welcome to the science for the public lecture series science from the public is an organization committed to bringing science information issues to the general public this is our website for our program steams and model of cosmic evolution which he'll discuss tonight this model shows that underline connections between the pockets of the universe from subatomic particles at the very beginning to the emergence of galaxies stars planet life and finally human culture all these stages are enabled by a few underlying principles that guide the evolution of the cosmos dr received his ph d from harvard university in hundred seventy two he's since been associated with the harvard smithsonian center for astrophysics johns hopkins university the space telescope science institute in baltimore and tufts university where he was director of the right center for the science education for twenty years while at tufts he also taught in the department of physics when he returned at last to the harvard college observatory he developed a course on cosmic evolution the famous course is an example of his deep commitment to science education and illustration of that effort is his website construction which we urge you to see cosmic evolution from big bang to humankind you do not miss that is a member of numerous science organizations and advisory committees he's received many awards for both his research and his numerous books his astronomy textbook now it's an eight edition is the most widely used astronomy textbook about but tonight will focus on his most recent books for general readers the first cosmic evolution the rise of complexity in nature and the second the epic of evolution seven ages of the cosmos it is a very great pleasure to welcome dr sun welcome sir thank you for and i'll start right in thank you  start right in with asking how did this very complex idea rise in your head how did you come to that about the evolution of the whole cosmos well you know when i was a student in cambridge  i tried to take a course that i realized i couldn't because it didn't exist i had always wanted that bigger picture of their world view i wanted to know more about how i fit into the biggest game of things so then after many years of transitioning  system as a student or a post struck and becoming a young faculty member coerced a senior faculty member to come with me to create this course that i had always wanted to take as a student so other students might take the course but i never knew whether anyone would show an interest in it that you have a unifying theme in can you explain it as a how did you put the whole universe together what twenty words or less than well you know basically i look out the window yeah and i wonder where everything came from how it all came to be in particular among the galaxies stars planets life and society that you mention if how complexity is risen over the course of time in a particular sense i'm fundamentally therm of the nemesis and i realise that the universe must be according to the second law breaking down over the course of time how is it that these islands of complexity have arisen increasingly so so that's what's driven me to understand and stand quantitatively how is it that islands of complexity can exist for long periods of trumping all the time it was all chance but he never really said that in fact was a long conversation they had a mountain in switzerland with ernst meyer who was who live entry lived to age one hundred but he would have been in his eighty's at the time who stressed upon me that if you really read carefully the origin of species which hardly any biologist i know has read actually you realize that darwin suggested that it was a both a mixture of chance and determinism or chance  natural selection and so ernst mayr used to always say really in putting in another term that it was a mixture of chance and non random elimination if a life form or for galaxy or if any kind of a system that had some degree of complexity or was suddenly changed by chance it would then respond it would either adapt or just but it would do so according to fundamentally the laws of physics and it's not have a chance nor necessity it's not randomness  evolution is hardly more than another word a fancy word for change and again if you look out the window there's nothing permanent except changes we often say we sometimes attribute that to the greek philosopher heraclitus i don't think he ever said that he did say pun change which i then call cosmic evolution and apply it to not just life forms but in animate systems indeed more advanced systems such as culture systems and see whether or not we could we can demonstrate a unity in evolution from the physical  the biological evolution through cultural evolution as a result the kind of evolution we know best which is near darwinism it becomes a small subset lp in a very important one in a much grander scheme of evolution writ large throughout the entire tested so i might have had this idea as others did too but as i throw more and more data on the idea and test the idea with more and more observations and experiments in a pyrrhic of findings i find the idea continues to hold up reasonably well but it's not just an idea it's an idea that's been quantified an idea that being tested yeah very important part of science and scientific method of course in all of its confusion and bias and subjectivity is that we must test those idea right you have talked about complexity a great deal can you tell us this because this evolves as well tell us about what you had in mind with complexity well the simplicity in this complexity if you backed into the caught up with the bright lights on as we have here and asked me what i mean complexity i'd have to say something like a state of intricacy complication here involvement among all the interconnected parts of a system a system which is an assemblage of things of components that are interacting independently aside from and differentiated  surrounding environment so you have systems and you have environments and in many ways of these systems should there be this is my apotheosis a sufficiently optimum flow of energy through those systems those systems can maintain their structural and years but basically all these systems seem to be growing in complexity some faster than others so more and more robustly than others because they have a flow of energy through this system is and then the flow of wastes and the products into the environment ok just one more thing on thought that can you say in general when do you call it complex when do you call a system complex that's why we're trying to develop a complexity metric nobody has i don't know how to measure entropy i don't know even as a physicist how to define it well i certainly don't know how to utilize it in a mathematical setting as well as i'd like to among our biology friends of the rather than energy they would prefer in many ways to embrace information and information theory i'm a simple physicist what kind of like a country doctor i take something that i can understand that i can define that i can measure that i have an intuitive feel for and that's energy it's an invention is just right the amount of energy flow through these systems ok so they don't really have a real good handle on complexity i got a lot of these concepts at least there's an understanding that there there is such a thing we just don't know where to draw a line per but i can show you one of the lines of your own between in a moment let's say galaxies stars planets life in society in terms of the amount of energy flowing through those systems  then flowing through the sun that was i thought an excellent point in your book i remember that vividly and the scale going up to your brain and then it becomes almost staggering and the human brain which is not that big but it uses this disproportionate amount of energy if you take that into consideration so thank you for setting the stage there i'd like to run through and unfortunately we're running through your you've got a pox in the universe and this is done so beautifully in the book that i think in the books i guess taken together that people will be well rewarded to read then start with the beginning with the particle you make some very good arguments if i recall about the different models of the universe you went through these three models would you start us with that my favorite model philosophically as an idea is an oscillating universe one that has no beginning and has no end it just always has been oscillating currently it's expanding and then will come back and pounce into another and avoids any need for a big bang or an ultimate end however there's not a shred of evidence for that so i have to kind of put that in my back pocket and hope that maybe some day i'll serve something that might have bolstered but right now the leading model is one that has a beginning and probably has no end is the big bang like a lot of the debt or seem to be that we acquire telescopes in the spacecraft pointing increasingly so toward a notion toward an idea that the universe science to examine what is the origin of the origin but for whatever reason it did go bang not as an explosion but as an expansion and we're along for the ride yeah and the universe evolves to changes as dynamic it's not static inflation for example and then usually retreated and said this isn't working the oscillating but what would be the evidence that you would accept that would tell you if the universe were slowing its rate of leaving the particle but i can't really as i play but i'd like to dwell on the galaxy even talk a little bit you brought out several things there but one of the most interesting things about your view of that is that people really don't understand the emergence of galaxies very well is that still true yes it's probably the origin of galaxies is probably one of the two or three great missing links in this entire story origin of life an argument teligent maybe others but the origin of galaxies which must have a kernel long ago because they're all old there are no young galaxies northern and dead galaxies that we know they must have all formed in the earliest universe and that means the formal far away in space but long ago in time and we can't see them very well they did him in the dirty in their dusty in there far away and so we like to say the hard observatory that galaxy research is probably fifty years behind stellar research stellar research really came into its own in the early part middle part of the twentieth century we're just catching up now and among the galaxy research efforts but every single day the lunches i go to the seminars i go to  understand by bringing home more data from the earliest frontiers of the universe how those b b galaxies became mature galaxies how those b b galaxies emerged yeah how those first structures brought together enough atoms to make a galaxy eleven or one hundred billions of galaxies again it's chance and assessing yes must have been a mixture in the early universe the same as there is now whereas there were elements of chance that brought out of us together but then the laws of physics also were involved with chance to assemble and to to to bolster the development of these early galaxies and that's what we're struggling now with telescopes like hubble and yet excessive called webb telescope and the spitzer telescope on to really see we'd love to see a baby galaxy we're not sure if we've ever seen a pro galaxy yet because we don't have a machine that we have built as human beings that can see well enough to those earliest epics in the universe where those galaxies had to afford we will get there do you have a pet theory yet about the formation of galaxies we hear about seeding you know obviously the hard thing about galaxy origins is that somehow some way the notion of dark matter it appears from a variety of circumstantial evidence nothing direct but lots and lots of relatively strong and so not knowing what this dark matter is and how the dark man actually interacted in the early universe i don't have a favorite moment because i'd like to hang my head again as an experimentalist or an observation  need for dark matter by changing the law of gravity even what's around with the law of gravity and instead of it being a want to over the distance squared exactly make it one over the distance to the one point nine per hour or to the two point one power you can start altering and making messy newton's laws are einstein's laws but by altering the law of gravity you can actually do away with dark matter so not too many people are going there yet yeah there's something element and it's now coming into play it's very heavily on display the how to desert area in advance seminars and that's computer simulation people build computer codes that are very very complicated guessing how the galaxies might have come together and then as  it's very very dark and very very dim in fact some of them i just now in our local environments around the nuclear way being fried because we had previously overlooked them they're so dim but this is analogous to to the dwarf stars in the of the ones that give a great deal of energy you know ok i won't then well on that too much i'll just run along because people have heard of black holes and that's a whole subject all by itself but step to say that you accept that it seems that black holes are at the center well i just last week i had a long conversation with an australian scientist at lunch and he just put down his glasses and he looked at me and he said stars and black hole they might be they've even been given been given a name cork stars star just made of cork which are the very fundamental ramming blocks of material but which are not as bizarre as fully truly theory is wrong in many ways if you have an idea here like black holes as exotic an idea as black holes it's hard to prove that that idea here is so robust that they yeah they definitely exist there's something strange going on very bizarre very  my point was that i don't see the evidence yeah i observe these objects repeatedly looking for what he has said and i don't see the evidence right i thought at one point he sort of projected it it was almost almost trivial because the th people who are certainly as well but it's important for the public to know that there is a lot of uncertainty and there's no way to confirm something until you find but there is no question  few other locations within our galaxy such as an optical sigma six one it's something very bizarre going on a kinda a black hole all right so then i'd like to go on to the stars here and  one of the most well there are a couple of special things in there and one is the interstellar clouds which you do bring up job of describing because people don't talk about magnetism very much for reasons i don't understand virtually an equal amount of material in the darkness among stars is not dark matter it's actual matter that we can find its atoms it's mostly hydrogen and we can sense it only with radio telescopes and if you cases with infrared telescopes but you have to look in the darkness with devices at longer wavelengths we say to sense of these regions called in the stella cause because this is a very cold but much of the material out of which stars come and much of the material out of  tell us that was that was my research question that was when i did my doctoral thesis on in the star processes because that's where again the stars form yeah and if you were interested as we were in the seventy's and eighty's and understanding how stars form you could look in these dark and regions forever development of radio telescopes and presumably in the future other advanced technology that will open our eyes so to speak to what i don't that's why we're living in a golden age out of physics no more than anything else so we've opened up the entire children not the generation my parents but our generation is now working the the entire election the internet you mean we're seeing just wonder as things at all these various wavelengths do you expect speaking of that way wavelengths and stuff do you think there is anything else that they frequency milters very interested in that so there's a lot of effort being done there at longer wavelengths wavelengths there as long as mountains we've leans to the lungs continence they're interested because you can those kind of in particular some people are now beginning to build for astronomy and the outback of australia and particularly in south africa lags large arrays that might be able to see longer wavelength radiation that's coming from the early universe yes so forward it's because we're gaining better and better resolution with more and more sophisticated equipment the history of astronomy shows that advances been made in astronomy asked physics probably at the rate at which humans have built  better machine and seen things more clearly they've increased their clarity of view and resolution of the sky and hopefully with the next generation of the vices in orbit in particular but also from the ground now as well will see things numbers because they feel i think in many ways in the medical community with imaging desires that we have a jump on the here because we're imaging this guy and but everybody's working in the same way to move toward acquisition that do you have a candidate that you would tell us the you think is a star that doesn't put you to sleep or something but see i think neutron stars are kind of boring because they're dead stuff and they're not starving we call them no fusion going on they're just dead remnants of formerly robust stars and in particular neutron stars if we're going to handle on them and we're still grasping that probably just giant balls but no bigger than the city of cambridge of carbon yeah as just and so in many ways that remnant of a former star that had to become recently complex has reverted to something that's relatively simple if an object like a neutron star is just  because they're not demonstrating a great deal of complexity they were once the heart and soul i guess of a central region of a star that it was considerably moderately complex but now that they're no longer so are they're dead they're on their way to the yes and because that is particularly interesting i'm not sure again whether people are aware that people in biochemistry and stuff say life is chemistry over and over again us about this you made a gorgeous case of i doubt if it's shari galaxies aware of itself but we seem to be aware of ourself but life because it is more complex anything alive in my backyard appears to be more complex than anything in the to where they live no matter what their personal persuasion is what is matter and they all say anything has mass and takes a place but if i have a room full of twelve biologists and ask them what's life i come up with twelve answers it's why there he did one of which of course is i know it when i see it which can't seems to be is the universe is expanding and probably only because the universe is expanding is a prime mover that complexity is rising in these islands of growing order but it doesn't necessarily mean that those increased complex clearly not alive could become increasingly complex in the far future but evolution is not a predictive science it's not like newtonian dynamics where you throw a baseball if you know all the spin  i would often say you know we're never going to know sitting around a table just talking about it we've got to go out there and do an experiment in particular use a radio tell us room ideally to try to use or up one of the civilizations that might be there it's hard to believe if you want to you know central nervous system and becoming intelligent exactly and a lot of it looks entirely accidental but the potential exists and you brought up if i read member something that i always personally find missing in these things and that is time that these things require time and so in terms of life developing it's very clear in our fossil record it was very slow and you had to have certain conditions some of them catastrophic before you could really move in evolution do you think that that is a big factor that having large amounts of time but what i'm trying to say is that many people looking at life say a half a cup of this a teaspoon of that put it in of that add a little electricity shake well and tomorrow you'll get some amino acids you can actually in your bathtub  dividing line between what's not living and what's living i think it's a degree of of the planet and that must threshold of emergence must be must be bettered in not if a something to move itself onto the  that we would call that we would call living and maybe it takes all the conditions that have to be right visibility for your eyes you know you're not in washington recently was that our entire galaxy is like a huge chantilly could ever imagine where there would be a chandelier of a billion bulbs and as each bulb which represents a star having a habitable planet orbiting around it experiences evolution the ball gets screwed in the ball blights  but in any given time in the history of the galaxy there may be very few bulbs in fact there might only be one bold at any given time limit right now my imaginary galaxy has us way out of the edge of the in the suburbs of the galaxy as a rather dim and dirty ball we're hanging on kind of you know hoping that light stays let but any given time although all the bulbs in the chandelier will eventually light over the history of the universe at any one time there may be very few bald inter his nobody necessarily to talk to at any given time well there's some different distances involved as well but on the other hand it wasn't that long ago as i remember it vividly that when people started looking for planets they were considered completely crazy planets just in the last decade or so yeah but that makes my puzzle even deeper namely if we now have experimental evidence that there are thousands of habitable planets probably more like billions actually suggested without me to even hint for me that culture is the quest by society to control injury and so again you can back to the same kind of nuts and bolts of my story that stars have a flow of energy galaxies planets life forms societies culture itself in the form of a civilization has a certain amount of energy flow per unit time for unit mass and that is increased with time for example since the birth of agriculture just ten thousand years ago even before that hunter gatherers use a certain amount of energy agriculture is use more industrialists use more technology is very colace else the per capita use of energy is biological evolution of life and cultural evolution of advanced truly sentience it's a very interesting point because i don't know if anybody else has ever thought to treat culture in quite that way as a natural it's my point you can treat it in the same page you can you can examine everything you see out the window over the entire history of the universe in the same manner you over our system man or you know treating this separately  or specially from another you treated everything in the seeing tabletop it's a level playing field everything i see of my window right i hope that people will be encouraged to read these books well either one of the ther one that's more accessible than the other but i think it will change their perspectives very considerably very rich reading and thank you for doing that job for us i think you said it took one thousand years book that would appeal to most people i think because it's more readable took me six weeks to write because all in my head it was that one i wanted to ask you a question that relation cosmology although that's probably the most speculative of all the disciplines that were discussed this evening but given that speculation  for universe in which complexity could increase without end however at least one interpretation of this acceleration of expansion which would be based on some repulsive force of i guess some called dark energy is that eventually not only do all the other galaxies disappear from our horizon but that at some point a big rip it curves which would seem to be what would you do to break all matter down to its subatomic components and be the opposite of complexity i was wondering if you reconcile that model with ultimately i do think that there  will break down in some way and become once again simple but we're talking so far into the future we're talking so speculative really i really don't necessarily want to go there because again i'm that observational is that experimental of physics these days unlike the physics that i was trained to know and love in the seventies and eighties is not boasted as much these days by experimental and observational data and many of these ideas as to what the universe might be going to do in the far far future or what have illusion is going to where it's going to take us and it just entirely speculative and the ideas are not even boasted with not just a lack of testable idea testable data but testable in principle right physics we need to come back a little bit i think we need to have good solid ideas that have a degree of speculation but  the the the the job of the good of the greatest theorists in the history of science is that they also proposed tests that can be made of their ideas that can disprove or you know going to prove an idea right again you can  but that's how science operates and i think right now we have such a plethora of speculative ideas and it's a rip idea i think is one of those multiple universes another string theory is yet another and  dimensions that goes on and on and on and we did these ideas all come from their wonderful ideas but they've got to be tested in some way because before they come into the fabric of of what we call physics and less physics itself is that the that the complexity the arrow of time gets asked wants to go faster and faster and faster and that these epics are generated as a way as time's way  moving faster faster faster generating complexity faster faster better and more and more complexity that's why this year you perspective right more or less why because the universe is expanding i do think the reason for what you're driving at is you're asking what is the prime mover of all this and i think in an expanding universe which did begin to expand for whatever reason that i don't know the prime mover is that  expanding universe the flow of energy will continuously increase it's not it's not an increase in energy specifically but it's a flow of what we call them of the damocles free energy it's freely available for use  all to the generation of of biology here on this planet that's what drives at some level natural selection is an argument can be made for that and i'm making that in some part i'm suggesting that natural selection operates in part because of the flow of energy through open thermodynamic systems which are living part of natural selection is due to the flow of energy right naturally some other parts are due to information contained within the genes but this level of time about what's driving this excess of what is that is the thing that is driving the succession to biology to culture the same thing that was driving the succession from galaxies to star systems and so on  i'm suggesting to that you that yes the answer is the same flow of energy flow of energy per unit man's per unit time associated with these islands of complexity it's the same process operate hundred eighty thousand years after the big bang when the universe decoupled and and had a symmetry break from a universe that was full of simplicity to one in which atoms could then begin to come together somehow some way to build the gal es to first galaxies and once that begins to occur you build your galaxies which are environments suitable for eventual spawning of stars the stars with it come as a byproduct the planets on some of those planets maybe only one i doubt it perhaps many more habitable zone sufficient to give rise eventually to life life evolves through the same process of energy flow in part become more intelligent and then to reflect back upon this whole story and to enable us as a sentience species to to to to tell the story that's the sad part about it if we don't if we ever were alone and don't survive this great experiment called life would end in which case the stars in the galaxies would continue shining in twirling but nobody would know anything about it we have emerged on this one planet at least and it's hard for me to believe that others aren't there out there as well to tell the story in many ways this should be i suppose i could claim it is the greatest story that ever might be told the cosmic evolutionary story from big bang to humankind big bang demon kind of beyond but i don't know what that beyond is because again evolution is not a predictive science and not to speculate about but your points are very very well taken you know life life seems to be unique in that it be very special paulo open all open complex systems share that same peculiarity of the stars planets life society we all have a flow of energy into our system let entropy of the universe but so is a star so is the galaxy so is a planet i mean that's the problem we're having now as we ramp up and the use of energy as a civilization we are creating a lot of waste creating a lot of disorder in our surrounding environment but that is the natural way in which the second largest in the erik's governs each of these systems life is no different from any of these systems i've been describing it takes in a certain amount of energy and utilize it to build structure and to exercise function the energy is acquired the energy is stored the injuries expressed but after the after the function has occurred out goes the waste goes the products goes the the  so all these systems complex systems are temporary islands of decreased entropy sitting in an environment of increased entropy in fact you want to do the calculation as i always do and some of these  some of these journal articles and books that i write to make certain that the sum of both the the system lets say your body and the environment or a star in its environment or a black hole candidate in his environment that although the ent decreasing within the system per se that it better be increasing the entropy better be increasing when you consider the system and its environment otherwise you are in violation of the second law and boy i don't want to go there the second la life per se clusters of life clusters of society of civilization take cities have been examining cities in great extent lately fifty five percent of people all people live in cities and within about twenty years about of people are expected according to united nations to live in cities the greatest human migration is under way now a million people on average are flocking to the cities per week is the tremendous movement of people towards cities problems elsewhere in the universe