MR. KOJO NNAMDIFrom WAMU 88.5 at American University in Washington, welcome to "The Kojo Nnamdi Show," connecting your neighborhood with the world. Historic is a word used to describe so many of the most frequently visited attractions in Washington. But historic doesn't quite fully capture the scope of the newest acquisition of the Smithsonian National Museum of Natural History. Kirk Johnson, the museum's director, spent this past week overseeing the delivery of a roughly 65 million-year-old T. rex skeleton from Montana to the museum here in D.C.

MR. KOJO NNAMDIThe seven-ton skeleton is more than 35 feet long and is widely considered to be one of the best preserved T. rex skeletons ever found. Museum officials plan to make it the centerpiece of its dinosaur hall, which will close down later this month for a lengthy renovation, a massive redevelopment, a massive development for one of the star attraction at what's now the second most visited museum in the entire world.

MR. KOJO NNAMDIJoining us to explore what's at stake in this new dinosaur projects and his broader vision from the future of one of America's most treasured museums is Kirk Johnson. He is the director of the Smithsonian National Museum of Natural History. He is on his way here. He joins us now by telephone. Kirk Johnson, thank you for joining us.

MR. KIRK JOHNSONHey, Kojo, how are you? Good to hear you.

NNAMDII am doing very well. It seems you have been caught up in cherry blossom fever, have you not?

JOHNSONWe are trapped on a bridge and haven't moved for 15 minutes, but I'm happy to hear your voice and glad to talk about our brand new Tyrannosaurus rex.

NNAMDIHappy that you could join us. Allow me to invite our listeners to join the conversation by calling 800-433-8850. Are you a regular visitor to the Smithsonian's Natural History Museum? What do you see is at stake in it acquisition of the new T. rex skeleton and its forthcoming project to renovate its dinosaur hall? 800-433-8850. You can send us email to kojo@wamu.org or just shoot us a tweet @kojoshow.

NNAMDIKirk Johnson, you just came back from a road trip with one of the oldest and most fearsome companions anyone could ever ask for on a cross-country drive. Massive skeleton belonging to what you're now calling the nation's T. rex. What's so special about this dinosaur that you brought back from Montana? And what's your vision for its place at the museum?

JOHNSONYou know, we have this fabulous museum on the Mall. It's the world's largest (word?) museum and we're about to undertake this vast sort of ancient of a hall and we've never had in Washington an original Tyrannosaurus rex skeleton. The first ones are found about 1905, 1906 in Montana and were taken back to the American Museum in New York. And I've always felt since I got here that this place needs a T. rex.

JOHNSONAnd that was a feeling that had been around for about a decade. And we work with the Museum of the Rockies in Bozeman, MT and the U.S. Army Corps of Engineers to engineer the acquisition of our 50-year loan of this incredible skeleton. It's found in 1988 on the banks of the Fort Peck Reservoir by a rancher who was hiking. And she found one little bone, but it was a key bone, it was the arm bone of T. rex. And that led to an excavation that recovered nearly 85 percent of a skeleton of this amazing animal.

NNAMDIYou're a paleontologist. When you look at something this old and this, well, intact, what goes through your head?

JOHNSONWell, you know, it's luck. When you have something that's that old, to find one and really complete as this is just tremendous luck. And the rancher that found it did the right thing. She took the bone to the Museum of the Rockies in Bozeman and showed it to Jack Horner. And he was amazed at what he saw because she had the humerus, which is the upper arm bone of the animal. And (word?) is an animal that's 38 feet long, the upper arm bone is actually no longer than my upper arm.

JOHNSONAnd Tyrannosaurus rex is notorious for having these tiny, tiny upper arms. And that was based, really, not on a complete discovery of one, but based on the idea that the bone is attached to just, like, a small arm and humerus is a small arm. And Horner was amazed to learn that Kathy had stumbled on the bone that science knew existed but have not yet found. And so he was delighted to go out and see if there was the rest of the skeleton there.

JOHNSONAnd, in fact, there it was. So, it's a very historic specimen because it was excavated by Jack Horner in the late '80s, early '90s, '88 to '90, which predates the "Jurassic Park" movie series, which of course is based on Jack Horner's work in the discovery of dinosaurs. So in many ways, this acquisition links Washington, D.C. not only to Tyrannosaurus rex, but also to the entire "Jurassic Park" craze which spawned so many paleontologists and so many people interested in paleontology in general.

NNAMDIKirk, it's my understanding that you had to pack the bones in more than a dozen crates and you put them in a truck. You literally FedEx'd a T. rex. What went into that process of getting it over here?

JOHNSONWell, it's an elaborate process. People expect to have a gigantic fossil. But in reality, every giant body is made up of bones. And the T. rex bones are, in many cases, not even attach to each other. There were some bones that were broken in many pieces. So we had 16 large wooden crates that were all carefully packed so that the bones would have a very smooth ride across the country in a very air conditioned and shock absorbed T. rex FedEx truck.

JOHNSONAnd we spent about a week with the team from Museum of the Rockies and the John (unintelligible) and the museum, making sure that every single bone was nestled in a firm cradle so that it'd survive the trip very well. And we shipped the load off on Friday morning and watched the truck head off on the highway. We drove with it for a little while. I had to go back and clear over the top, like we do, to receive it on the back side. And we expect it to arrive later today for its opening tomorrow morning.

NNAMDIOn to the telephones. Rebecca in Silver Spring, Md., has a question that I suspect you can anticipate. Rebecca, you're on the air, go ahead please.

REBECCAHi, Kojo. Hi, John. Thank you for taking my call. I'm a huge fan of Natural History Museums, I've seen (unintelligible) dinosaur in Berlin and I've seen through in Chicago. And I was wondering, in your marketing, are you going to name this T. rex such as they have Sue in Chicago?

NNAMDIKirk?

JOHNSONSo, this T. rex has a couple of names already. It's -- we call MOR 555, that's Museum of the Rockies 555, that's the number. We also call it the Wankel rex, because it was found by Kathy Wankel, the rancher. But we've taken to calling the Nation's Rex. It's going to be here on display in Washington, D.C. and it's -- more than 7 million people a year will see it for the next 50 years at least. So we're looking at something like 350 million people seeing this animal in our nation's museum. So we'd like to name the Nation's T. rex.

NNAMDIRebecca, thank you very much for your call. You too can call us, 800-433-8850. You can send email to kojo--k-o-j-o@wamu.org. Are you a dinosaur geek? What do you think explains the appeal of dinosaurs to so many adults and children all over the world? You can also go to our website, kojoshow.org and ask a question or make a comment there. In case you're just joining us, our guest is irk Johnson.

NNAMDIHe is the director of the Smithsonian National Museum of Natural History. Kirk, what have museum-goers been looking at this whole time in your dinosaur hall? There's what looks like a giant T. rex there and it gets a ton of attention.

JOHNSONThat's right. What you're seeing is a plastic cast of a Tyrannosaurus rex named Stan that was collected in 1992 in Northwestern South Dakota. And that specimen, the original one is mounted in a small private museum in South Dakota and we have on loan a cast of it. So if you look carefully, it looks very much like a T. rex but it's a replica of one. And as a museum specialist, it's really important that we show the real object. And so we had a nice replica of one. But now we're going to show the real thing.

NNAMDIWhat is it about the T. rex that people find so compelling? You told Josh du Lac of the Washington Post that if, for instance, you put a replica of the Hope Diamond on display, people would probably feel and react differently.

JOHNSONIt's all part of museums, Kojo. This is the one place in our culture where we can see the authentic objects, the real things, the one of a kind. And if we just had a plastic replica or glass replica, you can do that in a mall anywhere in the country. We really want to show with museums is the real objects that underpin how we know what we know about the natural world.

JOHNSONSo having a real specimen there raises a ton more questions if you can actually see the details of that individual animal's body and see the story of its fossilization, preservation, excavation and its potential future scientific impact.

NNAMDIWhat will happen to the Nation's T. rex when it comes out of its crates in Washington, D.C.?

JOHNSONWe're going to do sort of the reverse of what we did in Montana, which is to inspect every single bones to make sure that they're in exactly the same condition they were when they left Montana. And then we're going to do a three-dimensional scan using lasers of the entire suite of bones to be able to then build a digital Tyrannosaurus rex and we'll use that digital Tyrannosaurus rex to shape the life posture that will mount the actual bones in.

JOHNSONAnd mounting a dinosaur skeleton is a very tricky process because you're taking bones that have turned to stone and in the process have become somewhat distorted and then making an armature of steel that will hold those bones in a position that is probably going to be life-like. And that's a challenge when crushed bones turn to stone and to create a life-like posture that's make easier by having this three-dimensional scan. That should take about two and a half, three months to scan every single bone to create that digital T. rex.

NNAMDIHere is Joe in Richmond, VA. Joe, you're on the air, go ahead please.

JOEAh, yes. I was curious to know, is there a certain part of the world or the country or a specific climate that's more or less conducive to preserving, you know, obviously ancient bones and such? Because I noticed, it seemed like there's a lot of dinosaur bones seem to come from certain parts of the world or is that just a misconception on my part?

NNAMDIKirk Johnson?

JOHNSONYou know, that's a great question, Joe. Fossils are found because the rocks that contain them are exposed to surface, which means that we often find dinosaur fossils in desserts because there's no modern vegetation obscuring the rocks. But the question is a little bit even more subtle than that is to say that in order to find a fossil, you have to find a place that was the surface of the earth when that fossil was a living animal or plant.

JOHNSONAnd that surface had to be a low-lying area that was sinking, so it was accumulating sediments and burying the remains of plants and animals. So you had to find a landscape that was sinking, settling down. I call those kind of places deposition landscapes where you actually streams and lakes are piling up mud and sand and it's accruing. And then eventually those get buried deeply enough so the sediment turns to sedimentary rock.

JOHNSONAnd then what has to happen next is that sedimentary rock has to be uplifted and exposed at the surface again and has to be exposed in a place that doesn't have much modern vegetation. So the sweet spots for fossils or dinosaurs in the world are places that used to be depositional landscapes but are now modern deserts. So you hear about the fossils from the American West or the Gobi Desert or the Sahara or Patagonia. It's not that dinosaurs lived in deserts, it's just that deserts are the places that we find them today.

NNAMDIJoe, thank you very much for your call. Kirk Johnson, dinosaurs have been a huge part of this museum ever since the originally named Hall of Extinct Monsters opened decades ago. But the hall that houses so many of your dinosaurs is about to close in a few days for a major renovation. It's going to take years to complete. What are you aiming to do and what concerns do you have about temporarily shutting down one of your very, very biggest attractions?

JOHNSONWell, we see millions of people every year in this space and we know that they're going to be coming to the museum expecting to see dinosaurs. So we're going to start building a series of temporary spaces, which will have various dinosaur skeletons and dinosaur-themed objects. And we'll open the first of those on November 25th, the temporary exhibit called The Last American Dinosaurs.

JOHNSONAnd this is an exhibit about the dinosaurs that lived with Tyrannosaurus rex. And T. rex lived between about 66 and 68 million years ago. And the animals that lived with it included things triceratops and the duck-billed dinosaur called Edmontosaurus, some very curious animals called Pachycephalosaurus, the dome-head dinosaurs and a dinosaur that was recently published called Anzu, which is a giant, bird-like dinosaur with great, big hand claws.

JOHNSONSo we're going to show life on the -- this world of -- the T. rex lived in as a temporary attraction while we're doing the huge work of dismantling this hall, which has been opened continuously since 1911 and renovated the building beneath that hall and then building the space and then putting a new exhibit back into that space. And that's a fairly elaborate series of interlocked processes.

JOHNSONIt's going to take a number of years to pull it off. But what we'll going to get in the end is a truly fantastic exhibit, which talks about the entire history of life on this planet and puts humans in context to that history.

NNAMDIWe're going to talk a little bit more about that. But first, we've got to take a short break. Our guest is Kirk Johnson. He is director of the Smithsonian National Museum of Natural History. We're inviting your calls at 800-433-8850. What would you say the Smithsonian's Natural History Museum and more specifically it's dinosaur hall means to D.C.'s cultural identity? Give us a call, 800-433-8850 or send us an email to kojo@wamu.org and shoot us a tweet @kojoshow. I'm Kojo Nnamdi.

NNAMDIWelcome back. We're talking with Kirk Johnson, the director of the Smithsonian National Museum of Natural History about what's going on with fossil hall there and the acquisition of the new T. rex skeleton known as the Nation's T. rex. He joins us by telephone. You can join the conversation by calling 800-433-8850, by sending us a tweet @kojoshow or emailing us at kojo@wamu.org.

NNAMDIKirk Johnson, as you talk about shutting fossil hall for a while, what boggles my mind is the thought of what kind of work deconstructing the displays themselves involve.

JOHNSONYou know, it's an amazing process, Kojo. I've been through it a couple of times at small scale and you just (unintelligible) ...

NNAMDIOkay, I mentioned that we were talking with Kirk Johnson by telephone even as he is getting closer to the radio station, we seem to be having some problem hearing exactly what he is saying. So as he continues to listen, we will take a caller, Victoria in Washington, D.C., and see if by the time Kirk responds, he's got a better reception. Here is Victoria in Washington. Victoria, you're on the air, go ahead please.

VICTORIAHi, Kojo. It's me and I used to be a docent at Natural History.

NNAMDII didn't know that. You've told me that.

VICTORIAYeah. And I think that he mentioned in the new various displays where they're going to have some of the dinosaurs, he mentioned one that I think is a holotype or a halotype of which the paleontology division should be very proud, there are many of them. And I'd love for him to mention them, and also mention the age and the originality of the Diplodocus set they're going to be taking down, which I think is going to be a difficult task. I believe it was the first ever displayed in natural history of a Diplodocus. I'd love for him to talk about that.

NNAMDIKirk Johnson, can you hear me now?

JOHNSONI can. Do you hear me?

NNAMDIYes, I can.

JOHNSONOkay, excellent. Now a Diplodocus is a favorite dinosaur. It's actually the long neck dinosaur in the middle of the hall collected in -- near Vernal, UT during the discovery of the Dinosaur National Monument. And that specimen is then in its exact location since 1931, if you can believe. And to answer your earlier question, Kojo, dismantling a dinosaur like this is a very interesting process because when the specimen was mounted in 1931 a number of choices are made that were -- they had missing parts of the body.

JOHNSONThey would reconstruct those things and they painted both the body -- the bones and the reconstruction as the same color. So we're kind of trying to find out the first step in the process how much of that skeleton is actually real fossil bone and how much is 1931 reconstruction. And what we'll do as we clean the bones and prepare to remount them is we'll make it much for clear for our successors what's real bone and which of the parts we had to reconstruct using plastic to fill up the entire skeleton.

NNAMDIYou know, we have on the line Natalie in Sterling, VA. And Vicky, thank you very much for your call. Natalie in Sterling, Va., who, I think, is going to miss being a part of all of this. Natalie, you're on the air, go ahead please.

NATALIEOkay, I'm on the air and way back when, I would say, about 20 or so years ago I was actually an employee of the -- at the Natural History Museum and I worked in the Department of Paleobiology and I absolutely loved working with the fossils. And at one point in time I even was able to -- I got a job working at the -- for the summer -- working up at the (unintelligible). Sorry for having -- (unintelligible) in Canada.

NNAMDIYes.

NATALIEAnd, unfortunately, the only dinosaur bones that I ever was able to dig up were little itty bitty things. The kind of stuff that you pull up, fit in your hand and you go, oh, my God, I found dinosaur bone. It's wonderful. And so I'm just absolutely envious of anybody that could dig up a huge dinosaur and have it come to the museum.

NNAMDII think your envy is shared by about millions of people in that regard, Natalie. And it's one of the things that makes the work that Kirk Johnson does so interesting. Kirk, care to comment at all on Natalie's small discovery?

JOHNSONWell, you know, I think it's one of the great places. I've been a paleontologist my whole life effectively. I found a fossil when I was six years old and I had the great pleasure of having a career that match out with my childhood dreams. And over the years working in Cretaceous and Triassic and Jurassic rocks, I've stumbled on lots and lots of dinosaurs. And it's always a thrill when you see just even a fragment of a dinosaur and you can peer back into this ancient world that is so different from our present world.

NNAMDIIndeed. Thank you very much for your call, Natalie. We got an email from Susan in Winchester who said, "I recently saw the documentary, "Dinosaur 13" at the Sundance Film Festival that followed the controversial discovery and subsequent custody battle of the T. rex Sue that is now in Chicago. We know the Smithsonian tried to get that. Has your guest seen this film. And if so, does he have any comments on it?"

NNAMDI"I realize that there are two sides to every story, but it was a fascinating account of the politics that can affect fossil exploration" Kirk Johnson, care to comment?

JOHNSONYeah, that discovery was -- happened in 1990 in South Dakota. It was an amazing Tyrannosaurus rex specimen that was unearthed on an Indian reservation in South Dakota. And it was a very complicated argument about who owned the land and who owned the specimen that led to several legal battles. And that's what the story of "Dinosaur 13." And it just shows how much people are intrigued with Tyrannosaurus rex and that's sort of the almost the curse of T. rex.

JOHNSONIs what happened to the people that found that is one of them spent some time in the jail and it took a while before that specimen was acquired by the field museum in Chicago where it now stands. And it's a great saga of paleontology. And what we did with this T. rex is take a much simpler task towards acquiring it by simply partnering with the federal agency who owned the Tyrannosaurus rex, thus avoiding all of the kinds of things that can happen when fossils are found with dispute of ownership.

NNAMDIOver and above the work you're doing with the exhibits themselves, what plans do you have to make changes, make upgrade for the part of the building that houses the fossils?

JOHNSONWell, remember, this is a building that was built between 1903 and 1910 before they have all sorts of different building codes and structures. So we have to go back and take this amazing 1910 building on the Mall and do all sorts of deferred maintenance and -- excuse me for just a second, Kojo, I'm about...

NNAMDIWell, we're going to take a short break because he is here. Kirk Johnson has arrived in the building. So we're going to take a short break. And when we come back, he will be joining us in studio. You can still continue to call right now, 800-433-8850. You can send us email to kojo@wamu.org or shoot us an email @kojoshow.

NNAMDIHave you ever been inspired by something you saw or learned at a museum to dive deeper and learn even more about that topic? What was it that captured your imagination? 800-433-8850. I'm Kojo Nnamdi.

NNAMDIWelcome back. Our guest is Kirk Johnson. He is now in studio. He is the director of the Smithsonian National Museum of Natural History. Good to see you in person in the studio.

JOHNSONPleasure to see you, I can assure you.

NNAMDIWhen we were interrupted, we were talking about the plans you have for changes or upgrades to the part of the building that houses the fossils.

JOHNSONYeah, this building is an amazing building. It's 1.3 million square feet. It hosts the world's largest Natural History Museum collections, plus the world's largest Natural History Museum visitation. So to do a major renovation in the building while we still have collections and while we still have the visitation is quite a challenge. And then there's all the underground infrastructure that is inherent in a building that's over a hundred years.

JOHNSONSo it's going to be a massive project, and that will be going on as we're designing the new hall and as we're dismounting and repairing and preparing the fossils. So there's multiple projects happening simultaneously as we take on the next challenge in the next couple of years.

NNAMDIThere's a lot more to your museum than fossils and we'll get to that in a minute. But I got to ask you, we should mention that part of why we're spending so much time talking about dinosaurs with you is that you're, well, kind of a fossil guy. You came to this post with a long background in paleontology. What did it mean to you when you were chosen for this job a few years ago given how much time you spent in that field of study?

JOHNSONWell, you know, as a paleontologist, you realize that there haven't been paleontologists for that long. There's an awful lot of the earth out there. There's a huge volume of rock that has fossils. So we know as paleontologists that the best fossils are still on the ground, which is a very intoxicating thought to realize that everything you see in a museum, that's just the tip of the iceberg.

JOHNSONThere's discoveries to be made on all continents, in all time periods. And it makes me want to zip out with a pick axe and a shovel and go to work to dig fossils. And I have routinely done that for my entire life. And this was a challenge to come to Washington, D.C. where in someway you think, well, there's not that many fossils in Washington, D.C. But I'm here to say that yesterday I was in the Calvert Cliffs in Maryland looking at a fossil dolphin skull in the side of the cliffs.

JOHNSONSo there are fossils actually near Washington, D.C. There's fossils under Washington, D.C. There's a dinosaur bone from directly beneath downtown Washington, D.C. So, often fossils are all over, you just don't know that they're there because you don't have the traditional fossil kind of landscape, that bad lands that (unintelligible).

NNAMDII was about to ask while you're busy doing all of these things, how do you still plan to get out and enjoy yourself as a paleontologist going to dig sites and hanging around people with shovels who are making discoveries?

JOHNSONWell, it's fairly engrained in my body and spirit to dig holes in the ground, Kojo. So I'll find a day on a weekend or I'll disappear somewhere to where I can actually find a fossil. And there are fossils everywhere, so it's not that hard to do.

NNAMDIYou said before, you took this post that the museum doesn't need to be fixed so much as it needs to be optimized. What do you mean by that?

JOHNSONWell, here we have this phenomenal facility, which is the most visited science education complex in the world. And the potential for understanding and sharing that understanding with a huge population is no where greater than the Mall in Washington, D.C. So, for me, the point is let's not change it, let's just make it better. Let's make it more comfortable for the customer, the visitors. Let's make it more interesting.

JOHNSONLet's bring it up to date in terms of the quality of science. And thinking about what's happened in the last century since this building was built, we've had tremendous increases in what we know about the natural world. So we're looking at a way to take this exhibit and not only rebuild it and make it new, but also to embed the insights of the last century. And one of the amazing things we've learned is that humanity is a pretty big force in this planet.

JOHNSONAnd so this exhibit will not just end in the past, like all previous exhibits of past life, this exhibit will end in the future. It will actually put humans in context in the story of life on earth as we know it.

NNAMDIOn to the telephones again. Here's Connor in Reston, VA. Connor, you're on the air, go ahead please.

CONNORWhat's the process for preserving the fossil once it's dug up? And what is the heaviest bone in the new T. rex fossil?

NNAMDIConnor, you don't know this stuff already? You sound as if you read up on this stuff.

CONNORNo, I haven't.

NNAMDIOkay. Well, here's Kirk Johnson.

JOHNSONSo, Connor, that's a great question. There's lots of -- it depends on where you find the bone, what the process is. In many cases, the bone will be broken in the ground. And you don't want to take a broken bone out, because you don't want to lose the pieces. So what we often do is put a lot of glue on the bone and then we'll take plaster of Paris and burlap and we'll build a plaster cast around the bone.

JOHNSONAnd then we can flip it over and plaster the other side and basically encase the bone, the glued bone in this block of plaster, then we'll bring it back to the museum, cut the plaster off, fix up the glue joints and have the bone in the museum. In the case of this T. rex, the heaviest bone is the pelvis. It's the biggest body in the bone and it's a big chunk. It's about four and a half feet long and about three feet high and about two and a half feet wide.

JOHNSONAnd I think it weighs about 450 pounds. It's a real whopper of a bone, it needs a forklift to move it. And one of challenges of mounting the skeleton will be supporting that big block of rock up in the air because it's about 12 feet above the ground where that pelvis will be mounted on a steel fixture.

NNAMDIConnor, how old are you?

CONNORI am eight.

NNAMDIAnd what's your favorite dinosaur?

CONNORAnkylosaurus.

NNAMDIThere you go.

JOHNSONWow. Good job. Kojo, what's your favorite dinosaur?

NNAMDIT. rex.

JOHNSONThere we go. Nice answer.

NNAMDIThank you very much for you call, Connor. You too can call us, 800-433-8850 is the number. We move on now to Steve in Arlington, VA. Steve, you're on the air, go ahead please.

CONNORHi, Kojo, thanks for taking my call. And I was just curious. My wife and I were out in the Grand Canyon. I've always wanted an answer to this question. We were in the Grand Canyon, we were hiking down one of the trails, then we looked up the wall of the canyon and we saw two sets of some sort of lizard print or whatever in the sandstone. One of them, as I recall, had a tail dragging between it. It was really cool.

STEVEI mean, because it's, you know, it's in the sandstone. And then we realized that there was about an inch difference in the depths of those two prints. You know, that one was an inch deeper into the sandstone. There was an entire layer of sandstone over the top. And I've just always been curious to how many years separated those two things. And I was wondering if your guest had an estimate.

NNAMDIYears, millennial, whatever.

JOHNSONSo, dating rocks and the fossils that are enclosed in them is a very interesting field. And geologic time is almost incomprehensibly long. The rocks exposed in the Grand Canyon, the very youngest rocks exposed in the Canyon that are layered rocks are about 250 millions years old. So they actually predate dinosaurs in the planet. And I'm not quite sure what kind of tracks you'd seen, but if you wanted to ask the question how precisely old are those tracks, it becomes a little bit of a challenging question.

JOHNSONAnd if you look at two layers, it's pretty tough to say was it a week, a month, a hundred years or a thousand years. There are better examples now of us being able to date things and that's one of the growing areas of geology is what's called geo-chronology or the dating of rocks. And the best studies now are dating rocks with the precision of plus or minus about one-thirtieth of one percent.

JOHNSONSo you can actually date something that happened a hundred million years ago, plus or minus about 30,000 years. So often our dating precision is longer than the things you want to date. So it'd be pretty hard to know precisely how long those two track were separated in time.

NNAMDISteve, thank you very much for you call.

STEVEThank you.

NNAMDIYou, too, can call us, 800-433-8850 is the number. Kirk Johnson, what opportunities did this museum present to you as a scientist? You testified before Congress earlier this year, you made it clear that you feel science is the foundation of this museum and of the entire Smithsonian system.

JOHNSONKojo, there's a couple things that happen behind the scenes at museums that are tremendously important. And I always say that museums, natural history museums specifically, have three main things they do. They excite the audience about the world of science and knowing about what goes on around them.

JOHNSONBut they also preserve, for the public good, collections of objects about the natural world. We're the repositories that store things like the original skeletons of dinosaurs or the first example of a species of a bird or the Hope diamond, for instance. And the third thing is the discovery of new knowledge. The work that scientists do in museums to make new discoveries. And at the Natural History Museum this last year, we had over 400 scientists on staff that described more than 330 new species of animals, plants, insects and fish.

JOHNSONThey published over 700 different scientific volumes and books. And they did research in 71 countries. All that happens behind the scenes. And the collections that we have are the result of over 150 years of scientists doing just that. So if you want to think about a museum, it's really the storehouse of our culture's knowledge about the natural world. And we're continually adding to that with scientific research.

NNAMDIFor those who are not familiar with this part of the museum's mission, what kind of research does the museum support?

JOHNSONWe do primary research on areas of plants and all kinds of animals, both marine animals and land animals, on human cultures and archeology, on paleontology and on mineralogy and meteorites. So basically, anything -- you look out the window and see any chunk of the natural world, whether it's a tree or an outcrop or a shooting star, anything you'd think about the natural world.

JOHNSONWe have a museum full of experts who are doing primary scientific research and discovering new things on a regular basis. It's an amazing place to work because any given day someone will be finding out some new information we didn't know yesterday about the natural world.

NNAMDIOn to Alex, in Bethesda, Md. Alex, your turn.

ALEXHello, Kojo.

NNAMDIHello? Go ahead. Yeah, Alex, you're on the air.

ALEXThank you very much, Kojo. I wanted to ask Mr. Johnson, you know, I've been loving dinosaur media basically since I was a kid, "Jurassic Park," all those kind of things. But there's always been one gnawing question for me. It's like what's the biggest misconception most people have about dinosaurs?

JOHNSONI love this question. I think -- it's happened again and again with things like "Jurassic Park," and "Walking With Dinosaurs," where we've been given the opportunity to peer back and see what it looked like in the past. But the misconception is this, which is we have these beautiful digital reconstruction of dinosaurs, but they're not reconstructing the landscape.

JOHNSONThey're taking ancient animals, reconstructing them and putting them in places that look like arboretums and parks today. And that's because the dinosaurs are the stars of the show, but in reality, the world's landscapes have changed every bit as much as dinosaurs have changed or as dinosaurs have given a way to mammals. So that perception of an ancient landscape is one that you're only going to see in a museum because the TV shows and the movies are just not going to take the time to make an exact Jurassic world.

JOHNSONSo you're sort of seeing Jurassic animals in a yesterday's world, which, to me, is a tremendous misconception because it doesn't help you understand that the world changes, not just the animals that live on the world, but the whole world changes.

NNAMDIThank you very much for your call. We've had the good fortune of speaking with NIH director Francis Collins on this program several times. The last time he bemoaned the effect of the sequester on federal support for science. To what degree do you find yourself making a case for the federal government's role in science and why do you feel there might be a gap in understanding here?

JOHNSONI think one of gaps, Kojo, is that scientific research is an interesting thing and hard to explain. Many people who do scientific research on basic science, like the discovery of new fishes, for instance, or new trees or new fossils, are doing basic information acquisition. They're going out into the world and understanding what's out there. And discoveries often happen to them. So you do research and you make discoveries.

JOHNSONAnd very often, the discoveries you make are not the research that you're doing. You might find, for instance, that you're -- and I have many examples from the museum. I have one scientist who studies this certain type of marine worm, called the nemertine worm. And you might think, "Well, why would you study a marine worm? What could be more boring?"

JOHNSONBut in fact, it turns out that this worm has an incredible ability to regenerate its entire body from a cubic millimeter of its tissue. If you think about the implications of that, you wouldn't know that and you wouldn't study a worm in order to figure that out, but you accidentally discover something that is incidental.

JOHNSONAnd if you look back in the history of science, most major discoveries have been made by people who are looking for something else. And that's a very counterintuitive feature about basic science. And people say, well, why fund basic science? And it's because that is how we know what we know about the world we live in.

NNAMDIHow would you measure the impact of last year's government shut down on your museum?

JOHNSONIt was pretty significant. We lost a couple million dollars of revenue. And we also had to turn away a quarter of a million visitors from the doors of the museum. So we also -- the two weeks we were closed we were not able to allow our employees to work. So it was a cessation, a temporary cessation of the work that we do at the museum. And I'm glad we're back at work.

NNAMDIOn to the telephones again. This time Adam, in Silver Spring, Md. Adam, you're on the air. Go ahead, please.

ADAMHi. Thanks for taking my call. So I had a quick question. When you find a new specie and you only have maybe one or two samples, how do you tell the difference between pathology and morphology? Is it something that went wrong or something that makes us different?

JOHNSONThat's a good question. It's -- usually you can tell quite well because pathology does present itself as pathology. If you find a bone that's been broken and healed back over, it's very clear in that bone pathology that it was a healed bone. So we find a bone that has a very distinctive anatomical morphology, it's -- and it's distinct from anything we've ever seen before, it's pretty clear you're looking at a new species.

JOHNSONAnd that description of what is the unknown, is based on a very solid understanding of what is known. So most of our experts who are describing things can describe something that's new because they know that they've seen everything else and they know this isn't that. So the pathology problem is something we don't usually have to worry about too much.

NNAMDIThank you very much for your call. We got an email from Clark, which is a little long, but I'll try to get through it. "I grew up in D.C., but have raised my family in Western North Carolina. My oldest son has long been fascinated with paleontology, but has been confronted by a very fundamentalist intolerance of his interest in his public schools. When we visited the Museum of Natural History two years ago -- when we visited, he explained this to a paleontologist on duty and asked her what he could do to improve his chances for a sound education."

NNAMDI"Her response was that he needed to move to a different state. While this was a very honest response, I wonder if the museum can do more to appeal to public schools throughout the nation to encourage an education rich in scientific facts and material. What does Kirk Johnson see as programs concerning schools that will dove-tail with this new acquisition?"

JOHNSONYou know, that's a really I interesting question and one that we've been working on from a variety of different ways. First is that the National Museum really is the mother ship of the nation's museums and the world's museums. And with our big, behind-the-house supply of specimens and scientists, we can act as a resource to other museums around the country and to schools.

JOHNSONWe've just opened, in December, a new facility called "Curious," which is on the Constitution Street entrance. It's a 10,000 square foot space where we've made available for direct handling, by the public, more than 6,000 specimens from our collections. And they can look at these things through not just education-grade microscopes, but actually research-grade microscopes. And the research-grade microscopes have attracted our researchers to the space.

JOHNSONSo the public can actually rub shoulders with the scientists and hold the specimens, but we've also built into this facility the ability to communicate to distant classrooms. And it'll be able to connect our scientists and our objects to classrooms around the country, to other museums, with the idea that maybe if your local community doesn't have a naturalist museum or your local teacher isn't so inclined to talk about fossils, there are lots of ways to digitally access the Smithsonian and take advantage of it's amazing richnesses of science and objects.

NNAMDIYou may have answered my next question, but I'll ask it anyway. Last year in December we hosted an event at National Geographic about the future of the past. It included outgoing Smithsonian Secretary Wayne Clough. Part of what we talked about was the evolution of discoveries that are made and the evolution of how those discoveries are shared with the public. What's your vision of how your museum can engage differently with its audience, not just those who come through the doors, but online and in the field as well? As I said, you may have just partially answered that question.

JOHNSONYeah, Kojo. Well, I sort of look for -- for me the golden standard is a great scientist who is also a great communicator because the complexity of science increases every year, but at the end of the day it's pretty simple. It's about the increase of knowledge. We know more than we did last year. And if you can have someone who can explain that in real concrete examples about what they do in a way that's compelling, that's worth its weight in gold.

JOHNSONWe've all watched the remaking of the "Cosmos," series, with Neil deGrasse Tyson, who's doing a fabulous job of taking Carl Sagan's series and repurposing it with new information and new graphics. And what you see there is the impact that one great communicator, who's also a great scientist, can have. And that's what we like to do with museums, is challenge our scientists to become great communicators, or hire scientists who are great communicators and great scientists, and then use our capacity to communicate, not with just our visitors, but also in many other ways to get the word out and to inspire people at the end of the day.

JOHNSONAnd museums are just about that. When you walk into a museum what you're often greeted with is this realization that, wow, the world has got some amazing things in it. I want to know more about those things.

NNAMDIDeGrasse Tyson has stolen my Sunday nights away from the good wife and that's a good thing. Here is Allen, in Rockville, Md. Allen…

ALLENThat's me.

NNAMDIYou're on the air, Allen. Go ahead, please.

ALLENHi. Can you hear me?

NNAMDIYes, we can. Very clearly.

ALLENOh, good. Okay. So I was wondering -- I guess two related questions. One, what is the largest sauropod that you've discovered? And what do you, as a paleontologist, think is the theoretical maximum size of those huge things?

JOHNSONThose sauropods are the long-necked, long-tailed dinosaurs. And they first appear in the Jurassic period and they go through the end of the Cretaceous period. So they had a pretty good run. They were on the planet for about 80 million years. And they got awfully big. And I've personally encountered several among outcrops and been impressed by 5' long thigh bones.

JOHNSONThe largest one ever discovered is a very curious specimen with a very checkered past. It's called Amphicoelias longus. And it was found in Canyon City, Colo., in the late 1800s. And they only found one bone. They found one vertebra, but the vertebrae was about 6' tall. And unfortunately that vertebra has been lost and we haven't been able to find another example of that one. So that stands out there as sort of the quasi-mythological, but possibly real, largest animal.

JOHNSONThe largest sauropod -- it's also hard to tell because we don't have very complete skeletons of any of the various species that have been described as the largest. So largest could be the fattest, the longest, the tallest, the widest, and ultimately there's four or five different long-necked dinosaurs that are competing for the biggest dinosaur of all time. And theoretically, I'm amazed those things existed at all.

JOHNSONSo I can hardly give you an upper end for their potential size. But, as I said, the best fossils are still in the ground and we're always eagerly awaiting each summer because new people are looking for more dinosaurs. And one day we will find a complete specimen of one of these real monster, long-necked dinosaurs.

NNAMDIKirk Johnson, he is the director of the Smithsonian National Museum of Natural History. He joins us in studio where we're taking your calls at 800-433-8850. Are you a regular visitor to the Smithsonian's Natural History Museum? What do you see is at stake in its acquisition of a new T. rex skeleton and its forthcoming project to renovate its Fossil Hall? 800-433-8850. Let's talk with Fidel, in Tysons Corner, Va. Fidel, you're on the air. Go ahead, please.

FIDELGood afternoon, Kojo. Thanks for taking my call. I have a quick question. My question is what is the relationship between dinosaurs and ancient Asian texts regarding dragons?

JOHNSONWell, that's a great question, Fidel. I've been to China and to Mongolia collecting dinosaurs. And in many places in Mongolia and China the dinosaur fossil's exposed at the surface. You're walking along an outcrop and there is the dinosaur. You can see the skull and the body. And there's an animal called protoceratops, which is a small dinosaur, but it's got a real dragon-like look.

JOHNSONAnd I was in the Forbidden City in Beijing, looking at some of the ornaments on the rooftop. And I thought, boy, that's a protoceratops. So I think, you know, I don't know if this is true or not, but my theory is that dinosaurs have been visible in the landscape in China for thousands of years. And people clearly saw those things.

JOHNSONAnd whether or not they were the original inspiration for the concept of dragons, I don't know. But there's a marked similarity and the fossils are there and they don't take paleontologists to find them. So that's my guess for what the connection between dragons and dinosaurs is.

NNAMDIGot an email from Dave, in Reston. "If you could bring back any dinosaur, what would it be?"

JOHNSONOh, boy, that's a great question.

NNAMDII know.

JOHNSONI -- well, this is like kid in the candy store for me. I'm going to have to ponder for just a second. And I'm going to go for a sauropod, for the same -- I think those long-necked, long-tailed dinosaurs make no sense at all. Here's an animal, it's 80' long. It's got a head that's smaller than the head of a horse.

JOHNSONAnd it's got just a few little pencil-size teeth in its mouth. And we have no clue what these things ate or how they behaved. And I'd love to bring one back and just watch it, see what it did, see if -- my theory is it was eating protein shakes or something like that, but that would be a great way to test that theory.

NNAMDISee, that's the kid in Kirk Johnson. Here is Eric in McLean, Va. Eric, you're on the air. Go ahead, please.

ERICHey, one of the questions I have for your guest, one of the things that struck me when I went to the Smithsonian of Natural History was how small the dinosaurs were compared to my previous perception. Maybe the media distorted them in that regard, but I remember just being shocked. I imagined them much larger than I, you know, when I actually saw the bones. I want to know if your guest maybe -- do you think the media has anything to do with that or what?

JOHNSONThere's a couple things going on there. I mean, obviously, movies like, "Godzilla," dramatically distorted the size of dinosaurs. But there's often kind of what we call the Hollywood-effect, where, you know, you might want that thing to look a little bit bigger. So, you know, maybe it's the -- maybe the fossils are smaller ones, we'll just double the size and get away with that.

JOHNSONThe second thing is you're looking at skeletons. And skeletons are not fleshed out. So the skeletons in the museum actually are smaller than the body of the animal would be. And I think the third thing is when you went to our museum you saw Diplodocus, which is a long-necked dinosaur. It's 80' long, but that's not one of the big sauropods.

JOHNSONThe bigger ones, like Apatosaurus are much, much larger, much more bulky bones and much bigger bodies. So it's a combination of all three of those things. And if you stood next to an Argentinosaurus, I guarantee you wouldn't think that it was small.

NNAMDIThank you very much for your call. We move on to Sean, in Arlington, Va. Sean, your turn.

SEANHey, how you guys doing today?

NNAMDIDoing well.

SEANYou know, I saw -- it popped up when I was reading the news on Facebook about a month ago, that a group of scientists, you know, overseas -- I don't remember where -- but supposedly they cloned a dinosaur. Is there any truth to that?

JOHNSONThe answer to that would be no. The cloning of animals is really very early science and they've been doing it with living animals, but with extinct animals like dinosaurs, the genetic material simply doesn't even been preserved. I mean even DNA -- it's pretty rare to find DNA preserved that's over a few tens of thousands of years old.

JOHNSONAnd the last dinosaur, and I will say that word to emphasis because birds in fact, now known to be descendants of dinosaurs and therefore they are dinosaurs, but the last non-bird dinosaur died out 66 million years ago, which is a long time ago. And the DNA from that time has not been preserved.

NNAMDIFinally, here's Walter, in Springfield, Va. Walter, we only have about a minute left. But you're on the air, Walter. Walter?

WALTER(unintelligible) demonstrate we've been talking big things, but I'd like to mention the Entomological Society of Washington…

NNAMDIYes.

WALTER…which has been meeting there at the museum for over 100 years, talking about insects and things. And that's a real jewel I would like people to know about.

NNAMDIAnd we put you on because we would like people to know about that also, Walter. So thank you very much for your call. Kirk Johnson, I'm afraid we're just about out of time, but we got an email from Melinda, who's in marketing, who says, "You've got to name the dinosaur. You can use it as a tool to make some much needed money for the Smithsonian."

JOHNSONWell, we think the Nation's T. rex has a nice ring to it. And if anyone has any other ideas on how to make money for the Smithsonian, just give me a call.

NNAMDIYou'll be hearing from Melinda. Kirk Johnson is the director of the Smithsonian National Museum of Natural History. Thank you so much for joining us.

JOHNSONMy pleasure, Kojo.

NNAMDIAnd thank you all for listening. I'm Kojo Nnamdi.