What is a vacuum, and what makes a false one? What happened in the early universe to bring about our current physics? Will it happen again? If so, when? I discuss these questions and more in today’s Ask a Spaceman!!

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EPISODE TRANSCRIPTION (AUTO-GENERATED)

this episode of Ask a Spaceman is brought to you by the very stylish people at my science shop dot com. Check this out. They make some really amazing globes of the planets and moons of our solar system. They are gorgeous. II, I can tell you for real that they are absolutely gorgeous. They make great centerpieces. They look great on a bookshelf. They look good on your nightstand. I'm not gonna judge where you put them, because wherever you put them, it's gonna look amazing. And they're educational, too. It's it's fun to just go up to a globe and point and and see and the interesting features. And they have all the interesting features on these globes labeled, uh, we're talking Pluto, Mars, the moon Titan, Europa, Jupiter and more. You can get a discount. You need to go to my science shop dot com slash globe 15. Use that coupon code Globe 15 to get 15% off of your globe purchase. And and these are high quality. These are limited edition.

These are custom made. So So why didn't you order it now? Why? Oh, ok. Finish the episode and then go order these amazing Globes. This episode is also brought to you by the good people at better help. That's better. Help dot com I I know a lot of you listen to this show as a form of therapy A as a way of, of escaping the world and and just going among the stars on this wonderful journey. Uh, I am a big advocate for therapy. I personally see a therapist, and you would be surprised if you don't currently see a therapist how much they can really help you Just navigate a difficult life just like you see a doctor to help you with physical conditions, you should see a therapist Better help dot com is a way to do that. That's convenient. It's affordable. Uh, these are licensed professional counselors that you can connect to online a range of expertise worldwide. It really is an invaluable resource.

Uh, as a listener, you can get 10% off your first month by visiting our sponsor at better help dot com slash spaceman. You can join 1 million people who have taken charge of their mental health again. That's better. Help HE LP dot com slash spaceman. Let's lighten the mood a little bit and talk about the end of the universe. I know it's exactly what we all need right now, but, hey, if we're gonna go in that direction, let's just go all the way. And one very interesting way to approach the question of the end of the universe is to ask if our universe is stable and stable, has a very specific meaning in physics and the analogy I like to use and I don't know why. I like to use this analogy because it's pretty terrible all around, but it's literally the only thing I can think of it. It involves skiing and skiing down a ski slope. I I've never even gone skiing.

I. I grew up in the Midwest, you know, skills like this or ski mountains or ski whatever. See, that's how ignorant I am about skiing, and yet I go to it as a source of a metaphor. But I want you to imagine, and but I I've watched it on TV, so so that makes me expert enough. I think if you're standing at the top of a mountain and it's icy and snowy and conditions are pretty rough and you're standing there with your skis on. And all it takes is the gents. Little breeze. Someone could breathe on you and you're gonna go tumbling down the mountain. That is unstable. You're in a situation that is likely going to collapse and transition into something else. But if you're at the bottom of the hill, you're all the way at the bottom and you're just standing there. Same slipperiness, same iciness, same snowiness. You still have your your your skis on. Nothing has changed. But if you're at the bottom of a hill and someone taps you brushes up against you, you don't move at all.

You are stable. That's the difference between unstable and stable. And we need to introduce a third character into this discussion as a kind of spoiler alert. But I, I can't get away from it, which is a condition called Metastable. So unstable is any little thing is gonna send you in a new direction, send you in the direction of a new state. Stable is you. You can't be bothered. You're so chill. Doesn't matter. You're gonna hang out there forever. Metastable is a state in between stable and unstable, where you're not going anywhere, but you can be knocked off, but it's gonna take a little bit more than a gentle nudge or a breeze. There has to be some sort of perturbation. There has to be some sort of energy introduced to knock you out of that metastable state and send you on down to the actual stable state. So what I like to imagine is, if you're skiing down the slope and you get stuck in in a little divot or in a in a in a grove of trees and you're not all the way down the mountain, but you're hanging out there and if you don't move, if you hold your breath, you're gonna hang out there and you can hang out there for a very long time.

You can wait for the rescue chopper, but if you try to get up, if some other skier comes by and knocks into you, if a yeti appears, then you are going to get sent out of that metastable state and you're gonna go skiing down the mountain heading towards the true stable state. So when we ask, what is the state of our universe? Is it stable? Is it unstable? is it metastable What is going on? And on one hand, on one hand, it looks like the universe is obviously stable. It's been in roughly the same state for over 13 billion years, which is a long time. The physics that operate that govern the universe have been the same physics for a very, very long time. The the the chemistry involved has been the same chemistry since the Big Bang. It's it's it's obviously stable, right? But on the other hand, the universe is anything but stable. It's expanding, stars explode.

People fall in love. Nothing is ever the same day today. So when we ask about the long term fate of the universe and we ask if the universe is stable, what we're really asking the question we're asking is Is the vacuum stable? The vacuum? Yes. You heard me, right? The vacuum The vacuum of space is not what you think a vacuum should be. You think a vacuum as a place where there's nothing. You take a box, you suck out all the particles You suck out all the radiation. You suck out all the neutrinos you suck out all the dark matter, you suck out all the everything. You have a totally, perfectly empty box. You have a box full of vacuum. That vacuum is not nothing. The vacuum is not nothing. The vacuum of space time It's the weirdest thing. Among the weirdest things. The vacuum of space. Time is a thing. It's an entity. It's a dynamic, frothing, sloshing mess. It exists in the vacuum of space.

Time influences the behaviors of objects. I know it's weird, but that's quantum mechanics. For you, the vacuum of space time is the combination of all the quantum fields that give rise to the particles and forces that we know. It is a slashing, chaotic film, and you have to remember, in order for this to make sense, which it barely barely makes sense. The primary physical object in physics, the thing in physics, what high energy theoretical physicists care about? What we point to, as this is, what reality is made of, is not the particle, the particles, the electrons, the photons, the top quarks. These are not the fundamental physical entities. The particles are not what makes physics physics. Instead, it's the fields, fields, the quantum fields, soak all of space and time they overlap on top of each other through out all of space and time, and each kind of particle is associated with its own kind of field. So the photon is associated with a field. We call it the electromagnetic field.

The electron is associated with an electron field. The top quark is associated with the top quark field. Everybody gets a field. It's like Oprah. You get a field and you get a field and you get a field. Everyone gets fields, and it's through the interaction of the fields that physics arises. So what we see of as particles are really just local excitation of a field little pinched off bits of a field. When we see particles interacting, it's really their fields interacting. And when you empty out all the particles from a box, you still have the fields. The quantum fields remain because they are baked into space time itself. And so the vacuum of space is really full of quantum fields, and what we're asking is if those quantum fields are stable, we are asking if the quantum fields themselves the arrangement of quantum fields in our universe. This particular arrangement of sloshing ness is going to hang around forever or not very long at all, and this matters.

We we feel justified in asking this question because it's happened before. This is not the first rodeo for our universe. The universe has changed its configuration of quantum fields before, and it was really, really not fun when it happened. Thankfully, this all happened in the very earliest moments of the existence of the universe. We're talking less than a second into the Big Bang. It's it's the wildest thing to imagine that there was a time in our universe's past where physics was literally different, where the forces of nature were not the forces of nature that we recognize today, where the particles that participated in those interactions were not the particles that we recognize today. They were different, and what happened in those early days was that the forces were unified.

We have four forces of nature strong nuclear, weak nuclear electromagnetic gravity. In the distant past, there were fewer than four forces of nature. At one time, there were only three forces of nature. There were two and presumably we think although we have no idea what's going on, that there was at one point a single force of nature, and that as the universe expanded and cooled off, these forces of nature split off from each other. The quantum fields that interacted that created the vacuum and create physics as we know it changed character through a radical process called a phase transition. The last phase transition to happen. The the last time that anything interesting happened in our universe was when the electromagnetic force split off from the weak nuclear force. That's right. At one time they were unified in the electro weak force. We can re create these conditions inside of particle accelerators. It's super fun. I suggest you try it if you get the chance. And in the earliest moments of the universe and inside of a particle colliders, when we reach the right energies and temperatures, there are not four forces of nature.

There are three. There's gravity, strong nuclear and electro weak, a unified force. There are three forces of nature, different force carriers. Physics looks different inside of a particle accelerator, and physics looks different in the earliest moments of the universe. And then they underwent a radical phase transition. It transformed those forces broke apart. Everything was different if you were alive and thriving and having a great time when our universe was point. 001 seconds old. And then this phase transition happens. You are done. You are literally dead because there is a new sheriff in town. There's new rules, and those rules are governed by four forces of nature and new sets of particles that participate in those interactions a brand new vacuum state of the universe. Sometimes when I'm staying up late at night and I can't sleep, I wonder if some sort of life or consciousness arose in the earliest moments of the universe.

And then everything changed for them, and that's kind of a bummer, and that doesn't help me get to sleep at all. So what we're asking is if that split, that happened when the electro weak force split off into electromagnetic and weak nuclear forces. If that was the final split, if that was the last phase transition that our universe encountered, or are there more splits to come? Are we at the bottom of the ski slope or are we caught in a little clump of trees here? Like I said, the universe has been the same for a 13.7 billion years. That's quite a long time. But that's not enough to guarantee that this is truly stable, that we are in the ground state, that we are in the final lowest energy, most calm, most long lived state of the vacuum. So we want to know, how do we figure this out? The stability and I apologize in advance. If in this episode, sometimes I'll say stability, sometimes I'll say stability. I used to always say stability and pronounce it that way.

And then when I was narrating the book, uh, how to die in space, my editor said, You're totally He's saying this word wrong. It's stability, not stability. And but I don't cause stable, unstable stability. But so if you get a little eyelid twitch every time I say stability, I'm sorry. I'll do my best to say stability, even though stability makes more sense to me. But I'm not in charge of language. The stability of the vacuum, as far as we can tell, depends on all things the Higgs bows on and the top quark. Yep. You heard me, right. The mass of the Higgs boson and the mass of the top quark we believe, informs us about the stability of the universe. I know it's wild. Why? Because remember that whole electromagnetic weak nuclear force splitting thing, the little divorce they had that led to our present day universe. The Higgs boson did the work of making that split and and go back and listen to the episode if you want to. About the Higgs boson.

The Higgs boson is what created the split. What triggered that split? The dis unification of the electromagnetic and weak nuclear forces. It is the arm in the elevator door. It is the toe at the bottom of the door. It it's the chaperone at a high school prom. It is keeping those two forces apart, and it is playing a major role in what we recognize as physics today. So we want to know. We want to know if the Higgs will be able to keep this up forever, or if it's eventually going to give up and just blow up the universe. Kidding, But but not not really. We want to know how stable the Higgs boson is, how stable that quantum field is, or if it's going to disassociate, transform into something else and give rise to a new phase transition that might feature brand new physics in our universe. We need to know if the Higgs will keep this up forever when it comes to quantum fields. To figure this out, we need to know the mass because in quantum physics, mass is everything.

The heavier you are, the more unstable you are. The most common particles in the universe electrons up and down quarks that combine to make protons and neutrons. These are the lowest mass versions of all those species of particles. They're the most stable ones. They're the most long lived ones. In fact, they probably live forever. Higher mass cousins like the electron has a higher mass cousin or sibling called the muon. The muon decays because it can transform into other things that have lower mass. There are heavier quarks that decay because they're too heavy. They don't last long. If the Higgs is too heavy, it will eventually decay, and it will generate a new set of quantum fields, which will be a new vacuum, which will be a phase transition of the universe. So we need to measure the mass of the Higgs boson. Where does the top quark come in? Because in the weird, sloshy way of life of quantum field, your mass depends on your interaction with literally everybody else.

Mass is like your reputation in a community. It's not just what you bring to the table. It's also what everyone else thinks of you, so your mass depends on how other things interact with you. In fact, that's how the Higgs mechanism generates mass for the electron, which go listen app, so I don't want to dig too deep into that. Right now, the top quark is the heaviest quark. I mean, the top quark is massive. It's the same mass as a gold atom. A single subatomic particle weighs weighs more than a gold atom. This is ridiculous. So it has the most influence on the Higgs boson mass. And what it says about the Higgs is the most important because as the biggest influence, because it itself is the biggest quark. We don't really know the Higgs Mass at high energies until we have a solid handle on the top quark mass. These feed into each other. So, yes, we have measurements of the Higgs boson Mass from the Large Hadron Collider experiments. But at the energy scales we're talking about where we're worrying about phase transitions in the universe, we need to listen to what the top quark has to say.

Like, Hey, is this Higgs boson? Can we trust it is it is just a bozo. What's going on here? We need to talk to the top and talking to the top Quark is pretty tough because it's so massive and doesn't live long summarizing all of that. We have a pretty decent measurement of the Higgs boson mass, but our measurement of the top quark Mass is a little more uncertain. So we don't know exactly how the Higgs boson is going to behave long term, and it turns out the measurements that we have pin it right in that metastable range. Before I continue, I want to let you know that this show is brought to you by the wonderful folks at brilliant dot org. Brilliant is an online stem learning platform, and it really is hands on, which is the best way to learn. That's how I learned in undergrad, and it's it's just so much fun. I love their style. I love the way they approach things. They have two courses in particular that I think you would absolutely love. There's one on special relativity and one on gravitational physics. And how many times in this show do I say that? Really?

I'm just translating the mathematics for you because math doesn't really work out so well in a podcast. And I know a lot of you want to dig deeper without actually enrolling in a university course, which would be somewhat cumbersome. And this is the perfect place to fill that gap, where you can dig deeper in an interactive, fun, engaging way and and learn some cool stuff about the universe. Head over to brilliant dot org slash spaceman to get started with a free trial and get 20% off in annual membership. That's brilliant dot org slash spaceman for 20% off unlimited access to all. The awesome course is on brilliant for a whole year. Our universe is obviously not unstable. Otherwise it would have transformed already. It has been stable for 13.7 billion years, but you can hang out in that little batch of trees on the ski slope for a very, very long time until you get hungry or something. So is our universe in its true ground state. Is this the true, solid, unchanging, stable configuration of the vacuum?

Or is there going to be a shift someday? Are we just waiting around for the rescue copter or are we? Are we at the bottom of the hill? Measurements indicate that we are stuck in the trees that the quantum fields that we have that govern our physics today are not the quantum fields that will be around forever. It means any day now the universe could change. What would this look like? Good question. So we would have what we would recognize now is the vacuum is really the false vacuum. This is not the true ground state of the universe. This is not the most stable configuration of quantum fields that our universe could possibly achieve. There is some other configuration out there that is more stable, more long lived. Happier than the configuration we have right now. Will the world end in fire or in ice? Well, how about the world ending in bubble Nucleation? That sounds fun. What? What What happens is quantum fields are stupid in the sense that they can just do whatever they want.

You can just have a quantum field, hang out here in the vacuum, minding its own business. You're not bothering it. It's not bothering you. It's And it can say, You know what? I am gonna randomly jump up to a higher energy level. It's like having someone in a quiet office just only starts screaming for no reason. All right, that's the quantum fields. And what can happen is in just one random patch of the universe one day, pop. There it is. It quantum mechanically excites to a higher energy level that gives it the energy it needs. That patch of the universe it has now is the energy it needs to discover the true vacuum. And it it settles into its true ground state. It's like if you were stuck in the clump of trees, you need a little bit of energy. Someone needs to push you. Someone needs to kick you. Uh, you know, something needs to. The yeti needs to scare you. You need a little jump start. But once you get out of the the batch of trees, you make your way all the way down to the bottom of the hill so randomly a patch of the universe can randomly just have enough energy that gets unstuck inside the bubble.

In the true vacuum of our universe, the true ground state. There's a lower energy configuration, the boundary of the bubble, though, uh, that this region has positive energy because there's a transition happening there. And so what happens is if this random patch of the universe that suddenly discovers the true ground state finally discovers who the universe is as a person. If that region is too small, it will just pop. It'll evaporate away. But if it's big enough, a big, uh, larger than a certain critical threshold in the critical threshold depends on all sorts of weird quantum stuff that we don't fully understand. It can just keep growing, and it can feed energy as it grows, so the growing can accelerate very quickly. The little region starts to expand. This expansion very quickly approaches the speed of light, which means you can't see it coming. What this means is that outside of this bubble, this phase changed Nucleation bubble.

It's normal. Everyday Universe four forces of nature electrons. Everyone's chill inside the bubble brand new universe, and you can't see it coming because it's approaching you at nearly the speed of light. So it means it could have already happened. It could have already happened over in the Andromeda galaxy, and we won't see it happening until it's already upon us. You one day you're sitting around eating a hot dog and, uh, and all of a sudden in in like that, the laws of physics have been completely rewritten. What does the new universe look like with the new ground state? Well, we don't really know. We don't know what the true ground state of the universe actually looks like. There's various possibilities, and I've categorized these possibilities into five different levels of increasing Interesting This, uh, slash horror. The level one true ground state category is that the new universe looks exactly the same as the old universe. There's some tiny shift somewhere, saying the Higgs Mass.

That doesn't really affect any physics at all, and everything is exactly unchanged. Level two in terms of of of in interesting slash horror is, um, maybe it just shifts something, but it doesn't affect us. like. Maybe there's a whole bunch of new neutrino masses and nobody cares about neutrinos, and so that's basically it. Otherwise, life goes on the same. Another level is, maybe there's no more dark energy or and we don't understand dark energy, but it it probably has a quantum field associated with it, because who doesn't remember? Everyone gets a quantum field. And so maybe dark energy just does something new. Maybe it starts evolving. Or maybe it goes away, and it affects the long term fate of the universe, but otherwise still day to day, maybe Level four, everyone inside the bubble, every single human being starts contributing to patreon. That's patreon dot com slash PM Sutter so that we can keep the show going in the new universe. I really do appreciate it.

And the new universe version of me also. Thank you, But maybe maybe, uh, physics itself. Interactions don't change. Uh, maybe there's AD just a decrease in the average vacuum energy of the universe, you know, So things like, uh, the kasmir effect are slightly changed, and maybe it affects the long term stability of the proton. But other things again, largely unchanged, like some interesting corner of physics has changed, but largely everything's the same. But Level five is the worst case scenario is there's a brand new force in set of fundamental particles. It could be that the true ground state vacuum of the universe has all new forces, all new particles where there's no such thing as the strong nuclear force anymore. There's no such thing as the electromagnetic force anymore. There are new forces with other lame names. There are new particles. The electrons don't exist anymore. Why? Because because it's a brand new set of quantum fields, and it's the sum total of all the interactions of quantum fields that give us physics as we recognize it.

And if you change the quantum fields, you change physics. Yes, that would mean inside the new universe life as we know it. Chemistry as we know it. Nuclear physics as we know it would all be impossible. It's like if you were living in our universe when it was less than a second old and you were totally cool with the way things were and then everything changes. You're not gonna survive that transition, and we may not be able to survive in the new universe in the true ground state in the universe. Ultimately, though, we don't know. We don't know what the true ground state vacuum of the universe would bring us because it would be new. That's literally the definition of new. We've never encountered it before. It should be brand new quantum fields. And we've We've never done this. We haven't tried that before. We cannot recreate that in the laboratory. And I really hope we don't try to. There are some caveats to this. All right, this whole our universe is right on the line of Metastability. It looks like it could just have a bubble Nucleation phase transition. Our universe radically transforms. OK, it That's not exactly known for sure.

Because for one thing, even if we truly are in the metastable region and bubble Nucleation true ground state discovery, phase transition, all that goodness slash badness can happen. Uh, we need to include the effects of gravity in that calculation, and we haven't really And it could be that once you include the, uh, gravitational effects in how bubbles actually operate and how phase transitions actually operate in the modern day universe, it could be that the bubbles are always unstable. They're always unstable. They always just the the universe could have tried to find its true ground state 100 times by now. And it just goes nowhere. So I'm finally gonna start working out. I'm gonna There's gonna be a new me a New year, New me new universe. And then it is OK, never mind. Those doughnuts are way too tempting anyway. And we don't get doughnuts in the new universe, folks. So we have to incorporate that cave. We really don't know also, this whole calculation of metastability and Higgs boson mass.

And who knows? We don't know what the universe is gonna do. Uh, we don't have a complete description of physics, new physics beyond the standard model. We know our standard model of particle physics is incorrect or incomplete. We know that there are holes. We know that there are things that it can't explain. It could be that once we develop a theory of physics that is able to explain all that, then all the fast changes in the stable, not stable, not stable boundary zone shifts, and it turns out we actually are stable. We're obviously I will emphasize we're obviously not unstable. Otherwise, we would have changed already. It could be that the whole metastable thing just goes away once we figure out some new physics. Either way, our universe, like I said, has been stable for over 13 billion years, which is a good thing. I do want to end this show with a little quote that I found. It's such AAA lovely quote because we're We're talking about the end of the universe, which is pretty dark, right, the whole universe transforming and not just us and art and music and the craft of cheese.

We're talking about Galaxies going away. We're talking about stars going away. Nuclear fusion may not work anymore, a completely new universe. But there's a quote from physicist Sidney Coleman and Frank DeLucia that when we're contemplating the potential end of the universe in a radical phase transition as it discovers a true ground state vacuum, they said, however, one could always draw stoic comfort from the possibility that perhaps in the course of time, the new vacuum would sustain, if not life as we know it, at least some structures capable of knowing joy And who says physicists aren't poets. Thank you so much to gully Foyle on YouTube, Jerry on YouTube Shannon Dion email Bar tech on, uh, the website Spaceman Allen H on Facebook and Colin E on email for asking the questions that led to today's episode.

And, of course, thank you to my top patreon con Thank you to all my patreon contributors. Man, you really do help out. I really do appreciate it. I am in a very stable or at least met a stable, hopefully stable position. Thanks to your efforts, I really do appreciate it. This is how I make my living and I love it, and I'd like to thank my top Patreon contributors. Justin G, Chris L, Barbara K Duncan M Cody Justin Z, Nate H, Andrew F, NAIA Aaron S, Scott M, Rob H, Lowell T, Justin Lewis M, Paul G and John W. Those are the top contributors. Go to patreon dot com slash PM Sutter to learn how you can join the space cadet core. And don't forget, keep sending me questions. Ask us spaceman at gmail dot com. The website Social media hashtag ask us spaceman all the visual ways keep leaving iTunes reviews. I really, really, really do appreciate it, and it helps get the word out about the show. Keep asking questions. Contribute if you can.

But in the meantime, I will see you next time for more complete knowledge of time and space. Unless there's a phase transition and then, well, we'll we'll, we'll figure it out then after that.

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