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tv   Geoscience Lessons from Apollo 11  CSPAN  August 17, 2019 2:19pm-3:55pm EDT

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true. >> and at 6:00 on american exhibit on 400 years of african-american history. >> they were not content with their lot, they wanted to resist their enslavement, and they tried to run away. they were not successful, they were captured, and as punishment for their attempt to escape, robert carter got permission from the court in 1708 to have their toes cut off. explore nations passed on american history tv every weekend on c-span3. american history tv products are available at the new c-span online store. go to c-span store.org to see what is new for american history tv, and check out all of the c-span products. 's on american history tv, a
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discussant about geoscience and how lunar samples from the apollo mission help scientists understand our moon and solar system. the national archives and american geophysical union cohosted this event. [captions copyright national cable satellite corp. 2019] i am thevening, archivist of the united states. it's a pleasure to welcome you to the william g mcallen theatre, whether you are here in the room with us, or participating through facebook or youtube, and a special welcome to our c-span audience. if you could please join us for tonight's program, small steps 11 giant leaps, how apollo shaped our understanding of earth and beyond. tonight's program is presented in partnership with the american episcopal union, celebrating its geophysicalrsary --
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union, celebrating its 100th anniversary, and the generous support of the boeing company. days, we arefour commemorating the 50th anniversary of the historic flight of apollo 11 and the first moon landing. we will night, july 18, screen a celebrated documentary, apollo 11, grafted from newly discovered video and audio recorded here at the national archives. film, a discussion will be moderated with the and others. on july 19, we will show two films in the afternoon at noon. we will have episode six from the earth to the moon, and we will show moon walk one, a
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1970's nasa documentary. and we will screen the 2018 feature film, first man, starring ryan gosling is neil armstrong. upstairs, be sure to see our special display of document that shows a multitude of smaller steps and details necessary to the success of the apollo 11 mission. profilerds include the of the eight days of the mission, the plan for the hour that the lunar module landed on the moon, pages of moon landing transcripts and the details of the itinerary the astronauts were to follow during the moonwalk. those documents will be on display through august 7. to keep informed about these events throughout the year, you can alsosite, sign up to get email updates and find information about other national archives programs and activities.
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another way to get more involved is to become a member of the national archives foundation, which supports all of our education and outreach activities. now it is my pleasure to turn the program over to christine, the executive director of the american geophysical union. it's a worldwide scientific community that advances the understanding of earth and space through cooperation in research. she's the third executive director in their 100 year history. for over 25 years, she's made her mark as a leader and innovator. in 2011 she was chosen for women mentoring leaders, and was featured as one of the top 100 women leaders in stem. please welcome christine maca t --mac and teen --m christine. and ourhalf of agu
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hundred thousand scientists that reside in 130 come to -- countries around the world, welcome to tonight's special , how apollo 11 shaped our understanding of earth and beyond. and space earth scientists and their collaborators so they can advance and communicate science and its power to ensure a sustainable future. we are proud to cope present this event this year and are sent to neil year as an organization. agu was when a gu -- founded, the world was a different place. despite a century's worth of change, the ability of earth and space science to improve our society, and the desire scientists to provide that benefit to humanity has remained the same. has has the odd discovery that all of us witnessed, as i did as
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a 14-year-old girl in a small town in western pennsylvania, to watch the lunar landing on black-and-white tv. earlier in the year i was stilliewing dr. drew five , who commanded an expedition to the international space station. during our conversation he spoke about the residence of the apollo -- the residents about the apollo 11 mission for him personally and for humanity and drove home the point that the lion share the research done was geoscience, including the collection of lunar samples, the deployment of scientific instruments, and the collection of core samples on the lunar surface. geoscience will continue to play a similar role in the future of lunar and other planetary missions. he also spoke about how over the course of his 197 days in space
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on his latest mission, he saw the changes that the earth was having in its climate, how floods affect the planet and other geophysical phenomena are impacting the surface. he also experience what astronauts have dubbed the overview effect, when viewing the earth from space, many astronauts see the fragility of our global environment, and how we are all protected and nourished by our planet's thin atmosphere. boundaries between nations disappear and the issues of separate people are viewed as less important. what becomes clear is the need to create a more unified global society, one that works to protect all of the inhabitants of this pale blue dot we call our home. during times of uncertainty and change to earth's climate and the scientific enterprise, all of us, particularly the scientific community, must join
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together to address these concerns. like all of us, and those who are part of witnessing more being on the apollo 11 mission, we had to be creative and passionate, committed, and determined. we must advance research, and do so with the integrity and transparency that is the foundation of scientific discovery. i am now proud to introduce the agu, a member of 30 years and became president-elect in 2017, she's the past president of our cryo-spheres section. she received her undergraduate degree in geology from middle berry college, in vermont, and her phd in geophysics from columbia. since completing her doctorate, she has led research at the lamont doherty earth observatory on ice sheets, tectonics,
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rivers, and made ocean ridges. please join me in welcoming her. [laughter] [applause] >> i'm very excited. anyone who has ever come within 10 feet of me realizes i'm an actual geek. and when i realized we were going to have this wonderful event, first i thought i could mark whereas i wish were you when apollo 11 landed? everyone in my community was becausento the room there was only one tv in the community and we had about 45 people jammed into the room. but i thought i should look a
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little deeper than just the consider myhat i living legacy. so i began to poke around at my institution, because it turns do that lamont had a lot to and i knew there was a gravity meter i had been tripping over my entire life. i went looking for it. i went first to the attic of lamont hall, where they match the bottom of the ocean floor. it was not there. 11 slides and pictures but no gravity meter. mention, noe gravity meter, and i went to the of the-- cellar building, there were jars of jellyfish and i knew they were not from the moon.
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i finally opened the door and there it was, there was the mock gravity meter that went on the back of the vehicle. that is out on the table if you want to see it. i brought it down on amtrak. i think it is the first time the gravity meter has had a trip on amtrak. someone on my committee conveyed these very important lessons in science. you don't give up. tried, something happened. so it was apollo 13. apollo 14, the drill got stuck and they only got one measurement. apollo 16 is the first time an apology from the
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astronauts back to the scientists because something bad happened. in his obituary, it says a misstep. they tripped over it and pulled the wire. but marcus stuck with it. apollo 17, the astronauts are on the moon and joking about how not to trip over it. t i took away from his lesson was to not give up, be patient, and you can get what you want. i took colleagues down to the ellar and we found the heat flow instrument. wonderful to learn the stories of the measurements they made, of how the philosophy of moon rocks is not that different. it shows scientists can be very
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patient, recover from disasters, and have the sense of humor --a sense of humor. i hope you will enjoy the program as much as i am looking forward to tonight. we will learn a lot. there are some amazing people we will learn from. agu, role as president of i realize now having watched the eyes of my cohorts when i went cellar entrepreneur to just how inspiring this work generation.xt just being able to hear the stories and here where their parents were when the moon landing happened, it actually lights up their eyes and gets people inspired to work on science on this planet and on other planets. so now, i'm very pleased to introduce dr. jim green, who is nasa's chief scientist. he received his phd in space physics from the university of iowa and worked at nasa's marshall space flight center where he developed and managed
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the space physics analysis network. before becoming nasa's chief scientist, he was the director of the planetary science at nasa headquarters where he saw missions, including the new horizons flyby of pluto, that youflight to jupiter -- the juno flight to jupiter, and the landing of the curiosity rover on mars. we are very lucky to have him as a moderator of this panel tonight. please join me in welcoming dr. jim green. [applause] green: i'm glad the rain could not stop you from coming tonight. discovering about
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many more things about the moon and the origin and evolution of the solar system. it is going to be a really exciting time for we will also talk about the future of lunar exploration truth without further ado, i want to mention a couple of important things. cards.e should have these are important because you can write questions down. please write your questions as they come up. i find that is usually the best way to go. hang on to them. and at the end, we will pass them down and go through as many as we can. in addition to the audience that is here, we also have remote viewers. for them, let me read on twitter what hashtag they should send questions to. #agu100.and
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for those online, please get ready with your questions. we will try to get to as many of them as possible. tonight, we will have a moderated panel. i am delighted to have been asked to moderate the panel. we have some of the best planetary scientists in the world, those that have worked with even apollo 11 data all the lunar reconnaissance orbiter that is they are now. without further ado, let me begin introductions. first, i would like to invite the assistant professor of geophysics at stanford university on to the stage. [applause]
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dr. green: next is dr. sean solomon, director of the observatory. [applause] dr. green: we also have heather postdoc fellow at the lunar and planetary institute in houston, texas. heather. [applause] dr. green: and last but not chair the professor and of the earth, environmental, and planetary sciences at case western reserve university. [applause] dr. green: we are going to start out by talking about the legacy of apollo, what it meant to the
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country going back now 50 years. we will go back in the way back machine. on this panel, two people observed the landing. that was shone as a working scientist and as a young high school student, jim green here. fond memories. i'm going to ask sean to take us back to the lunar landing. what was the feeling of the science community at that time? what were they excited about? >> i hope some of you will remember the apollo 11 landing. i was a graduate student in geophysics at m.i.t., and the world had been following the apollo program and the leadup to it. we had the anniversary of the launch of apollo yesterday, apollo 11. this saturday, we will have the anniversary of the landing.
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1969,vening, july 20, late afternoon was the landing. i would say there were probably billions of people around the world watching that event all over the globe. together toumanity look at a technological achievement in a largely apolitical way. less than eight years after president kennedy announced in his speech in houston in early 1961 challenging the country to go to the moon before the end of the decade, to send humans to the moon and bring them back safely. we did that. 1961 was such an early phase of the space program. the first humans had orbited the planet.
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it was only four years after sputnik. yet in eight years, we could carry a apollo 11. really extraordinary. the backing of the country, it had resources, and really amazing engineers who figured out very challenging problems. one of the things the scientific community realized is they were witnessing a remarkable event in history and a remarkable achievement. scientifically, the apollo 11 mission was enormously important ourur perspective of how planet fits into the solar system and what the early history of the solar system was like. i cannot understate the importance of the apollo 11 mission in particular for bringing back lunar rocks and samples into the best earth with many of the
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instrument's having been purchased by nasa specifically for the apollo program and were ready to look at lunar samples. the moon is very agent. we immediately learned it was volcanic. themmediately learned that bright areas of the moon were a product of an early stage in lunar history when the entire planet was molten and the crust formed as a result of the cooling of the magma ocean. all of that came from the apollo 11 mission. it led to an explosion of understanding of the early ,istory of the planetary system the part of the system of our planet not preserved in the rock record. i am not sure i realized all of that as a graduate student
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sitting in front of the television and listening to walter cronkite, but that is what happened. did not take-- it long before the scientific community realized what a watershed event it was. dr. green: we are celebrating the 50th anniversary. i think a lot of the general public think of it as human explanation, but science was there from the beginning. when i watched it, one of the startling things i saw was when neil armstrong walked out of the capsule, he looked around and saw how the lunar limb was sitting on the surface and how deep the legs might have been crushing into it. there were some debates on how thick that might be. was right off the bat talking science. that was pretty spectacular. -- what did we put down on the moon for apollo 11?
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apollo 11 was the first of the landed spacecraft. there were a total of six that landed successfully. it was not the most ambitious by far in the experience -- experiments it brought to the surface. but one of the opportunities provided by the apollo missions was the opportunity to do seismology, to study natural tectonic events and the impacts of meteoroids on the surface of the moon using seismometers. analogous to what terrestrial jews of -- geophysicists had of a centuryr 3/4 studying earthquakes around the world and using the waves to learn about the interior structure of the earth. institution, my
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current institution, and a few others, got together and sent a seismic system on apollo, including apollo 11. for reasons of cost, for reasons of schedule, the very first passive seismic experiment carried by apollo 11 did not have a power source so it only lasted three weeks. that theed signals best seismologists in the world could not understand. so for three weeks, there were seismic signals being recorded by the seismic system on the lunar surface. then the power ran out and the signal stopped. really distinguished who had been working on lunar seismology and thinking about it for years prior to the mission did not
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know what they had in the way of the signal. shown on the screen is a nation -- an explanation. the top four are the lunar seismic graham and the bottom is the earth seismic graham. they thought they would see signals like you see on earth. they saw signals that were very different. they did not have distinct arriving phases and rang on for an hour. it was said that the moon rang like a bell. signals, nobody figured out what they were. it took apollo 12. 12 difference was the apollo landed in a different place. it had a power source.
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then they left the moon again. asked nasaogists had for permission when the astronauts docked with the command module in lunar orbit the vehicleneed anymore to send the ascent vehicle back down to the moon where it would crash and create seismic waves. it would crash in a no place at a known time. so for the first time, they had a seismic source the characteristics of which they seismogramsproduced like the ones that came in on apollo 11. moment, this is what seismograms look like on the moon. it took another experiment. it took the cooperation of the flight folks at nasa to re-create and event so we could understand how different the moon is from the earth. it is different for a variety of
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technical reasons. because theent outer tens of kilometers are fractured and broken up trade and the moon is extraordinarily so the waves go on for hours instead of minutes. none of that was known before the apollo mission. if you take a terrestrial experiment to a new planetary body, you really have to think out-of-the-box sometimes to interpret what you find. dr. green: indeed. these are fabulous sets of data. if you are really excited about these, please see me after the lecture. variety ofollected a samples and did a fabulous job. back to have about 50 pounds worth of samples the apollo 11 crew brought back. why do we need those samples? what can we learn from those?
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>> the apollo samples are not just a bunch of souvenirs, even though they are really cool. but they represent this incredible treasure trove of knowledge about processes occurring in the early solar system. not just how the earth and moon formed, but also the incredible bombardment of giant impacts occurring in the first billion years or so after the solar system was initially formed. what is great about getting whole rock samples from the moon on these missions is we can bring them back to earth and cut them up into 100 pieces and send them to 100 different labs and do 100 different experiments. it is because of this that we can address a much wider diversity of science questions then you can with a few instruments you could put on a rover. diversityve a higher
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of viewpoints from different scientists with different perspectives addressing those questions. from that perspective, getting actual rock samples from the moon is integral. we have lunar meteorites. moon rocks fall to earth all the time. but what is great about the apollo samples is we know exactly where they came from. we know exactly what geology they represent. thanks to these samples, we learned some incredible things. we have learned the earth and moon are very similar to each and in some sense, we have a common origin. this led to the giant impact hypothesis that the moon formed by the impact of a mars-sized body into the earth and all of this debris that was launched from earth re-coalesced into the moon. we would not know any of this without the samples. fromn date rock samples
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impacts hitting the lunar surface and melting rocks and recrystallizeing. can date them and figured out windy impacts happen. we learn the first one billion years of our solar system's history was chaotic. we know about the impacts that killed the dinosaurs. in the first 2 billion years of earth history, stuff that big or times basedned more on studying the moon. that is the power of lunar samples from the apollo mission. it is fantastic we get to work with them. dr. green: over all the six apollo missions, we brought back about 840 pounds worth of lunar material. as it came back, the first thing we did is we set aside about 25% not to be looked at. it is done that way because as we learn things about how we analyze the current material in our hands, we can then approach
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the new material that way. ourthese last 50 years, ability in the laboratory to look inside these rocks with c.t. scans and individual atoms in allting the isotopes of the complexity of the samples provide us is now becoming well in hand. this year, we are opening brand-new samples we have never opened before. panelists think about some of the great images from the apollo program. we have asked them to give us those. let's talk about these. here is our first one. apollo 8. from this is yours, sean. what did you feel like when you saw it? "theose of you who read washington post" should have seen a story yesterday on this image.
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i think it is one of the most compelling images to come out of the apollo program. was before any but sentding astronauts to loop around the moon before they came back. when the spacecraft came from out of the shadow side of the rising view the earth above the horizon, anders took this famous image, earthrise. someone was quoted in the post yesterday saying all three of the astronauts were awestruck by the image because of the beauty of the home planet because it was almost the only color in the
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sky, because you can see the fragility of earth's atmosphere, and yet we rely on that with every breath we take. you could see land. you can see the oceans. you can see from space, there are no political boundaries. completelyt with the arid and desolate so beautiful had was more striking than been appreciated up to that moment. thehe 50 years since then, magnificence of this space view of earth and the realization that the changes mankind has imparted to our atmosphere and a lesshave made it habitable place than it was 50 years ago just underscores how
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and in our how unique this planet is. it took the venturing of humans into space to look back from surface ant ncient surface and give new appreciation to our home. "life"en: i remember magazine had it front and center. it was awe-inspiring. they were not the only ones inspired. iconic image, one of the great images of the last century. next one. >> oh, ok. [laughter] >> all right. this is one of my favorite photos. it is from apollo 15 and is a
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picture of commander dave scott collecting samples on the lunar surface. i am a sample scientist. this is my bread and butter. of how they were going about it in this photo. bag in his left hand that already has a rock in it. there is a sample back and they put these tiny rocks they pick up off the ground into them. he is messing around with this larger rock in the center. on top of it is this funny stick looking tripod thing. it creates a shadow. what was cool about it is when you are on the moon, you don't have a compass that can tell you which way is north, south, east, or west. if people on earth wanted to reconstruct what direction they were studying, they had to use the sunlight angle cast on this
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stick at the top of the tripod onto the ground. with the sunlight angle coupled with the time, they could figure out which direction was what. this photo is amazing because it gives you a sense of how they were going about their business on the surface. you have the footprints in the soil. you have the spacesuit, the sample bags, the whole thing. i have to say my favorite part of the image unfortunately got cut off. upwards, atto tilt the top in dave scott's helmet, you have the best selfie of all time because there is a reflection of the other in the image. it just goes to show you instagram is not a modern phenomenon. [laughter] >> they totally were rulers at that even during the apollo era. dr. green: these were really
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bulky suits. it is hard to be able to pick up material on the ground, so they had a variety of implements, things they would use to pick them up. one of the astronauts wanted to pick up this very heavy rock and knew that it might take him down . he actually put his leg up against it and with one of the rolled it up, he his leg and threw it in the box. indeed, we have to look at our rocks. in the archives today, we have an orientation and talks about where the sun was during that time when the rock was collected. we try to maintain all of that data. mine.hink this one was this is an image i think captures a lot of what apollo 11
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astronauts were doing when they were on the surface. in the foreground, we see the seismometer sean was talking about earlier that was solar 1969 and thatn they were able to install quite quickly. the ones that came on later missions took them longer and lasted longer. on the top of it, you see a white stick. that is the antenna that allowed us to get data back from the moon to the earth. sort ofhat, you can see where the white stick is what looks like a white triangle. this is an experiment that is still operating today from apollo on the surface of the moon. it is a lunar laser reflector. its purpose is to do a better
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job of reflecting laser light back from the surface of the moon. experiment ingenious because it required no power. you just had to sit there. and all of the technological advances happened on earth. as our lasers got better, telescopes got better. scientists use this to measure the rotation of the moon, the distance of the move. in the major thing we learned about is what the inside of the moon looks like. how does it respond to the title stresses it receives on the earth? that tells us what the deep interior of the moon is like. this is an experiment that has been going on for 50 years. in the background, we can see other iconic parts of the apollo
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11 image. we can see the flag in place, the lander. in the far distance, we can see the television cameras used to provide the first interplanetary television shop. -- show. [laughter] dr. green: that is right. next one, please. >> that is me. sean took my favorite image, so we will have to do with this b oot print. sensing specialist so i work on data from orbit. most of what we do from orbit depends entirely on the properties of the surface. apollo taught us about the properties of the topsoil and those properties so we could derive meaningful information from orbit. this boot print may not look like much, but if you are a
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sherlock holmes fan, there is a lot of information here. that is the uppermost part of the surface. it is like dirt. the fact you have this large imprint in the surface indicates there had to be some space between the grains of dirt in order for it to compress. it is that into space with the porosity. that actually affects the way we see light reflected back from the surface. it's critically important for making sure we are interpreting things correctly when we are looking back down. >> indeed. two.had to go for >> that's what neil was looking at. >> they had these little rods that stuck in. it was telling us the uppermost part of the soil was not as porous as we expected, but still
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fairly porous that the lunar module could sink just a little bit. it is perfectly sufficient to support the weight of the astronauts, nobody got stuck. the properties are important, not only for orbital, but for ground operations, you need to know you can move around on a surface. we would not send rovers if we knew they would get stuck in the sand. these are critical considerations that were beautifully demonstrated by apollo 11. we got surprised it was not as porous as we thought. as scientists, we delve into for a, and we get excited variety of things that people think our minutia. what are some of those things that you think the general public would be interested in knowing that you really got excited about? panel.open it up to the
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[laughter] well, i could talk about magnetism now. the moon used to be magnetic. you probably know the earth has a magnetic field. it's invisible, but we are sitting in it. we use where north is if a compass. the moon used to have a magnetic field too. you probably are wondering, why does this matter at all? of theo to the image moon and its magnetic field -- ea, there it is. --yay, there it is. 's conception.ist we can't see inside the planet, and magnetic fields are
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invisible. therefore we need some help from this artist, who is amazing. magnetic fields, the way i think of them, they are almost like the heartbeat of a planetary body. but are this invisible detectable signal that tells you there is some activity going on inside at the core. in the case of magnetism, the process that is occurring is organized motion of molten metal , hot liquid iron at the center of a planetary body. it tells you that the planet is alive and it is cooling down, that motion is driven by thermal conduction inside the core of the planetary body. it's a signal -- a signal that
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the moon was active. we did not learn much about it from the initial landing at the apollo 11 site, because they neglected to bring a magnetometer on that mission. but we fixed that on apollo 12. if we go to that image, there were two, yeah, that one. the image on the left that you is, at the end of that rope .his little box looking thing that is a magnetometer. you have a magnetometer inside your cell phone now, all smartphones have them, so this is a testament to how technology has changed over time.
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they were able to measure the field at the surface of the moon. it's almost like the moon was magnetized at some point, there was something there. there probably was a core inside the moon that might have had a magnetic field. magnetism is looking -- is a weird way of looking at this problem. it was an obvious the moon has a core, but if you can detect the ornetic field on the moon show they had one in the past, you can say this is the internal structure of the moon, and we know for sure they had one. surface measurements were a hint of that. what really nailed it was studying the magnetism that was the time therom
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initially formed billions of years ago. astronaut about to .ick up what they were able to do is once the samples were brought back to earth, they were sent back to labs that study paleomagnetism. not paleontology. paleo means old. what we can do is we can stick a rock in a magnetometer, we can figure out whether or not it's magnetized, rocks acquire magnetism when they form, and it preserves it after that. what the apollo era paleomagnetism's found was that
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-- iton used to have seems the moon used to have a magnetic field that imprinted magnetism in these rocks prior to 3.5 billion years ago, and it was at that time period it was as strong and adverse as a magnetic field as today. you are further away from the corridor, it is not going to have such a big field. what persisted was people weren't sure whether the field was from inside of the moon or not. there were hypotheses that giant cloud --an create we kept ourselves busy for 50 years, and we came up with all these to show whether the rocks recorded an internal magnetic field generated by the moon or
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these other exotic field sources. what we found is the moon did generate a field. it didn't just last three and half billion years ago. it lasted the past 2.5 billion years ago. which is much longer than people conceived of at the time. it tells us that the room was alive and active. >> you will learn that planets evolve over time. years go back 3 billion and look at the moon and it be very different. what else? >> we have gone by us -- gone past the slide twice. it's a little bit like the case that didn't bark in the night. shortly enduring out -- shortly active ina was
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sending robotic spacecraft to other planetary bodies. and in very rapid succession we have sending spacecraft to mars and mercury and jupiter and saturn, nearly 70. it was only 16 months after the that thelo mission first spacecraft viewed the planet mercury at a close range. mercury outwardly looks a lot like the moon. it's got a heavily cratered surface. it has planes, which we have since learned are volcanic. moonmercury has that the did not, illustrated by these images on a later mission, is that mercury is crisscrossed by -- huge fault.
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there are the faults that underline the great mountain , also the kinds --faults that accommodate these faults are seen throughout the planet mercury. the interpretation was that recruit -- was that mercury shrank, it contracted as a planet, because it cooled sue much -- cooled so much that the amount of contraction was visible and the features were
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preserved on the surface. mercury is only a little bit larger in diameter than the moon. the moon does not have this global pattern of great faults that accommodate horizontal shortening. it got me interested in the question of why mercury contracted enough to produce all these faults, and the moon over its history did not contract enough to produce a comparable pattern. that speaks to the thermal history, the history of the core , so this particular question, actively involved. nothat else may the public know about these discoveries? >> i think one of the things that may not be well understood orbiting.ronauts were i'm sure we will talk about this. on board those -- the command modules were in orbit. there were scientific instruments. some that became precursors of things that were really important that we did later in
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and in someation, cases expiration of our own planet. for example, apollo 17, there was a radar which could see beneath the surface. we were using radar to understand what was the depth of the rock from orbit? technology we use here on earth to understand how deep are the ice sheets in greenland and antarctica. ,here was the laser altimeter which tells us the topography of the surface. was in graduate school, one of the scientists, who was a geochemist who worked in apollo missions, he was interested in studying the gammaray spectrometer, which could measure certain radioactive elements emanating from the
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surface. and there was this particular one, thorium. these apollo command modules went around the crater. it suggests there were these hotspots of thorium. looking at the lunar sample, they had a suggestion it came from this large -- one of the last large impacts. later, when the clementine spacecraft and the prospector went there and was able to map the entire planet, they were able to see their hypotheses, the distribution of this one element we found on the surface, was largely attributed to a single impact that happened early in the planets's history. >> throwing material all over. the moon took one for earth that day. >> it kind of works like that. big large impacts on my
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specialty. he covered what i was going to talk about. , one of thet thing important things for what i do, is how important the samples were. , the apollo,s because they had these instrument packets where they can do these great orbital science and tied directly to the areas we sampled meant that we could extrapolate other areas. we weren't limited to just the apollo sites, we can look at other areas and say, this is exactly the -- exactly what we saw the other apollo side. crux. the crock's -- the getting these samples, those are key. cheesy,g to sound so but the moon is our archive.
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the history is hidden in the rocks. we need to get those samples not just for the chemistry, but for the ages. we use the relationship for the large impact and they are the agents that we know, or think we know, we use that for global topography today, and say, i know that area is approximately 3 billion years old. so the information we have from apollo as the basis for all of that. it's relatively few data points. it's not to get good information, but we need more, but it is a spectacular foundation. >> this brings up another segment. after the apollo program,
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everybody thought we took a hiatus. we did a little bit from robotic instruments. in the 90's we started getting back to the moon. we have a whole series of missions. we've learned an enormous amount by them. what are some of your favorite discoveries from some of our more recent lunar missions? >> i think one of the more exciting pieces of information with therned has to do discovery of ice at the lunar poles. we have this, as the astronauts saw. dry, wer rocks are very don't see evidence of water. at least, not then. , we thought the moon was bone dry. we called it bone drivers --bone dry for a couple of decades. >> we were able to start to peer intoo -- to
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pieces of the north and south pole. because of the way the moon rotates, these are places that never see sunlight. , the water remains frozen. the water remains frozen. hintshad some tantalizing from apollo raised on imagery that there were weird volcanic apollo raised on imagery that there were weird volcanic things. data, that, based on there are tons of them. reason these are interesting is because it suggests the moon's volcanic history lasted a lot longer than we thought it did. it's possible these things formed in the last billion years. for a geologist, that's like yesterday.
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and no one thought lunar volcanism lasted that long, because we thought it was dead. we have these hence we can now go in and investigate. we can now go in and investigate. man had another question. i would say one of the surprising things we have continue to learn about is how incompletely we understand the origin of the moon. agoent to the moon 50 years saying we know three ideas for how the moon was formed. it was a sister planet of the earth, it was ejected from the body by a rapidly spinning -- i forgot the third. oceans.unar magma >> it doesn't matter.
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>> the third one at the time was the capture of another body , and all of them were dynamically implausible, but those were the best ideas we had, and we thought the apollo missions would allow us to select it. said, these are really bad ideas. but we have a tough idea that was hung on to now for a couple of decades. it took the signs of the community more than 10 years to coalesce behind the hypothesis from ae moon was born giant impact, a mars sized object that hit the earth. what has challenged us in the 35 years is that hypothesis became
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totally accepted is that the deeper we study the chemical and ofticularly similarities earth and lunar materials, the more difficult it is to understand this giant impact hypothesis. was worked out several decades ago through the isotopes of oxygen, which were marked -- which were remarkably similar. if the earth was hit by a mars-sized object, surely it would be a remarkable coincidence for the impact to start out. why should the moon, which is in it -- which is a mix, and up with a system for our ability to measure it. in the last few years we have gone down other hypothesis with other elements that show a similar remarkable coincidence.
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and we still don't understand it. model traditional dynamic for throwing out a giant impact would produce a body that is different from the earth in ways that the moon is not different. 50 years after the apollo mission, we are still chasing the question -- the stepows us to take of figuring out what the next step of measurements we need. while we continue discussing have began ins the aisle. some of them have started to collect. and those online, using the appropriate hash tag, please submit your questions. minute, beforet the questions come to me and we start the question and answer period -- and they are already
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here. >> wow, that was fast. , that's great. -- >> that's great. we unfortunately can't answer all the questions. we are going to be able to answer many of them and have them online. question from the audiences, should we directly challenge thele who done -- who deny moon landing ever took place. and what is the most effective way of doing that? go ahead and start. the lunar reconnaissance orbiting the moon right now was launched 10 years ago, and it has done a marvelous job mapping the moon to high resolution. moon,s table sat on the it would see it.
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consequently, we see these apollo sites, we see the lunar limb takeoff platform, we see where the astronauts walked, we see where they deploy the instruments, we see their backpacks that they threw off their back before they walked to then leave the moon. we then see the lunar rover vehicle. we can't easily show those images, talk about those images and begin the dialogue than of what happened in that time .eriod lunarork for the reconnaissance orbiter camera team. i have applied images of the landing site that didn't make it into our -- you can also google it and it will turn out the
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correct images. you can't make the samples on earth. some of the minerals are similar. the rocks don't form in the same way. >> if you look at a moon under a microscope, you will see some minerals that are different. free oxygenhave floating around in our atmosphere, and oxygen likes to react with iron. on the moon there is none of that, so it is just metal. when you look at moon under a microscope, you can say this is not from here, we don't have free metallic iron and basaltic rocks on earth. are not fromey earth no matter what.
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>> from twitter. moon andtudying the other planetary bodies helped us better understand the earth that we wouldn't have known otherwise? this is enormously important. we are so lucky to have venus planets that compared to terrestrial planets. material -- lunar they have all evolved. what happened on venus can happen on earth, what happened on mars can happen on earth. comparing other planets really tells us a lot about how we've evolved and potentially how we are going to continue to evolve. >> i think by studying the other planets, it's really important for our ability to understand.
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part of that comes from the same physics, the same chemistry. clearly they were different you look atn different planets in our solar system. this is a real opportunity, because it allows us to understand how those processes work in different environments. you were talking about how venus and earth had very different outcomes. venus is in it -- is an extraordinarily hot greenhouse planet. it has gone under a massive amount of change on its surface. of the things that is really important and one of the fundamental questions in earth science is why do we have
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plate tectonics? look at othero planets to help us understand that question, and what is interesting is that mercury doesn't have plate tectonics, mars doesn't have plate tectonics. what is it that is special about here on earth? we start to ask those kinds of questions. >> my favorite angle is the bombardment record, we mentioned the --e history of we do have plate tectonics, which destroys everything. we have erosion. mars is eroded. mercury is covered in lava. .enus is covered in lava the moon is a unique place to see this. them apartment record, these large impacts, those are
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preserved they are where they are not otherwise preserved. when did life evolve, could it have evolved when we think it did? you had all these impacts going on. it had to happen way before this massive influx. also just on our own planet, what piece of history are we talking about his life a relatively new thing? the moon is one of the keys to unlocking a question. >> they hypothesis that an asteroid impact killed the beenaurs would not have accepted without the lunar program. --st in the geologists
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simply dismissed as unimportant as part of the geological process. earlier, theed earliest history of the solar system is not preserved in the rocks on earth, we have no rocks that date from the first half billion years. as well as we can study our own planet, the earliest chapters are not available to us. missions,k the lunar the exploration of other planets how chaotic and how disruptive the early history of the solar system was. common,t impacts were how the growth of the planets was a long drawn out
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process that involved gravitational interaction, and this benefited the city over the early history of the solar system. that impacted all of the other planets as well. it is found in the dynamics of the solar system. something about the challenging environment that our planet first phase. and the contrast between venus, earth, and mars. the starting conditions letter more nearly comparable. and yet outcomes today that are so different. atmosphere on mars that was
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largely lost after it lost its magnetic field. leaving a cold, area body. lessons forportant the sensitivity of our own planet and climate. differences in atmospheric composition. profoundhat can have differences. because the man is such a , the crustved body basically holds on to what is going on geologically. it is great for understanding what the earth was like early on.
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at some point, plate tectonics turned on. but the earth may not have started right off the bat with plate tectonics. it may have more resembled mercury and mars and the man at the beginning. with a solid outer crusts and a mantle underneath. the moon is a cool laboratory for understanding possible outcomes for bodies that have a solid outer shell. you have this crazy asymmetry on the moon. what you might not know is that the other side of the man does not look like that. impact basins on the far side of the man but they are not as big as on the near side. and they are not filled with that much lava.
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it tells you that in the planetary bodies, you may have some weird magnetism going in on the interior of the body. we see asymmetries and other bodies. all of these hypotheses are raging. >> this is a very important topic. let's go to another question from the audience. who made the lunar laser light reflector and what have we those flashing laser light coming back to us? [laughter] >> i can't remember who made those. >> so that is lost to history.
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[laughter] those?e we learning from bythose reflectors were left several of the apollo missions. is toe learn theaordinary precision, rotation rate and the distance to the man. by measuring that over many understand the interior. that is one of the main questions. try to understand in the interior, what is it like? moonis the core of the
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look like? .s it still liquid that is one of the fundamental questions. those are the kind of things we are using. >> the distance? we do it every year for 15 years? did we get it right the first time? >> it doesn't mean it is not changing. >> the man is moving away from the earth about an inch and a half every year. >> that tells us about the title interaction between the earth and the men. that is an important way to understand it. if the moon does not show while itcontraction cooled as mercury did, is it possible the moon is hollow?
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>> no. [laughter] >> let's tease this out a little bit. the ringing is in the crusts. there are seismic impacts. traces from the seismic measurement that are interior to that? that go down to the core. >> this is an example of why you archived data. the apollo seismic experiment until the endo 12 of the fiscal year 1977. the collected about eight years quakes -- men
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moonquakes both shallow and deep. the data was preserved. decades later, in the late seismologists returned to that data with new techniques that have been developed since the apollo era and were able to see features and the seismographs. they were able to see reflections from the lunar core. core is that the divided into a fluid outer part in a solid inner part. and to see a distinctive layer above the outer core which may be close to partial melting. they did that with waves that traveled all the way down to the center of the men.
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>> would earth exist without the men -- the moon? i can partially answer that. the direct answer is difficult. there is an interesting contrast between the earth and mars in the history of climate over millions of years. mars does not have a major man. as a result, the position of the spin access relative to its orbit plane changes drastically.
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the obliquity on mars varies all over the place. ice is left over new the equator . the reason we have seasons on the earth is there is a tilt to the axis. it is stabilized by the moon. the moon helps to keep the earth sewing tatian and space.
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right now it is 23.5 degrees. it hardly moves. even that produces an enormous changes in our climate. the moon provides that. really been an important stabilization for us. if you had a blank check as a scientist, what instruments would you send to the moon on the very next mission? >> something that could derive the age of rocks. we would not have to bring them back to earth, we could just wander around the surface.
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if you had an instrument on site that could do that, and there are instruments like this under like trying it is to put a laboratory the size of this room into a tiny little box. it is very challenging. if you could do that, you could do a whole lot with the chronology and lists -- learn about the history of the source of some. >> some instruments that we put there had some limitations. one of them was the duration which they were operational. another one had to do with the location. they're all on the near side. that limited our ability to understand where earthquakes
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were throughout the men. and the structure of the man. we need more data in order to understand how big is that core. now due tois there the analyzing of archived data. questions in the scientific field about exactly how big it is. how big the solid portion is. these are things that are really important for being able to understand the history of that core that can lead to the history of the magnetic field. >> one would expect that court to be smaller.
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smaller.o be >> if i had a blank checkbook, i probably would not go to the men next. advantage of the latest discoveries at the pole. i would want to core the ice. we know that there are 200 million tons of water ice in those craters. that accumulated over time. we want to understand that. the only way to do it is to get a core and be able to look at it. that will be tough to go into a place that is dark, ice is there
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, it and get that core. >> give me your blank check, i will do it. >> i really liked the idea of drilling deeply into the men -- moon. wouldd have a device that drill more than a kilometer down into the service. -- surface. what is cool about a big body that cooled slowly on earth is that it slowly separates into layers. may be something similar happened on the men -- moon. the most powerful fields on the moon are impact craters. where in the crater is that coming from?
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it is a big mystery right now. >> next question. of the exciting technological advances you think will revolutionize the place -- space exploration? >> i would say miniaturization. we can make everything smaller now. we can send 100 shoebox size .robes crashing toward the moon you could learn so much from that. putting small instruments on a rover and dating moon rocks at the surface. the fact that we can do all of , you small lab on a rover can learn so much from that. >> our ability to communicate.
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of radio communication, we are moving toward laser communication. we can bring back an enormous amount of data. science, we are very limited in terms of the data we can get back. unless you change the wavelength. technologies are right around the corner. the ability to go from point a to point b. -- ere able to saddle up to
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>> you look like you were going to say something. >> one of the things that is exciting is strong technology. just selected that technology to fly into the atmosphere of titan.
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the ability to take that technology and be able to , toore greater distances choose where you going to explore is exceptionally exciting. there are other places we can that areoing things more of flight, whether it is at or the top atmospheres of the larger planets in our solecism. >> we have a helicopter on a mission going to mars. we are going to launch in july. it is a rover. that helicopter will drive away.
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it will have a go pro camera on it. it will look at its path ahead of the rover. theill send down radio for rover to make decisions on how it will move forward. this is just the start of how we might be able to use these new vehicles. because mars has an atmosphere, and although it is very thin, we are able to navigate and it. it is a really exciting time. to end our little over you. it has been a delight. [applause] thank you so much for coming.
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that may mention a couple things about what is coming up. we will be going back to the man. -- the moon. with many more landed systems over the next few years. the plans are to have humans on the surface of the moon by 2024. , the youngsters in the audience who did not see the original landings, will have the opportunity to live what we lived in our young couriers. i don't think you will be prepared to see what will happen. it will be so exciting. we will have the first woman and the next man stepped on the surface of the moon in the southern polar region. unlike what we see with the os,, we will have severe
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reviews with very long shadows and a whole host of new science things we're going to do. a tremendously exciting era coming up. much forn, thanks so coming and allowing us to talk about our exciting first set of missions that have gone to the moon and robotic missions. only plan we have for the next decade. [applause] >> tonight, at 10:00 p.m. eastern, the 1970 film
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communists on campus. >> yes, they are communists. >> there has to be 100,000. my wife said there will be more than 300,000. just like that. i saw that field. i was looking at a dream that came true. 6:00, an exhibit on 400 years of african-american history. they were not content with their lot. they wanted to resist their enslavement. they tried to run away. unfortunately, they were not
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successful. as punishment, they had their toes cut off. past onre our nation's american history tv. >> sunday, at 9:00 p.m. eastern, afterwards. knowledge of :the gap. it is not that they cannot make an inference. they make inferences in their lives all the time. even a toddler can make an inference. that is not the problem as much as they lack the background knowledge and vocabulary to understand a passage. that has been a big problem that has been overlooked.
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>> up next, we take you to missouri headwaters state park to hear about lewis and clark in the corps of discovery as they passed through western montana. southwest montana is defined by all of the rivers that flow through this area. the three forks area is an important area. has been important historically too many peoples, even before european encroachment. it was always an important crossroads for many ancient people to come to this area. it was rich in resources. the rivers had fish in them. there's a lot of game in this area.

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