senator grassley is the champion who has held hearings about that will have more hearings. but if we don't unite and come forward then it will be a problem but what we see now in europe it is slowly catching on. just to protect them but a movement in the right direction it is not perfect clearly and we need to have strong for whistle-blower protections and departments that are held accountable if it's not accountable the what does that say about this system? because it would be much more powerful than we need people to make changes and hopefully that will work in our favor.

. . >> when the government turns on you and you are defenseless. they can pretty much but there government behind them self to crush you in many ways. i had a gentleman visit with me

and he refused to give the bush administration the names of all of the clients after nine/11. he said i can't do it, so they came up with some backdated options and put them in jail. they spent $30 million defending himself. if you read it it is quite amazing to see what went on. this is the hysterical knee-jerk reaction after 9/11. it's a a horrible thing of course, but why. but then on my side of the coin we're talking i said yeah, gave osama bin laden support, he had a 14,000,000 dollar million dollar count. he lived in cambridge, massachusetts. no connection. but granted you think there's a connection he might want to go down that path, but they had no

interest in doing that. then i told them when i gave the account of the middle east and geneva they set out that's in enough account. we had 7,000,000,000 dollars. well, that's. well, that's nice to know. you understand that a lot of of blood to holdings in new york city. you wouldn't want to go there. just one essence of investigation to cover all your bases. i guess not because you might not want to see what you uncover. >> thank you very much. [applause] thank you. thank you. [inaudible]

i be happy to sign the books for you. >> you are watching book tv on c-span two. with top nonfiction books and authors every weekend. book. book tv, television for serious readers. [applause] >> thank you. and welcome to the american museum of natural history. i'm your host for the evening. i'm co-author of the book talk, i am neil degrasse tyson. i serve as the director of the hayden planetarium. the place we went to as a kid. i was never the same after that.

like to come back and actually become director. we also want to welcome c-span. they are recording it for book tv. so c-span is in the house. [applause] tonight's book is called welcome to the universe. i love saying that. welcome to the universe. you go to director school they teach you how to speak like that. [laughter] communities my co-authors. the first michael strauss. [applause] and g richard goff the third. these are my two co-authors. [applause] >> have a seat. so just a bit of introduction. i taught for ten years at

princeton university from 1994 through 2003. before i transferred my activities here to this museum, over that time i taught a course on introductory astrophysics. it got very popular. we. we moved to a bigger space and we realized we could energize the course even more by adding other talent that has particular expertise that could feed the syllabus. in particular, michael strauss is an expert on our galaxy, its structure of the universe in particular, in fact the phd thesis was mapping the universe. and in fact we met in the andes mountains of chile, both of us doing phd's in the 19 eighties. 80s.

we became good friends and later colleagues. j richard.the.the third is one of the world's experts on einstein's theory of relativity. so while michael and i take you from stars, planets, galaxies, to the big bang, then then we hand off to rich. he, will where to go after that. can you have a deeper understanding of the universe in this descriptive things that it contains and what it does. and there we learn all of the beautiful and bizarre nuances that makes our universe what it is. pivoting on the brilliance of people like albert einstein and his theories of relativity. so rich, what are you begin, i, i had to tell one quick anecdote. we are equal co-authors in this book and the chapters have our

names associated with the lectures we had given. we speak for the publishers at princeton press and they said rolled tyson you are better known than the other two we have to make your name big. and i said no. we are equal authors in this. and then they said no we need your name big because the publishing industry. you name starts out small and as you get more know then your name is the same size as the title and then eventually it's your name in your title somewhere on the cover. so you're selling your name rather than the title and i said we can have that, we are colleagues, so they colleagues, so they handed it to the artist for the artist to figure out how to do. so my name, yes it's the biggest thing on the cover, but they but they put it on a planet that happens to be closer to you. do you see that, so we are all on planets recede into the

background. serves like okay, if you you have to do it be artistically clever about it. so rich, give us a perspective of lake show and tell here and we'll just sit back and watched because rich, i never know it he he pulls out of his bag, even today. >> let me start off, when my granddaughter allison was born one of the first things i said to her was welcome to the universe. it's a phrase phrase you often hear from neil. when you are bored you become a citizen of the universe. they lose you to get curious about your surroundings in this book will help you with that. we start off telling you how big the universes. so. so i brought some models to illustrate that. this is a hydrogen atom. it is a billion times bigger than it is supposed to be.

this is enlarged by a factor of 1,000,000,000. you know what 1,000,000,000 is, you have a dollar, it may be if you're lucky you can get a hamburger, if you are billion dollars, you are billionaire. that's a big number. this is 1,000,000,000 times bigger than a hydrogen model. this. this is the electron in orbit around the proton which is the central nucleus of the atom. this is a proton on the actual size of the proton on the scale would be 110,007-inch. most of the hydrogen is actually empty space. this is most common atom in the universe. it is the is most common atom in your body. most people might think the only thing, there's nothing really intermediate in size between and adam in the nucleus of the atom. actually we found some things. one is called mu on a cartridge

inches it's a hydrogen with, instead of an electron orbiting around it it has a muon which is a heavy cousin of the electron. it weighs 207 times as much is the electron. the orbit of it is 207 times smaller. on the scale it would be about a 20th of an inch. it reminds me of that movie, honey i shrunk the kids, did anybody see that. the professors apps the kid and they shrink to about one quarter of an inch in height and then i have adventures in the backyard. it's not quite as crazy as it sounds. if all of your electrons were replaced by muons you would shrink in size by 207 so you would be timely. unfortunately the muons dk back

into electrons by emitting a muon and an anti- electron and so they do this on the scale of 2,000,000 silvis exit. it would be a very short film. it's a. it's a go for the short film oscar. another thing that is intermediate to is if you take uranium, it has 92 protons and 146 neutrons in its nucleus. if you stripped all of the electrons except for one because of the large charge it would be 92 times smaller than this. so about one tenth of an inch. there are some things and we have made these in the lab, both of those things. there are some things intermediate in size between the atom and the nucleus of the atom. this is small, let's go the other way.

>> hold on just a minute. >> meal could hold that. >> you suspended something in the middle. >> that symbolic of the proton. so that you can see it. let me go the other way. i am going to go up by a factor of 1,000,000,000. suppose we shrink the earth by a factor of 1,000,000,000. here it is, the marble half an inch across and believe me, i have continents painted on here. this is an actual continents painted on here. this is an actual globe of the earth shrunk by a factor of 1 billion. this is one over a billion scale model of the earth and then let me get, i have have the moon in here but the moon is so small. here is the moon.

>> we can all see that rich, really good. [laughter] it is one of marriage. and the moon would be 15 inches away. this is how far humans have gone in the apollo program. this is all the further we have gone in the universe, 15 inches on a scale of one and 1,000,000,000. that is how is how far the moon is away from the earth. >> and then how big is the sun? i have the circumference of the sun appear. this is how big this sunday. >> is a hot wheels track? >> yes. but i have to spin it so it makes us fear. this is how big the sun is. it is a 55-inch beach ball and it's

about 500 feet away. that's how big the suddenness. >> if if were a marble, you've heard of the earth as a blue marble, one in a billion. this is the sun how big the suddenness and it's a 500 feet away. and now the question would be, how far away is the next nearest star. the sun sun is a star. but the next nearest star call proxima's -- here it is. so here is proxima sentara. it is a red door*smaller than the sun. it sun. it is 4.3 light-years away roughly. it is, that means means it takes lights about four years to get to us from it. >> to be clear that is the actual size of proxima's

relative to the sun symbolic to the earth here too. so this is a scale of of one in 1 billion. it's smaller than the sun. this would be on the model, this would be 24000 miles away. so we could go all the way around the circumference of the earth, i will hand it to. we will get to that. you can go go over there, stand over there. so he is going to hold so he is holding -- that's 25 miles away from us on this model scale. and then we recently discovered a planet going around the star. it's a little bit bigger than the earth and so it's about

24 feet away from its star, this is a planet bigger than the earth. it is close enough to the star that it is locked. it only should always keep one face toward the star and one face away as it orbits around. so one side's gonna be too hot in the other side too cold. so not too likely to be habitable. this is the nearest planet to us that we have found. that's how. that's how far away it is. >> so rich, while keeping the same scale, you have the moon, blue marble, the moon, 15 inches away from the little blue marble and in the sun the size and then proxima's, 24,000 miles away. >> that's a lot of empty space and is the nearest star. >> so the for this we been is the moon, what hope do you have

for the future of space travel? >> well, you just have to get that much better. [laughter] you have to spend more money. [laughter] 's okay let's go up by another factor of 1 billion and i will show you a model and the scale of one, not not one over a billion which is what we just saw which is one over a billion billion. this this is a billion times smaller also. here's the sun and there is the alpha sentara, this is another solar type star. it's part of a triple star system that includes proxima's

-- is a triple star system but the brightest one is a solar type star and it is again about 4.3 light-years away. here, on the same galas of blue star, you've seen that, you seen that in the northern sky, the brightest star in the sky, it's about nine light-years away. these are some near stars to us and we are living in the milky way. it has 300 billion stars in it and it would be about eight tenths of a mile across on the scale, a big disk of stars. they are about this distance apart. if you want to this model in a scale of one over a billion, billion, it would be like going through a snowstorm of stars. the next big galaxy to us is andromeda about 20 miles away on the scale. >> so rich, if you get another

299 billion, 200 million, 297 light. >> i would be read. >> we could reconstruct. >> i just need to work on the model a little bit more. so now we have the skill but let's go up another factor of 1 billion. so now will look at one over a billion, billion, billion. a billion times more than this. and then you will the entire visible universe here, we are at the center of this. this is the cosmic microwave background radiation, it's as far as we can see. the universe is 13.8 billion

years old, since the big bang. the radiation from this background which is left over from the big bang has been coming toward us for 13,800,000,000 years. the radius of this and what we call look back at what we call look back at distance is 13.8 billion light-years, thus the radius of the sphere. so we look out in space .. in time because of the speed of light. this is as as far as we can see. inside the sphere there are 130,000,000,000 other galaxies, each one was several hundred billion stars in them. so this in them. so this is the cosmic microwave background that we can see. now we can't see anything be honest but light from those regions have not had time to get to us. >> you just put yourself in a rather privileged vantage point to even show that. >> this is what we see, it's just like if you stand on top of the empire state building you are going to see a circle out to the horizon, that's his right as you can see. is centered on the empire state building.

if you go to the willis tower in chicago you're going to see part of chicago and it's can be centered on you. the part you can see is always centered on you, that doesn't mean you're special. everybody sees that. so everywhere you go there you are. we see this and we have reason to believe though that the universe is much bigger than this. the fluctuations in this are only one part and 100,000. we believe the universe is at least 100,000 times as large as this improperly larger. large as this and probably larger. the best theory for explaining in detail the pattern of fluctuations that we see witches this is based on observations from the w map satellite is a theory of inflation. which alan put forward in 1981, in that theory that explains how the big bang got started. what it says is that you could

have started the universe with a very tiny region, minus 27 centimeters across of high-energy vacuum state, what is that? well, we're used to thinking of the vacuum is being empty. if everybody left the auditorium and if we took away all of the air in a completely empty space he would think that would be zero energy density. but in fact, because of going through the universe like the hicks field, the universe can have a vacuum energy, and non-zero vacuum energy. zero vacuum energy. so if it has a nonzero vacuum energy, because we would like the vacuum not to have any privileged standard of rest. so if rocket ships going through this vacuum at different speeds are all going to measure the

same vacuum energy by the logic of special relativity. it must be the vacuum energy is associated with a negative vacuum pressure that operates in three direction, front, back, left, right, up, and down. this is uniform pressure. it exerts no hydrogen effects. so we have an air pressure 15 pounds per square inch but you don't notice it because it's uniform. you have to have difference in pressure. so this is uniform pressure, no hydrogen effect, but it has a gravitational effect according to general relativity. because pressure gravitates as well as energy in general relativity, so that means it has a repulsive effect because it's a negative pressure and it operates in three direction so is three times more potent than the

attraction caused the energy density. this causes a gravitational gravitational repulsion and it starts universe expanding. it expands faster and faster at an accelerated rate. it keeps doubling in size once every ten to the minus 38 seconds. so in the first ten to the mind 35 seconds of the universe existence it could double in size 1000 times. that is ten to the 305, so it can become truly enormous. this explains why the universe is so this explains why the universe is so enormous and why it is so uniform and in detail it can explain the pattern of fluctuations that we see. so the theory of inflation is very effective at explaining this. one of the problems is that what you want to have happen is you want this high-energy vacuum in the universe to decay into

normal particles to make the hot big bang that we see. we wanted to dump its energy into elementary particles. the problem is that you are trying to like blow water on the stove and the water represents this inflating see a vacuum energy which is inflating very fast and you wanted to turn into steam and ordinary particles. what happens is if you have ever boiled water on the stove it forms bubbles. so we expect expected to get bubbles of particles forming in this and that didn't like uniform. i was one of the people, myself and andre who proposed in 1982 that what happened was we were living in one of the bubbles. these were individual bubble universes that were expanding.

from inside the bubble looks perfectly uniform. the other bubbles are so far away the light has not gotten to you yet. so this would solve the problem of nonuniformity with inflation. this is called new inflation, that theory predicts in a rather general way that once you get inflation started, it's really impossible to stop. it's just going to keep making more more bubble universes forever as it continues to double in size. eventually you'll get an infinite number bubble universes. these bubble universes. these can have different laws of physics in them. so you get a multi-verse. we think we live in a multi- verse. so this is all fast compared to the tiny region of what we can see. one of the the reasons we believe these other universes out there exist is the theory of inflation predicted and the theory of inflation in the book it beautifully explains the

pattern of fluctuation that we observe in the cosmic background. another reason we believe in inflation is we're observing inflation starting again and universe in a rather low-key fashion. we're seeing the universe today in an accelerated expansion. two groups from this in 1997 per they won the nobel prize for this. the this. the universe is going to be doubling in size once every 12.2 billion years. today it has a very low vacuum energy of seven times ten to the minus 30 grams per cubic centimeter. so we have seen a low grading for form of inflation occurring today. this is another reason we believe in inflation. i've talked about sizes in the universe and one of the reasons people think that pluto got

demoted because of its minuscule size. so i would like neil to tell us about that story because he was a big participant. [applause] >> rich, you took us from the hydrogen atom to multi-verses and verses and then you don't pluto in my lap, just to be clear. >> in the visual above my head that we have what we call the terrestrial planets. these are the planets who services you can walk on, mercury, venus, earth, and mars. the moon is also shown there which looks quite small but something to know about our moon is that it is one of the largest it is one of the largest moons in the solar system. even most of the moons of

jupiter and saturn are dwarfed by the size of our moon. we have an uncommonly large moon relative to us. in spite of how small that looks. the point i want to make is that pluto, people we have history here with pluto in this institution. back in 2001 we open the row center for earth and space we are the first out-of-the-box to reassociate pluto's identity from the company planets to the icy, vice, the ice balls of the outer solar system. so we were raked over the coals by the press saying, especially little kids send their angry, pissed off third-graders same just because it's small how could you do that. there thinking that size was an issue.

in fact it had much less to do with size than you might imagine. if we can go to the next slide which we have. now we now you have the gas giants, jupiter, saturn, uranus, and neptune. and then you get to see how small earth is relative to the action there. earth is included in this for scale. here's a point i will make and i don't get to make it often enough. jupiter is more bigger compared to earth than earth is compared to pluto. i don't know how else to conjugate those verbs in that sentence. so in other words, if we are on earth saying we are big enough to be a planet but pluto isn't, then imagine what joe behan's could be saying. they're saying the solar system has only four planets, jupiter, saturn, grayness, saturn, gratis, neptune everything else is

debris. [laughter] so i'm certain all life forms jupiter thinking exactly that way. so you cannot invoke sizes exclusively to this pluto in this regard. allow me me to tell you that our moon, a small as it was compared to earth has five times the mass of pluto. so pluto lovers were never told that where you. welcome to the company of informed people regarding pluto but we knew this, so pluto had other issues so after some thinking about this, pluto got the motor to a dwarf planet

status on several grounds. one of which that it orbits the sun in a region of the solar system where there is plenty of other stuff orbiting their which in total doors the mass of pluto itself. so pluto does not own its own orbital place in the solar system. it it is shared with countless thousands of other icy bodies that rivaled pluto in size and composition. so what we really discovered was that pluto never really was the planet we wanted it to be. in fact it went 60 years before we discovered is icy brethren orbiting beyond neptune. and that that could be named for an astronomer midcentury named gerard who hypothesize there could be this repository of excess debris that did not participate in the formation of the rest of the planets. pluto is very healthy object but

a really lame planet. so just to make that clear. now when we look for other planets which have been quite the pastime these last several years, by by the way i'm curious if anybody in the audience is 21 and younger. razor ham. it means you are born in 1995 or later. we'll 1995 was the year we discovered our community of physicists discovered the first xo planet. so i want to say to you you are the xo planet. you've only known life in a world that we've gone beyond the backyard of the solar system. so so what a privilege that is. so in our book we calculate how you might go about finding xo

planets that will be of particular interest to us. what is that you would be after, not necessarily rings although they are quite beautiful, at the end of the day you are after weather can harbor life. life as we know it, perhaps life of any kind. so there are ways to approach that problem one of them is called the drake equation named after frank drake. >> let's put that up, that's an image of frank drake in the corner. i think he's much older than that now. is he still alive? >> baskets no he is 130 last i saw. [laughter] so frank trait, who is early in this exercise of asking what is the likelihood of us communicating with alien

intelligence that can work in a planet in the galaxy. he came up up with a clever way to attack the problem. you come up with an equation and that is him writing him writing the drake equation sitting under his pen in that photo. what i've done in the slightest made a simplified version to get the idea across. there several other terms in the the equation that he is written. we'll start with this version see get the idea. we want to calculate the number of civilizations that could be out there. let's start with that. this would be life in its creative organized societies. so that's the curly end. the number of soulful as asians. how would you go about doing that. you want to split the problem into multiple bits. each part of that problem could be entire science projects to try and address. that way if you unpack the

problem separate in the variables. otherwise you don't know if you're coming or going and what's influencing what. we struggle with how many total stars there are that you could be searching. that is in stars. so it would be the number of stars in the galaxy and that's coming in lately at about 300 billing. billing. you may have seen a hundred billion, this is just all the numbers of the same to us. what's a few hundred billion between friends really i say that not facetiously, they are galaxies that have a trillion stars and galaxies that have only a few hundred million. so if you're in a few factors of 100,000,000,000 that's the same number given the range of sizes of things that are out there. so to start with a number of stars and what you want to do is ask what fraction of those stars

have planets. you want to look for life for there's a planet presumably. you don't expect life thriving in stars. that's hazardous to molecules. in life. what fraction of those have planets. that would be be its own astral physical exercise. you created telescope mounted on the satellite which we have done it measured a piece of the sky and look for what fraction of the stars have planets. you can do that. now it turns out not all planets are good for life. some might be too close to the host star and be too hot. too far away, too cold. too hot or too cold for what? life as we know requires liquid. so you would want the zone around a star to be just right.

the goldilocks zone. if you are looking for planets you want a planet in that zone print if you're looking for life as we know it. what we did that it in its own term fraction of planets, you can imagine that as its own term separately measured in just a fraction of stars with planets around. so now we have some fraction of the total stars left that have planets that have planets that can sustain life in the goldilocks him. so how many do sustain life, is it half, one tenth, we don't really know. so not all these terms have equal confidence in the numbers we insert.

but you keep going, if it does have life what fraction of those planets and stars that have planets of the goldilocks zone that have life, what fraction of those have intelligent life? so here we are hacking away at the number 300 billion. is it one and 100 times one and the thousand times whatever these fractions are your hacking away at the number but it's a big big number. there's a lot of wiggle room to give you something left over at the end. by the way, these are civilizations he would you would talk to in some way. well, how would you do that if they don't have technology to send signals through space how think about it. most of human cultural history we had what we called intelligence but there's no way they could have a conversation with an alien. they didn't have technology or radio waves. they didn't know anything about it.

so just because you're intelligent doesn't mean you are a candidate to communicate with. as it set up were counting civilizations. add up those terms and ask how long have we been able to use radio waves? maybe 100 years out of the thousands of years of cultural human history. sophie started the timeline of civilization, and do that blindly, what fraction of the time does that hit us with the capability to mitigate with aliens. it's a tiny fraction. if you call upon a planet randomly in its life what are you likely to find? that's the questions that are addressed in this equation. when you put in the latest numbers and all the numbers in terms, what we come up with his

was the number of civilizations in the galaxy? 1.8 billion happen all planets. >> these are planets in the habitable zone. >> earthlike size 1.8 billion. >> and may be as many as. >> so that would be like those are planets capable of hosting life as we know it. >> and the other one could be as big as, may be smaller than but could be as big as 100 that are communicating with radio waves now. >> so that's hopeful when there are other galaxies don't forget about them.

>> so here's an image taken from the southern hemisphere of the milky way galaxy. let me explain to new yorkers, this, this is what the sky looks like. if you remove the buildings, the like, the, the pollution, one day want to write a novel that implicates the amateur astronomy community for all of the major blackouts that new york has experienced. you parked and there they were unplugging new york and forcing you to come out, look up and notice we miss in the moon and things. it is stunning. just to embrace the sheer scale to recognize there is 180 billion planets in habitable zone.

>> scattered across the galaxy. that is the plane of the milky way galaxy. we are in the galaxy, within it. that is the. that is the plane. all of the other stars above and below are part of our galaxy. they're just really close to us. they're like a blueberry embedded in the pancake. you can look out above and below and escape the door of the pancake. but if you look within the dough of the pancake is pancake all around. so when you look at the plane of the galaxy it's galaxy all the way around. completely wraps the sky. want to know for you it was mentioned that our nearest large galaxy is the andromeda galaxy name so because it appears among the stars identified with a constellation andromeda. but it's much for their way. the stars in the constellation are part of our galaxy looking through a screen door out to the rest of the universe. this image in the southern

hemisphere has two fuzzy, cloudy things off to the bottom and. >> so was that not clear? i said two fuzzy things down there so they look like clouds. while native inhabitants of the southern hemisphere surely knew all about this, we in the west first learned of it from the journals of magellan who a pound circumnavigating the globe one to this set there and hemisphere, saw the clouds and notice they never left but he still called them clouds because that's what they look like. to this day we refer to them as the magellanic clouds. we know now to be good dwarf galaxies in orbit gravitationally bound to the

milky way. so they are nearby. by the way it is not all roses for small galaxies in orbit, we have a record of small galaxies that once orbited us. they have been completely cannibalized. we see the remnants of streams of stars fully absorbed into our own system. so door galaxies have limited lives when they have to hang out around these big systems. the the mention that because will make reference again to the large cloud, the larger of these two fuzzy things in the sky. i think that's my last -- >> just to be clear, i don't know if we can dim the lights briefly and bring them back up and we'll see if c-span can handle it. what you have here is one of the

most famous images ever taken. it is by the hubble's base telescope and is called the hubble ultra deep field. by deep we mean how far into the universe is that pitcher breach. it is a nasa photo. notice there is a reddish object with spikes. that's a star sitting on our nose in our own galaxy. that that might be the only star in the photo, every other smudge and speck of light is beyond the stars of our milky way in the represent entire other galaxies, each containing hundreds of billions of stars. we talk about the probability of life we contain it within our own milky way. but if you want to multiply up by the skill of the universe and all the galaxies contained within, you would have commute

be inexcusably egocentric to suggest that where the only life in this universe. by the way, this area on the sky is a tiny fraction of the area of the full moon. so you take this and multiplied out by all the points in the tiles that you can fill up the sky with and that is how you recover these numbers such as the universe contains -- 130,000,000,000 galaxies. we can bring the lights back up. let the lights back up. let me hand off to mike. >> i have to move. >> we are going to go back to the milky way. this is the view of the milky way from the inter-american observatory which is where neil and i met almost 30 years ago. >> it was a couple of years ago.

>> meal i think you are using the telescope there. >> i was primarily in the .9. >> i was using the 1.5 meter. you can see the milky way rising dramatically in coming over our head. one of the frustrations if you get away from new york city's bright lights, one of the frustrations is that the brightest parts of the milky way are not visit or trade visible to us. actually looking straight to the galaxy galaxy center. >> i add something. >> this is at the summit of a mountain in the andes. occasionally you get weather that is below you. so clouds, total cloud cover below you on the top of this mountain. if there is any moonlight data and you look out over the edge of the mountain it

is like you are somewhere unreal. you are otherworldly. you're an island in the middle of clouds and there is no earth. it is just just you, the telescope in the cosmos. [laughter] so with that i get a finish. so, i may be the last, we we may be the last generation of astrophysicist who actually went to mountaintops to obtain her data. in the pilgrimage that this represents, applying to santiago and transport and then practically mule train up the mountain, and then you invert and live nocturnal he because the night becomes your day as

the day becomes your nights. within a few years of that we now have what's called surface observing, we send send your coordinates and give the specs and they point the telescope, it's automated and they send you back the data and you never left your desk in your office. it's way more efficient but i think it's absent some of the romance. i will shut up. >> so what we do is set up a long exposure with the telescope. in telescopes 30 years ago are automated so they took care of themselves. so we go out and enjoy the view. it is spectacular. it's wonderful. there are several telescopes the observatory. we would bump into each other on the mountaintop enjoying the view. in addition to neil and myself working on our respective pieces i met the woman who would later become my wife, sophia. she was on the .9-meter about 30

years ago. i just wanted to mention that here. so let's talk about what the nature of the milky way is. it is 300 billion stars. so what is a star? neil has said there tremendously hot, we've heard how enormous they are. a star is a ball of gas held together by its own gravity but held up by internal pressure. giving off a great deal of heat and light which in the case of the sun is what keeps us alive. one of the great triumphs of astrophysics is learning what the stars are made of. one of the great discoveries indeed is that stars are made up of almost entirely of hydrogen and helium.

what we have are elements of the periodic table indicating the size of each box proportional to the fraction of the mass of you find in stars. hydrogen and helium dominate the elements of the universe by far. everything else represents a trace. the makeup of our bodies and neon and magnesium are just a small fraction, tiny fraction of the atoms in the universe. one of the fundamental questions we want task is wise that the case. how is it that the universe can come this way. the hydrogen and helium in the universe came to us from the big bang itself. the early universe was hotter than the surface of stars, temperatures temperatures that range to billions of degrees. >> you can say that far better than i can. >> point to me when you need me to say. >> it was so hot that stars

cannot exist, molecules could not exist and even adams could not exist. it was so hot the thing that could exist were protons and neutrons, protons be be in the nuclear of hydrogen atom. as the universe expanded and cooled in the first few minutes some of the protons and neutrons came together to make helium. one of the great triumphs of our understanding of the early universe is that we can predict the amount of healing that were produced in the early phases of the big bang. it matches with the experimental values by measuring the spectra stars. basically the early universe gives us hydrogen and helium. his first thought we would be able to explain the rest of the periodic table from the big bang itself. it turns out not to work. so we need another explanation

to see how the heavy elements are made. the answers going back to the stars. if you go back to the sun and ask ask the question what is happening in the center? what is the fuel source that is causing the sun to shine the answers is it in the very core of the sun with 15 million degrees in tremendously high pressure, under those conditions the hydrogen nuclear confused together a process called nuclear fusion to make helium nuclei and release energy in the process. we describe that process in the book. hydrogen is being formed into helium. that's a. that's a process going on in the sun right now. the story gets more interesting for more massive stars.

our own son would be able to burn hydrogen and helium and later turned helium into carbon and oxygen which are primary elements that make up our own bonding. if you want to get to the rest of the periodic table uni massive stars. a star maybe times as massive as the sun as it continues to grow and use up the hydrogen than the helium, then the carbon and oxygen can burn heavier elements and start creating elements of ever larger masses, working your way up the periodic table. turns out ira and which is a limit number 26 in the period of table end of the story. you cannot combine iron with anything and get energy out. it it requires energy to combining with anything to make a heavier element when the star gets to the point where the court is

made purely of iron, then the energy sources gone. the stars been held together by gravity. i told you the furnace in the center is giving your pressure that's holding the star up. you turn the furnace up on the star has no choice but to collapse. it's cap collapses catastrophically. the outer parts that have not yet reacted undergo nuclear reactions at a tremendous rate. the star explodes. >> we know the supernova exist because we can see the leftovers, this is a particularly famous called the crab nebula observed by the hubble space telescope. what we're seen is the smithereens of the star, broken into, this is known to be a star that exploded in ten 5480. because the chinese because the chinese left records that they

actually saw it explode. they said it was a star in the sky and it was bright enough to be seen several weeks even during the day. then we find this dramatic residue of that exploded star. the gas that we see here has all those heavier elements built into it. >> just be this is the guts of the star, this is the bonaparte guts. >> it's really nasty looking but also physicist today celebrate that explosion every year because the chinese observed it on july 4. so we fireworks in the astrophysics community celebrating, just fyi. >> it turns out in that explosion it did not destroy the star completely. right in the middle, maybe that spot right there is something called a neutron star.

a dense center part of the star. may be about the mass of the sun. made up appear neutrons. again again the mass of the sun may be only 10 kilometers across. one symbol full and i think we have said it weighs about 100 million elephants. if you can get your thoughts in mind around such an incredible thing. so remember, the iron that the star can make only iron and then the process stops. then the star explodes as a supernova. they're so much energy in the explosion that heavy elements can be made. and so there's two different stories that were trying to understand as possible ways to make the heavier element beyond element, one is they are formed in the explosion and the other

imagine you had to neutron stars and they quite together which could happen under special circumstances. that's another way to give you the energy to get heavy elements. so the golden my wedding ring here is formed in the center of an explosion just like to see. in fact, most of the atoms in our body and all the other elements other than the hydrogen and heal were forged in the interior stars. it's an awesome thought to think about. . . .

>> >> certainly one of the most dramatic the closest supernova has exploded in 400 years plus the very literal translation means

new in fact, it is a dying star the label later learned a new star to you. >> m1 to go back to the milky way. he did not mention his own specialty to study the stars this is the movie from the european observatory eighth walking into the milky way the very center is a special place one but at the very center refined something that is dramatic there is of black call in the middle of the milky way. it is black as you probably know something so dense nothing can escape, not even light so how can we in for its existence is by definition? >> one and has no light but

we do see that influence is a diagram one from the colleagues at ucla but she has mapped the orbits of individual stars at the very center of the milky way and they all seem to orbit around a single point to write in the middle. no light is seen buchanan for how much mass must be associated and also get a limit on how large the object is his invisible very tidy incredibly massive. and what is that object? hit did say black coal.

>> one of the great discoveries of the last 15 or 20 years is the realization the milky way has a super massive black coal but all large galaxies seem to have a similar one of to make few billion times >> one of the things is to study those massive black calls it is so dense we cannot see it there is a way to run for the presence of of black call imagine going into that as a close so bright that quasar canby's

seem most and to the edge of the observable universe it is 8 billion light years and that represents a limit that has time for the light to reach us. did things have that aero to point to the quasar that is 13 billion light where -- let years away. that is the mirror 900 million years. so that gives us important clues. >> so give varying a series of lectures when discovering pluto with that algorithm how did you know, ?

he said there was a narrow pointing to which. [laughter] very much a needle in a haystack. they are interesting but the real dramatic discovery over the last year we could get into the book at the last minute the most direct evidence as the general theory of relativity imagine to a black holes. einstein's theory predicts that to black holes as they go around each other they wore space and time to send ripples like when you throw a stone into a pond. they said out anergy that

causes them to get closer and closer together eventually to merge. and of the observatory was built to measure incredibly subtle distortions in the fabric of space and time. it basically consist and measure is a change of the 4-kilometer long which is the with the base single proton. saying it is 29 times the mass of the other to merge together as shown in the movie to make a single black coal with the mass of 62 times the sum of view say that does not make sense.

something seems to be missing is the energy lost? remember einstein told you = mc squared. end of the two black calls -- black calls. to show that quantitative detail that the black coal exist. >> that is equivalent to energy to make this the most energetic being in the universe by the factor of a thousand. >> incredibly dramatic but now we're at the threshold

in our study of astronomy not to see what is happening with the gravitational wave that should be exciting development. this is just a quick diagram to show the actual measurements and compare with what was observed now i will skip that to talk about the future one of the wonderful things about the universe is a very big place and there is a lot of exploration to do we are very much in the expletive -- exploration mode to learn fundamental the things of the universe to see what is out there. with that artist's conception and with that

observatory from what i have seen before. and out and 20 or 22 to have love map of the sky multiple maps repeatedly how does he differs change? can we see those times x and then and then reread lucky to travel last year for the 25th anniversary and the ceremony starting us start of construction standing on the of none top and again

starting the construction. >> are we allowed to stand at close to the emergency found? laugh laugh. >> so with that we will go back to rich. >> in the book we have a map of the universe stretching over several pages from laugh to to write a panorama looking now from the earth's equator to show this is so vague - - away from the earth so each coniston step out is another away from the earth. so let me point out and

there is the satellites. >> it is made very clear the shoreline of the cosmic ocean it has them with us for some time. >> this is that satellite. >> this is those that the observatory. >> now we get into the realm of the planets. >> close talk about those that could render us extinct [laughter] but what this would lead to is see if they will hit us in the head.

>> haley's comet we have voyager number one and two. and with the rest of the galaxy. >> and then he died. so another zone of commons and then those reservoir comments. >> just to be clear they are serious. every tick market is a

factor of 10. said they had reached base which was run includes hiller olympics some of the first signals that aliens will receive timothy hundred billion stars you count as they go by. >> we talked about the embedded the distance with factors of 10 with each check mark. >> now into the of realm of the galaxies andromeda and a number of others that we have named whirlpool and sombrero. laugh laugh we call them as we see them.

you know, i am right the crab nebula. >> did each represents a single goal galaxy. and then that would be right here. >> and then stretching is the backgrounds here. and then to see all round us. and that is the universe. [applause]

and that is about 5% of the the of book. we have tim microphones. >> we will be out in the hall to sign books this is the only occasion role three of us will sign the book. this is unique just so you know, . with people lining up if you must leave now because you part to a faraway you can pick up a book that is pre-signed c. don't have to wait in line.

>> we encourage people with children and particular one. >> >> xx plan to do a video lecture series based on the book lacks. >> may be. >> the way to get it is the book. >> can you explain why there is no center of the universe even if you look from where the edge of the universe is quite. >> if you imagine a big balloon in did is pulling up this is the picture of space expanding if he sits ulysses

all the other queens fleeing from you so looks like you're at the center. we think we're standing on top of the year and australia is upside-down and everybody thinks they are at the center there is no particular center all the coins are equivalent but you see the region around you. >> the very word mediterranean. so wherever people work they thought they were in the middle. >> with the occasion marriages another part of a reflection.

and it was never stripped away. so what effect do you have to be looking for? with then uh goldilocks on. >> there is a lot of research how important was the of moon not and formation of life itself but if you have the stability necessary to develop the complexities that the biodiversity has given us. >> my opinion it is it is a live overstated.

>> and think of how diverse life already is. in us tropics for all we know that could have even added more. so i'm not worried. that we have a big moon stabilizing. >> to be very specific about that situation but some parts of that do make sense. there is a variety of ways to do that. >> the tide helps with the

moonves so does the sun but that could help get them onto the land. it does not seem absolutely necessary. >> why is the moon so big compared to others? >> our moon has a fascinating back story it did not take shape until after the apollo era where they brought back samples from the surface that we see it is made of the same of the earth crust foreign object of that size is shed have a mixture of what is in the solar system with courage and -- carbon and oxygen and hydrogen.

but it has hardly any iron. because when we formed it is heavier so it goes to the court and is solidifies. but the amount if has no iron or does not have the iron core what happened? that led people to think that maybe it was formed later after earth had already differentiated leading to the hypophysis the mars sized object sideswiped earth to scoop up our material to reform what became the moon because of that part this very heavy bombardment had leftover material from the formation of the solar system. but by the way just to be clear, the moon is a little heavier than one

one-hundredth of the mass of the year. so with is not that much material to give of yourself to make a moon. i promise you will not miss it. >> ed is a completelcompletel why different story line. that is how we get a big one. >> i am a fan of smart talk. >> it is a labor of love. you are well known to be on top of science and pop culture. i am curious how someone like you call do manage to

do both? where to get your news? >> i am a clone. [laughter] it is nearly impossible. but i cheat. looked to see in the number one tv show and catch a few episodes. what is the hottest team? it is the cubs let me check up on that. sold then i allocate my a energy with did deepest and most public attention. but then i take the laws of physics of the universe to find ways they can plug into what they care about. you come to the party with the pop culture scaffolding then you walk away not having to learn to know what

you know and love. there were two examples of this. channel surfing f-15 minutes than a football game ends in a tie so a goes into 15 and over time. i can't get that in. let me watch. why not? there is a new rule has to change can say couple of times then it is sudden-death. they get close enough so then he kicks and it is stretching it to the of left hitting it considered

weightless check the distance did check the orientation of the stadium. [laughter] and i carry the to. [laughter] and i said this winning field goal by the one-third of an inch draft powered by the rotation of the earth. [applause] >> i don't have to explain what led a field goal is and i just gave you the course. >> ag got phone calls from.

>> did not have any special knowledge but war i and. >> soda gcs getting to see officer injuries system in the next 100 years and spent iq artaud king about the recent announcement, that is compelled by the pressure of high speeds steven and we have in l. a -- still neck-and-neck princeton said

they're working on that. >> >> next time try not to come up to the microphone and then a cough. [laughter] >> is of milky way collapsing and? >> imagine what if the sun turns into a black call tomorrow. one often has a mental image but if that is not.

>> negative did have qualified but by an elected the central buckle one but the orbits are perfectly stable. >> i would say 10 million or so but this thing whether

the buckle in is a vacuum there is a joke there is no such thing as gravity. [laughter]

but then you see where it says things are going badly. [laughter] but you never see that part because the of light signals are never getting back out. but you can see that process and the reverberation.

and then we have the gravity waves to show it to. >> is happening at the edge. you can see things but if you use a spaceship is alive >> we don't want to go into the sound byte mode for answers. [laughter] so presumably yes some point

is it possible for the vacuum. >> we had a very low vacuum is rich in des want somebody available and therefore but apparently with those new were billable universe. >> that would be bad.

let's and did the far future for? >> going really quick. go her. >> just in the layman's terms. [laughter]

but then that process of less the magnetic field is anopheles understood in the case of the earth for that matter. >> but hopes that you have either and that can move as a core but they deere is complete the cools down respect that magnetic field to go away entirely. for example, it does not have fired.

>> does universe expands from the center or the sides and then she'll let you about those stupid measures is just getting bigger the faces expand but the senator more than any of other. >> snow expanding this but that is for everything was at the beginning. one for any of those galaxies that exist. >> at what speed but if we

sit here and everything can the faster it is moving. one and maybe even 1,000 kilometers every second. but we talk about the speed of light in some details to make it is a proven fact. >> we will take for fast questions. >> what made a foot -- motivated you? >> we will save that for last. >> how many black holes are and done galaxy price limit there is only one in the big center people argue about

that those may exist but that is hard to see. this is from what i learned. [laughter] >> what is in your basement? to your parents know what you're doing? >> as you guys said but

therefore all there is is it is an iron and a block kohl's. >> the universe will attend in exactly the way that you describe ; the gas clouds will run at of their ingredients the stars will run and a fuel they will burnout no new stores will be made n did you look at the night sky those stars will disappear one by one never to be replaced again and we will have an entire universe. have a nice day.

>> will our species ever interfere plaques. [laughter] and. >> key is worried about what will happen in 7 billion years. hours species has did around

one so our species will not be around. when is to lessen. >> but it will be an awesome train wreck because those patterns that the galaxies in july. and i always wonder where the gravitational legions could be compromised. so it will be a fascinating future it is about 7 billion

years from now so put that on your smart phone. unless you invent something that enables you to see that. >> >> if duquesne if you have a black call -- of black hole and see that again so it is possible in principle but not really practice

depending on how far away the black call was very practical answer is imagining other aliens at a certain distance so think of the galaxy 65 million light years away. that it sends out 65 million years ago was happening and faster ride so 65 million light years away you'll see the t rex croak in realtime that would be really cool. i would think. >> you briefly mention the

gravitational waves with uh dilation of the atomic nucleus would if you have to massive black cole's class. >> the europeans are developing the satellite of 4 million kilometers of super massive black holes. but that typical resistance is even larger so stay tune. >> you are 12 and you ask?

>> i was interested did eight years old there was a book with peso was jailed low. >> accused of resold in a place called a bookstore. i joined the yond astronomers club. >> given high school live was reading a lot of blocking at the night sky i want to be an astronomer he said you can i get a job doing that. >> and keeps us very busy.