How Did Our Universe Emerge From Chaos?

[Music] for millennia if not since time immemorial cultures around the world have woven the sun into their understanding of reality to some ancient egyptians humans were created from the sun god ra's tears in viking mythology saul would cross the sky with her brother the moon and in doing so help humanity tell the time and in one aboriginal australian story the sun mother is sent on a mission to a barren earth to awaken sleeping spirits and give them form as both plants and animals and as science has advanced instead of refuting these early notions as the expanding of our horizons has cooled time on so many other ancient beliefs it has become clearer and clearer that these myths are not so far from the truth in many ways the sun is our god on the most fundamental level the light of our closest star warms the surface and air keeping temperatures within a narrow band so that water persists as a liquid photosynthetic organisms capture solar energy and convert it into their own source of chemical nourishment creatures who cannot produce their own food in turn consume this converted sunlight powering their cells without it our planet would be a lifeless frozen rock drifting in oblivion but more than just this there is something deeper at play for we do not only receive energy from the sun's rays but we are made up of its ancestors remains in ancient tales sun gods were sometimes born from a more primordial deity the aztec god whitser the pochle came into being when his mother was touched by a ball of feathers that had fallen from heaven amitarasu the japanese sun goddess was born from the left eye of her created deity father izanagi and just as these legends hinted a lineage so our sun is not the first it was born from a stellar nursery filled with gas the greater portion collapsing under the power of gravity until mata was dense enough hot enough to shine and it is from this attracted matter that our earth was born but what begot these vast latent nebulae what created these scattered elements that make up us our sun is in fact the latest iteration of an epoch spanning cosmic recycling what astronomers call a population one star it descends from other now long dead stars which transformed the matter within themselves forging new elements within their massive cores before scattering their ashes in vast supernovae like the sons and daughters of solar mythology our sun was born of an older source of light but it was not simply a clone of its parents its chemical composition is very different to those that came before a byproduct of its ancestors life cycle while some of these older stars must die to seed the universe many of the less massive stars from this generation persist to this day in the milky way population 2 stars reside primarily in ancient clusters outside of the galactic disk in what is known as the galactic halo and these stars too had ancestors of their own receiving their constituents from the most ancient suns with the most pristine of ingredients the purest of mixes the yet to be observed population three stars the very first to be forged in the universe but again these were not the first cosmic cradles of creation for the ingredients of these enigmatic giants were created in the very first seconds of time a brief instance when the entire universe was hotter than the sun's core it was once said that we are star stuff but that is only half the story the no hair theorem states that black holes only have three properties mass angular momentum and electric charge nothing else can help differentiate them and as albert einstein james clark maxwell and max plank can attest your hair or a well-shaped moustache or beard can certainly help you stick out in a crowd henson razors have been kind enough to support this video and they are the cutting edge razor makers having switched in 2020 from making aerospace parts including for the actual international space station and mars rover they have taken that precision expertise and need for perfection into the world of razors in fact they've convinced me to switch from using my terrible electric razor and i feel much better for it they're also totally plastic free and should last for decades and in the long term because they basically never break they should save you lots of money the blades are only 10 cents and you can get them easily on amazon meaning that it's barely five dollars a year to maintain so click on the link in the description to get a hundred free blades with the purchase of a razer and start having a nice smooth face thanks to henson for supporting educational content on youtube [Music] the year is 1782 a recent inductee to great britain's academy of sciences the royal society makes a claim that if true would answer centuries if not millennia of scientific inquiry thirty-year-old james price had discovered a way to turn base metals into gold more specifically price claimed that he had developed a white powder that could turn a gram of mercury into 50 of silver and a red powder that could turn the same mercury into 60 grams of gold but unlike your run-of-the-mill charlatan price had performed experiments that backed up his implausible claim with witnesses while his fellow chemists at the royal society remained unconvinced the university of oxford saw fit to award him an honorary medical degree for his labors not explicitly for these experiments but perfectly timed to suggest they played a factor to the greater public price had finally demonstrated that alchemy was more than magic it was science but as his fellow royal society members demanded a replication of these experiments for their own eyes price quickly grew reluctant he claimed the creation of the powders was too strenuous on his health and that the process would never be financially profitable the value of the silver and gold created did not exceed the value of the materials put into making them his reputation as an honorable chemist he claimed should be enough for his peers to take him at his word buckling under the pressure in january of 1783 price finally agreed to the royal society's demands of course price knew he was unable to prove his implausible claim of alchemy and so instead of turning mercury to gold before the eyes of the gathered fellows he drank a vial of concentrated laurel water and died but the human desire to transmute one element into another did not die with him modern tales of this desire tend to stem from one man the so-called father of nuclear physics ernest rutherford born in britain's new zealand colony in 1871 rutherford escaped the small single single-teacher town of havelock at the age of 15 eventually making his way to the university of cambridge as the first non-graduate of cambridge to earn a spot as a student researcher not long after the discovery of radioactivity rutherford set his sights on the new field and set up a lab at mcgill university in canada to investigate these mysterious new compounds during one such observation in 1901 rutherford and his english colleague frederick soddy caught a sample of solid thorium slowly converting into radium gas sodi excitedly exclaimed the thorium was naturally undergoing transmutation the changing of one element to another to which rutherford supposedly responded for mike's sake sodi don't call it transmutation they'll have our heads off as alchemists rutherford's aversion to the term aside this was a huge moment would the pseudoscience of alchemy edge its way into reality by the 1920s rutherford had demonstrated that by bombarding nitrogen atoms with alpha particles he could create hydrogen and in 1925 to prove it once and for all he tasked his student patrick blackett to photograph the disintegration process using a tool known as a cloud chamber definitive proof that nitrogen could be changed into oxygen blackhead had done what james price could not even though it wasn't silver or gold he had intentionally turned one element into another like it was awarded the nobel physics prize in 1948 alchemy was possible if not what the ancients had envisioned rutherford would go on to say it is now possible by modern methods to produce exceedingly minute quantities of gold but only by the transmutation of an even more costly element platinum the 20th century had thus ushered in the error of the subatomic atoms were not as their greek name suggested uncuttable elements became defined based not on their overall mass but on their proton count transmutation therefore merely required that proton count to change and such a feat was possible through several means [Music] the first was through natural radioactive decay which required no human input whatsoever an unstable nucleus would emit a particle thus becoming a lighter element the second was nuclear fission reactions wherein human influence triggered an already unstable atom to crack apart be that the nuclear power plant or within the heart of a nuclear bomb and finally through the process of nuclear fusion the combination of two or more atomic nuclei a power which humanity has yet to truly harness atomic nuclei being composed of protons and neutrons are positively charged and as we learned from our first exposure to magnets two positive sources of electromagnetism repel one another the closer to nuclei get the stronger the urge for them to fly apart but there is another force which can come into play the strong nuclear force binds protons and neutrons together but its strength drops dramatically beyond the edge of a nucleus therefore scientists must generate enough force to push two nuclei close enough together that the strong force can take over in the core of our sun this is achieved at the temperature as low as 15 million degrees celsius but on earth where we lack the crushing pressure of the sun's continually gravitationally collapsing matter we need to get our fuel even hotter at least by 10 times a full century after the discovery of nuclear transmutation today's scientists are still pursuing the quest to imitate the immense power source that maintains our sun's billions of year lifespan and created many of the elements that make up the universe the quest for man-made nuclear fusion what is the source of the heat which the sun and stars are constantly squandering in 1920 english astronomer and physicist arthur eddington posed this question to his peers at the annual meeting of the british association for the advancement of science in cardiff scientists of the day would answer the question with gravity the collective collapse of the gaseous matter from which the sun is constructed would generate a release of heat just as the rocks and metals of the earth did a leftover energy set in place when the solar system first collapsed into its various orbs but these same scientists also knew that answer could not be correct the age of the earth and by extension the solar system was already known to be in the billions but at the rate with which the sun shone it would have run out of energy to release in a mere 20 million years eddington asserted that it was mere tradition that kept this hypothesis alive or rather not alive he wrote but an unburied corpse instead he looked to the burgeoning field of his contemporary rutherford for a new answer a star is drawing on some vast reservoir of energy by means unknown to us this reservoir can scarcely be other than sub-atomic energy eddington speculated that deep within the sun hydrogen was turning into helium and perhaps even heavier elements and releasing energy in the process indeed it was the stars themselves that operated as cosmic factories eddington estimated that through the subatomic the sun could shine for 15 billion years while that estimate turned out to be several billion years in excess eddington's concept of stellar nuclear fusion was spot on and he went beyond proposing merely how all stars shine but what that meant for humanity the possibility that we could harness nuclear fusion for the well-being of the human race or for its destruction [Music] and over the past hundred years scientists have worked towards at least one of those fates and it turns out the key to exploiting the power of the sun may lie in imitating its weaker sibling brown dwarfs are often called failed stars they are so dim that they elude capture but scientists believe that for every true star in the universe there may be an equal number of brown dwarfs they are the intermediaries between gas giants like jupiter and the smallest stars failing to accrue the mass necessary to begin the process of fusion all true stars do specifically the ability to fuse lone protons what we typically describe as hydrogen into helium but brown dwarfs are capable of another kind of fusion they mainly require a different kind of hydrogen deuterium is the lightest composite atomic nucleus meaning it consists of more than one nucleon like all hydrogen it has one proton but bound to that proton by way of the strong nuclear force is an additional neutron the abundance of deuterium depends on where you search in earth sea water there is approximately one deuterium nucleus for every 5 000 or so hydrogen nuclei composed of only one lone proton known as protium meanwhile in the atmosphere of jupiter the ratio drops to 1 for roughly every 40 000 protium atoms far closer to the true ratio of deuterium to protium across the greater universe and it is this deuterium that brown dwarfs are capable of fusing with protium this is because the presence of that single neutron makes it slightly easier for the nuclei to overcome their mutual electromagnetic repulsion less energy is required to fuse them together as deuterium is naturally abundant in sea water with only one liter of water capable of generating the equivalent amount of energy is burning 300 liters of gasoline scientists on earth have turned to this isotope as a possible way forward into fusion technology a type of alchemy where the most valuable product is not the proverbial gold made from lead not the helium made from hydrogen but the energy released in the process price and his alchemist predecessors would stand utterly confounded by the machines we use today to transmute matter in one pioneering experiment this is the modern version of his lead a micro capsule of synthetic diamond placed within a golden cylinder roughly the size of a pencil eraser this capsule is cooled to temperatures just above absolute zero and placed at the center of a giant spherical chamber five meters to the inner edge and it now becomes the target of 192 ultraviolet lasers in far less than the blink of an eye these lasers impart a pulse of invisible energy to the capsule it disintegrates its diamond coating inducing an implosion to heat the contents inside from all sides with so much intensity that humanity can harness the vast power of a brown dwarf this is the national ignition facility or nif in california the most efficient way for humans to go about turning hydrogen into helium fuses deuterium not with protium but with tritium tritium is as the name suggests a third isotope of hydrogen one proton two neutrons together they yield a nucleus of helium-4 the most abundant form of helium and a lone neutron and 80 percent of the energy liberated by the fusion process is carried by that neutron in august of 2021 a single nif experiment fused roughly 200 micrograms of deuterium and tritium to produce an equivalent of 10 quadrillion watts of power roughly 700 times the output of the united states entire electrical grid however it could only be sustained for 100 trillionths of a second meaning the actual amount of energy it created was just enough to power a light bulb for six hours still this experiment also claimed the world record for the most energy-efficient fusion reaction seventy percent of the energy they put in came back out but for comparison this is only an additional three percent above the record set for deuterium tritium reactions nearly 25 years earlier and of course to ever be a source of power it must exceed 100 percent and so this nif experiment illustrates two major hurdles scientists must overcome before nuclear fusion can be incorporated into humanity's power generating infrastructure first a reaction must produce more usable energy than it consumes while the deuterium tritium reaction is easier to achieve at the outset than it is with other nuclear fuels it is more difficult to convert the byproducts of that reaction into electrical power this is because the vast majority of the energy generated by the fusion reaction is carried away by a neutral particle the second challenge is that the reaction must be sustained for sufficient lengths of time the international iter project based in france claims that it will be the first project to create net positive energy through nuclear fusion more specifically the group hopes to produce 10 times the amount of energy that they put into making it however even if it succeeds in its goals the energy it generates cannot be captured it will be up to yet more experiments to harness deuterium's power [Music] it is clear that the deuterium tritium reaction is not the perfect solution to humanity's energy woes [Music] other kinds of nuclear fuel such as helium-3 offer a cleaner alternative while being more difficult to fuse it is thought that our moon may hold a treasure trove of this isotope built up over 4 billion years of being bombarded with individual nuclei ejected by our sun assuming the technology can be developed to create positive net energy from such a fusion reaction the question becomes whether or not certain areas of our moon have helium-3 in sufficient quantity to justify mining it as a resource we may yet see ourselves in the middle of a second space race as science continues its stare down with the challenge of sustained nuclear fusion humanity's modern alchemists hope to one day recreate the processes stars are capable of doing all on their own processes that over billions of years of death and rebirth have created nearly all the elements we see today but there was a time when stars were not needed to fuse nuclei together before brown dwarfs supernovae or even population 3 stars there was a brief moment in which our entire universe was a fusion reactor [Music] why would a person throw themselves into a volcano if you are the 5th century bc philosopher in pedicles it might be to try and convince your followers that you are a god indeed the myth of impediclee's death is just that despite this surprisingly today he is most well known for a singular proposal originating in his poem perry physios or on nature as the title hints and pedicles sought to identify the very makeup of the universe only fragments of the poem still remain but the thoughts expressed have permeated western culture well into modernity impedicles proposed that every observable substance in nature is composed of some combination of fundamental substances he called rhizomata or roots which he attributed to four deities today scholars generally translate these as fire earth ether and water plato then replaced the term roots for stoichion which in english we call elements while aristotle would say that empedocles was the first philosopher to distinguish the four elements even modifying the hypothesis to include air other cultures had certainly formulated their own versions of a similar concept around the world humans were realizing that everything we can sense in the universe is actually when you break it down made of more fundamental building blocks today we know of 118 elements most frequently organized into a table which shows the periodicity of certain properties the heaviest of these elements do not exist in nature in any measurable quantities due to their incredibly short life spans and the vast majority are made in the violent deaths of stars and stellar remnants through various different reactions inside stars scientists have been able to account for a lot of the elements that make up our world but for many heavier elements our sun is just not big enough carbon and oxygen require a star around half to four times the mass of our sun whereas more than four times the mass and the star confuse oxygen to silicon and the creation of iron within the core of a star more than 10 times more massive than our sun acts as a metallic death knell for its host a sign of imminent supernova so how can we explain a universe rich in far heavier metals one answer is in the brutal supernova that scatters those elements across the cosmos many heavier elements are believed to be formed in the energetic chaos of a star tearing itself apart another is in slow neutron capture in certain types of stars over thousands of years but yet another solution may lie in an event even more violent in 2017 the newly operated ligo laser interferometer gravitational wave observatory detected two neutron stars colliding neutron stars are the densest thing before a black hole the dead heart of a massive star and using the previously inaccessible medium of gravitational waves ripples in the very fabric of space-time ligo was able to pick up the faint echo of a circling pair's final moments but their detection was just the beginning the scientists were able to use information from ligo to focus other instruments on the killenova event that followed the merger and through re-analyzing the spectroscopic data in the explosion detected a heavy element strontium with the atomic number 38 proof that the most catastrophic events in the galaxy are responsible for at least some of the heavier elements and so the explosive demise of these stellar objects gifted us with the various elements that make up the world we know today but what gave them life in the first place what made up the first stars as with their heavier cousins these primordial elements arose in an instance of vast cosmic violence the most energetic moment in the history of the universe the big bang in the very first moments of our universe a super fundamental particles and anti-particles sprung forth from a sea of energy with rapid expansion came rapid cooling though temperatures were still incomprehensible to mortal mines 10 trillion degrees celsius as the first microsecond came to its end still it was now cool enough for lone quarks to bind together into composite particles we call hadrons while we know of six flavors of quark only two govern our daily lives their names however fail to convey their importance they are merely known as up and down combine two up quarks and one down quark and you have made a proton as all hydrogen atoms are defined by a proton count of one these were the first hydrogen nuclei meanwhile each neutron is born of one up quark and two down quarks together these two hadrons provided the necessary ingredients for big bang nucleosynthesis the distant ancestor of every star every planet and every life form alive today the process of big bang was first described in 1948 by then graduate student ralph alpha and his supervisor george gamoth the third author on the paper hans beeta was added by gamoff as a joke the alpha beta gamma paper was born in this paper alpha predicted that the incredibly high temperatures and pressures found at the origins of the universe could induce a multi-step process of nuclear transformation hydrogen the only element then in existence would become helium for the very first time and the first step in this alchemical process was to synthesize deuterium the bonding of one proton and one neutron into hydrogen's second isotope while protons and neutrons had existed in equal quantities when hadrons first formed and could just as easily transform from one into the other time was proverbially waiting for no one temperatures kept dropping making it harder to craft neutrons neutrons it turned out were ever so slightly more massive than protons and that extra mass meant slightly more energy was required to create them additionally neutrons were less stable than their positively charged counterparts as they continue to be today powered by the weak nuclear force a lone neutron will eventually undergo radioactive decay becoming a proton electron and anti-electron neutrino by the time the universe was ready for nucleosynthesis there was only one neutron for every seven protons a ratio which utterly shaped the subsequent 13.8 billion years of the universe's evolution while deuterium could form just a few seconds after the big bang it was still so hot that if a stray particle of light hit a deuterium atom it would break apart scientists call this the deuterium bottleneck and it meant that for at least a time nucleosynthesis could not move beyond a single element could not progress onto or past the fusing of one neutron and one proton but somewhere around 300 seconds after the big bang that bottleneck widened deuterium could finally exist without the threat of breaking down from a stray photon and by then the universe was well into the process of creating helium there was however a ticking clock the universe was cooling expanding just how many elements could the universe birth in the brutal heat of its own creation once there was roughly one deuterium nucleus for every 100 000 lone protons they too engaged in nuclear fusion reactions the process still used today at least briefly by the brown dwarfs hiding in our night sky and it was from this union that a second element finally arose helium-3 nuclei constructed from two protons and one neutron while hydrogen can exist without neutrons helium cannot its two protons exert a mutual positive force that threatened to tear the nucleus asunder as such there was no way for two lone protons to create helium on their own but with just one neutron there was enough pull from the strong nuclear force to overpower the electromagnetic push a helium-3 nucleus whether made at the dawn of the universe or by a stray cosmic ray in the modern day is stable left alone it will persist until the end of time however the most abundant form of helium is helium iv two protons two neutrons in this early universal forge helium-4 arises mostly from the union of a deuterium nucleus with one of either helium-3 or tritium and with helium-4 came the most stable composite nucleus in all of existence the most difficult to break apart in nuclear physics it is the simplest of the nuclei we call doubly magic if the early universe preferred the proton over the neutron it preferred the helium-4 nucleus over all others safe proteome the march of times therefore dictated that in these first few minutes most of the protons and neutrons in the universe that began the process of nucleosynthesis became trapped inside helium-4 and went no further together with the overall density of matter at the time the ratio of protons to neutrons restricted just how much helium could be made if mata were more compact at the time of big bang nucleosynthesis more helium would have formed perhaps so much helium the least reactive of all the noble gases that little to no chemistry may have ever happened throughout the rest of time we often say that the early universe was 75 protium and 25 percent helium 4 specifically when measured by mass photons neutrinos dark matter and so forth are not incorporated into this statistic but it is an important one as it is also the composition of the very first stars and these are the population three stars which astronomers continue to hunt for [Music] but hydrogen and helium are only two of the 180 elements in our modern periodic tables where did the rest come from the universe keeps cooling fusion continues next up three protons this is lithium in big bang nucleosynthesis two isotopes are created lithium-6 and lithium-7 the latter in greater abundance beryllium is next with four protons but it is unstable decaying into lithium in an average of 53 days and beryllium-8 meanwhile exists for less than a billionth of a second indeed no isotope composed of eight hadrons is stable and so here nucleosynthesis hits another bottleneck with fewer heavy nuclei in abundance and with ever-dropping temperatures it becomes almost impossible for the universe to create an isotope with at least nine hadrons if any boron carbon nitrogen or oxygen were crafted it was in such limited amounts that there is no record of the universe having done so finally 20 minutes after the big bang the nuclear furnace that spans the entire observable universe dies only four elements exist and only three exist long enough to see the first stars shine hydrogen helium and a trace amount of lithium it would be at least 200 million years before the universe had another opportunity to seed itself with heavier elements when blazing spheres of hydrogen and helium compressed their cores with sufficient force to achieve the temperatures long missing but it is through those stars or rather their descendants that we must piece together the state of the universe at this ancient time and in doing so scientists have discovered a mystery that lingers at the heart of this lineage of celestial bodies an imbalance that threatens our understanding of the entire timeline [Music] in 2013 astronomers made an impossible measurement observing a star which had been an occasional target for at least a century they finally pinned down its age or did they at first glance this star appeared to be older than the universe 14 and a half billion years old and it was located only a mere 109 light years away in our own solar neighborhood its designation [Music] hd140283 but in popular media it became known by the biblical name methuselah of course it was far more likely that there was some kind of error made in either the measurement taking or in the fundamental understanding of how these measurements correspond to a star's age than it was that the ancient star was born before the known universe and indeed when the team accounted for the various uncertainties in their measurements the minimum possible age became 13.66 billion years methuselah was not older than the universe further research published in 2021 suggests the star may be even younger as young as 11.5 billion years old calculations completed this past decade still suggest a wide array of ages though all within the first billion or so years of the universe so we may never know its true age but its composition does tell us something crucial about cosmic history [Music] based on the abundance of metals in methuselah's atmosphere astronomers know that it was not one of the very first but instead formed soon after stars from the first generation died stars like the big bang before them go through their own version of nucleosynthesis both during their lives and at the moment of their deaths this means that the abundance of metals be it iron or oxygen increases amongst all subsequent generations forcing us further and further away from the image of a universe before any stars at all population three stars with metallicities as near to zero as the universe allows gave birth to population two with metallicities of roughly 0.1 percent and through their lives and deaths they eventually in turn gave birth to those stars classified as population one with metallicities in excess of one percent methuselah appears to be one of the most ancient population 2 stars and it is this generation which astronomers have been forced to study to try and confirm what models predict the original elemental abundances after big bang nucleosynthesis ended and the composition of the ever elusive population 3 stars astronomers also look beyond individual population 2 stars in their attempts to extrapolate back to even more ancient days they turn to the least massive irregularly structured dwarf galaxies that contain them with less mass there is less hydrogen to collapse and form stars so due to their relative lack of star formation these minuscule galaxies tend to have the lowest metallicities and so they are the closest proxy to the abundance of elements in a time before stars measuring a galaxy with near zero metallicity implies the amount of helium has not been altered through stellar nucleosynthesis the abundances of hydrogen and helium mimics the ratio found in the first half hour of the universe hundreds of millions of years before the very first stars indeed there is little disagreement between the abundances of hydrogen including deuterium and helium-4 in these only slightly less ancient days compared to the primordial levels predicted by mathematical models lithium however is a trickier matter a mystery science has yet to solve stars it turns out are particularly good at destroying any lithium inside them be it what they formed with or what they made along the way to heavier metals thus they obscure the story of how much lithium was created in the big bang's metaphorical forge nevertheless by narrowing in on how readily lithium is both created and destroyed observations of population 2 stars in particular the oldest hottest stars we can find in the milky way's halo can still provide estimates but these estimates do not match what other analyses imply according to current astrophysical theory the amount of lithium crafted after the big bang as well as every other primordial element is ultimately dependent upon a single variable the ratio of photons to protons and neutrons at the moment big bang nucleosynthesis began by looking at the cosmic microwave background which reveals the oldest light our telescopes will ever see astronomers can measure that ratio and therefore predict according to the known laws of physics how much lithium-7 should have been created but that expected value is roughly three times greater than what is actually observed astronomers have given this unique discrepancy a name the cosmological lithium problem and there are three possible solutions [Music] the first looks to the stars the measurements we take of them and the equations describing their inner workings only the outer layer of a given star can be observed so some of the apparently missing lithium may be concealed at a greater depth or used up in the fusion process that our current physics cannot depict in full but astronomers are also not directly measuring the abundance of all lithium-7 some must be inferred given the local temperature however determining the temperature of any one spot within a star is rather more complicated than it might seem at first glance so a small deviation from the true temperature manifests as a much greater error in the amount of lithium astronomers believe they must add to what they already do detect a second solution is found at the nuclear level specifically the ease at which different nuclei interact with each other bind together or break apart may not match our current understanding for example since primordial lithium-7 is created by the decay of beryllium-7 if it were actually harder for beryllium-7 to form than our models suggest or less likely to decay into lithium-7 that could explain why we observe a lower quantity of primordial lithium a team of researchers considered this possibility in 2015 but their analysis created an even starker divide between observed quantities and theoretical ones and finally it may be that our theories that describe the nature of reality paint an inaccurate picture our underlying assumptions were not just big bang nucleosynthesis but for all astrophysical processes are incomplete at best the theoretical abundance of all the primordial elements stems from cosmologists understanding of the fundamental processes of reality the four fundamental forces of gravity electromagnetism and the strong and weak nuclear forces the expansion of space the properties of subatomic particles it also depends on the state of the universe in those early moments its size temperature and density and how rapidly each of those is changing indeed we already know that our models are inaccurate in specific matters such as the fact that neutrinos actually have mass or that dark matter almost certainly exists and is likely made from particles which remain unaccounted for in the standard model exotic particles which existed at the dawn of time but no longer or still existing particles we have yet to discover could have tipped the scales in a process we are as of yet blind to or perhaps it is the universe as a whole that is not what we think it is the cosmos is assumed to be homogeneous over large scales our position in the universe is no different no more special than any other position stretching across billions and billions of light years from each world alien astronomers would measure the same overall structure but what if that weren't true if our region of the cosmos was in fact special say a little less dense than the overall average the measurements we take may be biased only time of course will tell with more advanced telescopes more sophisticated computer systems to crunch the numbers at finer details scientists may one day resolve this primordial lithium problem perhaps it is simply a matter of our current methods being insufficient to fully capture the true nature of the universe or perhaps the true nature of the universe is itself something other than we imagine and so we continue on to try and comprehend how our universe went from an energetic soup of a handful of fundamental particles to the vast cosmos we see experience and take part in today you've been watching the entire history of the universe don't forget to like and subscribe and leave a comment to tell us what you think thanks for watching and we'll see you next time [Music]

Channel: History of the Universe

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Length: 46min 54sec (2814 seconds)

Published: Sun Aug 28 2022