I think up until well, really, up to the year 1600 when we didnt have any particular tools to investigate the natural world, our five senses were the primary means by which we obtained all information about the universe, and not even knowing that our five senses had limits. If its everything you know you think its everything the universe is trying to give you, but in fact its not. And so around 1600 with the invention of the microscope in one direction and then the telescope in the other direction, each invented wind a decade of one another, all of a sudden pieces of the universe become available to us that transcend our senses. The fact that they could look inside of a drop of pond water and see microorganizisms just doing the bag stroke, right . That your eyebrain sensory system could not have detected were not for the microscope, and you can say does that make sense . That you could have entire living creatures inside of a drop of water . Well, today we know that because we learn it from childhood, but in the day it made no sense at all. In fact hehad communication with the royal academy. The Royal Society in london, and they thought he was drinking too much gin. Write another letter when youve from this drunken stupor and we can continued for conversation. So they were in denial until they sent someone to verify which is natural thing to happen among scientist. One eye witness testimony about one result is not a science tick discovery you need verification of it to confirm its real and especially in modern times, 20th century and onward, we have part kell accelerators and discussed quantum physics which is rule otherwise matter behave outside of our senses and our expectations for how life would or the how anything should work. Particles popping in and out of existence, matter turning into energy and back and forth. So, then we discover block holes and the expanding universe, how other could everything there is be expanding at all . And so if you keep invokingthat doesnt make sense, you are going to miss out on a lot of what we have learned discovered to be true about this universe. Host what significant about the year 1600 . Guest well, optics had taken off. It was a lot of the dutch were very good at optics and lenses and this sort of thing, and we knew about what one lens would do. You can make a little hag any magnifying lens and when you add them together, it opened the flood gates to what else to do when you combine lenses and then galileo made a good version in the early 1600s and then sky is the limit. Host was galileo treated as a devil . Guest well host he was suspicious. Guest a little bit of cleansing. Depending on how long is the writeup on the account of his time, life and times, that was determine how much Background Information youll get. So, the simple story is he makes these discoveries, they conflict with the teachings of the Catholic Church, they put him on trial, find him guilty of saying that earth goes around the and not vice obvious a as well as other discoveries and they put him under house arrest. What it dont would tell you if you read a longer biography is that he actually made fun of the pope. Public fun of the pope. He wrote a book in italian, not in latin, the academic language of the day inch italian, means the local people can read im. In it he invens a conversation between tea simpleton and one who is wise of the ways of the universe, and if you track the statements of the simpleton, theyre all statements that have come by official career decree from the Catholic Church so he is really pompous ahole if i can say that. Host this is cspan. Guest he debt did not get the respect he should have for people who had more power over him. He could have published in latin, have it spread around the world and im betting he would not have gone to trial. Thats my read of this and in the third debitor is the renaissance, and new thought and appreciate thought was not some weird thing, so he was just heed a it coming because he didnt know how to appease authority. Host back to your book, astro physics for people in a hurry. 14 billion years ago the universe started. How do we know that . Guest so, the way knowledge is acquired, scientifically, is you have an idea and you propose an experiment to test the idea, and then you if its an expensive experiment, you probably dont have the money to do it in your garage. So now you propose to get funding from sources, typically if its pure research, it will gay government resource, the National Science foundation, mass sample other fields, biology, human fissionology are might bet a grant from in the National Institute of health. And soso have this idea, build an experiment and test it. The results of the experiment march your expectations then the foundation of your idea gains some currency in the conversations you might have at the scientific coffee lounges, at workshops or the journals. Then youre a come pelt tough competitor of mine and say i never liked you. I have a different view. Scientist are human. Were people, too, right . So, i think youre wrong. And heres the experiment im going to build to youre ongoing. Then you build anker andment and get a result that kind of matches my result. Thats interesting. You had no intend of matching me. You dont even like my me. Now the results match and someone else do does it. Always have some outliers bass of the experimental uncertainties that exist in all experiments, always be some outlier, when theres a general lean towards a truth, an emerging truth, you look back and say, oh, okay. All of these internals opinion to approximately the same result. We have ufew outout liars here outliers here. Now this the new truth, the objectively established truth. Thats science. It is the most effective way we have ever devised as a species, as a culture, in decoding what is and what is not true about the natural world. Nothing rivals it at all. And so once we have done this, then i say, here is how the world works. Then we go on to the next problem. This is a celebrated thing. Its what got us real festivity quantum physics and gravity and empowered the entire Industrial Revolution. You couldnt have these machines a machine is something that converts energy that lives as one form into energy that is useful to us in another form. What is a car . It takes Chemical Energy and gas and turns it into energy of motion, Kinetic Energy, of your car. That requires machines to do that. All this came out of the Industrial Revolution. Before the Industrial Revolution there were no machines such as this. They had what we call simple machines, lever and a pulley, those dont require high technology. Those are called machines in the world office secondsment a lever, pulley, an incline plain. They make your job easier. So, it is simple. Watch how this works. I have this ledge and a very heavy thing and want to lift it up to that ledge. Im not Strong Enough to do that but if i make a ramp, then i can just lift it up little bit at a time. The distance over which i have to lift it is longer, but it takes this height and spreads that out over time so that it makes it easier for me to complete the task. The same amount of total energy is exerted but the rate at which i expend that energy is different and thats what simple machines have always done for us, and modern machines are basically empower all of civilization. Host first ten secondeds of the universe. What happened . Guest some busy moment sorry, i didnt focus in on your question about how do we know its 14 billion years. We look up in the universe and we say, okay, we see galaxies. Hubble discovered the fuzzy thinged in night sky are entire galaxies such or our milky way. Major discovery in 1926. Then in 1929 he discovers that these fuzzy things that we now identify as whole galaxies are hurtling away from one another and this is the first evidence that the universe is expanding. So, people didnt just think this up. It was an observation, and then we looked to see if it fit einsteins general theory of relativity, and it did. The theory is the modern understanding of gravity and if anything is happening in the universe its going to involve gravity. And it fits with the equations. So we didnt have to reinvent the theory of the universe because it worked, and so then we say, all right, if the universe is getting bigger, today than yesterday, and that must mean it was bigger yesterday than it was the day before. And then the day before. And then the day before. So, what happens if we just turn the clock back . When you do this, because you see how fast were expanding. Just reverse that. You can do it on a pen and paper, on the back of an envelope. Calculate what happens if you reverse this rate of expansion and the whole known universe is in the same place at the same time 14 billion years ago. That is the origin of the idea of the big bang. Host first ten seconds. Host first ten second. So, everything we know about matter that is come pressed and under pressure tells that at the temperature will rise. The simplest example is if you ride a bicycle and your tire gets flat so you ump a hand pump, pump air into the bicycle tire. Thedown feel the valve when youre done. Its hot. You were come pressing air through it. Cocome pressing air compressing air through it. So thats related. Not exactly the same thing but related thermodomestically, the science of the them thermodynamically. So i would have been hotter in the past than in the present. And so now you keep universe actually now has temperature and you can measure it. Got measured in the 1960s. Very cool. You look in every direction and you see the heat signature left over after the 14 billion years, and so now you go back in time and you say, okay think universe was hotter and hotter and hotter. How much hotter would it have been 14 billion years ago when the universe was thing big . You get stupendously high temperature. And now you ask, what is the behavior of matter and energy under those temperatures . Now you turn the particle accelerators that slam part particles together, high temperature, high energy. So you start proximate mating the condition of the early universe. Thats what an atom or nucleus does. Now you take knowledge gleaned from modern physics physics andl sis physics and apply it to the first few moments of the universe when it was hot, small and dense and that gives you a pathway in, a pathway of insights into what was going on then. Know what we find . You have an era where all part kells formed. The basic foundational part celts that Everything Else is comprised of. Light in the form of photons. We have quarks that make up protons and nudity neutrons. Theyre made of quarks, and quarks are fundmental, and electrons. And they all have antimatter counterparts. Its called the possetron, very cool name. Something that Science Fiction people pick up on. Just to be clear, we invent antimatter and discovered it. That was not a Science Fiction invention although it works great Science Fiction telling. Happened in the real universe first. Now you put bring your insights to those first few moments of the universe and say what must have happened then, given what we know goes nonparticle accelerators and they say you would be making hydrogen as the predominant atom in the universal. One proton in the nucleus. You make this much hydrogen, this much helium two protons in the nucleus, youll make trace amount of lithium, the third almost 0 of the periodic table of elements. And nothing else. We will be a universe born with High Hydrogen and helium in barely any liggum. You say, if thats sew it would mean that the very oldest stars we can find, ones born closest to the big bang, that would still be alive today, would be comprised of only hydrogen and helium. That is exactly what we measure. The very oldest stars have the least amount of heavier elements which we know from the mid20th century, from calculations enabled by the Nuclear Research from the Manhattan Project and the atomic bomb because we are calculating what atoms do. We know that after that time, stars are born, Pure Hydrogen and helium. They manufacture heavy elements in their core, then some of them explode, scattering enrichment to gas clouds that have yet to form stars. These stars hey enrichment and will make even more enrichment. Enclosed and then carry that extra enrichment to the next generation and this continues through. We, our solar system, was born four and a half billion year ago. More than nine billion years after the start of the universe. We have had the benefit of multiple generations of enrichment so now in our proto cloud, collapsed, to make the sun, it had all these other ingredients in it that it used to make planets. Rocks are not made of hydrogen or helium. Theyre theyre mid of silicon and oxygen and aluminum and arsenic, iron, cocoa cobalt, nickel and theyre in abundance in late generation stars. The lesson is however weird it is to assert that 14 billion years ago the universe was thing big i, literally this big and explodessed from there you say you werent there. How do you know . Youre right issue wasnt there. But if everything we know happens to matter, happened then, then it accurately predicts things we do measure. That is what gives us the confidence to sit here and describe the first ten seconds of the universe like we were there. Host all started with he big bang. Guest ha is there a song in there . Host do we know what that big bang was . What we can tell you is that the big bang account of the again of the universe is a description of what matter and energy was doing from the earliest moments onwards. Theres a point before which its a little mysterious to us. Its called the plank time, name after max plank, one of the many tours of quantum physics. A plank earlier than which its kind of the limbs of our limit of our able to under what nature is doing. We pick it up after the blankfein, which is one trillion trillion of a second after the big bang. Noone billion trillion trillion, is that right 1512 yeah, thats just about right. The one million trillion trillionnt of a second after whatever was the beginning, then our physics we now measure in our labs apply, and then we can talk about what is going on. Host in your book, welcome to universe, you write that in five billion years, the earth will be a charred ember. Guest oh, yeah. Its weird. Every now and then i tweet. That every couple of years i tweet that. And apparently it blows peoples minds. And i dont know if thats good thing or bad thing, but the tweet guess varies but goes something lying i in five billion years the sun will expand so large that it will engulf the entire orbit of our planet. As we that will engulf the entire will engulf earth as earth and earth will be a charred ember as it descends interest the star while it vaporizes. Have a nice day. Something like that. And people so, its just a reality. Its remarkable we can know our fate in that way over that much time. How do we know it . We will be there . Probably not. How do we know . There are other stars no shortage of stars in the universe with see stars being born, liver ought their lives and in the act of dying and you can staple these bits of information together and create a coherent story. In other words, we dont live long enough to see a star bosh, liver out its life and die. Takes millions, sometimes billions, sometimes trillions of years years and were erode around for a few decade. How do we know this . Because theres so many stars that in any snapshot of the universe we see stars being born, stars in middle age, stars dying. And we look to see, oh, these their steps of the same, arc ofa star. Just different stars that were catch agent different timesment wouldnt be any different if were an alien and took a snapshot of civilization, you would see some humans in a box underground. What are they doing there . You see other humans who are Little Things crawling on the carpet . Youll see other humans who are dont have any hair, that are little and others that dont have any hair who are older. This is just a snapshot. Can you dont live long enough to see the whole thing. If youre alien and live just 90 seconds, so youll say, how die make sense out of this . Are people born in a box in the ground and theyre all shrively and then come out of the box box and then they get littler and littler and littler and then disappear inside of another person . Or is it the opposite. You keep spreading owl these photos and then you can piece together a coherent story of what is going on, and for the stars in the universe, this took decades. We didnt just look at one snapshot. This took effort. This was major telescopes brought to bear. A lot of human intellectual capital invested in trying to understand what stars and how the why they work. A lot hoff this traces back to Harvard College observatory, cambridge, massachusetts, roomful of computers, human calculators, computers, and theyre all women because that was judged to be menial work and the men stayed in their offices doing highlevel thinking, and in this room of women, was the foundation of our understanding of star revolution, and tkaf dava sobol wrote a book, called the glass universe host way covered it. Guest yes, as an oimagine to glass ceiling, a glass universe. Little dud the high and mighty men know that when you calculate data that was collected from all the worlds telescopes on stars, thin therein was the source this seed how why stars are born, live out our lies and die. Host this, is book tv on cspan2. Our nonly in depth month and this month we have neil degrass tyson. We spend three hours with one author talking about his or her body of work, and this month its dr. Tyson. Beginning in 1989, dr. Tyson has written several books, berlins tour of the universe was his first. Universe down to earth in 1994. Just visiting this planet, 1998. The sky is not the limit. That whats fourth book, 2000. One universe also came out in 2000. And then cosmic horizons came out in 2001. Origins came out in 2004. Death by black hole, 2002. The pollute foe files, 2009, space chronicles ken last year, star tack star talk, and welcome to user and the recent book, astrophysics for people in a hurry. If you want to participate, heres how to do so. Host dr. Tyson, back to you most reap book, astro physics for people in a hurry. 40 billion earth, like planes in the milky way alone. I have two questions. What this is the micky way and how big a space are we talking about. 40 billion earth, like planet snooze so, it was hard earned to le