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0:00
hi I'm Eric Lerner I'm chief scientist at LPP fusion and I'm going to be talking in this video series about the crisis in cosmology now if you've been paying attention to the subject at all you've probably been reading quite a bit lately about the crisis in cosmology we have Scientific American cosmological crisis new scientist cosmological crisis we have even wire cosmology is in crisis and Business Insider they're interested to crisis in cosmology so is there a
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crisis in cosmology damn straight there is but the real crisis in cosmology the one I'm going to be talking about in this series is a lot bigger and has been going on for a lot longer than the one you've been hearing and reading about researchers have been talking about this crisis literally for decades back in 2005 the crisis was sufficiently severe that a couple of dozen colleagues and myself got together and had a conference in Portugal and the American Institute
1:31
of Physics published the Proceedings of the first crisis in cosmology conference 2005 you can find in the literature even in popular accounts references to the crisis in cosmology dating back to 1995 now it's perfectly true that the awareness of this crisis has increased rapidly especially over the last year I did a sort of unscientific study of Google references to determine crisis and cosmology and sure enough back in 1995 there were about 1 reference every year
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by the beginning of this century had gone up to 5 references per year 12 references by the latter part of the present decade it was about two dozen references per year and then this year 2019 it shot up to a hundred and thirty references per year so what's expanded is the awareness of this crisis this has become a general awareness both in the field and in the popular media but what's really behind this crisis well the real crisis in cosmology is that as I wrote back in 1991 in my book
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the real crisis in cosmology is that the Big Bang never happened the real crisis in cosmology is that the underlying model that most cosmologists are working from is invalid it's not scientifically validated despite its popularity so the first thing I'm going to be talking about in this series is how do we judge the Big Bang Theory well when you want to judge a theory what you have to do is compare predictions to observations that were made after the prediction has
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happened now why after well that's what makes science useful to us the ability to predict things that we haven't observed is what science has enabled humanity to develop technology that has allowed us to survive and survive on a larger and larger scale at a higher in higher-level so what I'm going to do is basically grade the Big Bang Theory against observations so this is a list of grading the Big Bang Theory and we're talking of course about the scientific theory not the TV show when I discuss
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comparing a theory with observations we're not talking about expecting a perfect grade any theory is limited in its applicability and so is going to give some wrong answers outside its range of ability but to be useful it has to give many more right answers than wrong answers at least in a certain field of applicability and the Big Bang Theory is supposed to be talking about the entire universe it doesn't matter for judging the validity of a theory whether or not there's a better theory
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out there science isn't judged on a curve the theory has to be valid in terms of its predictions to make an analogy if this was a century ago and someone was trying to persuade you to get on to their airplane and the airplane always crashed but they always had an explanation afterwards you wouldn't consider it a good argument that everybody else's airplane was crashing to have a valid theory of the control of aerodynamics you would be waiting for the Wright brothers to come
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along and they had a valid theory which was proved by they could predict that the airplane would stay up so that's how we're going to be judging this in the course of the series I am going to get into question of is there an alternative way of looking at the history of the universe the evolution of the universe that is more about and we will get into that as well but first we have to judge is the Big Bang Theory right now over time the Big Bang Theory has become
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quite complicated but I want to begin with the bedrock hypothesis of the Big Bang Theory which is that the universe has gone through a very brief but very important period of extremely high temperature extremely high density that period never existed and there is no Big Bang so one thing that we know can be predicted that if the universe was at high density in high temperature we know from millions of experiments from our observations of stars from our development of Technology that when
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matter is subjected to high density and very high temperatures one thing that's certain to happen is fusion reactions fusion reactions are when the nuclei of atoms come together at high temperature and form the nuclei of other atoms so for example hydrogen confused into intermediate nuclei that eventually confused into the different compound helium so scientists long ago determined that if the bag Big Bang happened then it was inevitable that large amounts of helium would be produced and small
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amounts of two other light elements one is the light isotope deuterium which consists of one time and one Neutron ordinary hydrogen consists of only one proton deuterium would be produced in small amounts and in very tiny amounts also lithium would be produced let me in consists of three protons and four neutrons so these were the three light elements that would be produced from the Big Bang and the amount of these light elements the abundance we would see is predicted from
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the Big Bang Theory knowing only one variable which is essentially the ratio during this period of the number of protons because it was assumed that the protons were formed first the hydrogen nuclei two photons to the particles of light in essence to put it in today's observations if you know the density of the universe how much matter there is per unit volume and you can predict these three numbers this isn't a huge prediction but it's a prediction of something important so this is the first
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key prediction of the Big Bang Theory which was called the Big Bang nucleosynthesis predictions so back in the nineteen nine eighty s and 90s people said well it was very difficult to actually measure how much matter there is in the universe because it's very irregularly clocked its clumped into stars which are clumped into galaxies it's very difficult to get an average so they said alright let's measure the abundance of one of these three elements and then that will give
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us through our calculations the density of the universe and then we can use the density to predict the other two so now we one measurement gives two predictions not a big gain but it's something so let's see what happened back in the 1990s people measured the abundance of helium from the spectra of galaxies the abundance of deuterium basically from various measurements including the abundance of deuterium in our own solar system in the abundance of lithium again
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from spectra in very old stars and from this they obtained a measure which they called ADA of the density of the universe and they said well everything's consistent if ADA is around between 3 & 4 and you get lithium down here and that seems to be about right this is an abundance of 10 to the minus 10 compared with hydrogen deuterium is in this wide range here around a few times 10 to the minus fifth and helium which is the second most abundant element in the universe is way up here about 1/4 the
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mass of the universe well time went by and observations got better and we'll get into the story more in a coming episode cosmologists decided that they could actually determine the density of the universe they could predict the density of the universe by measuring the Cosmic Microwave Background cosmic Mike part where a background of course is a very even glow in the microwave part of the spectrum similar to the part of the spectrum we used for cellphones that
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comes from all directions but it has very tiny fluctuations and by tiny I mean a few parts per hundred thousand tens of parts per million and cosmologists thought that by measuring the pattern of these fluctuations basically the size they could derive an estimate a very accurate estimate of the density of the universe and therefore they could make much more precise these predictions about the light elements again we'll be getting into the details of how they think they can do
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this let's just look at this part of the prediction so when we get to basically the present day after satellites like W map and plunk have made very accurate measurements of the Cosmic Microwave Background now we have this picture again this dimension is the density of the universe this is the abundance of lithium deuterium helium well the first thing you notice about this called gran F is that there's very precise measurement now of the density of the universe which
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is around very close to 6:00 in these 80 units of measurement it's not at all the same place 3 2 4 6 it's not the same number it's not even close it's basically wrong by a factor of 2 so the first thing is if these measurements back in 91 were considered a prediction of what would be found when they took these measurements in these calculations of the Cosmic Microwave Background we would have to say that's a pretty poor prediction it's off by a factor of 2 and
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much larger than the errors second thing to notice is these horizontal bands in both diagrams are supposed to be the observations but if you look at the observations of helium in the app in the present time and the observations back in 1991 they don't even overlap the observations back in 91 was that the abundance of helium was between 22 and 24 percent by weight I max the observations in this recently published figure the range is twenty four and a half to twenty six and a
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quarter percent the ranges don't overlap well you can imagine that as measurements got more precise the Rangers wouldn't now but why would they move entirely well this gets into a subject we'll be discussing a lot which is how scientists fool themselves and other people by using incorrect techniques to get the results that they expect now this is an article that was written by Regina Newt so when was published in the prominent magazine nature back in 2015 and the author
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describes some key very common methods by which scientists make mistakes and deceive themselves and one of the four that she mentions is a symmetric attention rigorously checking unexpected results but giving expected ones a free pass well that's what happened here the observations of galaxies that had to love a helium measure for the predictions that were subsequently made made subsequently - these observations researchers found reasons observational reasons theoretical reasons other
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reasons to throw those observations out of the sample and to make adjustments to other observations until the answer came out that the observation smashed the predictions and at the time these new predictions were first made at the beginning of this century none of the helium observations for as high as the predicted range the predicted value which is about 25% none of them but now we have complete observational agreement because the observation of the didn't
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fit were flown out now the situation is really worse than that because in the course of the first decades of the century scientists realized with better observations that there were other ways of measuring the abundance of helium in theory you can measure the abundance of helium in older stars directly now if you could do with that spectroscopically that would be great but the problem is helium has to be heated very hot to observe its line in a distant star so we
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can only use indirect methods now there's a very good indirect method which is based on a combination of measuring the luminosity the star how bright it is intrinsically not how bright it appears to you what at the distance you're seeing how hot it is which we can measure from its spectrum and how much of heavier elements than helium carbon nitrogen oxygen which in the strange terminology of astronomy are all called metals how much of these are present in the star which can be
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measured spectroscopically if you put that together you can combine that with are very good theories of power Starbucks is partially based on our abundant observations of our nearby star the Sun and you can determine what the level abundance of helium is in the star and if the Big Bang Theory is right as you go to lower and lower metallicity less and less carbon nitrogen and oxygen and therefore you're looking at stars that are formed closer and closer to the
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origin of our own galaxy so they haven't been contaminated with the carbon nitrogen and oxygen made by other stars and you should converge on this 25% level well people did this these studies and lo and behold they had the crisis because what happens is as you go down in Z which is the letter they use for this metallicity as you get to purer and purer more pristine stars the abundance of helium first starts going down rather slowly but then it drops very quickly
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and it drops way below 25 percent to 20 percent 15 percent 10 percent and even below down to a few percent as you get closer and closer to zero carbon nitrogen and oxygen so what this data said was that the first stars in our galaxy had no humanism or at least less than 10 percent a complete contradiction to the predictions the very precise predictions of the Big Bang Theory so this was called the helium problem and it started back in 2007 and has only gotten worse and
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people have of course tried to figure out all sorts of reasons why the theories might be wrong the observations might be wrong but they haven't been able to come up with anything fact is the predictions of the Big Bang for helium abundance are simply wrong so if we start want to start grading the Big Bang Theory we start with the predictions of the light elements for helium we have to give the Big Bang 0 well can the theory do any better with lithium I actually no it does even worse
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so lithium the situation is much more clear-cut because with lithium we can measure directly spectroscopically because each element produces certain lines in the spectrum the amount of lithium in older and older stars and again what we're talking about older and older his stars that have less and less carbon nitrogen oxygen iron in their spectrum because less and less other stars have lived before that star was created and therefore less and less as a material of other stars was incorporated
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into it when it was formed out of the plasma that exists in the galaxy so if we look at the lithium predictions this is a graph of lithium in parts per billion relative to hydrogen and iron in parts per billion now iron is a good marker because iron is only produced in supernovae so you definitely have to have stars living their entire lives producing iron that's incorporated into the star we're looking at so if there's less and less iron fewer and fewer other stars have
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lived before that star it's an older star well people have known for decades that if you look at these older stars the level of lithium them is about 4 or 5 times less than the amount that was predicted so again this isn't even close but what's worse than that is again in the last 20 years people have found older and older stars and when you get below about 6 parts per billion of iron the amount of lithium gets less and less and in fact it approaches zero so statistically speaking the amount of
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lithium in the oldest stars is consistent with zero with no lithium having been produced before stars started to form in our galaxy and the upper limit is somewhere around 20 times lower than the predictions of the Big Bang so if if we look at these two elements together historically what we see is that observations have gotten better and predictions have gotten more precise the gap has grown and has grown at an accelerating rate so this is a graph of the number of standard
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deviations by which the observations don't match the predictions the standard deviation it's just a measure of your expected error if your two standard deviations off well that could be expected by chance 5% of the time but if the standard deviations keep going up and up and up until today the helium observations are about a dozen standard deviations away from predictions and with lithium there are about two dozen standard deviations the chance that your predictions are correct
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is essentially zero so with lithium as with helium we have to give the Big Bang Theory a grade of zero what about deuterium ah well stories different with deuterium deuterium can be measured in the spectra of distant galaxies distant quasars and by Georg it actually comes out pretty close to the predictions so we have to give the Big Bang Theory a pat on the back a hundred percent for deuterium but you have to remember this theory is part of the theory which is a
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very core theory only predicts three numbers of these three numbers two are completely wrong so the overall grade for light elements predictions is 33% in my book and I think in your book as well that would be a grade of F that's pretty fundamental because this is one of the basic predictions of the Big Bang Theory is that from a hot dense universe you get these light elements including the second most important the second most abundant element in the universe which is helium well is there other
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direct predictions from this basic core assumption that the universe went through a period of high density and high time well yeah there is and again it's not good news with a Big Bang Theory scientists know that if you have matter at very high temperatures this is much higher than those in the Centers of the Sun then in the presence of particles of matter photons can create antimatter and matter pairs of particle now antimatter despite its strange name is something
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that we've observed a lot in the laboratory it's not that unusual when a photon passes near another a nuclei it can produce pairs of protons and antiprotons or at much lower energy pairs of electrons and anti electrons in the conditions hypothesized in the Big Bang what you would have is a sea of protons and antiprotons produced in exactly equal numbers as this sea of protons and antiprotons expanded and cooled the protons and antiprotons would be colliding with each other now a
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strange thing happens when a particle and it's antiparticle collide they're annihilated their energy the energy that's trapped in their mass is a hundred percent converted into electromagnetic energy into gamma rays so they disappear so if you start with equal amounts of matter and antimatter most of that matter and antimatter will be completely annihilated and you'll only get a very few survivors and you can figure out how few those by we'll be and therefore what the density
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of matter should be in the universe of the present time so that's a prediction of the Big Bang Theory it's not a widely noted prediction but people are aware of it problem is it's much further off than what I've been talking about the prediction is about 100 billion times less than the amount of matter that we observe in the universe now that's true we don't know exactly the density but we know roughly what the density is and this is a hundred billion times less
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like in scientists have known about this problem for decades and decades ago they invented a solution for it on a hypothesis that had to be added to the Big Bang Theory to make it work and that was that there was some force that slightly changed the symmetry between matter and antimatter in our big accelerators and in our experiments we always serve matter and antimatter are produced in exactly equal amounts but this theory said well for some reason there's going to be a little bit more
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matter produced so when the annihilation occurs there's gonna be a hundred billion times more matter left over then is predicted by these our calculation is based on real symmetry well first of all no such asymmetry of the nature that would be needed for this prediction has ever been found in our accelerator experiments but for very basic reasons in our understanding of physics if this asymmetry exists then there's a inevitable prediction about the protons that we observe today
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and that are part of every atom in the universe and every atom in ourselves and that prediction is that the protons must decay in our observations in the lab protons are stable particles they don't have a lifetime they don't spontaneously decay the way a radioactive material does but in order for this asymmetry to occur when the Big Bang was happening it is inevitable that there has to be some small amount of decay in the proton and therefore the proton has to have a
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finite half-life where by this time 1/2 protons would decay into something else so the initial prediction for the half-life was a really long period 10 to the 30th years that's 10 billion times 10 billion times 10 billion 10 to the 30th years well how could that be tested experimentally well actually it's not all that difficult if you put together 10 to the 30th atoms and each of them are decaying once every 10 to the 30th year then just by chance one of them
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will decay during a year and experiments have been set up to observe these decays that would look very different than other reactions that were occurred if you have to shield this experiment from cosmic rays and other things so most of them are put at the bottom of minds but if you want to be really sure you just use a lot of material because when 10 to the 24th sounds like it a lot but it's less than a gram hydrogen 10 to the 30th is less than a ton of hydrogen so if you put
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tons and tons of material together then you can get measure these very long lifetimes so people have been doing this for decades looking for the decay of the proton and G they haven't found a single proton decay so right now the upper limit of the the lower limit on the lifetime of the proton is 10 to the 33rd years a thousand times longer than this gigantic lifetime predicted by the Big Bang Theory but in fact no protons have ever been observed to decay so the proton is forever again this is a
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clear-cut prediction of the Big Bang Theory which is clearly predicted now by experiments in the laboratory very expensive experiments that have been running for decades if the proton doesn't decay then we know for certain that matter and antimatter must be produced as we observe it in the lab in equal amounts and any hot dense period for the universe would have resulted in a hundred billion times less matter than we observe in the universe so if we grade the Big Bang Theory on its
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prediction of matter density a hundred billion times all we have to again give it a zero for its prediction of proton decay at least a thousand times off and probably completely off because it never decays again a zero so 2 more FS our grading sheet of the Big Bang Theory
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we'll have more exciting rating coming up in future episodes thanks for watching
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