What We Still Don't Know - Why Are We Here (Episode 2)

the universe is still a place of mystery and Wonder as a cosmologists I'm exhilarated if we can make some progress towards tackling what seemed very fundamental questions these programs focus on was they were beginning whether we are alone that's the future of the cosmos what is the nature of reality with each advance new questions come into sharper focus the key issue is what we still don't know it's perhaps the oldest question of all why are we here in this vast and complex universe are we important many people have a fascination with their environment not just the immediate environment it leads you to think about our place in the wider cosmos and it's not just a question for philosophers science has been tackling the question to asking whether there is a hidden purpose to our creation or are we just an accident of creation and in trying to find out why we're here they asked first how we were created and the question led to a shocking revelation it seems our creation was far more precarious than anyone had ever imagined the result of two mysterious but crucial constituents of the universe that until recently had entirely evaded detection without them it could not exist so what are they and can they help us to answer the biggest question of the more the aim of science is to try and find patterns and regularities in nature the first success was actually in astronomy because the ancients realized that the planets moved in regular courses the seasons and the calendar were regular and they were able to understand these patterns to some extent it took much longer to achieve any success in subjects other than astronomy because the stars and planets in their courses display far greater regularity did almost anything else we can study in nature in trying to understand how we got here science turned from patterns in the heavens to patterns here on earth was there a common essence from which everything was made we've always suspected that in some mysterious way we were connected to the world around us and that despite the apparent complexity of the world this common essence could be found by reducing everything into its basic parts the Greeks did this and many of them had the idea that everything is made up for substances earth air fire and water in different combinations that was a marvelous unifying idea we now realize it didn't explain things in detail people have always been asking these big questions I think for as long as humans have walked the earth and the big change is that now we have measurements we have data but started out with the chemists realizing that them even though there seemed to be thousands of different kinds of stuff there was only a hundred or so kept different chemical elements out of which you could build everything else despite the complexity of our world everything including us is built by combining these basic chemical elements atoms the bedrock of 20th century science was to understand that we and everything else are made up of atoms and to understand those atoms and to actually do experiments so we can learn what the individual atoms are we now know that there are 92 different kinds of atoms which occur naturally the same atoms combined together in different ways make up everything every substance is a particular combination of atoms in particular proportions atoms are the building blocks the fundamental essence of everything on earth the difference between complex and simple structures depends on how many different kinds of atoms are combined a single crystal of salt contains only two of the 92 elements sodium and chlorine to build a crystal and just keep piling on these atoms in exactly the same way repeating repeating repeating all over again making it ultimately very very simple to describe the crystal is an example of something which is not particularly complicated but most things most interesting things in nature don't have such a simple recipe the big difference between on one hand the dead thing like a crystal and on the other hand a living thing isn't what they're made of because they're both made of the same building blocks the same kind of atoms it's rather the complexity in how they're put together that's certainly the case of the simplest organisms an ant for instance if you were to peel away layer after layer you'd get interesting structure on all scales all the way down to the single atoms an ants body is made of cells which make up everything from its eyes to its legs each of these cells is made up of molecules like proteins and DNA long chains of different atoms bound together yet this unique creature is made of the same atoms that can be found everywhere on earth to get something really complicated there must be very large numbers of atoms put together if you want to build a squirrel you meant to build one cell of the squirrel one chromosome you have to take these atoms and keep putting them in new and different ways without repeating yourself and that's how you get this fantastic complexity which is to me the really the hallmark of life that's what makes the living world complicated compared to a crystal and the most complicated object that nature has ever constructed out of atoms is us we can say with some confidence that human beings are the most complicated things in the universe by certain the most complicated things we know about human being has contained 10,000 trillion trillion atoms linked together in a very complicated way but the important thing about us is not to be made up of these atoms but the way those atoms are combined which determines the complexity of life from just 92 atoms everything on earth is constructed billions of different combinations creating everything we can see from the simplest assault crystal to living things and the most complex living thing us but how did atoms ever combine to create us to get them a complex universe built out of Lego hearts or atoms as their fundamental building blocks you basically need only two things you need lots of Lego and you need lots of space and time to play with them a key property of guidance is that they can combine with others and make these complicated molecules and that's the property that they've always had ever since the beginning the rest is just limited by the imagination of nature and doing clever architecture with him and since the beginning every atom on earth has remained unchanged but they have been endlessly combining in different ways joining and rejoining passing through different substances living and inanimate and the pinnacle of this process is us is taken nature about 4 billion years to get from the simplest life in the primordial earth to us we don't quite know how that happened we just don't know the mix of atoms here on earth now carbon auction and the rest is the same as it was when he earth formed four and a half billion years ago because atoms can't be created or destroyed by any process we know about that's going on here on earth those atoms must therefore have been produced somewhere somehow before our solar system formed so to truly figure out our origins to understand how and perhaps why nature created us we have to discover where the 92 elements that formed the earth came from in trying to discover if there might be a reason for our existence scientists had found everything is built from the same 92 elements that have been present on earth since its creation if you want to know where the atoms we are made of come from the answer leads us back before the solar system was formed towards thinking about the entire cosmos and everything had happened since the very beginning of our universe early on people thought the world was up in the heavens had nothing to do with us they didn't even think that the same laws of physics apply into the heavens as to us this idea is very deeply entrenched in much Greek philosophy for example that the heavens these crystal spheres why doesn't the moon fall down on our head because it's a heavenly object it's not a rock but the truth is quite different not only does the cosmos obey the same physical rules it is made of the same atoms the first clue to this came from the Sun it is 92 million miles away yet astronomers can tell what it's made of from right here on earth if you take light from some source on earth and send it through a prism you see these spectral lines in there which which tell you what it's made of so when this was done with the Sun they saw these spectral lines of hydrogen and for the first time ever that somebody realized this most central object that everybody before them had seen was actually made of earth stuff that's been a really shocking revelation which has come gradually that stuff up there has everything to do with us and every star that we analyzed confirmed the same story no matter how distant it seemed that the entire universe was made of the same 92 elements it's remarkable that the substances which make up ourselves and everything on earth so far we can tell identical to what we find in the Sun and in the most distant stars so the question was no longer where did the stuff of our planet come from but where did the stuff of the universe come from we believe everything started off in a so-called Big Bang a very hot dense state nearly 14 billion years ago the Big Bang is the cosmologists story of how everything in the universe was created in a giant explosion but the early universe contained a far simpler atomic mix and today in fact just two elements existed the simplest atoms imaginable if you'd be looking at the universe when it was say a few million years old you could have been a rather boring place you could have been at about watery temperatures sort of temperature we're at in this room today but everything in it would have been just a very diffuse uniform gas nothing else that gas would it be just simplest atoms hydrogen and helium but what transformed these two most basic elements hydrogen and helium into the 92 elements that make up every galaxy every star every planet and on earth everything from crystals to us you want to know how from that simple beginning everything transformed into the cosmos we see around us today and of which we are apart the transformation occurred because simple atomic matter was not all that existed there was a force an ever-present fundamental force that to this day is both familiar and strange the main force that changed the universe from being simple and boring to being rich and complex was gravity we're used to gravity's effect on earth but gravity extends throughout the universe it keeps the moon in orbit around the Earth and the earth tied to the Sun it holds all planets to their stars it causes stars to cluster in their billions to form galaxies wherever in the universe there is matter gravity tries to draw together the more stuff you have you know the more gravity there's gonna be nobody is above the law of gravity that is made of matter and from the beginning the clouds of hydrogen and helium atoms were subjected to the gentle but ever-present force of gravity and we see the results wherever we look in the night skies early on if you had a large crowd cloud of gas it would exert a very very large pull on all the guests around it which would result in the whole thing contracting together and getting smaller and hotter and denser and gradually this gravitational contraction would overpower the the pressure which was trying to blow it apart to the extent that it would get so hot that you would make a star sometimes people ask why should we be interested at all in these stars stars thousands of light-years away which live out their lives and then die and the answer is that there's a rather intimate link between these stars and us on earth had it not been for these stars we wouldn't be here throughout the ages alchemists people dreaming of getting rich we're trying to make some ethnic elements out of others typically expensive things like gold out of cheap things like lead right and all the achieve typically was lead poisoning but they weren't actually wrong we now know it is possible to do alchemy and create new elements out of others it's just that you need much more energy than those guys had in their makeshift little chemistry labs you need so much energy that in fact only stars so stars manufacture atoms in a fusion reaction the exact same thing that we humans have still failed to do under control forms we can only do it in a hydrogen bomb the heat at the core of the first stars began to transform the hydrogen and helium into other atoms early on when the universe first began to produce the Harz started with just hydrogen and helium and as the Stars contracted they the temperature and the cores rose higher and higher and eventually it began to be possible for hydrogen nuclei to bang into each other and produce helium and then they contracted further it got hotter the helium began to react and produce the other elements that are fairly abundant carbon nitrogen oxygen so stars fuse together smaller atoms to make bigger atoms but how did these large atoms get from the heart of stars to the earth at certain moments during this process the stars can become unstable and then they spew out material this happens in great explosions of supernova explosions and so it is the life and death of stars that have created the 92 elements the underlying constituents of the universe of planets rocks crystals water ants and us collected from space scattered there by exploding stars we are literally the ashes of long dead stars a furnace romantic we are the nuclear waste from the fuel that made those stars shine everything we see around us now since it was made by stars this is actually something which our grandparents had no idea about everything came from stars in China understand our cosmos were very much also trying to understand ourselves and how we got here created in the heart of a star and recycled through different forms all over the galaxy atoms are virtually indestructible a single atom like say an atom of carbon can't be created or destroyed by any processes goes on on the earth let's imagine one atom that's in a particular blood cell in my body now some stage I probably breathe that in as carbon dioxide in the air that carbon dioxide might have been put out from a chimney wear clothes being burned and if therefore be a relic of some primordial forest maybe 200 million years ago we can trace it back further to when the earth first formed some earlier star exploded as a supernova and flung out into space the process debris of the nuclear fuel that kept it shining so the scientific quest to discover why we were here had answered at least the more straightforward question how we were here our creation was part of a wider process that happens across space and throughout time and it seemed to be very deeply ingrained in the laws of the universe but scientists were soon to discover that a major part of the story of our creation was missing we could imagine a universe where there was nothing but atoms but our universe seems to be rather more complicated than that in the search for an answer to the question why are we here scientists approved that we were made of the very same atoms that made up the entire universe over billions of years the combination of atoms and gravity had created everything then out of the blue we discovered that atoms are not the only ingredient of the cosmos when we look at the universe there's no particular reason to believe we are getting a complete image of what's actually there we've had some surprises we've discovered that does not just atoms but there's a lot of stuff in universe which isn't made of atoms at all dark matter the first evidence for dark matter in fact goes back to 1930s long before I was born galaxies rotate and at their outer edges the stars are traveling at phenomenal speeds the only force holding those outer stars to the rest of the galaxy is the combined gravitational pull of all the atoms in the stars at its center but when astronomers calculated the amount of gravity required to prevent those stars from flying off into space they discovered that there simply wasn't enough matter in the galaxy to hold the outer stars in place something was very wrong by measuring for example the speed with which stars will run them round the Centers of galaxies like our own Milky Way the stars ball run too fast and unless there is some gravitational confining force some sort of invisible glue keeping the stars together the galaxies would have used this all it was already realized then that some clusters of galaxies galaxies moving around would have thrown apart had they not been held together by a gravitational pull of something more than we saw as that was the first intimation of dark matter but for many astronomers the idea that there could exist in our universe a type of matter made from something other than atoms was just too strange to contemplate people didn't want to think that the universe was full of dark stuff that we couldn't study and after all justifying a huge investment in the telescope requires telling the funding agencies we're going to discover where the universe is made of people were telling you look new telescopes only see a little bit of what is there and I'm not necessarily popular so partly for that reason and partly because there was no serious to what the dark matter could be that idea lay dormant it was a niggling thought in the back of people's minds until the 1970s when more direct and compelling more than evidence for dark matter was acquired and then he was staying us in the face we couldn't ignore it anymore and when they calculated the amount of dark matter in the universe astronomers were even more surprised this mysterious material made up the majority of the universe nearly 85% of it the realization that most of the mass in the universe is dark matter has come as a big shock to the community and we have no idea what it is unlike ordinary matter that we understand and we know and love we know how to make it and we know its composition we know relatively little about dark matter the name dark matter just reflects the fact that we're talking about matter that does not emit light or radiation of any sort we believe that the dark matter is made of elementary particles these particles which are still hypothetical I should say this is something that has yet to be confirmed in the laboratory go straight through you and you're not the wiser and that makes it very difficult to detect these particles because the way you detect the particles by stopping and intercepting it if you just go straight through the detector then you don't know that there was a particle man and so they're harmless from that point of view but that all over the place there's a billions of these dark matter particles crossing my hand every second as we speak and you just don't feel it they don't interact they just do nothing in fact they'll happily go right through planet Earth and out the other side without even interacting which makes it feel almost metaphysical if there's no experiment you can do which will let us capture one of these particles how do we know that they exist the actual nature of the dark matter is a mystery there are lots of candidates which could exist in the early universe in the Big Bang in the first microsecond and if they are still around now they will be Kansas for the dark matter it's not a wacky idea it sounds sort of frivolous to invent something which you can't see can't touch to say that nonetheless exists so far we only know that they exist because the gravitational pull a very interesting question to me is is the universe more complicated than it needs to be to have us here in other words is there anything in the universe which is just here to amuse physicists it's happened again and again that there was something which seemed like you is just the frivolity like that we're later we've realized that in fact no if it weren't for that little thing we wouldn't be here I'm not convinced actually that we have anything in this universe which is completely unnecessary to life surely this mysterious and abundant matter must have had an effect on the history of the universe and if so it must have played an important role in our own creation with the power of modern supercomputers we are now able to replicate cosmic evolution with great precision through simulations so we are now able to make replicas of the universe in a computer and this is a very powerful tool that cosmologists have developed in order to understand the universe if you are able to synthesize cosmic evolution in the computer you can then play games with the universe I worked on trying to make universes without dark matter in a computer and they were always a disaster they just never worked so a universe without dark matter is just a failed universe it's a pretty boring barren place galaxies just don't for money galaxies don't form stars don't form and it starts on form assumably people don't form it was only when we got the right chemistry you know the right mix of dark matter and an ordinary matter that we suddenly came up with replica universes that for all intents and purposes look just like the real thing they have the right number of galaxies the violet color some right sizes and in the right places it's beautiful universes without dark matter we would not be here how could a cosmic ingredient so fundamental to our own existence have escaped detection for so long in my opinion we should not have been surprised by this there's no particular reason by everything in the universe should shine the conspicuous things shine but much could be dark if you take a picture of the Earth from space at nights then you get a few cities lit up and oil fields in the Middle East etc but you get a very distorted and complete picture of what's really there so I think we shouldn't have been too surprised by the presence of dark matter is gratifying to have evidence for it there was no dark matter then life probably would not exist because the origin of stars planets and people relies on the action of dark matter because the dark matter is the engine or the mortar that allows complexity to evolve even though ordinary matter is a minority in terms of mass and in terms of amounts of course where all the excitement is because that's where stars which shine and planets that are exciting people come from but would this mysterious substance so vital to our evolution play a part in our future we have achieved amazing success in being able to delineate the structure of the universe as we observe it and what it's made of it took several hundred years for navigators to explore the earth and map out the continents and work out the size of the earth and its shape in the last 10 or 20 years we've done something analogous for the vast universe we can observe the universe extending more than 10 billion light-years from us having figured out the role dark-matter had played in creating us the most complex collection of atoms in the universe cosmologists were keen to see how it might affect our future and to assess how Dark Matter might affect the future scientists had first appear into the past since its beginning in the Big Bang the universe had been expanding outwards intuitively scientists expected that this expansion would be slowing down the amount the expansion is slowing down would be determined by how much gravitating stuff there is because everything exerts a gravitational pull and everything else so the more gravity there is the more is just slowing down if you could find out that it was slowing enough to someday would turn around and come to a halt then effectively you would have found out that the universe was going to come to an end and of course you could find out the opposite that the universe was slowing but not enough to ever come to a halt then you know the universe is going to last forever and I figured what could be a better a better project than that than to measure the fate of the universe to study how much the expansion of the universe has slowed you need to know how fast it was expanding in the past and peering back in time is not as impossible as it sounds to look at any star is actually to look back in time because although light travels very fast it still takes time to reach us light from our nearest star the Sun takes eight minutes to reach us but to study the earliest stages of the universe astronomers had to search out the most distant stars and the brightest of them our exploding stars for decades astronomers have been fascinated by these exploding stars the supernovae and I think probably just because people love seeing a really dramatic explosion these things are so bright that they outshine almost the entire galaxy of stars that they that they explode and that's um you know ten hundred billion stars and this one star that explodes is brighter than all the rest just for the month or so that it that it's exploding and it's visible you can tell then how far away the supernovae are I have I'm bright they they got to me and the distance tells us how long ago it exploded the amazing thing is that by now we've seen supernova explosions which are so faint so that there is so far away that they represent an explosion that occurred some 10 billion years in the past and we're just seeing that pulse of light reaching us today that exploded from 10 billion years ago the color of the light from these supernovae tells us how fast the universe was expanding at the time they exploded because the expansion of the universe affects the color of the light from the supernova the supernova intrinsically when they explode are mostly blue so they if you were nearer on the supernova and survived what you would see would be a a mostly a blue explosion however while the universe is expanding the light travels to us from that supernova in an expanding universe and everything in that universe that's not held together by some force stretches with the universe and one of the things that stretches with the universe expansion is the very wavelengths of light that are travelling to us from that supernova the difference in the detected colors of supernovae of different ages tells astronomers exactly how much the expansion of the universe has slowed down Saul Perlmutter set himself the unlikely task of catching exploding stars as they started coming in you know the whole group of us we were all cheering and we you know had a party that weekend where we had a bottle of champagne for every one of the super no we discovered but as the data flowed in the slowing down effect they expected didn't materialize in fact quite the reverse after while we start realizing there's actually something that's causing the university to speed up nothing in the history of astronomy had prepared cosmologists for this in fact with the avid gravitational breaking of Dark Matter the acceleration seemed even more paradoxical this came out of the blue this would be something where the universe basically wants to expand faster and faster and faster and there's something apparently powering that that expansion and this is new this is not saying we've had before in our in our physics if you asked the physicists theoretical physicists what could do that they said well if you came up with some way of having a energy of a certain kind that spread out through all space then you can actually get that to cause the universe to accelerate faster and faster whereas dark matter shocked scientists by revealing that most of the substance of the universe was invisible now they had discovered that empty space possessed an inexplicable energy if you imagine taking a volume of space removing from it all the atoms all the energy all the magnetic and electric forces etc you might think you end up a zero but it looks as though you don't end up with something which is exactly zero there is still something there that something exerts a force which seems to be the opposite of the force exerted by normal gravity it's a force which seems to cause things to disappear away from each other and rather be attracted toward each other why empty space itself should be more than just nothingness and have these complicated properties is indeed a very deep mystery they named the source of this mysterious expansion dark energy it sounds like you know what it is if you call it if you give it a name if you call it dark energy but in fact if you talk to almost any scientist today and they would say they've got no idea what dark energy is cosmologists are also unsure of the role dark energy will play in the future of the universe it could make the universe expand forever pushing everything apart to its destruction but started with a big bang they end with a big rip in fact that beneficial building of complexity may have just been the first phase of the universe and that most universe actually will be spent tearing it all apart and that would be of course a rather disappointing conclusion to what looked like very promising and beginning others believe that the local process of building ever more complexity will continue regardless the extra force has no effect here on earth nor even in the solar system nor even in the galaxy but it comes into its own on the intergalactic scale when the gravitational pull is overwhelmed by a force which is actually pushing things apart rather than pulling them together and this force is due to the very mysterious dark energy although dark energy is key to understanding our ultimate fate physicists face a massive challenge to understand it you might think that the distance would have been crestfallen but in fact it works exactly the opposite way around physicists love a challenge and I think they love a mystery and so for them this was the most exciting most fun thing that happened in years but for some the likelihood that we have any role or purpose has been made less likely by the very discovery of the dark side of our universe I think the experience of doing science and learning about science leads to a rather melancholy view of man's position in the university we're not in any very important place in the universe or in the laws that govern the universe others disagree many cosmologists believe we may still have a special place in creation whatever part dark matter and dark energy have played up till now they haven't hindered our evolution indeed we wouldn't be here without them perhaps as we come to better understand dark matter and dark energy we will realize they are not the enemies of the complexity which created us but vital parts of it so the question of why we are here is still open as we've surveyed the cosmos in more detail and the more Versailles instruments we've compiled a more complete inventory of the things in it when we have a deeper understanding of the basic laws I suspect that we will think that it is natural that we have these three ingredients though it looks like a anesthetic complication at the moment in many scientists Minds it should be much simpler than that we we should be able to come up with a theory that makes sense out of all these things all at one time suddenly we'll say Oh with that fundamental simple principle it all makes sense you don't have to have lots of different explanations for different things it all fits into one big story that's the aha moment that we're looking for we want to have that real sense of ah that's no that must be the truth maybe a good clue to why the dark matter and dark energy are around in the amounts that the art is that she changed greatly the amounts of either one we wouldn't be here with no dark matter our galaxy wouldn't have had enough gravitational if you're pulling it together to factually form with the dark energy it's the opposite the dark matter is our friend we need it to form objects dark energies are enemy if you have too much of it it just stops things from forming blows things apart there's no particular reason why human brains had revolved just far enough to be able to assimilate the deepest levels of reality what is amazing this would be able to make so much sense as we have of the external world we have pinned down some of the general properties of our universe just as early navigators pin down the general configuration of the continents and the size of the earth but that was not the end of expiration of the earth and likewise we are at the beginning rather than at the end of our exploration of the universe and I believe when the history of science is written then what's being discovered about our universe in the last decade or two will be one of the most exciting chapters but the key question of course is what we still don't know and that is the challenge for the coming century more next week same time tomorrow at 8 respected and independent hang with American filmmaker Richard Linklater in the art show the next tonight check out the pom-poms on Kirsten Dunst in the cheerleading film bringing on you

Channel: mindfuckuniverse

Views: 577,908

Rating: 4.650156 out of 5

Keywords: what, we, still, dont, know, science, tv series, bbc, universe, cosmology, cosmologist, cosmos, chaos, string, theory

Id: JgiGbmdkMIo

Length: 48min 30sec (2910 seconds)

Published: Wed Apr 25 2012

Reddit Comments

[u/Jim-Jones]

Why Are We Here?

Heat.

A New Physics Theory of Life

From the standpoint of physics, there is one essential difference between living things and inanimate clumps of carbon atoms: The former tend to be much better at capturing energy from their environment and dissipating that energy as heat. Jeremy England, a 31-year-old assistant professor at the Massachusetts Institute of Technology, has derived a mathematical formula that he believes explains this capacity. The formula, based on established physics, indicates that when a group of atoms is driven by an external source of energy (like the sun or chemical fuel) and surrounded by a heat bath (like the ocean or atmosphere), it will often gradually restructure itself in order to dissipate increasingly more energy. This could mean that under certain conditions, matter inexorably acquires the key physical attribute associated with life.

“You start with a random clump of atoms, and if you shine light on it for long enough, it should not be so surprising that you get a plant,” England said.