One of the biggest, most basic questions you can ask is: “why is there something and not nothing?” The reality is that we don’t know the answer, we might never know the answer. Today we’ll investigate this mystery, recently covered by the physicist Lawrence Krauss in his book of the same name.
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Female Speaker: This episode of Astronomy Cast is brought to you by Swinburne Astronomy Online, the world’s longest-running online astronomy degree program. Visit astronomy.swin.edu.au for more information.
Fraser: Astronomy Cast Episode 397, why is there something and not nothing? Welcome to Astronomy Cast, our weekly facts-based journey through the cosmos, where we help you understand not only what we know, but how we know what we know. My name is Fraser Cane. I’m the publisher of the universe today. With me is Dr. Pamela Gay, a professor at Southern Illinois University Edwardsville, and the Director of Cosmo Quest. Hey Pamela. How you doing?
Pamela: I’m doing well. How are you doing?
Fraser: Great. As we are speaking right now, it is the height of the geminid meteor shower. We had beautiful, clear skies last night, and a couple of friends got a chance to see some. As soon as this show is over, I am gonna, because we’re recording in the evening, unusually, I’m gonna go out and try to catch some on Monday. Although it’s also bitterly cold here in Canada, so I’m gonna see how long I can last outside as I look for geminids. But the geminids are at their greatest, at their peak, which people don’t realize now. The geminids are really one of the biggest meteor showers that we can get.
Pamela: I was actually born during the geminid meteors, and somehow that has explained so many different things.
Fraser: Yeah, your birthday was yesterday?
Fraser: Saturday. Right, okay. Yeah. Okay. Well let’s get on with the show.
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Fraser: So one of the biggest most basic questions you can ask is why is there something and not nothing? And the reality is that we don’t know the answer. We might never know the answer. But let’s probe to the edge of what we can explain, and what ideas cosmologists have proposed to explain how we all got here. All right, Pamela. This is a special holiday gift to me that you’re willing to entertain my wild flights of fancy and talk about a topic that normally you wouldn’t touch with a ten foot pole.
Fraser: So I deeply appreciate you playing ball. And this is like my favorite question to ask to stump cosmologists and stump scientists. Because, obviously the answer is we don’t know, but what I love is how they explain we don’t know. So before we kinda get into this, let’s get right to the limit, and sort of – let’s talk about the big bang theory itself, and where it ends. If that makes sense.
Pamela: Okay. Yes. So the big bang theory basically explains that our entire universe originated 13.8 billion years ago, and it arose out of a single point. Now, as the theories go currently, the single point underwent rapid inflation, and within the first three minutes, pretty much everything we have in the universe went from a point of pure energy where all the forces were tangled together, to the forces breaking apart, to particles falling out of the energy to a burst of nuclear synthesis that got us helium, a touch of lithium, a bit of beryllium, and, of course, we had hydrogen.
And then the universe basically expanded and cooled, and expanded and cooled, and expanded and cooled until somewhere between 300 and 400 thousand years after the big bang, at which point the universe had expanded and cooled enough that atoms were finally able to form out of this malaise of colliding particles. And when this happened, the electrons glommed on to all of the completely ionized nuclei that were flying about, and we ended up with a neutral universe that was dense and dark and the release of the microwave background radiation.
Fraser: And there are multiple lines of evidence. We’ve done a whole show about this. I’ve done a video about this. There are multiple lines of evidence, each of which confirms that the universe is currently expanding, that everything in the universe is expanding away from each other, that if you run the clock backward, you get to that 13.8 billion years that you mentioned. So the big bang really wonderfully explains sort of that everything is moving away from each other, that it was once a singular point. That’s all great. But it falls apart, obviously, or fall apart isn’t the right term, right? It’s that it fails to explain what set off the whole process in the first place.
Pamela: Right. So we’re in a situation where, for the best of our understanding, we can say that everything went down to a point. Now the question that we get left with was this part of a wave function collapse where the point wasn’t a point that then stopped at the point, but rather was just sort passing through as things went flying, or as wave functions changed. We run into problems of we observationally can’t see anything from before the formation of the cosmic microwave background, so is it even valid to discuss what came before the big bang when we can’t even see what happened before the C and B.
And then you run into problems like how do you try and understand all of this within the context of the arrow of time, this fact that there’s so many things in our universe that require time to be a constant step in a single direction. For instance, well there’s a lot of movies of pool balls colliding, that if you ran them forward or backwards, you’d never be able to tell the difference. There are a lot of situations that the science only runs in one direction. For instance, if you throw a water balloon at someone. That’s a video you can tell instantly whether or not you’re watching it in reverse, because once that balloons pops, that water and plastic isn’t spontaneously going to recombine to recreate that water balloon.
How do we explain a universe that appears to be always be marching in one direction? It’s very uncomfortable to think about did it come out of an infinite past and go into an infinite future in this constantly line? It seems like it should somehow circle back on itself, but you can’t do that if time only marches in one direction. And so people are trying to figure out how do we uncouple all of these different problems. And then there’s the most fundamental problem at all, which is once you’re within the smallest fraction of a second, and once you’re within plank time, suddenly you have to be able to unify a general utility in quantum mechanics in order to have a coherent conversation. And those two things don’t work and play well with one another.
Fraser: So, I mean, our instinct is to sort of imagine, as you said, time marching forward, event after event, unfolding one after the other.
Fraser: But with the universe, as we currently understand it, not only was the whole universe sort of down to this initial singularity, but time itself began with the beginning of the expansion of the universe. And so, you know, it’s bordering on a nonsense question to ask what came before time, right? What is more north than north is one of the problems. But I think you’ve got at least a little bit of a stepping stone there, right, which is what you mentioned is that we can’t even still explain how gravity and the sort of grand unified strong force –
Pamela: There is no grand unified theory.
Fraser: Right. There is no grand unified theory that includes gravity. And so it’s like the last rung on the ladder to that singularity still hasn’t yet been figured out. So there’s still hope to push the boundary at least a little bit more forward.
Pamela: Right. And it’s a hope that some of us are starting to feel less and less sure is actually gonna hold out. And it’s possible that either gravity simply doesn’t have a string theory or a particle physics or a standard model way of being discussed that makes sense within our current paradigm, and it may be generations before someone who’s able to create that fundamentally new paradigm comes along. So there’s that challenge of we need to give birth to a new paradigm changer. Then there’s the problem of are we getting stuck by our own closed-mindedness.
A lot of people are constantly going down the same road of string theory, which is admittedly the only direction where new ideas have been generated for a while. But, there’s no evidence for string theory whatsoever. So the big theory that people are trying to figure out if they can work on is the idea that the big bang comes out of the collision of string theory membranes, or just branes is what they usually call them.
And the math actually works out with this theory that it’s sort of like three dimensional sheets of paper floating through a many-dimensional space, sort of like a two-dimensional sheet of paper blowing in the wind in our three dimensional space. And when two of these branes collide, they end up generating a stable new space in which we could maybe, possibly exist, but we don’t know. And so that’s one theory that’s being worked on.
Fraser: Right. And if I sort of understand that when you get these potential collisions between these membranes, which is probably not anything like what they are if this is correct. We imagine these sort of membranes, because our puny meat brains can only imagine this kind of thing. But that you sort of get the – we actually talked about this just a couple of episodes – the frustrating fact for most physicists that a lot of the pieces of the universe are these constants. This is how strong gravity is. This is how strong alpha is. This is how strong the weak force is. And that all of those sort of fell out as – they got hard coded into the universe when this interaction happened. So, that’s sort of one implication from string theory. But that’s just one possible idea. Right?
Pamela: That tangles it slightly. So we’re looking at a couple of different things. So the theory that I’m talking about is one that came from Paul Steinhardt and Neil Turok. And I started this work back in 1999 at a cosmology forum where they were both having this moment of how do we work ourselves out of this hole that the big bang has dug us into with the beginning of the universe? And with the collision of branes, what you actually can end up with an oscillating universe system.
So you have this multiverse, and with the multiverse you can have different physical parameters tumbling out of different colliding branes and out of different oscillations. But side by side with that you also have Andrei Lynde’s idea of infinite inflations where you have inflation once it’s gets going. You might end up with parts of it that just keep bubbling off, and each of these different bubbling bits and pieces is its own universe with its own physical constant. So there’s multiple ways to get to multiverses.
Fraser: And so what you’re saying with that other sort of multiple inflations, then, is that there is some other universe, and then, I guess, things inflated to the point that it almost like it branched off and began its own timeline with its own constants –
Fraser: that we then experience in. So time began for us in this universe, but maybe there was time previously in previous – in whatever was the universe that we branched out of.
Pamela: Or even a more interesting idea, and this is one that’s been getting worked on by Sean Carroll a lot, is that in this bubbling froth of bubbles, perhaps in our universe time is going in one direction, and in another universe time is going in another direction. And because there’s no particular favored direction for time, not that it can go sideways, but it sometimes feels like it goes sideways. But anyways, since you can have some universes with time going forwards, and some with time going backwards, you get closer to the North Pole as the farthest north you can go, but you can still keep walking. And so you don’t have that infinite beginning problem.
Fraser: One of the really interesting calculations that I’d seen Sean Carroll had done was this idea of sort of quantum fluctuations, that you can – the air in this room is most likely according, the probability is that the air in this room is gonna remain in this room. But there’s a really super remote chance that all of the air could suddenly rush up to one tiny little corner of the room, and I could suffocate. But most likely that’s not going to happen.
But then you sort of take that idea of quantum mechanics further, you could imagine sort of virtual particles appearing out of nowhere, and you can sort of take that to this idea that you could have, they talk about x, this idea that eventually, if you run the numbers long enough that actual particles and eventually even completely conscious minds could appear, which then would collapse other wave forms. That’s sort of, you know. But he even ran the numbers all the way to what it would take for an entirely new big bang to form. And the fact is that if the universe is – the universe might be infinite in size, and so if it is infinite in size, then if you run the numbers long enough, this is gonna happen. And not only that, it’s gonna happen an infinite number of times, that random luck is gonna organize all of the particles into another big bang.
But for sure, or it definitely appears that the universe is gonna be infinite in time. And so if we just wait long enough – I forget what it was, 10 to the power of 50 to the power of 50 to the power of 50 or something just ridiculous; a number that is so big it is beyond all comprehension – that you’ll get another big bang. That all of the particles of the universe will form themselves into a big bang, and then begin the expansion there. That they will all collapse down into this momentary point. And so with fairly reasonable theories that physicists have seen – this idea of quantum mechanics, virtual particles popping in and out of existence – that you could just do the math to come up with a situation where you get all that, which is kind of amazing.
Pamela: And one of the cool phrases that I ran across while prepping for this show was all you need to generate a universe is an empty vacuum and a shard of dark energy. And the idea is that wherever you have vacuum and energy, particles are going to spontaneously come into existence. And more to the point, bubbles of the universe are going to spontaneously come into existence. And each of those bubbles, most of them will just burst instantly, like soap bubbles. But occasionally you get just the right combination that they grow and grow and grow into something stable that is capable of rather than bursting, well, supporting entire civilizations.
Fraser: And yet, the question that you have to ask yourself is where did that come from, right? That how could you get an empty vacuum and a sliver of dark energy, right? That that one thing is a question that has to come from somewhere. So one interesting book, or lecture that I’ve seen – I haven’t read his book yet – this is Lawrence Krauss – he does this great calculation. And he calls his book A Universe from Nothing.
And the gist is that if you add up all of the positives and all of the negatives of the universe, right? So if you add up all of the matter, and if e equals mc squared, and you balance that against the dark energy, and you balance that against the dark matter, and you balance that against the potential gravity, right, the potential energy from the gravity, the mutual gravity of all those objects, you write this great big accounting of it, and you total it up at the bottom, you get zero. That all the positives and all the negatives in the universe, in the end, balance out to zero.
Which is the only reasonable answer you could get. Anything else would be quite baffling, if you ended up with a little bit more positive than negative in the universe, or a little bit more negative than positive in the universe. But the fact that it actually all balances out to zero is very reassuring. Right?
Pamela: So I have to admit, I didn’t even know that book existed. But what I found, which was actually a really excellent read, is Stephen Hawkings, on his website, which is hawking.org.uk, has a lecture that he gave on the origin of the universe. And it goes through and it talks about a lot of the stumbles that we’ve made, a lot of the attempts that people have gone down in terms of trying to understand. He’s the one who I ruthlessly stole the analogy of you can go all the way north, but you can still keep walking, which is where you start to get into a different version of circular time. So I strongly recommend going and checking out Hawking’s lecture. It’s also kinda neat to read because he wrote it to be read by a speech synthesizer, so there’s some really funky grammar – not grammar, really funky punctuation in there. It’s just there just to make sure his speech synthesizer sounds rational.
Fraser: Right. So what kinds of ev – as a physicist, as an astronomer, you’re always looking for evidence. So what are some kinds of evidence that maybe, that cosmologists and stuff are looking for that would try to give some kind of indication about which direction it is? What would be very intriguing?
Pamela: Well, so as always, people are always searching the cosmic microwave background, because that is where all evidence of all cosmological everything at the end of the day needs to appear. And people have been looking for small symmetries. They’ve been looking for echoes where things are the same in two directions. They’ve been looking for all manner of statistical fluctuations or lack of fluctuations that will support each of these different theories. Now, at the end of the day, so far the cosmic microwave background has remained mute on the matter. And we keep hoping the next instrument, the next instrument, the next instrument. So if COBE to WMAP, now to PLAY, we keep hoping.
Fraser: Can you explain that a little more deeply? You said an echo. What would that look like?
Pamela: So for instance, if we live in a somewhat small, finite universe, you will legitimately about to see the same light coming from two different directions as the light goes around, essentially, the four dimensional hypertoroid that is, quite possibly, our universe. And so as the light loops around from one point to our point, it’s coming at us from two sides.
Fraser: Right, okay. So it would be like living in a mirror box, and you would look to the left and you see your reflection of what’s on the right. And so you know that that tells you a little bit about the scale of the universe, and potentially, maybe what could be influencing it from the outside, if there even such a concept, right?
Pamela: So we also do look for particular hints that might lead us to say this is where our universe is colliding with another one. This is where we’re seeing echoes from different branes. There is a particularly cold spot in the cosmic microwave background that people have been baffled by, and periodically cosmologists pop up with theories of how it might be explained by the influence of a different universe outside of our own. But then another cosmologist always comes along and goes thump, no. So that is still a debate that isn’t solved.
Fraser: What about gravity? One of the ideas, I know, is that gravity is weaker than the other forces, and this is one of the, potentially, the implications from some of the theories on this, and that maybe that’s somehow leaking from other universes or from whatever, right?
Pamela: Right. Or other dimensions is usually what people talk about. Is since our universe is three observable dimensions plus time, and with string theory, and pretty much all theories trying to explain the aspects of different particles, you end up having to invoke additional dimensions, the number of additional dimensions depending on which particular theory. I haven’t, for a while, seen a reputable theory that had less than 11 dimensions. So they’re getting up there in number, and gravity, it’s thought, might be part of those other dimensions where it’s stronger.
And I would like to mention trying to understand all of these different things is part of what leads us to such weird notation like we talked about last week. I got an email from one of my faculty at the University of Texas, Bill Jeffries, who pointed out that one of the reasons that we use the term spin, even though you can’t look at an electron and say that sucker is spinning in one direction or another. Not valid thinking. Do not associate the idea of spin with it spinning like a top. But the reason we use is the mathematics that get used to explain how particles with different spins interact and work and function, it all requires us to take into account equations that look and act just like angular momentum. So there’s lots of stuff going on, and lots of people are trying to figure out how all of this ties together with a multidimensional theory.
Fraser: So and then I guess the other question is that maybe there can be some kind of echo. I mean, we talked about the cosmic microwave background radiation, but maybe there’s some kind of echo in the actual vacuum of space itself, the actual structure of space could somehow point us towards what might have come before.
Pamela: And we have been able to start determining certain characteristics about what happened prior to the formation of the cosmic microwave background by looking at what are called the sound waves in the cosmic microwave background. If you look at the statistical fluctuations with the hot spots and the cold spots, and how many there are of this size, and how many there are of that size, you get this structure of there’s this many in this band, this many in this band.
As we’re trying to figure out how to explain within the context of particle physics all of these different aspects that we can see and measure of particles – we don’t see them spinning actually, but we see something that is what induces the Pauli exclusion principle. And that something acts like angular momentum. We see magnetic moments. We see all of these different attributes. Color is, again, we just made that one up. But we see all these different attributes, and people are trying to use them multidimensional theories.
And in trying to understand our universe, with three observable dimensions plus time, we need to try and understand all of these things that are outside of our observable universe in a lot of ways. And it gets challenging and multiverses, where you can simply say there is a universe in which everything is possible just somehow alleviates all of that pain, because what we may not be able to explain except as fine tuning or something precisely made in just the right way, suddenly just becomes oh!, the universe rolled a Yahtzee, and a different universe didn’t roll a Yahtzee.
Fraser: Of course if the universe didn’t roll the Yahtzee, we wouldn’t be here to observe the dice. What of the other things that – you’ve mentioned this a little bit, and I think we should probably do a whole episode on this at some point – is this unsettling idea that the universe is one collapse away, one sort of energy drop away from total collapse. And maybe that is the way the universe ends, and then perhaps the way the next one begins, right?
Pamela: Its’s the whole idea that nothing likes to stay in an excited state. And we know that our universe isn’t in, essentially, a ground state energy. We are, essentially, in an excited state. So what happens when the universe decides it wants to, well, become less enthusiastic about existence and drops down to a lower energy, and we go poof.
Fraser: Right. Yeah, I think we’re gonna do a whole episode of that at some point. Yeah, which will be great. But I think we’ve sort of reached the end of this, so that’s it. Thank you so much, Pamela, for entertaining me, and allowing me to throw this topic on the slate. And yet we tried to keep it in the science. For the person who – I wanna sort of give people sort of one final piece of ammunition, which is when a person says, “Well, the big bang can’t explain where it all came from, therefore big bang is stupid.” How do you respond to them on that?
Pamela: I say we can’t always understand everything, and this is why we do science. And there’s lots of things that it’s just gonna take time to understand, and this is why we keep looking, and keep looking up, and keep doing the maths. And theories that we have right now, the basic big bang theory, it explains so many observables that have no other explanation. So we’re just one step away, or maybe a few hundred, to study science.
Fraser: Yeah. And the mystery is worth it, so let’s keep looking.
Pamela: And one final note, we are not going to be back before Christmas because I’m gonna be on an airplane back from a business trip next Monday. But I’m gonna remind you now that we have shirts, like the one I’m wearing right now, that says Astronomy Cast on it. These are available at astrogear.spreadshirt.com. And when you support that, you help us do things like replace Preston’s broken laptop. So help us replace Preston’s broken laptop so no more shows come out late.
Fraser: All right. Well thanks everyone, and thanks Pamela.
Pamela: My pleasure.
Fraser: Thanks for listening to Astronomy Cast, a non-profit resource provided by Astro Sphere New Media Association, Fraser Cain, and Dr. Pamela Gay. You can find show notes and transcripts for every episode at Astonomycast.com. You can email us at email@example.com. Tweet us @astronomycast. Like us on Facebook, or circle us on Google Plus. We record our show live on Google Plus every Monday at 12:00 pm Pacific, 3:00 pm Eastern, or 2000 Greenwich Mean Time. If you miss the live event, you can always catch up over at cosmoquest.org.
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