which is equal backwards in time and the way you go backwards in time in this particular way is you go back to old data than people take people took and save and a lot of people take pictures of the sky and and and there’s a lot of you just buying online like the Palomar sky surveys other subs you can find in old archives a lot of people take pictures of the sky and you take your very short amount of data that you have right there and you predict where it should have been a year ago in the in the past and you go look at pictures from a year ago and sure enough in pictures from a year ago there’s a star right where you think it should be and if you go look at pictures of two or three or four years ago that star wasn’t there doesn’t tell you for sure that it was really the start that’s really your object you know it could be some gamma ray burst or something horrible like that I’m going off in the sky but it but is but it was interesting that it could be around then you take that one and you go back another year and saying well if that was really real this one should be here and sure enough there’s something there and if there’s one here to be here and we eventually found this all the way back the very earliest image we found of this object ones from 1954 and it was from 1954 from the Palomar sky survey taken by the same telescope which i think is just kind of a shoot story so what kind of work but doesn’t have whatever we really really

wanted it to have a big circular orbit like like you know a real planet should so admit we were a little bit disappointed I’ve already said all this stuff as we were a little disappointed to see that the orbit was actually a very typical looking Kuiper belt morbid it was there’s Pluto again on it’s on it’s very crazy elongated orbit and this one is goes very far away from from the planets but it comes back in a lot of the other options in khyber model but most i would spend most of their time in that region around Pluto a lot of them and sort of flung out and come back in again to this one did not look like it had sort of a planetary orbit it looked very much like part of a peg repelled and what’s more is if you if you turn this one on the side you can see that here’s Pluto tilted by is crazy 20 degrees this thing is tilted by 45 degrees to the planets in the solution we still actually don’t understand that one usually when something funny is going on in the outer part of the solar system we blame a Neptune so I blame Neptune I don’t know what Neptune did we’re still trying to figure out what what happened in through there okay so we got the orbit says the gothy orbit we were starting to be a little suspiciously this thing might not be as big as mercury and some plants relative but we need to find a way to really get the size of the object astronomers have been now for four years have come up with these very clever ways of figuring out the size of objects when you can’t actually see them and see how big they are and you measure the amount of heat coming did you do you do all these other calculations and you come up with the size what we came up with what we thought we were very clever to come with this new idea we thought it would take a picture of it and see how big yeah so so the only reason we could possibly do this is if it was pretty big everything else in the outer solar system you can’t do this with and even this one you couldn’t do with except for one telescope with it works particularly well the Hubble Space Telescope is the only one we knew we think it just that it might just barely be able to resolve this thing so we were pretty excited about this one when the data came down it came down on the ground like in the middle of the night and I remember driving into my office and Pasadena to download it onto my time to my computer quickly displayed it on the screen and looked something like this and I said oh did we look at the wrong thing and so that’s not very excite in case you guys were wondering if this was exciting right now this was not very excited this is likely the most the best image you’ll never see this thing in your lives we won’t really have any better ways of doing it and it’s not very exciting not only is it not very exciting it’s even less exciting that it looks because most of what you’re seeing is even due to distortions of the Hubble Space Telescope which as good as it is still has and some inherent limitation okay there we go the actual object itself is only actually about that big and the only way we can tell it was by carefully comparing back and forth between stars and blah blah blah that at red circle is 2400 kilometers across or in the only units anybody cares about 5% bigger than to go with it I’m certain you about okay so so let’s learn on the phone plot in the meantime we found a bunch of other things there is there still play no one there there’s a lot of bigger ones in there too letting some kind of strange shape ones we found so we had been filling in this plot a lot by finding all these these bigger objects I was we’d found something that was three-quarters the size of Pluto we found some that were half and two thirds really had filled in a lot of this pot and now as one of this new one is ready looks like this wait here’s here was the solar system before here is the solar system before so I have very bad news for those who came all the way here to hear about this and for me who spends about the left is this doesn’t matter at all this makes zero difference to the solar system whether this object was there we’re not there makes no difference once a weapon it is it is in the grand scheme of things a fairly insignificant chunk of real estate in our sky and I think you can you can see that very well just by seeing what it’s like when you get really anybody so so this means nothing this changes nothing yet this discovery changes nothing in Australia the problem is it changes everything and I’m sure some of you are at the panel discussion yesterday night I said this before this it changes one

very important thing which is for a long time this debate had been about is Pluto a planet or not astronomers tend to be very conservative nobody nobody in astronomy wanted to get rid of Pluto well except me because they know it just be hassle and they would have to deal with you know I rate people sitting next to them on airplanes and things like that so nobody wanted to get ready for the most now but when you suddenly find something that’s bigger than Pluto you have to actually ask the answer the one question which is with that thing who cares a Pluto is per minute what’s that and you have to answer that question you were suddenly forced to answer that question and of course everybody knows the story of how that question was answered the August astronomers of the IU bickered into thought and and made for a very general hilarious time for those of us who are watching overseas and reading the newspapers and eventually came down on the side of Pluto’s not a planet there are eight planets and then there’s a there’s a class of dwarf lands and it was course big and huge and controversial and a lot of people even scientists at the time we’re not not very happy but I think most the scientists are pretty happy about to these days and most people have decided that they don’t really care that much anymore in fact if you if you run into a stronger anywhere and you ask them about about Pluto a planet the first thing they’ll always say is none of this matters this is not matter it’s just it’s just a question of semantics and it doesn’t matter what we call Pluto and then don’t spend the next three hours telling you I think their definition is right and so I hope you guys have three hours because this is this is where I not tell you what I right everybody else’s life but I’ll do it in less than three hours ago so here’s what I would say if you ran into me on an airplane and you said you know so what’s up with loot oh I would say I wouldn’t say it doesn’t matter i would say it actually matters critically what we call Pluto other things in the solar system it doesn’t matter in a scientific sense because scientifically it’s all just a question of classification scientists always classify things they they always approach any new set of phenomenon as something to first classify and classification as a as the first step towards understanding and so a set of a you know birds or rocks or planets or stars or anything you can classify in so many different ways you can classify birds that live in the water birds they’re red birds that have big orange beaks you can classify any of these things and they’re all perfectly valid classifications some of them are more useful than others depending on what you’re studying but they’re all just ways in classifying these so there are astronomers who have really wanted to class on planets as everything that’s round is a planet and everything that’s not round is not a planet as opposed to the big eight things here are planets and everything else it happens I I believe that simply by showing you this picture you almost get the entire argument that I don’t want i really don’t even have to make my or simply that it is very difficult as a rational being to look at this picture of the sizes of the objects in the solar system and to say okay I’m going to make a category and I’m going to put these things in one category Plus that that series that goes into that category and these one two three four these going to that kind of in the rest of neuronal different category it really is it very difficult to think about it as a very as the first classification scheme you would do for these objects it’s a perfectly good one round things kind of matter they might be geologically interesting and if you’re a geologist you might even care about that sort of thing but as as the single most profound description of the solar system I think what you need to say is that the solar system consists of Sun somewhere off the screen for terrestrial planets that are going to group to you for giant planets groups here a population in the middle here and a population on the outer road and if that’s your view of the soul in the eight planets are separate from those two populations you have the simplest and most profound view of what the solar system is this is the solar system that we as scientists trying to understand we try to understand why there were two retro planets in interior why they’re giant planets on the outside why are these places where you might have thought there should be planets in their art they’re these populations instead if your view is simply that you know Pluto’s planet and everything else sort of round as a planet then all you have done is said I know my things around things around because gravity and that’s that’s just the end of my stories all the time like this one much better as the much more profound of view of the solar system it’s still just classification so there’s no reason to say this classification is better than this one but problem is that there’s we talked about the panel yesterday again there’s this magical word plant most of the public will never learn anything about the solar system except that there are planets and there are certain number and I want them to have the best picture

in what the solar system is the best picture they could have if they’re not gonna learn anything else the best picture they can have is that they’re eight planets and that’s essentially the soul mate there are other things and these are very interesting important parts of the sources but if they only know that there are eight planets that’s at least start if they think that this will need to be a plan to your knees and they don’t know that this population is out there they feel like they really got in the wrong picture and that astronomers arguing about Pluto being planet that should be just sort of out of sentimental reasons I’ve really tried hard to give this wrong picture of what the solar system is which I find sort of deeply offensive to my educational sense so this ends the editorial portion of the talk but but I actually really as you might be able to tell me I say it really matters it is not just a question of semantics it’s a question of what people know about the solar system and I think this is the right thing for them to know I encourage you all to go and convert as many people as possible isn’t it ok so after the editorial portion the main reason for discovering these things of course is not just to get astronomers to argue amongst themselves although that’s added bonus the main reasons tickets to a little bit of sites and there’s some very cool science that you get to do when you buy these things as soon as we found this one I have to one quick aside that all there was this one I thought we’ll be climbing at this in this one so most of you of course know that this distance now has the name once it was decided what it was dwarf planet it finally was allowed to get name so it’s name is Harris urias and heiress of course is the Greek goddess of discord and strife which was just sitting there waiting for so it was like one of the major only major gods or goddesses and greco-roman mythology it hadn’t been used for a planet or an asteroid or Kuiper belt I just seeing their just makes you almost believe in astrology so I mean so so after that is happily married so we got we got basically heavy telescope that we could get our crazy fingers on we went and looked at them and one of the most exciting ones was it was very early on we got a chance to go to the Keck telescopes in Hawaii my favorite old telescopes are big telescopes now we in the background and the Keck telescopes this was brand new at the time i’m sure a lot of you’ve heard this by now the Keck telescopes had this brand new laser guide star adaptive optic system which is just about the coolest thing the world because the way these things work is you take a laser picture tells you shoot the laser up in the sky and at the favor retail for the sky there’s there’s a thin layer of debris left over from meteorites that are that are coming into the Earth’s atmosphere and from that thin layer debris the laser reflects and comes back down and you look at the laser in your telescope well of course the laser now to the atmosphere and so the lasers all wobbly and doing crazy things and then you have a little mirror at the bottom of it that you can adjust a couple hundred times a second to make that blazer that’s going on wildly to something go into a little point like that so you’ve now just had several tens of millions of dollars to take a picture of laser than they probably which is all exciting but the nice thing is secure if you know what you’re doing you make sure to point that laser right at something you really care about and the same thing happens that your star that you’re looking at initially going waving around because of the Earth’s atmosphere you turn on the laser and the system and it make you can watch it happen some real Teja spokes goes like this and something goes just to this little little spot this guy but sometimes it doesn’t sometimes it goes next to it and that little next to it is this this is this is the moon a Paris that we found in the system this is Munna varus of course you get to get to name all these things so the name of the moon is dice no Meah dish no means is that as a daughter of Eros and the demon spirit of lawlessness errors didn’t have very nice children there’s a good story behind this one too so the motorized one of the main one nice things about the motor soon as we found them own people said oh it’s kind of moon so so once me it’s a plan right and I had to point out that now something like a third of the objects in the Kuiper belt actually help have moods around them so having a moon doesn’t make you play 10 min I find out to get on Mercury Venus don’t have moves around them and there’s no plans for now so it’s not that well but it is of course is you get to do some real physics if you have a mood around you you can you could track the work of that moon and join the circle around you and figure out exactly how much this thing wait how much this thing weighs matter to me a lot at this point because you might remember if it was sort of five percent with someone certainly bigger than Pluto and you can do very precisely with with doing doing the orbit so he was a Kathy orbit from both the Keck telescope and from the Hubble Space Telescope very nice image of that and we got the orbit by looking at a bunch of different times and as we were finally doing that final calculation one of my graduate students made a beckman because she she was convinced that it was going to weigh

less than Pluto and she had no real reason to be convinced that except that she thought it’d be really funny if I had to go now is that in public and so she was she was really looking forward to making barrister and if I finally if I won if she won I was going to have to work ace of champagne and if i won she was gonna have to stick around in ground school for next year so turns out it’s twenty-five percent more massive than Pluto until you only about 1% so really is a good bit more massive and she did a really nice work that extra your girls mr. Whitman I said so they’re they’re a lot more things that that I would love to have the time to talk about its most the time you only get to hear about the one big object that was bigger than Pluto those found a lot of other very fascinating objects out there that we found including perhaps my favorite one hotmail which which is shaped like a big egg and rotates every four hours because it got smacked early on the solar system and debris went flying everywhere and you can you can track down the breeze have two moons or a crazy system that we’re still studying in gory detail there’s Maki Maki which is which is actually a little bit of a Pluto twin has a has an atmosphere and surface just like Pluto we’re finding these things finding the Pluto is no longer this oddball at the edge of the solar system but it really has sort of the prototype of this new large class of icy methane dwarf pilots they’re they’re very fascinating set to consider I will tell you in closing about one more object because it remains still I think the most intriguing object that we found it also points to what we might be fighting in the future this one was really was was one of the early one with once we found this was back in 2003 and in 2003 we found this object that was here so here’s the number of objects that were no 2003 and we found a subject that was way over there and now if you pay close attention of course you remember that’s sort of the same distance the Harris has found a way but a time we hadn’t found Aris we hadn’t done anything at that time how did those distances so we found sand we were so excited we were convinced that this has to be finite ask me a circular orbit this was going to be great we did that same trick finding images back and back and back and back to figure out what the orbit is and the orbit turns out you know we wait the two big questions where it’s been circular like a plan would be or is it going to come in like a comet would be your Kuiper belt object would do and the answer is no it actually does that this is this is setting up Sedna Sedna is the goddess of the sea and she lives in an ice cave under the Arctic Ocean and so she seemed like an appropriate name for something that’s so far away and so cold probably the coldest thing that we know of them in the solar system we still don’t know how this thing got on it’s it’s very crazy work but it’s actually very difficult thing to do you can’t do it with the planets that we have in the solar system something else intrude and there are a lot of theories as to what was the intruder was in early was a star that came by early cluster of stars another planet who knows what was out there so that’s scientifically that’s that’s interesting but the other interesting part of the story is that cezzah spend so much of its time so far away that we would almost never detect it it takes twelve thousand years to go around the Sun and we can see it during two hundred of those 12,000 years so if you’re the math that’s that’s 160 of them its orbit we had a chance of seeing it so here we were extremely lucky to find it or to know the way astronomers tend to think if you had a 160 chance finding it probably that means there are about 60 of them out there and you found the one that happened to be close and maybe we got a little lucky make their 30 and we we got lucky maybe maybe they’re 90 we’ve got a little bit unlucky that there’s a little one but there must be something like 60 of these objects the size of absenden out there said no it’s about three-quarters of size of Pluto this region out through here is huge compared to the Kuiper belt there are there are not that many objects three quarters of size of Pluto in the Kuiper belt in this region there are at least 60 if you extrapolate sizes of objects which is always a dangerous thing to do when you have one object of startling but if but if there are 16 objects what I’m gonna do it anyway simpler 60 objects three-quarters the size of Pluto and you have sort of typical sizes that you have in the solar system thing you would end up with probably 30 objects the size of you know it’s a lot of objects of sounds clue you would end up with maybe maybe ten objects twice the size of Pluto and you might go with with to that are that are two or three or four times the size of Pluto we’re getting to be the sizes of Mercury Mars even earth I think it’s very likely somewhere in these regions out there they’re going to have something that is that is Maura sighs birth sighs way out there in the outer part of the solar system you’ve spent the last couple of years looking too hard to see if we could find some number that were closed and did the problem if they spend most of their time in those very distant regions so they’re going to be hard to see as I said yesterday and the panel

discussion if if you already is that if we find this thing that’s out there that’s the size of the earth the size of Mars in this operator to find by the currently accepted definitions of planets in the conception of that initial plans it is still considered a dwarf planet it is not employment I suspect that this will open the can of worms once again and I won’t look ridiculous as the person who argue and I won’t absolutely that it should not be considered planet it should still be called the dwarf planet even if it’s bigger than Earth and I predict I will lose that argument so I’m saying that stay tuned that the place that we’re most likely to find this thing now we’ve looked all up in here assuming is not right there really really here attending the place most likely to find this thing it’s now the southern hemisphere the southern hemisphere is is unexplored territory so it’s it’s ready to go so we were starting a survey right now from from Australia telltale strannix it’s got sort of funny looking trees and the sky is always clowning so we’re this survey starting now I would say within the next year or two if there are big things down there we don’t know if there will be or not then you’ll be you’ll be starting to hear about so stay tuned and I hope to be able to come back sometime and tell you what the view looks like not from from eros the largest work plan but maybe from something even farther apps the largest plan out there may be the new 90 plant and just the shameless promotion part you want to follow along as we go i have a head you can read along on the blog which sometimes is more active than others but if you really want to know you know where I am DNA you can always find me on Twitter and of course the the book is coming out with December seventh and you can warp pre-order on amazon now it’s already in the top two million on Amazon anyway thanks for sticking out to the end of this and be happy to answer a few more questions now and if you don’t get your question in I’m somewhere over here for the next session for questioning attitude I’m going to always go to the end back the show ever does about seven flights back the picture of eros with just no Meah around it it was a slight kind of blew a bright blue is that because the planets not circular is it because we’re tracking it for a few hours and so it moved across the start in front of absolutely no because it the adaptive optics of CAC is not merely stable as I didna cult oh yes I see a hundred know it just came close so difficult yeah I the student who spends a small or large fortune on textbooks I just wanna make sure this is some giant conspiracy so i could buy more additions my truck Arnold giant conspiracy because textbooks already are John conspiracy and so y would make new additions no matter what so but they do get me kicked back so that’s when comics come in from a great distance they always talk about something perturbed the Oort cloud to get that coming in the inner solar system they talk you talk about passing stars it seems far-fetched but could there be something Earth to Mars man let me play mr. Garrity because the sophomore adventure really fast ourselves they don’t have to get very close if you have something that is that is really really far away from the Sun just incredibly loosely bound it doesn’t take much to give you a kick coming with there could be large objects out there that are doing too but but they are not our stars are so massive and such a huge region of influence so really is passive stars and collection Titus hey I have the same feeling you just seemed so unlikely there’s this spacecraft that’s visiting rectory most people don’t know is packed full of nuclear forgot to be smaller than expected what was actually for sure be now and they led if i combo’d look in that yeah so I should if I should have mentioned this Martin I Justin my mind saying is the question is okay so Pluto was not perturbing Neptune so what was perturbing Neptune the answer was nothing in it turned out to be magic that and there was a very careful analysis done in the in the early 1990s that went back and looked all the data and said look you know there really is no evidence when you when you do the job right there is no evidence whatsoever

any perturbs out there doesn’t mean there’s not something very far away out there but it just means that there was no need for that perturb ER and so the planet x that everyone was looking for was simply because appearing here serendipity where’s the work compared to the Kuiper belt yeah if I on that picture I showed you said know where you saw the outer edge of Sedna take that picture and then go out to the great American parking lot and then that’s about the righteousness without you about and there’s some guys out there that Bishop pope named eurozone to send it to a planet in clute oh and another moon and again you ever meet one of this engineers and that you could its planets that they send it hope yes some questions oh do I ever meet the engineers who built the probe to the planet Pluto which now it turns out to be dwarfed by the actually don’t think I built in met the engineers but I meet the astronomers who involved with it and the comeback which is no fun so given that we didn’t expect to find anything between the Kuiper belt in the Oort cloud and then there was Sedna in the realm of wild speculation could you suggest what might be in between those they’re farther more healthy yes as well I’m a big fan of wild speculation in fact in the paper where we announced the existence of Sedna we went down that road wild speculation and suggested that really what you’re seeing is the inner part through our club said the Oort cloud as we know what that thing that’s being purchased served by stars has to be really far away or it won’t be being perturbed by stars but there are things that could be that it’s going to continue all the way out to there I think the most likely explanation is as that that continuum was it was put in place at the birth of the sun by a cluster that the Sun itself formed and put all those things to perturb then put them all around there those cluster of stars then disappear and were left with essentially on a fossil record of birth of the Sun so I think this discovery is one of the most exciting scientific discoveries in the outer solar system said that Paris is great but I think senda is where the real scientists if we can find more of these things I think we’ll be able to read this fossil record and really tell you what the Sun what the conditions were when the Sun Sign was born it’s extraordinary hard we discovered in 2003 and it’s been my top priority since them to find another one and I have not found a single one week it’s not for lack of telescopes or anything else we’ve been trying really hard like I’m going to ask one final question as moderator because i really enjoy your thinking about the names so could you tell the audience a little bit about how these unusual names like maka maka came about and what your ideas are about further naming yeah so so the maintance that the discoverer gets privilege of naming which is which is fun and I take it very seriously because these things are going to stick with these names for forever and so I try very hard to have have some reason for what the neighbors so the very first big one we found was choir and choir is we didn’t know enough about borrower to have any sort of tie into the body itself but what we didn’t know is that you know this was the first large object found we were in sitting in my office in passing at a time and most of the objects in the Kuiper belt still were being named for for Greek and Roman gods and so we thought okay get it get away from that so we named it for the the local Native American tribe of the Tongva of the gabrielino gabrielino Indians are the ones who the mission indians from from los angeles basin and we wanted to name something after then we came up we found the same barber somewhere so we called up well first we had to figure out how to find them turns out to go to ww telecom it’s true and they have a phone number and yet you pick up the phone and you call and the chief answers also really drew chief answers and you know we say you know we’re we’re astronomers at Caltech and we found this thing out of this outer probably want to name it after one of your creation gods and he’s like sure don’t you talk to this guy so he sent this to the their their their chief historian and tribal dancer who’s a great guy we so we SAT and talked to him for a long time about what the appropriate names were and we came up with with choir work together and inquire more of course so they now have a tribal dance in honor of the Kuiper belt object choir we’re very excited fun and we’re we’re just in the last year or so we discovered a mood to quarrel and so I call it the Trident you know you guys guys name the moments of the moon’s name is too far worries there their creation force who sang and danced the world into existence and and his his son was waiting that’s that’s the name of the moon so all of these have a storage room that that we take it pretty seriously a lot of genres think it’s

just a big waste of time they don’t care and I think it’s both important and fun it’s important because people like the names people people think about the objects more if they have interesting names you know when when when Sedna was 2003 VP 12 nobody really it’s not never said that I got these pictures from school kids about about the objects farmers quasars in Hope stones all right what I’d like to suggest is that some of you may know that recently dr. Brown was elected to the California Academy of Sciences and avenue and party the reason was not just for his exceptional research but also for his interested in public education I think he did a wonderful demonstration of that today so thank you very much for an excellent you