Let's Find Out - The Greatest Mysteries in Physics: Forces, Numbers, Energies, and Sizes | ASMR

Episode Date: August 13, 2024

The greatest unsolved problems in physics are mysteries that range from the subatomic to the cosmic. Let's find out the boundaries of our knowledge about the universe. ▸ Want to leave a tip or connect?: https://linktr.ee/letsfindoutasmr ▸Timestamps: 0:00 There are major gaps in our scientific framework 9:57 The Fine Structure Constant (Dimensionless Physical Constants) 31:09 The Cosmological constant (Dark Energy) 37:11 Martin Rees's "Just Six Numbers" 47:05 Reconciling Gravity and Quantum Field Theory (Theories of Everything) 59:54 Cosmic voids and "vacuum energy" (catastrophe) 1:14:30 Dark Matter 1:25:15 Primordial, Direct-collapse Black Holes 1:29:40 The Heirarchy Problem ▸Music: -The two opening tracks are courtesy of Atmoslab by Jeremy Vessey @atmoslabmusic -All the rest are originals.

There is an unsettling number of intellectuals that believe that we are all living in a simulation. And the fundamental reason this is so unsettling is because we look to these very intellectuals to ground us in reality. We're at the mercy of science because it's so powerful at bending the world around us to our will. And the future and fate of humanity has been intertwined with our technology since at least the Industrial Revolution, if not before then. Since our advances in the 1800s of understanding electromagnetism, and then shortly thereafter, the revolutionary leaps in our understanding at the largest and smallest scales of the universe from Einstein's breakthrough intellectual insights. into special and general relativity, which told us so much about gravity

and its relation to not only space, but a four-dimensional construct called space-time. And then the later equally revolutionary insights into the world of the subatomic, partially sparked from Einstein himself, and then building incrementally on the other genius insights of the greatest physicists of the 20th century, up through and beyond the emergence of humanity into the nuclear age.

Think about the world we live in today, the technological world we've inherited from these generations of scientists, ever more deeply probing into the universe and its structure. We live in the nuclear era where nuclear energy can potentially provide limitless resources to us, to our devices that are ever shrinking, yet with battery and storage capacities ever growing. The nanotechnology and the secrets of the subatomic world that we're able to harness the energy from have had profound impacts on all areas of society, least of which is medicine. Think about the breakthroughs in medicine that are extending our lifespans through biochemistry,

biotechnology through vaccines and antibiotics through the discovery of human DNA its structure and the subsequent sequencing of the human genome think about the deep probings of nature on the smallest scales like at cern with the large hadron collider discovering the elementary particles that until they were discovered were only theoretical abstract mathematical symbols on paper And what about the largest scales, the longest expanses of time that we've been able to probe by gathering data raining in from the cosmos, from the cosmic microwave background that essentially proved that the universe wasn't static and eternal and fixed, as so many had believed throughout history, Einstein included, but instead apparently had a beginning.

and apparently is changing all the time telling us that we might just be at a special point in history that allows us to even exist and that's not to say anything about the revolutionary implications of technology like the internet and all the deeply socially relevant software that's running on top of that AI very much included we are immersed, we are becoming symbiotic with technology.

So much so that most of us grow up believing in science, believing in the power of science to solve our problems. We've come to believe that science in a world of murky, confusing matters of consciousness and spirituality, morality, ethics, Science and mathematics alone can harbor us from deep, dreaded, existential doubt. It's a place where we can look to for certainty and rational explanations of the natural world that we find ourselves thrown into. But there's one problem with that. If you start looking close enough at the paradigm of the physical world, the paradigm, the framework of the science that we've considered. that we've constructed with our mathematics. We start to find cracks in the bedrock of the scientific worldview,

whether it's at the subatomic or the intergalactic, and it takes only a few clicks across hyperlinks in the Wikipedia universe, for instance, before we find out that the bay of scientific rationality of reason and logic in which we so desperately want to anchor, our understanding of reality, we find out that this bay's waters might appear still and navigable from the surface and from a distance.

But as we explore it, we're discovering that these waters run deeper and are perhaps more turbulent than any of our vessels of reason and logic, any of our paradigms, might be able to actually reach and navigate through. It really begs the question of how can these leading intellectuals that we look for to understand and help us make sense of what is most true be so uncertain about such a fundamental level of reality? Well, I've found out that there's not just a few, but there's dozens of unsolved problems in physics.

And some are beyond unsolved. Some are incomprehensible. Some are not only incomplete and not only awaiting further technological breakthroughs, but there are fundamental confusions at the most foundational levels of the model that we currently use to understand the physical world we live within. These go from our complete lack of understanding of what dark matter is surrounding essentially almost every galaxy we've ever observed to the dark energy that appears to be ripping apart space and overpowering the combined gravitational interactions of all matter in the universe,

dark matter included. We have the mystery of matter and anti-matter asymmetry that fortunately for us has led to an abundance a positive asymmetry of regular ordinary matter of which we're made of and then there's the problem of the standard model of physics itself the very model that was used to predict the Higgs boson that we discovered in 2013 at CERN is still incompatible with another definitively proven correct model of the universe at much larger scales of the cosmos being Einstein's general relativity there's a fundamental incommensurability

between the three of the four fundamental forces being the electromagnetism than the strong and the weak forces of the subatomic world and the force of gravity as understood to be a distortion a bending of space time itself at the larger scales so tonight let's explore some of these unresolved or unsolved mysteries in physics let's see where these cracks in the bedrock of our understanding of reality lie. Physics is known to be a science that uses measurements and experiments to understand how different objects relate to one another and different concepts like energy and matter relate to one another. But throughout history there are these mysterious dimensionless fundamental physical constants.

that rise over and over again in experiments, many of which have no explanation. A dimensionless physical constant is a physical constant that is a pure number, having no units attached to it, no units like mass, distance, time, temperature, energy, and arguably one of the most competent, most accomplished, most genius physicists of the 20th century, of the 20th century, Richard Feynman, in his 1985 book, Quantum Electrodynamics,

the strange theory of light and matter, remarked about these fundamental constants, these dimensionless constants, and one in particular called the fine structure constant, denoted by alpha, he says there is a most profound and beautiful question associated with it. It's a simple number that has been experienced. experimentally determined to be close to about 0.0854-2455. Some physicists, he remarks, like to remember it as the inverse of its square, which is about 1 over 137.03597.97.

But it's been a mystery ever since it was discovered more than 50 years ago in the 1930s. And he says, all good theoretical physicists put this number up on their wall and worry about it. Immediately, you'd like to know where this number comes from. Is it related to pi? Or perhaps to the base of natural algorithms? Nobody knows. It's one of the greatest damned mysteries of physics, a magic number that comes to us with no understanding by man. You might say the hand of God wrote that number.

number. Or, quote, we don't know how he pushed his pencil. We know what kind of dance to experimentally do to measure this number very accurately. How he pushed his pencil, you might say. But we don't know why he pushed his pencil. And for what reason? We don't know what kind of dance to do on the computer, for instance, to make this number come out. without putting it in secretly. Now, the fine structure constant comes from what's called the fine structure, which describes the splitting of spectral lines of atoms due to the electron spin and relativistic corrections to the non-relativistic Schrodinger equation. This was actually first measured in 1887 by Michelson and Morley.

The same physicists who attempted to later measured the non-existent, ether in the universe, the medium through which light could travel. They knew that the specific spectral lines of particular elements had been known for decades at that point, but the mechanism for why they were produced and why each element appeared to have its own specific fingerprint wasn't yet known. It wasn't understood at that time that the electrons, the negative electrons,

surrounding the positive atomic nucleus could jump, could absorb photon energy, jumping to higher levels, or changing to different orbital configurations, and then having a tendency to drop back down, after a certain period of time to a more stable configuration closer to the nucleus, emitting photons of a very specific energy and therefore specific wavelength in the process. But as instruments got more sophisticated and scientists were able to probe and see and resolve

finer and finer images of these spectral lines and measure the wavelengths at ever finer ranges. They notice that some of the lines actually split into two lines. And this apparently arises from the specific spin that the electron has as it's emitting or as it's changing orbital configuration and emitting a photon. So it will emit a photon of just a very slightly different energy. energy in wavelength depending on its electron spin and given that electrons are moving at significant fractions of the speed of light around in their cloud around atoms relativity and

the relativistic effects of their momentum and their angular velocity has to be taken into account here. And when those relativistic corrections and the initial spins, whether they're up or down, are taken into account and added in the Schrodinger equation, which is a differential equation that governs the wave function of a quantum mechanical system, is adjusted for these initial conditions. We've understood and we can have some

predictive ability of how these lines this fine structure is created. And that laid the basis in the late 1800s Michael Sin and Morley's

measurement of these lines for the physicist Arnold Somerfeld. to have to elaborate and create a theoretical treatment in which he introduced the fine structure constant that is essentially a number a constant that doesn't change and relates the gross structure of the spectral lines being the more well-known energy levels of the principal quantum numbers, which denote the gaps between the different electron orbitals, the energy, discrete energy levels, the quanta between those levels.

Well, it was observed that those quanta can actually be split into fine and even the hyperfine lines, energy levels. And the gross structure energies is on the order of Z, where Z is the atomic number, multiplied by this dimensionless fine structure constant squared. And this tells us the scale of the fine structure splitting relative to the gross structure energies that are observed as electrons change from orbital to orbital and emit the appropriate. energy. This number was so intriguing to so many people that the physicist Wolfgang Polly of the Polly exclusion principle of fame, even he commented on the appearance of this number in physics, among others, in which he notes it approximates the prime number 137, the inverse of it, at least,

and it so intrigued him that he even collaborated with a famed psychoanalyst. Carl Young in a quest to understand its significance. He was quoted as saying, When I die, my first question to the devil will be, what is the meaning of the fine structure constant? Statistician I.J. Good argued that a numerological explanation would only be acceptable if it could be based on a good theory that is not yet known, but exists in the same sense of a platonic solid.

or a platonic ideal. And there's been other attempts, many attempts, to find a mathematical basis for it, even up to the present day. But so far, none has been accepted by the physics community. And even Stephen Hawking, in his book A Brief History of Time, began exploring the idea of a multiverse, among other physicists, and the fine structure constant was one of several,

universal constants that suggested the idea of a fine-tuned universe that we live within. And that makes you wonder just how profound of an impact some of these mysteries have on the greatest intellectual, rational, scientific minds of humanity. How despite the hubris, some would say, the pride and and the arrogance that comes from being able to unlock the energy held within the nucleus of an atom, for instance. Or predict particles and cosmic phenomena that aren't found for decades later. You know, like the Higgs boson being predicted in the 60s and 70s, the cosmic microwave background being predicted in the 30s, 30 years before it was even detected.

Einstein predicting black holes as just one of a number of unanticipated predictions out of his special and then more comprehensive general theories of relativity to me it's fascinating to think about or read about what these great minds what they were led to as a result of coming into contact with and intellectually and spiritually with these these deep, deep mysteries that are apparently baked into the cosmos at a fundamental mathematical and extremely high energetic level, things that can't be unlocked unless you probe and evolve technologically to the point where you can start up accelerators that are much,

miles in diameter and accelerate particles close to the speed of light and smash them together or send massive telescopes millions of miles out in the space to observe calmly, patiently, collecting very faint light, billions of times fainter than the human eye can detect for months and years to create an expansive, an expansive car. comprehensive, detailed picture of the universe we live within. It's so thought-provoking. It's really awe-inspiring to think about that even at the deepest levels

of the most potent theories in mathematics ever devised by humans, we still run into mysteries. And maybe it's the fact that they are at the deepest levels that makes them even more profound. these mysteries that the forces, these fundamental forces governing the ability of the subatomic particles like protons and neutrons and even the quarks that make these particles, these nucleons up, these fundamental forces that hold them together or apparently cause them to spontaneously and very unpredictably separate or emit. other particles and alter their chemical makeup, the electromagnetic forces that we, on human scales, really governs most of our day-to-day experience. Not to mention anything of the fact that our brains and the electromagnetic impulses that

make up our own thoughts are defined and governed by these exact. rules to some deep deep degree that we do not yet understand it's amazing that these forces we've been able to determine to a pretty certain degree that they are at the highest energies like those maybe even beyond the cores of stars but in the course of black holes or even at higher magnitudes at the beginning of the universe are themselves just different sides of the same coin that act as the same force that are at certain high enough energies unified with each other indistinguishable from each other and only separate break apart into these unique forces

detectable by us now at very low, relatively, relatively low energy levels of the present-day universe. And another great 20th century physicist, again, it would be up there in the top five, at least 10, potentially top five of all time. Paul Dirac echoed similar sentiments about the that the incomprehensibly deep feelings you get when you come up against these ideas, these fundamental mysteries that apparently have no other explanation than some divine

and divinely intelligent being sewing these fine-tuned features and massed. mathematical symmetries into the universe itself. He said, it seems to be one of the fundamental features of nature. That fundamental physical laws are described in terms of a mathematical theory of great beauty and power, needing quite a high standard of mathematics for one to understand it. And he was, if anybody, was one of the people who, part of that company. He said, you may wonder, why is nature constructed along these lines? Well, one can only answer that our present knowledge seems to show that nature is just so constructed.

We simply have to accept it. One could perhaps describe the situation by saying God is a mathematician of a very high order, and he used very advanced mathematics in constructing the universe. our feeble attempts at mathematics enable us to understand a bit of the universe and as we proceed to develop higher and higher mathematics we can hope

to understand the universe better and even if he isn't showing reverence for a traditional god or deity there he is paying some homage to some pre-existing structure, some orderliness of the universe. This comes from a Nobel Prize winner

and to even further boil down his pedigree. He's the famous creator of the Dirac equation. He was able to a great degree reconcile to some extent relativity with quantum mechanics.

quantum electrodynamics. He, Dirac, coined the terms fermions and bosons, after Enrico Fermi and the Indian physicist whose last name was Satchendra Nath Bose.

And that wasn't enough. He famously was mentioned by Albert Einstein in a letter to his friend Paul Aaronfest in which you wrote, I'm toiling over Dirac. This balancing on the dizzying path between genius and madness is awful.

So this dimensionless number, this dimensionless physical constant, alpha, the fine constant, is just one of many dimensionless numbers out there. In the original standard model of physics, whose modified framework still exist as the standard model today. This original standard model from the 70s contained as many as 19 fundamental dimensionless constants which described the masses of particles and the strengths of the electro weak and strong forces. But even since the 70s the complete standard model today now has 25 fundamental fundamental dimensionless constants.

At present, still to this day, their numerical values aren't understood in terms of any widely accepted theory. And so they're purely experimental measurements. In a list, the 25 are the fine structure constant, the strong coupling constant, then we have 15 masses of the fundamental particles relative to the plank mass. So they're given in terms of the plank mass. There are six quarks, six leptons, the Higgs boson, then the W boson, and finally the Z boson. Then you have four parameters of what's called the CKM matrix, which describes how quarks oscillate between different forms.

and then you have four parameters of the Ponticorvo Macchi Nakagawa Sakata matrix, which does the same thing for neutrinos. One constant that I've touched upon before in my cosmology videos is the cosmological constant. This is essentially dark energy. It's the number denoted by lambda, the Greek letter lambda, that originally in a kind of nascent form was theorized by Einstein himself when he originally applied general relativistic equations to describe the dynamics of stars and then galaxies in the universe and as Hubble found that light was being redshifted

by galaxies that appeared further and further away which meant that those galaxies were expanding in proportion to, at a speed proportionate to how far they were from us. And because it was symmetrically all around us, there wasn't just one direction of expansion. It was kind of expanding from every galaxy. All galaxies were expanding away from each other in a very uniform, an oddly uniform manner. Einstein's Lambda, his his kind of anti-gravity constant, which is what initially started out as, had to be removed from his equations. Einstein had initially, like many and pretty much all, scientists and cosmologists, which weren't then called cosmologists, but any astronomers and scientists

who observed the heavens before Einstein all thought in a very religious-centered worldview that the universe had no reason to be anything other than static, fixed, eternal, very unmoving and unevolving

throughout time, throughout eternity. In fact, there's no reason for those scientists, Einstein included up until that point in the early 1900s to presume that any creator, any prime mover, would have created a universe that was dynamic and had a starting point. If God was eternal, so should be the universe, they thought.

And if the universe was eternal and the stars, and soon to be discovered, galaxies didn't have any overall net motion other than the random motions around each other, then that would mean that for Einstein, well, his general relativistic equations essentially would have predicted that the universe would have collapsed long ago, given the distribution of matter and stars and their cumulative gravitational attraction towards each other, there would have to be some constant, some cosmological force counteracting that gravitational force. And that was his original cosmological constant, which he removed once he realized that

the innate instability predicted, of the cosmos, predicted by his general. relativistic equations being a the static version of the cosmos being a very precarious unstable solution to his general equations of general relativity when applied to the cosmos was actually the more natural choice the expansion of the universe ended up ironically enough being exactly what Einstein's equations predicted. His equations predicted that you would either have everything collapsing on itself over time or they would be slowly expanding at a given rate, which it turned out they were. But in the 1990s, Adam Reese and team, Alexander Philippenko being one of the other team members,

they were observing distant supernovae, and they found that. the light curve measured and observed of these supernovae whose characteristics the rise and fall of brightness and energy are fairly well known indicated that the universe was expanding at a much faster rate than any constant expansion would have so therefore they that showed that data showed that the universe showed that the universe was not only expanding but accelerating in expansion. In this cosmological constant, this density, this number that indicates the degree of density of dark energy in the universe has a value, an astonishingly small value, of approximately 10 to the negative 122,

essentially a decimal place with 122 zeros before reaching that one, or maybe 121, but something, you get the point. And Martin Rees, the famous astronomer, actually had a book published maybe around the late 90s called Just Six Numbers, in which he mulls over the following six dimensionless constants, whose values he deems fundamental to present-day physical. physical theory and understanding the known structure of the universe. The first is n equals about 10 to the 36 power, which is the ratio of the electrostatic and gravitational forces between two protons.

The other two forces being the strong and weak nuclear forces. This ratio, 10 to the 36, is How much more powerful electromagnetism the forces from electromagnetism is over gravity, and it governs the relative importance of gravity and electrostatic attraction and repulsion and explaining properties of ordinary what most people think of as matter, which is barionic matter. The second number is epsilon equals about 0.007, and this is the fraction of mass of four protons that is released as energy when fused into a helium nucleus.

This actually governs the energy output of stars, and it's determined by the coupling constant for the strong force, one of the itself, one of the dimensionless constants. Then the third number, I have this right, is the omega equal to about 0.3. This is the ratio of the actual density of the universe to the critical minimum density required for the universe to eventually collapse under its gravity. So omega on cosmological scales actually determines the ultimate phase. of our universe. This is one of the values that cosmologists are constantly using

telescopes like James Webb and many others measuring all wavelengths along the entire electromagnetic spectrum to observe and to have gained data that will allow us to calculate what this ratio is if this density of the universe is greater than or equal to one or parity the universe may experience it would be too dense to sustain expansion and would eventually actually collapse and that's what we call the big crunch so there are some theories that think that this might be a cyclical oscillating universe in which we have a big bang and then after a number of billions and possibly trillions of years it eventually doesn't quite reach the threshold for infinite expansion and will

eventually begin to collapse back on itself creating the big crunch and of course we don't have any idea of what would happen at the end of that big crunch. A lot of people presume it might initiate another big bang, but there are theories I've heard that say that there would be due to entropy and the general laws of thermodynamics, there would be energy dissipation, and therefore energy would not be conserved if this big crunch or this oscillating universe was actually the case. And so there would eventually be a limit to the number of oscillations. It would be damped until the big bang, I guess, became

smaller and smaller. Now, however, if the, so that's if the energy density, the, the just total density of matter and energy in the universe is beyond a certain number. Now, if it's smaller than a certain number, between 0.3 and 1, the number 1, then the universe might just expand forever. That, of course, just means that the universe has insufficient matter to gravitationally collapse back on itself and be attracted to a central point. And what's interesting about this number is that as of now, it's another mystery of physics here. Most measurements from cosmologists indicate that we are right on the threshold,

which is itself an impossibly unlikely occurrence in a universe governed by random choice or chance. Choice. Big difference there. So it could be a choice by some larger metaphysical being who either entirely or had a hand in creating our universe and its underlying mathematical structure. and so we appear to be right on the cusp of infinite expansion or possible gravitational collapse and we have yet to figure out which so as you can imagine that's a very very active area of research for cosmologists and physical theoretical physicists to discover just what the energy density of the universe really is. The fifth number of Martin Rees' six numbers, just six numbers, is Lambda.

This is the cosmological constant. This is another ratio of what is observed to what is a minimum threshold for a certain fate of the universe to play out. And so the omega 0.3 was the density of matter in the universe, and lambda is the density of dark energy in the universe, which is a very substantial portion of the entire. entire energy content of the universe, being something on the order of almost 70% of all energy.

And of course, Einstein's equations of relativity showed us that energy and matter are interchangeable. So if they are, that means that regardless of whether it's matter or energy, they can ultimately be lumped into the same category. So the fifth number is Q. That equals 10 to the negative 5, to the power of negative 5, which is 1 over 10,000 or 100,000, sorry. And this is the energy required to break up and disperse an instance

of the largest known structures in the universe, being either a galactic cluster or supercluster, depending on how you define them. And it's expressed as a fraction of the energy equivalent in that same energy mass equivalence equals MC squared of the rest mass of that structure. So it only has to be, so only one one hundred thousandth of the total energy, that super,

cluster is the energy required to break up and disperse the largest known structures. And then the last number is the number of macroscopic spatial dimensions, which is three dimensions. And something that we tangentially touched upon in that section there was the theory of everything, the reconciliation between gravity and the strong and weak nuclear forces and electromagnetic force. So those three latter forces are successfully implemented as fundamental driving features of quantum mechanics in the standard model that describes everything that we have ever measured and observed and experimented with on subatomic scales.

And then the fourth force is gravity. And that is, as far as we understand, up until we get to event horizons, and up until the first few minutes after the Big Bang, the energy level at those two, in those two phenomena, not those places in time and space, are beyond the realm, the predictive realm of general relativity, but everything else that we've ever observed has fallen in accord and been predicted and explained by Einstein's general relativistic equations, his field equations. But general relativity and the fact that gravity is so much weaker than the other. other three forces and acts at a much larger distance is for now irreconcilable.

It breaks down, it loses any predictive power beyond at scales smaller than atoms in the subatomic realm. So because the usual domains of applicability of general relativity and quantum mechanics are so different. They're operating on such different ends of the size and temporal scales of the universe. Most situations require that only one of those theories be used to analyze any given phenomena that's being studied. And like I mentioned earlier, the high-energy particle physics that we've been able to perform so far and the the the large hadron collider or hadron collider at CERN is definitely not the end-all be-all there I think in fact they're working on an even larger collider now I have to look that up maybe it hasn't broken ground yet but you can see here it's much larger

and the future circular collider it's called would be 90 to 100 kilometers in circumference and operates at six times higher energies large Hadron Collider is 14 terra electron volts and the FCC would be 100 terra electron volts of course this is all to attempt to recreate energies closer and closer to the conditions in the Big Bang, the initial seconds, minutes after the Big Bang, when energies were so high. In fact, all the forces were indistinguishable. As far as we know, currently the theory is that gravity itself was indistinguishable from the strong weak and electromagnetic

or those two together being the electro-weak force but we have yet to prove that so it's thought currently after the Big Bang that about one trillionth of a second

after the Big Bang is when the Electro-Weak forces the electromagnetism and the weak interaction separated into their own distinct forces and this was called the quark epic when it all four fundamental forces had separated but the temperature of the universe was still too high to allow quarks to bind together

and to form hadrons and the subsequent matter nucleons and electrons that we know today and I've heard it explained as though you have an iceberg floating in the the ocean and at high enough temperatures the iceberg would melt and at that point those that water would become indistinguishable from the surrounding ocean water of course that's a that's a very loose analogy but it is i think useful for a layman like myself to understand that you have at different energy levels and as you get lower and lower and lower that that red is that represents colder and colder temperatures that do, in fact, freeze out these fundamental interactions, these forces.

And so electromagnetism had been frozen out into its own separate force that is carried by the photon. And the standard model of particle physics today, so far not disproven by any experiment, especially one around CERN is that of the electromagnetic interaction and the weak interaction being two different aspects of the single same electro-week interaction. This was actually proposed by Stephen Weinberg and Sheldon Glashallon Abdis Salam in 1968 and 11 years later they won the 1979 Nobel Prize in physics for it. And the Higgs mechanism here provides an explanation in their theory

for the presence of three massive gauge bosons, W plus W negative, and then a Z boson, which would act as the carriers of the weak interaction in the same way that the photon represented by gamma is the massless gauge boson that carries the electromagnetic interaction. And so at small, low temperatures, the weak interaction only acts over very, very small distances, no longer or larger than a proton, the diameter of a proton inside the nucleus. But it is responsible for nuclear fusion and nuclear fusion,

the radioactive beta decay that transforms a neutron in a nucleus spontaneously into a proton, into a proton and that then changes the actual chemical element of the given atom and that produces an electron and then an electron antineutrinon and so it's thought theoretically currently although we have definite evidence of an electro-week force it's also thought that once we hit large enough energies in experiments and colliders, particle accelerators here on Earth, we will be able to find that experimental evidence of a strong electro-weak force,

being the combination of the strong force, the weak force, and electromagnetism. And it's thought that to unify all four fundamental forces, including gravity, that there needs to be an even deeper theory that would unify gravity with the other three forces. And now this would unify. It would harmoniously integrate the realms

of general relativity and quantum mechanics into a seamless whole. A theory of everything that could be defined in principle as describing all physical phenomena in the universe. And one of the most active areas of research today, the most prominent example of which is string theory is a pursuit of a quantum theory of gravity, which most of its detractors believe that you can't possibly prove it. There are no testable

predictions coming out of string theory. But it does posit that at the beginning of the universe up to a trillion trillionth of a second after the Big Bang, they were all one single unified fundamental force. In every particle in the universe, at this point in time, at its most ultra-microscopic level at the plank length, consists of varying combinations of vibrating strings or strands with preferred patterns of vibration. And it claims that through these specific oscillatory patterns of strings, that a particle of unique mass and force charge is created. That's to say the electron is a type of string that vibrates one way,

while the up quark is a type of string vibrating another way and so forth. So that is essentially what string theory or M theory, different variations on the theme there, propose. is the result of about six or seven dimensions of hyperspace, in addition to the four common dimensions of space, time. Three of space, one of time, making for a total of 10 or 11 dimensions of reality. That's the best or at least the most,

widely known popularized theory of everything at the moment and there's multiple other people including Eric Weinstein and Stephen Wolfram positing their own theories of everything that allow for unification of gravity with the other three fundamental forces but so far none not only have been agreed upon to be going down the right path but none appear to even be testable at the moment. Another aspect, another mysterious aspect of cosmology that I didn't directly touch upon yet is the vacuum energy in the complete vacuum, the absence of any matter or energy in space. and there is many incomprehensibly large bubbles of emptiness in the universe.

These are voids around which essentially created by the absence of any galaxies or any intergalactic dust or matter. There are voids hundreds of millions of light years across. And we simply do not yet understand the repercussions that these voids have on the wider entirety of the universe. We know that at scales beyond these voids, beyond 500 million light years across, beyond a billion light years across, the universe does eventually even out into a more uniform, homogenous foam structure with the voids being the bubbles in a sponge-like material the galaxy filaments and sheets and walls stretching around these multiple hundred million light-year-wide voids making up

the material of the sponge if we continue that analogy but we don't know given general relativity And what it says about how matter, especially at large scales of galaxy clusters and superclusters, dramatically affects space and time in the flow of the rate of time and the length and volume that particular space takes up in those regions of high matter density. And what this might mean is that in regions of low matter density, and these voids essentially devoid of matter for hundreds of millions of light years, it must have some effect on the time. Time runs slower the closer to a gravitational center you are. So that must mean that time must run quicker in the recesses.

of these massless voids. And it must mean that the volume of space itself is not under the distortion of matter. And so that itself has an impact, an effect, on the volume and the length of any measurable unit of space-time itself in these voids. So it's the opposite of space-time. effect of how space would be dramatically curved at the center of galaxies and galaxy clusters.

There is a opposite impact that relativity tells us is going on, and we're not sure when you extrapolate the extent to which these voids exist in all directions throughout the universe. what the implications for their existence might be on the wider aspects of space and time across the longest stretches of time in the universe. So that's one thing to think about, is the nature of time across the broad universe

and how it might run differently due to these voids and whether or not we've truly taken into account their effects on us, on more massive regions of space time, and the broader evolution of the universe. Perhaps the beginning of the universe isn't as straightforward as extrapolating the expansion of space back to a single point when you take into account how time runs dramatically differently at different rates and maybe space itself might be dramatically varying in size across these voids and how that might affect light traveling through them and just as gravity is crucial in understanding the large-scale evolution of the universe and the mass and energy and space and time that dynamically relate

to each other to allow this evolution to have happen, physicists are desperately lacking a theory of gravity on the smallest scales, even within the recesses of space, whether it's in these voids or in the matter-dense superclusters. And in addition to the Big Bang and black holes, a major point of confusion at the merger of relativity and our theories of gravity and the standard model of particle physics and our understanding of the quantum domain and the energies latent in the universe is dark energy. We have no idea what this could be, even though we're measuring an acceleration of the universe that implies a 70% of total matter and energy in the universe attribution to

this mysterious force that is repelling and counterfeit. the gravity of all known matter in the universe. We have this concept in particle physics called vacuum energy, which is an underlying background energy that exists throughout the entirety of the universe, and is a special case of zero point energy that relates to the quantum vacuum. It's energy latent from probabilistic quantum mechanical effects and particles, symmetrically popping in and then back out of existence, almost entirely independent of the existence of matter in its vicinity.

And the effects of vacuum energy can be experimentally observed. It's been observed in various phenomena such as spontaneous emission, the Casimir effect, the lamb shift, and it is the prime candidate for the cosmological constant, the large cosmological scale repulsion of matter in the universe. But there's just one problem with vacuum energy as understood in quantum mechanical terms as being the contributing the main source, the main factor in this dark energy production. The problem is that the value of this theoretical zero point energy suggested by quantum field theory

is as much as 120 orders of magnitude larger than the observed dark energy in the universe. This discrepancy is so large and so bafflingly out of sync with observation that some physicists have described it as the largest discrepancy between theory and experiment in all of science, and quote, the worst theoretical prediction in the history of physics. Some physicists propose that the solution to this is an anthropic solution. And an anthropic solution is one that revolves around the existence of humans and human beings able to do science and measure these values. And the core of any anthropic principle is that the existence of us and our ability to reason

and think and evolve the idea of science and experimental testing of the universe itself is evidence that the universe is fine-tuned to allow our existence. And so therefore, other, perhaps an infinite number of other universes with different values for their fundamental constants, the fundamental dimensionless constants, the fundamental values in relationships between the symmetries and asymmetries of quantum particles, the values of gravity and the relations between the strong, weak, electromagnetic, and gravitational forces, all these values can constantly change and have different initial conditions based on the dynamics, the possibly different dynamics of perhaps an infinite number and variation of big bangs

in a vast multiverse that has different regions with different vacuum energies. These anthropic arguments in relation specifically to vacuum energy posit that only regions of small vacuum energy, such as the one we live in, are reasonably capable of supporting intelligent life. But the problem still exists, even in an anthropic universe, that there is a discrepancy between the prediction, predicted values, the massive 120 orders of magnitude, larger values that would emerge from the

summation of vacuum energies across 100 billion light years in our observable universe and possibly from 20 trillion to perhaps an infinite landscape of space time in the wider universe beyond the particle horizon of our particular bubble. There is such a discrepancy. that it really gives no clue as to just why the actual observed and experimental values seen from dark energy experiments is just so much smaller than physicists predict. Now there's been other proposals involving modifying gravity to diverge from general relativity. These proposals face the hurdle, though, that the results of observations in any, experiments so far have tended to be extremely consistent with general relativity and the lambda

gold dark matter model of the universe that relies fundamentally on general relativity as its theoretical model for the interaction of matter energy and space and time on the largest scales. But nevertheless, many physicists argue that due in part to a lack of matter, energy, and space, and time on the largest scales. But nevertheless, many physicists argue that due in part to a lack of better alternatives, proposals to modify gravity should still be considered. And some even say they should even be considered one of the most promising routes to tackling the cosmological constant problem in the issue of such a small value of dark energy. Bill Unra, a Canadian physicist, has argued that when the energy denser,

of the quantum vacuum is modeled more accurately as a fluctuating quantum field, the cosmological constant problem doesn't arise. This is a pretty active area of research in physics and cosmology, and there's been multiple attempts to either reduce the effect of quantum vacuum energy down to the level of observed dark energy, and even theories that particularly. that it should be zero in flat space time. Another group in 2018 devised a theoretical mechanism for canceling out lambda dark energy altogether

through symmetry-breaking potential in what's called a Lagrangian formalism in which matter shows a non-vanishing pressure, and this means that the model is assuming that standard matter and even cold-dark matter provides a pressure which countervester balances the action due to the cosmological constant. So it mitigates the runaway effect of a purely untempered vacuum energy

at scales across billions of light years. And in 1999, another group proposed that correlations between ultraviolet and infrared cutoffs and effect of quantum field theory are enough in themselves to reduce the theoretical cosmological constant down to measured values. But whatever the nature of dark energy even is, and whether it even has anything to do with quantum field theory vacuum energy of particle antiparticle pairs, it's more likely, given how hypothetical and theoretical,

any explanations of it we have really are, that dark matter is going to be understood before dark energy. Because dark energy, unlike dark matter, is thought to be extremely homogeneous, extremely rarefied, unmassive, spread out throughout the entire universe. It's not dense, and it's not known to interact through any of the fundamental forces other than gravity, which is just about the only thing that ties it to dark matter. dark matter is unlike dark energy much more localized in the universe and it's localized around galaxies in fact it's thought to be ubiquitous around any galaxy we've ever measured with the exception of

a handful of them the dominant influence of dark matter is its gravitational effect on the galaxies that it corrals it's thought to exist in these hands halos surrounding galaxies and causing the outermost stars to behave in a way that perturves their orbits and increases their angular velocities much more than the observed mass and stellar material can account for and this was the origin of dark matter it's called dark because it doesn't appear to interact with the electromagnetic field or anything the other fundamental forces doesn't appear to reflect, absorb, or emit electromagnetic radiation. No light, no radiation of any sort.

So it's extremely difficult, if not impossible, to detect other than its gravitational influence on the stars it surrounds. Its existence is more indirect than anything. It's implied by various astrophysical observations, the orbital velocities of stars around galaxies being the primary one. But it is one of the obstacles in general relativity explaining the entire universe and the dynamics on cosmological scales. Because unless there is more matter present than we can see,

and a lot more of it, not just 5 or 10%, something on the order of 500 to a thousand percent more matter, five to ten times, more than we can observe. And what this means is that there has to be a density of matter surrounding galaxies, and typically there are perimeters and peripheral regions, the outskirts of galaxies, on the order of the same volume of stars that can be observed in it, ten times more matter than all the billions of stars in any given galaxy in particular, which cannot, as far as physicists and astrophysicists, cosmologists understand about the formation of stars and planets

and the gaseous nebulae within galaxies. As far as we understand with stellar dynamics and galactic evolution, we do not know of any substance that could account for such a discrepancy in the mass that causes galaxies to rotate at the speed that they do. And even beyond individual galaxies, when we look at clusters and some of the largest clusters in which we can detect the galactic interactions. We can locate based on statistics and very sophisticated methods of observation, the mass, the central center of mass of these galactic cores and these groups of dynamically

interacting galaxies, and we can detect that it is not located very often where the observable light, whether it's visible or anywhere along the electromagnetic spectrum, exists at the cores and the obvious visible arms of galaxies is typically not what characterizes the motion, the interplay between interacting galaxies. So Dark Matters exact identity remains a complete mystery, like its name is. implies. So we don't know anything about whether it is a particle, whether it is an energy that has just gravitational effects and very localized domains of the cosmos. So we are, as far as we know, unable to detect it in the laboratory. And that's a huge motivation for particle physics

at the moment is to detect a particle that doesn't appear to interact with any of the known fundamental forces we know about, doesn't appear to interact with normal barionic matter, but nevertheless, one of the leading proposed explanations is that it is made of weakly interacting massive particles or whims as a somewhat... memorable acronym. And this might be some revolutionary subatomic particle, some elementary subatomic particle, some elementary particle who is so isolated in its lack of interaction and its inertness, that it has not yet appeared to manifest any small-scale effects in our experiments here on

Earth, yet somehow it coalesces, it congregates around the very cores of material being galaxies that normal matter does. So it could be a subatomic particle that we have yet to detect. Perhaps if we increase our particle colliders from the LHC to the much larger future circular collider that might be four to six times more powerful and a hundred kilometers in circumference perhaps once we get to energy levels that those large particle accelerators colliders will allow and allow to create we'll start being able to detect deeper and newer structures and particles from these extremely highly

energetic collisions of protons and other particles that were able to harness with these massive electromagnets. And although we've been able to recreate energies on the order of stellar cores with our current particle accelerators, they do not even touch the energies reached at the beginning of the universe in the first minutes. after the Big Bang. So there is plenty of room yet for us to learn and discover new particles, new energies, new relations between forces, and perhaps even the mysterious, weekly interacting massive particle

that makes up dark matter. But the other possibility is that it's not a dark matter, particle, but primordial black holes. So it's possible that every galaxy out there, despite how bizarre of an idea this kind of might be, is in fact surrounded by primordial first-generation black holes, and probably many smaller ones rather than a few massive ones, because they appear to be so uniformly distributed

in clusters and around individual galaxies. But there's still very little evidence. There hasn't been much at all detected in studies directly directed at discovering whether it's particles or black holes that is trying to account for all this unseen matter. But nonetheless, there are some aspects of it that we can characterize.

Dark matter can be classified as cold, warm, or hot. According to its velocity, or more precisely, its free streaming length, which in astronomy, a free streaming particle often is a photon, and it just means one that propagates through a medium without scattering or being really interacting with any surrounding matter. And recent models have favored what's called a cold dark matter scenario,

the basis of the Lambda Cold Dark Matter or Lambda CDM-L-CDM model of the universe, which is currently the most widely accepted standard model of cosmology by cosmologists, appropriately enough. And this Cold Dark Matter scenario is one in which structures emerge by the gradual accumulation of particles. You think of it as slowly interacting particles rather than a hot soup, like after the Big Bang. But they're still, even after about half a century since the 70s, of searching for these

gradually accumulating cold dark matter particles, there hasn't been much success on that front there. But between gravitational detectors and sophisticated space telescopes, like the James Webb out at L2, there's actually been observations that considerably strengthened the case for primordial and direct collapse black holes. Now, these direct collapse black holes are a fascinating concept, because they essentially subvert the normal stellar evolution, the stellar dynamics we're used to thinking about, that stars are gradually formed from the collapse of cores of clouds,

from the primordial universe, and these early stars are very quick to explode into supernovae, which then populate and seed the further evolution and generations of stars with heavier elements, and until we get to about third or fourth, or population two and one stars, that characterize most of the universe and whose... heavier products, our very origins, depend on, they direct collapse black holes detour. They bypass this evolutionary, this stellar evolution that we thought was fairly typical in the universe. And it's hypothesized that around very early in the universe, between 100 and 200 million years after the Big Bang, Seeds formed, instead of forming stars, the first generation of stars called Population 3 stars,

they formed directly into black holes. And these black holes are the products of not stars collapsing on themselves after millions or billions of years of slow burning. But these black holes, as these structures of gas collapse, of hydrogen and helium slowly start orbiting the center of mass. This mass on the order of a million solar masses starts gradually converging into strong, cold accretion flows. Now the cold flows produce a turbulence in the halo, which actually suppresses star formation.

And then, eventually, the cloud has gained enough momentum and collapsed to such a dense state, dense state that an occurrence of general relativistic instability happens and nearly instantaneously collapses it into a black hole. And in fact, in 2016, a team of Harvard University astrophysicists led by Fabio Pucci identified the first two candidate direct collapse black holes using the Hubble and X-ray Observatory. And these were found to be at a redshift greater than Z-Equil in the Candles Goods Southfield. And because they matched the spectral properties predicted for this type of black hole,

they're going to be followed up with the James Webb Space Telescope. Because JWST is specifically built to analyze and detect at a high, high resolution, mostly infrared radiation. And these direct collapse black holes actually produce significant excess infrared radiation relative to all their other stellar phenomena around them. So this is going to be a really crucial investigation into the properties of these sources, confirming their nature and possibly contributing a huge leap forward

in our understanding of what dark matter is and what the source of all this excess gravitational force is around galaxies. Another issue I haven't directly addressed yet, is called the hierarchy problem. The hierarchy problem, something that we tangentially touched upon, is the huge discrepancy between the three quantum field theory fundamental forces, the strong, weak, and electromagnetic forces, and gravity.

What makes it so strange is the enormous magnitude of difference between not just gravity and one of the other forces, but the fact that all three quantum, domain forces are roughly within a couple orders of magnitude of each other and gravity is 10 to the power of 24 times weaker than the weakest force which is the weak interaction or the weak force that's a one with 24 zeros after it and think about a billion has nine zeros a trillion has 12 so that's a trillion trillion times weaker than the weakest quantum field theory force.

To give you another idea, we can look at this chart here, and we can see the relative strength. The strongest force acts roughly on the same range of 10 to the negative 15th meters as the weak force does, and this is roughly across the range of a nucleon, proton or a neutron. The weak force interacts at a range slightly about a thousand times less, which seems like a lot, but really on the scale when you're talking about a one with 24 zeros at the end of it, talking about the relative differences between how weak gravity is on these subatomic scales.

The weak interaction has a range slightly less than the diameter of a proton, so it doesn't quite interact between nucleons, and the strong or strong nuclear force is the force that holds the nucleons, neutrons, and protons together, and that interacts across a range slightly more than the width of a proton. Now, comparing the relative strength, we see that the weak, strong, and electromagnetic forces are all within a couple one or two zeros, or orders of magnitude of each other. If we were to set the strength of gravity at unity, just the number one, with no zeros at the end of it, the relative strength of the strong nuclear force would be the strongest, would be 10 to the power of 38, one with 38 zeros at the end of it, then would come

the electromagnetic force 10 to the power of 36, 100 times less powerful, and then the weak force another thousand times less powerful than that but all of these forces are roughly within a thousand or ten thousand times as powerful as the others and they're all trillions of trillions of trillions of trillions of times more powerful than gravity is across any given range. Now what's strange, though, is that while the electromagnetism operates at about the same strength as these nuclear forces, it has a range essentially infinitely long, as does gravity. But gravity is so weak in the atomic realm that it is essentially essentially, essentially isolated from the equations in quantum electrodynamics, chromodynamics,

electro-weak theory. And given that general relativity is the theory that best and most eloquently describes gravity in its interactions on macroscopic scales, that is the domain. It has a very almost non-existent strength at the quantum level, yet an almost infinite, apparently infinite range in the universe. Electromagnetism, with its mediator particle being the photon or light, is the one anomaly. The weak and strong forces operated at the nuclear scale, it has relatively equivalent strengths, operating over relatively equivalent scales and ranges,

Yet electromagnetism seems to bridge the gap. Light is the one common thread connecting both nuclear quantum field theory and cosmic general relativity theory. Gravity can bend light, yet electromagnetism, whose force can be transmitted across atomic scales, also has a force and an exertion on scales all the way down from the cosmic to the quantum. And so it's incredibly strange that gravitation is the most important of the four fundamental forces on scales that we're used to and for the environment that we've evolved to move and navigate through and interact with. Gravity dominates. Yet these other forces appear to almost essentially completely characterize and predict the subatomic world

that all larger structures rest upon and are made of. And although on human scales, electromagnetism is far more powerful than gravity, and it can dictate and dominate certain phenomena. On celestial scales, on scales larger, much like, larger than humans. It is gravity that clearly, clearly dominates. Electromagnetism, although it can theoretically exert a massive force on celestial cosmic scales, it always tends to balance out. It is mediated by positive and negative charges, which, when found in approximate proportion to one another, produces no net force, and as most experiments have confirmed, there are no regions of cosmic scales

that have a net positive or net negative charge in them. So electromagnetism apparently doesn't have any net effect on cosmic phenomena and the evolution of the universe as a whole. But of course, a hole is made up of pieces and although you can analyze things on different resolutions and different scales at different energies and cross different lengths of time you always have to account for all the pieces that have been observed

and so far we cannot account for this huge discrepancy or the conciliance the fusion under one theory of all four of these forces. Another weird aspect of gravity is that it has only one charge. If you think of it in terms of an electric, positive or negative charge, or symmetric opposites like almost all particles have, gravity has only an attractive force.

Only a charge, a single charge, that pulls particles together. There is no repellent charge. There is no repulsive force in gravity. Now we have dark energy, we have vacuum energy, we have placeholders for observed effects that apparently appear to contradict, counteract gravity, and act almost essentially as a negative gravitational charge.

But the measured force of gravity is as of yet we will be able to understand and notice a discrepancy between special and general relativity and the quantum mechanics that we think we understand and believe

govern everything we know about the subatomic world. It turns out that there's a whole range of theoretical developments that are still needed to explain the deficiencies and there's quite a few of them beyond what we mentioned. here today, whether it's the strong CP problem, neutrino oscillations, and why the theory

doesn't predict oscillating neutrinos, although we detect oscillations and neutrinos, whether it's matter-antamatter symmetry and asymmetry, or whether it's just the fact that both theories, whether it's general relativity or the standard model of particle physics, completely break down under space time singularities like the Big Bang and black holes. So we are desperately

searching for a theory of everything, a theory which would unify all ranges, all realms, all scales of the universe, of time, lengths, dimensions, speeds, and energies under one

theoretical and experimentally verifiable umbrella, but maybe it's not until we are able to develop particle colliders and physical laboratories on the order of planets and even star systems. Maybe one day we'll harness entire galaxies to run experiments, or maybe we'll have supercomputers powered by stars and creating simulated physical worlds so advanced that we're able to let them evolve over billions of years clocked down so we can perceive them over human scales. And maybe in these simulations we'll be able to watch animals evolve consciousness on a quiet planet around a quiet star at the quiet fingertip of some distant arm

of a supercluster of simulated galaxies in our little experiment. And maybe they'll start performing experiments so sophisticated that they start knocking up against the walls and the limitations of the very simulation they're a part of. Maybe. Thanks for watching, guys, and we'll see you next time. And I want to say a huge thank you to all my Patreon supporters. You guys really encourage me and really keep the channel afloat. And your support means the world to me and definitely doesn't go unnoticed.

So I appreciate it. And I'm really glad you guys are enjoying the content. I'll see you next time.