The Surprising Evidence our Universe is Inside a Black Hole

What if I told you that everything you've ever known, every star you've ever seen, every galaxy scattered across the dark night sky in the cosmos, and even the very fabric of space and time, might exist inside of a black hole? Not orbiting a black hole, not near a black hole, but actually inside a black hole. Right now, as you watch this, you could be sitting comfortably within the event horizon, inside the event horizon of the most massive black hole imaginable, and you'd have absolutely no way of knowing it. Now, as crazy as this sounds, it's actually not science fiction. It's a legitimate scientific hypothesis that some physicists have seriously considered and put forward. And today, what I'd like to do is talk about the evidence and the reasoning behind this crazy-sounding idea, and I think truly it will fundamentally change how you think about reality itself. Now, before we can understand how it's possible that we might actually be living inside a gigantic black hole, we first need to understand what exactly a black hole is. Now, this story I think is actually fascinating, and it actually begins in the 18th century with a British clergyman and natural philosopher named John Mitchell. Now, way back in 1783, Mitchell proposed that if a star were massive enough and compact enough, its gravitational pull would be so strong that nothing could escape, not even light could escape. Now, he actually called these hypothetical objects dark stars, and to be honest, I wish the name stuck because I think it sounds way cooler than black hole. Now, this was actually an amazing idea because it was more than a century before Einstein actually revolutionized our understanding of gravity and space and time. Now, let's fast forward from the 1700s all the way to 1915, when Albert Einstein published his General Theory of Relativity, which described gravity not as a force between two objects, but as the curvature of space and time, which is unified under a common structure called space-time. So, the spatial coordinates, x, y, z, are coordinates you might be thinking of in your mind when you visualize a coordinate system, but the time coordinate actually is not an independent ticking separate from everything else. It is a coordinate attached to the spatial coordinates, and it turns out that mass and energy in Einstein's theory actually can change the relationship between the coordinates. That's what we call bending or warping of space-time. So, whereas gravity previously was described as a force that existed across space, now it's considered in that framework the curvature of space and time itself. Now, these massive objects like planets and stars, they bend this coordinate relationship between space and time kind of like a bowling ball placed on a stretched rubber sheet might depress and bend the nature of the sheet, but it's not a perfect analogy because when a sheet, which is a two-dimensional flat surface, is bent, that sheet is bent into another dimension that doesn't exist on the sheet, the third dimension, and so it's very hard for us to visualize in our mind how a four-dimensional space-time, x, y, z, and time could be bent, but really what's happening is the coordinate relationships between x, y, z, and time basically change in the vicinity of matter and energy. So, whereas we can't see it with our eyes, the manifestation of that is that objects traveling through appear to be bent from our outside perspective, even though on their own trajectories they're actually following a straight line or the straightest line that they can follow in a curved space-time. To us, it appears to be a curved path, even though they are traveling in a relative straight line in their own frame of reference. We perceive that as a force acting from the outside, but actually it's not a force, it's just a geometric effect of matter traveling through a curved space-time. Basically, there's an old saying, matter tells space-time how to curve and space-time tells matter how to move. So, if this is a star in an otherwise undisturbed space-time, the presence of the matter actually changes the relative coordinate relationships between space and time. That's what we call bending of space and time. So, matter, in this case a star, tells space-time how to curve. Now, when a separate piece of matter comes in the vicinity of this curvature, space-time tells matter how to move. That's the second part of it. And basically, this object here, as it's traveling near the gravitational well of this thing, in its own frame of reference is trying to take the shortest path through space-time. But much like when you walk on the surface of the Earth, you might be walking one foot after another, after another, after another, and to you, you're traveling in a straight line, because locally, when you look down at the surface of the Earth, you're traveling with one foot in front of the other. But, globally, the entire surface of the Earth is curved. So, locally, you're traveling in a straight line, but globally, when you look at it over a large distance, you're actually traveling in a curved path. But it's not because of a force pushing you around. It's because the actual geometry of the space is curved, on a scale that you don't perceive unless you get in an airplane and can somehow see it from far away. Now, what happened is Einstein published this monumental theory describing gravity as a geometric effect of space-time. And just months after he published that famous theory, a German physicist named Karl Schwarzschild found an exact solution to Einstein equations that describe what we now call a black hole. You see, when we think of equations, a lot of us, we think of what you learned in algebra, or maybe calculus or something, and usually you can write them down and solve them. But when Einstein published his equations, they're so difficult, and they're in so many multiple dimensions, that it's very hard, actually impossible in a lot of cases, to actually solve them and write down a solution. So people like Karl Schwarzschild, they spent a long time taking the equations that Einstein put forward and finding solutions to the space-time curvature in certain situations. And that's what happened. He basically figured out the solution to the Einstein field equations that lead to the structure that we now call a black hole. But of course, back then, they had no observational evidence for this. It was just a solution to a set of equations that predicted something. Now, what Schwarzschild discovered was that if you compress enough mass into a small enough radius, what happens is the density gets higher and higher, and you curve space-time so much that you can create kind of a point of no return, so to speak, a boundary. We now call it the event horizon, which is what you've probably heard. Now, if you cross that boundary and go inside that event horizon, the curvature of space-time is actually so extreme that all paths trying to get away from the thing curve back around and take you back to the object. So there's no escape for anything, no matter how fast you're going, not even light. Now, this is actually why black holes are black. They don't emit light because the light is trapped inside the event horizon. There's a little bit of a caveat I'll come back to, but what I've said so far is accurate. But there's a little caveat I need to bring up a little bit here. Now, how do we see black holes in the sky if they're black? And the answer is we don't actually see the black hole itself. What we observe is the brilliant chaos just outside the event horizon. That's what we can actually see. So what happens is as matter is sucked into this black hole, just like it would be attracted to a star, but it's more dense, so it's pulling it with more force, right? As it comes in, it starts to swirl into the black hole, and it forms a disk around the object. That's called an accretion disk. It's a swirling disk and plume of gas and dust that actually gets heated up to millions of degrees as it falls in due to friction, rubbing, and compression of the material as it comes into the black hole at a high rate of speed. Now, this superheated material actually emits intense radiation in various directions in the electromagnetic spectrum, in various directions in the sky, from radio waves to x-rays and beyond, and it creates kind of a luminous beacon around the darkness, which is at the very center of the black hole. So it's true that any photon from the surface of the black hole, as it tries to escape, it can't because the gravity is so strong and the space-time curvature just bends the trajectory back down, essentially, into the object. So if they're glowing or not, we don't know because any photons just come right back and we can't see the actual black hole itself. But what we do see, and what we have seen, is actually this accretion disk. So what the theory predicted ahead of time, before any observations, is that as matter gets swirling in and kind of coming into that black hole, it's being compressed as it's basically sucked in and accelerating and crashing into each other, almost like shock waves in the gas as it gets in there. Now, what happens to things when they heat up? I mean, if you take an iron piece of iron, put it in a fire, it heats up and it starts to glow. The gas behaves the same way. The compression heats it up, it starts to glow, but not just in visible light. It glows in x-rays and radio waves and all this stuff. So we can actually see the glowing accretion disk surrounding a pitch black center. Now, in 2019, humanity achieved something absolutely extraordinary. Something called the Event Horizon Telescope, cool name by the way, is a planet-sized array of radio telescopes working in concert all around the world, effectively giving it a very large aperture. And it captured the first direct image of a black hole's event horizon. Now, the target for that first image, which I'm sure you've seen, was the supermassive black hole at the center of a galaxy called M87. That's about 55 million light years away. Now, with that image, what we saw was breathtaking. What you see is a glowing orange ring of light surrounding a pitch black circular dark shadow in the center. That shadow is the black hole itself. We can't see anything in there because no light can come out of there. Basically, there's a photon sphere where light orbits the black hole before either escaping or falling in. Inside the event horizon, we can't see anything at all. But what we do see is the glowing photons coming from the matter that's being compressed as it falls in from the outside. Now, this glowing ring is the accretion disk we talked about. And as gas spirals in, it accelerates at a very, very high rate of speed, crashing, compressing, releasing photons. And that's what we see. So we don't see the black hole itself. We see the just outside the event horizon radiating light. Now, the image actually showed something else that's pretty remarkable. The bottom half of the ring appears to be brighter than the top part. This is due to something called relativistic beaming, where the material moving towards us appears brighter because of the extreme speeds involved. Now, sit down for a second because I have a truly mind-blowing fact I want you to internalize because it's crazy. At the center of most large galaxies, maybe even all galaxies, they appear to all have supermassive black holes at the center of the galaxies we can observe. Our own Milky Way galaxy, which is a pretty large, not the largest, but a pretty good-sized galaxy, hosts a black hole. It's called Sagittarius A star. It's a black hole with a mass of about 4 million times that of our sun. Now, it's really easy to overlook these big numbers. Think about that. Think of the sun in the sky. We think of it as this giant star. Actually, it's just an average-sized star. But we think of it as a big star. And Earth is tiny, right? Now, this black hole in the center of our galaxy is about 4 million times the mass of our sun. And our galaxy is not even like the biggest galaxy around. There's plenty of galaxies bigger than ours. So the size of these black holes are truly incomprehensible. Now, you might say, why don't we take a picture of the black hole at the center of our galaxy? Why are we looking so far out? Well, in 2022, the same telescope captured an image of the black hole at the center of our own galaxy, confirming that these cosmic monsters are not rare, but actually fundamental components to galactic structure. They may have even played a crucial role in the formation and evolution of galaxies throughout cosmic history. And by the way, why didn't they try to take a picture of this fairly close black hole first instead of the one 55 million light years away in the center of another galaxy? It's because looking toward the center of our galaxy, there's lots of dust in the way. Lots of rings of dust. And it kind of obscures what's happening in the center of our galaxy. They eventually got the picture, but they first trained the telescope on an external galaxy that is not blocked as much by dust. So we could get a good image of that. And then they subsequently took a picture of the black hole much closer to us. So now that we talked a little bit about black holes from the outside looking in, here's the truly wild part, the core of what I really want to talk about. What if, or is it possible, that we're on the inside of one of these black holes, bigger than we can even comprehend, as big as the universe? What evidence exists, if there is any evidence, that our entire observable universe might actually be inside of a black hole? Now this idea, it sounds crazy, right? But actually it is not quite as crazy as it first sounds. And it stems from some really puzzling observations about our universe that we've measured with instruments over the years. First, let's talk about the Big Bang, right? The standard cosmology Big Bang. It tells us that the universe began from an infinitely dense, infinitely hot singularity that suddenly began expanding about 13.8 billion years ago, right? Everywhere we look in the sky, we see everything rushing away from us. And we know from how the universe is constructed that if we lived in another galaxy, we would look everywhere from there, and we would see everything rushing away from us there. No matter where you are in the universe, everything is rushing away from you. So the common question is, where is the center of the universe? Where did the Big Bang happen? Well, that's not really the way it worked, because before the Big Bang, there was no time, and there was no space. The thing that you call space, the thing I'm raving my arms in, that did not exist before the Big Bang happened, according to Big Bang model of the universe, right? And so that means it's closer to the surface of a balloon. If you take a balloon, and it's very small, and you start blowing it up, if you put dots all over that balloon, like little dots with a marker, and blow it up, then as the balloon inflates, the dots are going to get farther and farther apart from each other. That is what you would guess. Now, if you lived on one of those dots, on the surface of that balloon, looking in all directions on the surface of that balloon, and you see a dot way over there, and a dot over there, and a dot way over there, as the universe were inflating, you would look in your perspective, and all the other dots around you would appear to be moving away. But what if you didn't live there? What if you lived on the other side of the balloon, on a different dot? You see, the whole universe is expanding, and space, which in this analogy is the surface of the balloon, it's been created as the thing expands. So, if I live on the other side of the balloon, on another dot, I would be looking at all the other dots in my vicinity, and I would see them all moving away from me. So, the center of the universe is everywhere, because no matter where you are, everywhere you look, everything is rushing away. So, I wouldn't really call it evidence, but I just want you to remember that we know the universe is expanding, and we know that it started from some sort of singularity event of rapid expansion a long, long time ago. But here's the thing. Black holes also contain singularities at their center, much as we posit that the early universe was a singularity as well. And these singularities, what they are, is points where the density of whatever matter or energy becomes infinite, and our current laws of physics break down. In other words, could the Big Bang singularity, and a black hole singularity, be somehow related? Some physicists might think there could be a connection. Now, admittedly, again, this is not really evidence. It's just more like, huh, check it out. Big Bang has something called a singularity. Black holes have something called a singularity. Hmm, what if we're inside one of these things, and our singularity, what we call the Big Bang, where did it come from? Maybe that's a natural cycle that happens on black holes over enormous timescales that we can't fathom, and enormous sizes as well. It's more of a gee whiz. Look, there's singularities in both cases. Is it possible that the observable boundary of the universe is us looking out towards the event horizon? Remember we said things that are inside, matter that is inside the event horizon, can never escape. And the event horizon is like a boundary, inside of which everything is stuck, and outside of which you can never observe. As we peer into the distant universe, we can see earlier and earlier galaxies, but there is a cosmic boundary to that which we can see looking back in time as we use bigger and bigger telescopes to look out into the universe. Is the boundary of what we can see, what we call the observable universe, is that really us on the inside of a black hole looking out towards the event horizon, beyond which we can't see? Again, it's not proof of anything, it's just like, wow, could that be the case? If that's the case, then everything in the universe is inside some event horizon, and we would have no way to probe anything on the outside to check any of it, but it's interesting to consider if there's a connection there. Let me stop for a second and talk about singularity. What am I talking about? All right, so when you learn about gravity, you learn that the force of gravity, I'm talking about Newtonian gravity, not relativity theory, is a gravitational constant G times the mass of one object times the mass of another object divided by R squared. R is the distance between the objects, and what that means is the farther objects are away, the weaker the gravity is. But the closer the objects are together, if you make R, the radius of the distance between them, go smaller and smaller and smaller and smaller, then you're dividing by R squared, you're dividing by a smaller number. That makes the gravitational force go up and up and up. But what happens if you could take two pieces of matter and put them right on top of each other or infinitely close to each other, then R would approach zero. It would get closer and closer to zero, and you're dividing by zero. You know what happens when you try to divide by zero in your calculator or your computer? Basically, you can't do it. It says error because you can't divide by nothing, right? Now, does this mean that it's a real singularity where the force of gravity goes literally to infinity when we take two protons and put them on top of each other? Well, really what it means is our theories of gravity, that Newtonian theory of gravity, breaks down when we bring things too close together, basically, because we get an infinity. Generally, if an equation gives us infinity for an answer, then we suspect probably something is not quite correct. Like maybe it's really good at describing in most situations, but in this extreme situation, when we bring things on top of each other, maybe it breaks down and it's not a good representation of what's going on. But in any case, that's what a singularity is. It's when your mathematical result blows up to infinity because you're dividing by zero, and in general, that's what we call a singularity. Now, for Newton's gravity, it's when you bring two things very close together and make the radius equal to zero. Well, in Einstein's field equations, when you look at Schwarzschild's solution for a black hole, you're going to find out that when you go to the very center of the thing, all of the equations blow up to infinity. So that means it's probably not quite right. We don't really think that the curvature of spacetime becomes literally infinite. I mean, usually things don't ever really and truly go all the way to infinity, but we have no way to experiment on those scales, so we can't probe it or come up with a new theory because it's not like we can build a black hole in the lab and study it. So what we know is that there's some kind of singularity there, where our current theories of physics and equations don't really apply or break down. So one of the strongest pieces of evidence from this connection of looking at black holes and looking at the Big Bang is basically looking at the mathematical similarity between the singularity you get in a black hole and the singularity you get in the Big Bang model of the universe. And when we look at the equations describing the interior of a black hole in general relativity, what we find is that space inside the event horizon is expanding. And it's not just matter falling in. We're saying that inside the singularity of a black hole, spacetime itself is actually stretching. Now, let me ask you a question. Does that sound familiar? That's exactly what we observe when we look out into the universe. Everything rushing away, expanding. Space itself is expanding. We observe this. It's factual. And we see that the galaxies are being carried away from each other, getting farther and farther apart with new space in between. The mathematical structure of an expanding universe and the interior of a black hole share really striking similarities. Now, sometimes when you make a point, you have to like really, really talk about the point because otherwise you could just mow over it and you don't even realize how important it is. Think about that for a second. What we're saying is not only in our theories of black holes from the Einstein field equations, we see singularities, right? Infinities basically. And when we study the Big Bang model, we have infinities at the beginning of the Big Bang, right? So that's pretty similar. But in general also, when you actually dive into the details of that Schwarzschild solution of what a black hole is, inside the event horizon, we don't have a good understanding of what's happening because the equations may not totally be accurate, you know, when space is extremely warped like that. But the current equations actually show, in some solutions, space-time expanding inside the event horizon of a black hole. Now, that's something that we don't usually talk about when we talk about black holes. You talk about stuff falling in from the outside, what happens as you fall in, time, you know, slowing down near a black hole due to time dilation and other things. We talk about the heating up and the compressing and the accretion disk and looking at it and all that. But normally we don't talk about what's happening inside the event horizon. But the solutions of Einstein field equations say that space-time inside the black hole, in some solutions, in some cases, could be expanding. Now, we have no way to test it because we can't go inside a black hole and do an experiment. But wait! If we look out in our universe, we actually see space expanding. We see everything rushing away from each other. And if you wind the clock backwards, all the way when things were closer together, there is a singularity there. So that is, again, not proof, but it is an interesting thing to think about because normally we think about, you know, things falling into a black hole, being ripped apart, and all of this stuff. But actually, what if the way atoms are structured, what if the way chemistry happens, what if the way photons work, what if the laws of the universe that we, you know, really don't know where they come from, but we study them, what if they, what if it's possible that they are the way they are? Because that is how space-time behaves inside an event horizon of a black hole. I mean, after all, how would we know? We can't go into the black hole of some neighboring black hole somewhere. So in other words, we might be inside of an enormous parent black hole, and inside of this parent black hole, which we call the universe, is little baby black holes everywhere at the center of all these galaxies. And all of the laws of physics that we have, you know, inertia, Newton's laws, gravitational, you know, time dilation, space-time, all that stuff that we're like, gee, where did all that come from? Maybe that's how space-time behaves inside an event horizon of a black hole. Maybe it's how it exists inside the event horizon of a black hole that's at the center of our galaxy, but we can't travel there and go inside to check it out. But maybe it's like that in there. Maybe the laws of physics have their own unique set of circumstances. Maybe it depends on how the black hole was formed or other variables we just, we can't interact with, so we don't know. But it's possible that all of these laws of And don't forget, we see black holes literally everywhere in this universe. Like, we think every galaxy, of which there are billions and billions of galaxies, have a black hole at the center, and there could be rogue black holes all over the place that are not at the center of galaxy as well. They're hard to detect, and we can only now, as of a few years ago, even image these gigantic monster black holes that are nearby. Now, I want to introduce you to the work of a physicist by the name of Nicoderm Poplowski, who proposed that black holes might act as cosmic wombs, so to speak, giving birth to new universes. So when matter collapses into a black hole, this physicist, Poplowski, he suggested that it might not just crush into a singularity, which is kind of what we think of when a black hole forms. It just goes, shoop, and it makes a singularity like that. But actually, it could instead undergo a bounce, so to speak, when it goes in there, maybe bouncing or having some other interaction at the moment of the formation of that singularity, creating an expanding universe on the other side, completely disconnected from the parent universe where the singularity formed. Again, some ideas are so big that we have to just put the brakes on, stop, and rephrase it again. What we're basically saying is, a couple hundred years ago, 150 years ago, people look up at the redshift of galaxies everywhere, and they're like, huh, all of the light from the galaxies are redshifted. That means they're moving away from us. And no matter where we look in the sky, everything's moving away from us. We're certainly not the center of the universe, so why is everything moving away from us? Well, maybe there's this big bang where everything is formed, space and time is being created, and if you rewind the cloud, the clock then this singularity of infinite density, of infinite density of mass and energy, you know, was there. And suddenly it had some event happen, and a rapid expansion happens, and that theory very much agrees with what we see in the universe. There's lots of evidence for the big bang theory of the universe. We know it's not complete, but there's lots of evidence. For instance, when we also look at the cold, dark reaches of space, again, in every direction, we see microwave background radiation. It's everywhere, and it's like a fingerprint of whatever happened a long time ago. It's in between the stars. It has nothing to do with the stars. It's everywhere, no matter where you look. It's kind of like if you lived inside of an oven, and I turn the oven up to a thousand degrees, but then I turn the oven off, and it cools down, right? And then suddenly some planet is in the center of this oven, and then eventually little creatures start to look around. They look at all of the walls of the oven, down, up, left, right, everywhere, and it's like, huh? And they see it always at a certain equilibrium temperature, no matter where they look. There's little variations, hotter and colder as they scan the whole sky, which is what we see when we look at the cosmic microwave background. But more or less, it's all a few degrees Kelvin above absolute zero in terms of the temperature of what you're looking at. And it turns out that the radiation released from the Big Bang, which is very energetic 13 and some odd billion years ago, as it gets stretched out and cools off as space and time stretch, pulling the electromagnetic radiation from the formation of the Big Bang, stretching the wavelength, and you fast forward the clock 13 billion years, we've calculated that whatever energetic energy was there, the wavelength should be stretched, so it's much, much colder now. And the temperature of the radiation that we would expect to see, if it's basically cooling off of radiation from the Big Bang, exactly matches what we actually see when we look in the night sky. So there's lots of evidence for the Big Bang theory of the universe, and there's more beyond this. It predicts the ratios of different atoms and isotopes that we see in the universe, predicts lots of things. But there's still one nagging question that everybody has, including me, and including every scientist, about the Big Bang model of the universe. Where did the singularity come from? In other words, you rewind the clock back, and everything gets to an infinite singularity point, infinite density of matter and energy. So the first question is, well, who put that there? You know, maybe your beliefs mean you think somebody put that there. Or if you don't believe that, maybe you think, how did that come to be? Where did that come from? What process could possibly put infinite matter and density into a point, which then starts to expand and go everywhere and make everything? Well, maybe, just an idea, according to this physicist, that maybe when a black hole forms, after all, remember, our theories of space and time break down because it's infinite matter and density. So we know that infinite matter and density are not real. So what it really means is the physics that's going on at the moment of the singularity is not understood by us. We can't do experiments to probe it. We know what's happening all the way up until the moment of singularity formation. So possibly, when something collapses into what we call the singularity, maybe it doesn't go to infinite matter and energy. Maybe what happens is some sort of bounce occurs, or it gets to some critical density, approaching a singularity, and an expansion in another dimension outside of the current universe. And maybe, again, it's just an idea, but maybe the singularity that happened to start our universe was from some black hole collapsing into a singularity before this one happened, before this universe happened. And when that collapse happened, it created a singularity, which then rapidly expanded into this. So maybe there's a metaverse way beyond what we can imagine, where these black holes, or whatever you want to call them, are forming and producing baby universes all the time. Now I know this sounds like Star Trek stuff, right? But here's the thing. We know how big the universe is. That is fact. We know how stars form. That is fact. We know that black holes form. That is fact. We cannot probe inside of a black hole, because we'll never be able to come out, and also they're all really far away. We can't travel there and really see with our material bodies what's inside of there. But we have theories of physics we know they break down inside. We have no way of making better theories, at least yet, because we can't really do experiments with that. Now we know that higher dimensionality exists. We know that we have three dimensions of space and one of time, but there are many theories of physics that propose higher dimensionality, and string theory, and loop quantum gravity, and other theories as well, that have higher dimensionality that we don't directly interact with, but do form the fundamental structure of our space-time. And it's possible that when a singularity forms, it triggers something in one of these other dimensions, and whatever evolves in that other dimension would only see what they have locally, and they would never know what came before. I'll leave you with one analogy. Again, it's just an analogy. Imagine a pot of water on the stove, and you put some water in it, and then you turn the fire on underneath the pot. Now let's say that after some time you start to see a little shimmering, a little heat happening in there, but eventually on the bottom of the pan you're going to see a bunch of little bubbles which are attached to the bottom before boiling happens. And these bubbles are going to start microscopic, but then they're going to get a little bit bigger, a couple millimeters, and there's going to be hundreds of them all on the bottom of the pan. Now if you keep going with the fire, eventually one of them will detach and float up like this, another one, and so on. But what if you didn't actually let the fire go that long? What if you just kind of watched it right when the bubbles were all attached to the sides and to the bottom of this pan? And what if you just as an external entity walked over and kind of tapped the side of the pan? You would send a shockwave through the metal, it would jiggle the bottom, and some of these bubbles would detach because of your force that you impart on the pot, right? And then as it floats up it's going to like start to vigorously bubble and so on. Maybe the formation of our universe in terms of a big bang and inflation and all the things that happen to create everything we see, maybe it's kind of like that. Maybe we live in some gigantic pot of water, not really, but I'm just saying as an analogy, where baby universes can be formed all the time through processes that we have no way of interacting with. And once one of them detaches from the bottom, they're on a rocket ship straight up to the top, and from their point of view, if they lived in a planet inside of that bubble, they'd be like, wow, we're moving through our space-time, and we're looking at all these bubbles everywhere, and they're all moving away from us, or whatever the case may be. But they would have no idea about the pot, they would have no idea about the fire, they would have no idea that some force kind of tapped it from the outside to start it. Much like if we are living inside of a black hole, we would have no idea about some prior black hole before, or whatever structure it is, collapsing and triggering this space-time to do whatever it did at the beginning of our universe. We have no way to interact with anything outside of our local bubble, just like those bubbles in the pot would have no way to travel between universes, really, if they're living inside of that pocket of water vapor or whatever it is. I know these ideas sound crazy and weird, but I do want you to give them serious consideration and thought, because the similarities between black holes and the Big Bang are actually pretty striking. So to wrap it all up in a bow, from our perspective, inside our universe, when we would see the Big Bang or observe everything, from the outside, observers would just see a black hole, but from the inside, we would see like a Big Bang happening. That's what we see when we look out. It's kind of like cosmic recycling where every black hole might contain its own universe, and our universe might be the interior of some mega black hole in some larger parent universe, unfortunately, that we can't really interact with. But I want to be clear, this is still totally theoretical. There's really no definitive experimental evidence proving that we're inside of a black hole. It's just an interesting idea, and like, hmm, are there any experiments we can do to try to prove or disprove this? Now, the scientific consensus remains that while these are really intriguing, they're totally speculative. So that brings us to the following point. Is there any way to test this? Can we prove or disprove this idea once and for all that we're living inside of some kind of mega black hole structure? Now, this is where things get actually pretty challenging, because the fundamental problem is that if we're inside of a black hole, we can't actually see beyond the event horizon from our perspective looking out, by definition. No energy can reach us from the outside, by definition, because it gets destroyed as it enters into the black hole. Everything gets ripped apart and all the entropy goes up and everything gets destroyed. So we have no way of directly confirming the existence of a parent universe if we're on the inside looking out. However, there might, and I do stress might, be indirect ways to at least test these ideas. One approach is actually looking for signatures in that cosmic microwave background energy that we talked about just a second ago, the afterglow, so to speak, of the Big Bang. Looking for signatures in that radiation which surrounds us in all directions. And the idea here is if our universe underwent some kind of a bounce inside of some larger black hole, rather than emerging from a true singularity, this might leave subtle imprints in the cosmic microwave background that differ from the standard predictions that we have, you know, in the regular model. And there's actually physicists looking into this right now. They're looking at that cosmic microwave background data from satellites, such as the Planck satellite, searching for anomalies or fingerprints in the cosmic microwave background that might hint at non-standard origins. In other words, we posit the Big Bang as some, you know, singularity. Are there differences in how one of these bounce situations would happen that would leave a certain kind of imprint on that microwave background radiation? Could we look at that and would it differ from the standard model enough to maybe say it could be true? Now another test involves the universe's overall geometry and topology. Now general relativity allows for different possible shapes of the universe. And some black hole universe models predict specific geometry and geometric properties that we could potentially measure in our universe right now through precise observation of very distant galaxies and that background radiation. We also have gravitational wave observatories and they might provide clues as well. So the LIGO and VIRGO detectors, those are gravity wave detectors that we actually have, have opened a new universe on detecting ripples in spacetime from colliding black holes in our universe and also neutron stars. Now as these detectors become more and more sensitive, and as new ones actually come online with newer technology, we might be able to detect, and I do say might be able to detect, gravitational wave signatures that could help distinguish between cosmological models. But I got to be honest here, we may never be able to definitively prove this or disprove this hypothesis. It's possible that being inside of a black hole and being in a universe that started with the Big Bang produce observationally indistinguishable results. In other words, we may not have anything we can look at to help us determine which path we're actually on and what our origins actually were. The two scenarios might be mathematically equivalent or so close that we can't tell the difference and so we won't be able to really tell potentially which reality we're actually in. Now as we reach the end of this cosmic journey, I want you to take a moment and let all of this stuff sink in because there's some big ideas here. You might be living inside a black hole right now. Everything you see, everything that exists in our observable universe might, and I do say might, be contained within an event horizon of a black hole of incomprehensibly massive size in some larger reality that we can never probe, experiment on, or really observe. And if that actually is true, then every black hole we've ever observed, from stellar mass black holes formed by collapsing stars to the supermassive giant black holes at the center of galaxies that we see when we look out there, they might contain their own universes, complete with their own galaxies, their own stars, planets, maybe even their own civilizations, pondering the same questions that we're pondering right now. So the next time you look up at the night sky, I want you to remember you might not just be looking out at the universe, you might be looking around at the interior of the most magnificent black hole ever conceived. And somewhere in some parent universe that we can't directly interact with, our entire cosmos might be nothing more than a point of darkness against their starry sky. So I want to close by saying thanks for hanging out with me today. These are big ideas, and I really want to know what you think and what you feel about all of this stuff, so please drop me a line. Let me know what you think. Do you think we're living inside of a black hole? What would it mean to you if we actually were? And as you ponder this and all other mysteries in nature, I want you to always remember to stay curious.