I quite you are listening to radio from the podcast from public radio And NPR hey, I'm Chad Abumrod and I'm Robert Kohl, which is radio lab the podcast. Yes, whoo That was exciting and this particular turn of our wheel we are going to be taking up a very odd odd idea which is Is it possible for a human a man or a woman probably a mature man of woman? We hope to build their own universe. Huh?
Do you mean like a theory? No? Actually this I'm going to this is a serious proposition There are people who are now thinking about it seriously at Stanford in Israel in Japan Theoretical physicists who are trying to figure out how one might go about this go about building a universe a whole universe as in like a Carpenter like an a carpentorial sort of way like here build a table a carpontorial sort of way No, you know whether that's not possible why because the universe is that which we are apart So how can you build something that is that we are already a part of it? To begin to begin this conversation We do have to consider this word universe which to most of us as you just said means everything that is everything Therefore my definition only be one of them.
Yes, but for physicists like Brian Green our friend Brian Green who came to my kitchen So we could have this discussion Do physicists like him? He's very comfortable with the idea of more than one universe and that's been the case for physicists for a while now I don't know the first time But the idea that there might be many universes has surprisingly cropped up in a variety of different contexts in physics For example Brian says the expansion of space the blossoming of a universe that we have called the Big Bang was not a single event But it's an event that happens over and over and over again and distant in far-flung regions of our universe other universe sprout out Have their own new Big Bangs giving rise to a kind of cosmic bubble bath of little bubble universes of which our universe is simply one And then this idea of universes or multiverse is a natural word to use to describe the collection of all these bubbles each of which if it hasn't Happened like us would think that that is the universe but now you see it's only one of many and this was something that somebody thought up in 1920 1930 1950 well the inflationary theory itself was developed in the early 1980s and This recognition that it could give rise to this many universes was developed by a number of incredibly creative physicists in the mid-80s And it's still study today, so it's kind of a new idea then this version of it is new But no explorer has ever ventured into one of these other universes of the best you know, right? This is simply a mental this is a conclusion of a mental process not of a Columbus or a Magellan kind of process That's true We are confined to our bubble and we really can't get out and explore the other bubbles So from that point of view it is a mental exercise but a powerful one but you can see how hard it is for somebody who doesn't read The world through mathematics which is reads to his senses or her senses that this Explanation seems nonsensical since you've no sensual experience of another universe The only one you've got is steering it at equations That's true But I'd say that the history of physics of the last century has taught us to Strenuously challenge our perceptions strenuously challenge the things that intuitively seem obvious We have learned that the atom is made up of particles that can be both wave-like or particle-like that in some sense They can be two places at once none of us have experienced any of those things none of those things feel right according to our intuition But I assure you the experiments that have been done over the last 80 years have confirmed each of those crazy ideas over and over and over again So I don't think it's a good guide to use our senses and our intuition to determine what we think is right or wrong We have really have to follow all the physics and see where they take us. Okay, you with me here, I am yes So let's say really really yeah, I mean, no, no, I'm here.
We're almost like gonna be I'm here All right, so let's say that you can have just in principle anyway more than one universe Okay, now the question is how do you go about building one? Yeah, that's what I don't know You said at the beginning we can build them ourselves right so this is not you know anything like a Active magic or a godlike thing. This is just as far as Brian is concerned. This is a practical albeit kind of crazy Practical engineering problem.
So then how would you engineer one? Let's get to our main subject Well, that's what I asked Brian the question the proposition here is that not only can you have more than one of them But that you you an ordinary human being and some pals can make one Is it conceivable to you that there could be something called a man-made universe? People have studied this and nobody's really been able to say that it's impossible and some of you've even suggested hypothetical ways that you might actually do it well I mean the first question I can I says how are there several ways to do this one way to do this how many how many different paths? Well, I'll say at the moment.
There's no one way that anybody has been convinced is Really compatible with everything that we know there are a number of suggested ways But they all rely upon more or less the same physics and that physics has to do with a strange feature of gravity that none of us have ever experienced but the math shows us is true and observations of space seem to confirm and that is the gravity can actually be not only Attractive it can only pull things together. It can also be repulsive they can push things apart if that were the case then wouldn't we all be combusted? Well the repulsive side of gravity only rears its head in very special environments And everyday life the earth so it's just and so forth are realms in which it doesn't rear its repulsive side strong enough to have any effect But we have learned that on the largest of scales even in our universe We believe that gravity is exerting its repulsive side Which is what's causing distant galaxies to be rushing away from us at an ever accelerated rate the rushing way faster and faster So the repulsive side there's actually direct observational support for what does that have to do with creating a universe? However, because it seems to me the creating a university want to somehow manage the thing and repulsive Particularly if it's a fierce repulsive force would seem to make it be a kind of an unmanageable situation Well, if you want a manageable way of building a universe what you want to be able to do is build something pretty small But a small thing is not a universe so it has to expand There's something to expand there's got to be some outward push there's got to be some repulsive push and that's where this repulsive side of gravity comes into the story So I want to build something that is a seed of another universe but inside my seed There has to be ladenly and then later actively some expansive thing something that just wants to grow now Is there such a device?
There are conditions which according to the laws of general relativity the laws at Einstein wrote down a long time ago well tested Those laws tell us that in this context of the right energy density carried by the right substance You will have repulsive gravity which means if you can build this little seed this little nugget in just the right way It will on its own roughly speaking Start to expand grow faster and faster and faster beginning tiny and sprouting into gigantic universe So I can have you see an expanding universe that is born in my kitchen and I don't have to worry about my Wait, wait, you're having a lot of fun here, but you left me behind a bit. What is this seed thing anyway? Well the exact nature of the seed thing is actually quite complicated Just to give it a shape for you the first thing I learned is that in order to start a universe in universe even our own universe The seed has to be very very small You can calculate that the nugget that we believe perhaps gave rise to our universe Maybe someone created it in their apartment and some other universe was about roughly you know 10 to the minus 26 centimeters across 10 to the minus 26 centimeters small that's really really really small Yeah, and it wouldn't and it could grow into in other words, there's enough push inside it repulsive force or push out Then they could grow into a thing like we would associate with universe universe scales our universe according to this theory again You know being facetious that it was created in somebody else's apartment But who knows but the seed of our universe we believe from our calculations and our observations was roughly 10 to the minus 26 10 to the minus 27 centimeters across weighed You know a few pounds about 10 pounds you wouldn't really think intuitively that you could build a whole universe from 10 pounds of stuff I think you would think that to build a whole universe I'm talking about universe with stars and galaxies hundreds of billions of stars and hundreds of billions of galaxies You think you need more than 10 pounds of this stuff But it turns out that that's all you need because the repulsive side of gravity so powerful that it actually injects energy from gravity itself Into the expanding space so from that point if you all you need is the seed and then gravity takes over and does the rest of the work Okay, Jess So that we now know the seed has to be smaller the second thing that Ryan told me is the seed should come in the form of what he Just like as a black hole the seed is a black hole Wait a second you said that it has to be small but black holes are huge But it turns out that black holes can be they don't have to be big no not at all well Can you get I mean I thought that we reasonably get the black holes because the star collapses so it's a fairly gigantic beginning And therefore it's a fairly gigantic thing Could you get a black hole the size of a wine cup or a thimble or less? Oh, yeah, absolutely You give me any object and if I squeeze it sufficiently small then according to the classical laws of general relativity If you make it small enough it will be a tiny black hole now Great, can you make a great little black hole?
Absolutely? Can you make a raspberry? Can you make a blueberry little black hole? Seriously, there's nothing that you give me that I couldn't turn into a black hole by squeezing it sufficiently small Would there be any example of a naturally occurring small black hole?
Sure, there are processes where particles can slam into each other at very high energies and the calculations show that if they slam together It's officially high energies in the right geometrical configuration They can create a tiny black hole and this is not just hypothetical. There's a new machine to Geneva Switzerland right now Called the large Hadron Collider and one of the things that may happen at the large Hadron Collider is the creation of microscopic black holes in the collision between Proton's and Proton's these will be tiny black holes, but black holes nonetheless Wow, this is getting kind of interesting. So, okay, you've got a black hole a tiny one and you've reached some I'll have to impregnate with this anti-gravity force What other ingredients do we need? Now we need a trigger something to turn the expansive force on so it'll go What's the trigger?
Well, the trigger is a very very very complex frankly I only kind of 80% got the trigger and I don't want to bore you with it But it's something about a compass with only one needle or something like that But anyway, what's your bit to don't ask? What's your got the trigger? Would you add to the a little black hole and now you got the expansive force lying that you pull the trigger and you will get a Universe of your own right there in your kitchen, but does not worry. I mean wouldn't that blow up everything?
It just seems that if you create one you would be you would be in danger People have studied that issue in great detail and found that at least according to the proposals that are on the table for How in principle you might create a universe that wouldn't be a worry that wouldn't happen instead this universe that you create would in Essence create its own space it wouldn't encroach on your space by expanding into your domain into your house into your region Instead it would expand like our universe does but it would expand by creating new space space it hadn't existed before So it would be off on its own if you will creating a new bubble a new bubble universe that would be a universe in its own right So what do we see from our side? Well, we see probably I'm not sure because Brian is with me during this Particularly I think I would say what you always see is our little black hole on our side and something something We you know going on very large on the other side and staying little on our side But getting bigger on the other side and can we jump through it? Well, that's the interesting thing you know you need to jump in to be able to see what's going on on the other side So if you were if you could make one of these you might be able to inspect it You'd be at a certain cost you could you couldn't come back. Oh you couldn't pass through but What you're creating on the other side is there and in principle you could go there so If you could make your own universe You would never ever ever be able to come back to visit anyone or anything you ever have known Could you ever imagine having made a creation on this scale?
Could you ever imagine visiting it forever never going back home never well no radio app? You know how many people would be sad so Small sliver of humanity if you could actually do this beyond theory, I mean I have to say I think I might have a little trouble resisting this possibility Just because it's so curious this idea that through your Volitional act in your kitchen sink you are creating a universe that would give rise patat perhaps the things like we've seen the world around Really you can think of our universe potentially as being the outcome of the hypothetical processes that we're talking about Our universe speaking of which we should say our universe or our corner of it is funded by the Sloan Foundation of Corporation of Public Broadcasting and the National Science Foundation and also Thank you to Brian Green who is professor of let's see physics and mathematics at Columbia University in New York It also the author of the elegant universe and the fabric of the cosmos one day He may create himself a little bit of cosmos. Is this possible to you? It's very tough to say I do consider this speculation on speculation So I think I would stress that the reason for thinking about this is not so much to do it But it's more to push the laws of physics to their breaking point because that's often where we learn new things about how the world works Until next time yes two weeks.
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