Daniel and Jorge Explain the UniverseListener Questions: Black Holes, Dark Entropy and a Radio Free Zone!
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Hey everyone, it's Daniel and Jorge and we are excited to make a very special and dnouncement about a new project we've been working on kind of in secret for the last year.
Or so is this related to your new wardrobe, Daniel.
Nope, my wardrobe is unfortunately frozen in time as physics professor casual. But that's a great question and a great lead into our new project, which is all about questions.
Actually, that's right, Daniel and I have written a new book. It's very exciting. It's called Frequently Ask Questions about the Universe, another humble title for our work.
And it's inspired by all the questions that you folks have been asking us, all the questions you wonder about the nature of the universe and how it works, and all the questions that science is working on.
So we took some of your most awesome questions that you've sent to us and we put them in book form and actually answered.
Them as best as we can. There are questions like where does the universe come from? And why can't we teleport? Or can we?
And have aliens visited us? And why is it exactly that we can't make it out there into the cosmos.
So the book is coming out this NOE second, twenty twenty one, but it's available right now for pre order, so go to Universe faq dot com and order your copy today.
So stop what you're doing right now. Go to Universe faq dot com and pre order our new book. Frequently asked questions about the universe.
It's filled with science, silly jokes, and Jorgees awesome cartoons, and maybe even a few answers, hopefully. I mean it's it's in the title. The title just says questions.
Oh nice, Hey, Corey, did you know what? What?
What's going on?
Daniel? We have to be quiet?
Why what's happening?
It's noise pollution.
If our podcast has been broadcast near a radio telescope, we might be ruining their data.
Oh no, what if we're making a dumb banana joke right when an alien message arrives? Yeah?
Or what if the scientists think our jokes are so bad? We must be aliens?
Humor is so difficult to translate and we should just be quiet.
Hi.
I am Horhead made cartoonist and the creator of PhD comics.
Hi. I'm Daniel. I'm a particle physicist. But I will definitely laugh at all the aliens bad jokes when they come here.
Really, what if it offends them for you to laugh at their jokes? But you know it's quick be a totally different culture.
Daniel, it's a relaxed smiling and nodding. Could be something totally different in other culture.
You are like doing the okay sign with your fingers. Could this an insult in some cultures.
I'm probably not the right person then to send to talk to the Aliens the first time.
Or to sit in on their comedy shows. But welcome to our podcast. Daniel and Jorge Explain the Universe, a production of iHeartRadio in which we make.
Light and laugh at all of the crazy the mysteries of the universe, everything that we know about the universe, the bonkers, crazy ideas that we have learned about this beautiful, strange universe we find ourselves in, and everything that we don't know about the universe, the very edge of science, the things that scientists are thinking about, the questions that they are pondering, and the questions that you are thinking about every single day as you live in this universe.
Yeah, because it is a pretty big cosmos. There's a lot out there too, perplexes and there's a lot for us to ponder about how things work and why things are the way they are, And so it's natural for everyone to have questions about what's going on?
That's right. You are here to have the universe explain to you because you are curious about the universe. You want to understand it. You want to somehow take the entire universe and fold it up into a little idea that fits in your neurons. Amazing as it sounds, that might actually be possible. But along the way sometimes two ideas don't quite fit, or you wonder does this connect with that? Or this doesn't really make sense to me, even though I've heard the words. And that's what we're here for, to explain all of it to you.
Yeah, because it all starts with questions, right, Daniel, Yeah, science, would you say, starts with a question like what's going on there? Or how can I get more things to eat? Or what should I eat without dying?
Yeah, science is nothing but questions. It's just people asking questions. I was giving a talk to some students from Puerto Rico last weekend and one of them asked me how do scientists figure out what question to ask next? And I thought that was an amazing question, and I told them that it's just people asking questions about the universe. Scientists are just people with questions that they want to know the answers to so badly that they decided to spend their lives trying to figure it out.
I see, you just turn it around and ask them a question giving an answer. Is that what science is? Daniel's all questions, no answers.
It's mostly questions leading to other questions. But the questions are personal. I want to know what the universe is made out. If somebody else wants to know we can make some special kind of superconducting do and somebody else wants to figure out how life started. All of these questions are being pursued by people who decided this is the most important question, This is the thing I want to know most about the universe. So science is about questions, but those questions are also very personal.
Yeah, and it's not just scientists that have questions. Regular people have questions too.
Yeah, Or you could say regular people are also scientists because they have questions. Right, we're all doing science, we're all asking questions. We're all trying to understand this crazy cosmos.
That's why we're all in this together. And so people have questions and sometimes they write to us with their questions hoping that we would maybe answer it in an email or a tweet, or maybe in one of our podcast episodes.
Yeah, they do it all the time. We get dozens of questions every single day. If you have a question about something you heard about that you don't quite understand, or you'd like us to explain to you, please don't be shy right to us. We love your emails questions at Danielandhorge dot com.
Daniel, you actually answer most or if not all, of the questions you get.
I answer every single question I get, usually within just a few minutes. Sometimes I get surprised responses from people saying, what, I can't believe you actually wrote me back. But yeah, I'm just sitting here plugging away my research and I love that ding when I get a new email.
Really, and I react so well to my new email things.
You actually listen to those new email things. I was pretty sure you had that turned off.
I don't know if that's a feature on my phone or I'll have to check, but I'm glad you're answering the questions because I think I would just answer with more questions, like, hey, maybe you should ask Daniel this question.
I think maybe they should, or.
I would point to Wikipedia that that's helpful too. But yeah, we get a lot of questions, and sometimes we do episodes where we answer these questions live on the air, or at least live on the podcast.
Yeah. Sometimes people ask a question and I think, I bet other people want to know the answer to this one, so let's talk about it. Or I just think it'll be fun, or it stumped me a little bit. I had to go off and do some research and figure it out, and then I'm excited to talk about it.
M all right. So today on the podcast, we'll be talking about Listener Questions number fifteen.
Fifteen.
Wow, I can't believe we've done fifteen of these Listener Question episodes. It's been a while.
Yeah, Listener Questions is a teenager now. It's growing up.
Oh no, is it now? And it's rebellious face and refuses to acknowledge us or to clean up the room.
But we secretly know it still wants to hear the answers.
Oh I see, I see. It's it's just a phase.
Yeah, exactly, It's just a thin vernier of attitude.
All right, Well, today we have three great questions from three great listeners and fans out there. We have a question about peanuts, right, black holes, and also radio burbs and quiet zones, which would be great to implement here in my house sometimes. All right, so our first question comes from Beckham from California, who is six years old. Here is this question.
Hi, I am Beckham and I'm six years old from California. H And if you squeeze the earth to the size of a peanut and it turned into a black hole, how far away would you have to be it to not get sucked in? The would it beat the whole earth?
And thank you?
All right? I love black hole questions from six year olds.
All right, do you get excited about all questions about black holes or other questions about black holes where you're.
Like, ooh, those are the best questions about black holes. When somebody asked me something I hadn't thought about before, and it makes me think about black holes in a new way, or go open up that General Relativity book again or something that's the fun moment.
M all right, well, what do you think back on what's thinking about? Yes, if you squeeze the earth into a peanut and it became a black hole, how far away would you have to be to not get sucked in?
Hmm wow.
Yeah, I think he's trying to make black holes sort of concrete. Instead of thinking about black holes as something weird and far away, you're thinking, you know, could we turn the Earth into a black hole? And what that be? Like?
Hmmm, I see, because I guess you can make a black hole out of anything, right, It's not like something exotic out there in space. You can literally make a black hole out of peanuts or by turning the dirt into a peanut.
Yeah, it's just a bunch of mass and energy capactified in a small enough space that the curvature gets so intense that light can't escape it. That's really all a black hole is. And you're right, you can make it out of any kind of matter or energy. You could even make it out of photons. We talked about it once on the podcast that if you have really big laser beams and you cross them in theory, you can make a black hole where they intersect.
Right, Because it's not about how much mass or the size of something or how heavy it is. It's really about the density. Like, if you have enough stuff in a small enough space, it becomes a black hole. And that could be something really small or it could be you know, the size of ginormous like a super massive black hole.
Yeah, exactly. And we think that you can make a black hole out of basically anything if you make it dense enough. There might be a minimum size to a black hole as things get down to like the on some level, it's not clear off you we can make a black hole out of like an electron size amount of mass, but you definitely can make a black hole out of like an Earth size mass or a Sun size mass. Now, most of the black holes we see out there in the universe come from stars, and so they're like ten to eighty times the mass of the Sun, or they're at the center of galaxies and then they're like thousands, millions billions times the mass of the Sun. So we don't see very many black holes out there that are like the mass of the Earth. In fact, we've never seen one at all. That doesn't mean they're not out there. They could have been made in the very early universe, these primordial black holes that could be very very small up to very very large sizes.
Right, because I guess black holes that size don't get naturally made, right, Like, there's no natural common process for them. To make an Earth sized black hole, like most of the ways are. You know, stars going supernova is how they're made.
Yeah, gravity is a runaway process and once it gets going, then it compactifies itself more, and then it gets more powerful, and it compactifies itself more and gets more power. The Earth, for example, is not going to collapse into a black hole. It doesn't have enough stuff in it to start that gravitational runaway process. So like the bonds between the stuff in the Earth is more powerful than the force of gravity. So you know, the structure of the rock and all that stuff is holding itself, so the Earth will not collapse into a black hole.
All right. So then if you took all of the mass of the Earth and then you squeezed it all into the size of a peanut, then you would get a black hole. That's what Beckham is asking.
Yeah, and you would take some external force, right, you have to crush and compact all that mass. But yes, in principle, you could get a black hole just from the stuff of the Earth, and you'd have to really squeeze it down. If you wanted the Earth to be a black hole, you'd have to take the mass of the Earth all that stuff and squeeze it down to something less than a centimeter wide.
Wow, so including all the peanuts on Earth, Like, can you fit all the peanuts on Earth into a peanut?
You can? And in fact, because a peanut is about the right size, you know, it's about one centimeter or maybe we should have a new unit called the peanut.
The pea valley for the peanut is one centimeter apparently.
Yeah, just about. So, Yeah, you can fit all the peanuts on Earth, and all the menannas on Earth, and all the rocks, and all the gold and all the uranium and all the helium and all that stuff down in a really compact space. Remember that the space between things, the volume of things, depends on the forces between them. Like the reason that a rock has the size it has, it's not because of the pile of stuff it's made out of, but because the forces between those particles sort of pressing against each other, fluffing it up. It's really like a pile of the bubbles, where those bubbles are made by the electrostatic forces repelling each other. If you can overcome that, then you can squeeze it down to whatever you like and eventually get a black hole, right.
So that could happen to the Earth if somebody came in and squeeze it all into a black hole. But then I guess Beckham's question is whether or not we would get automatically sucked in, or like, are we doomed if the Earth suddenly became a black hole? Or do we have a chance of getting away? The question is how away would you have to be to not get sucked in?
Well, I consider myself to be part of the Earth and so and I'm usually on the Earth. So if somebody comes along and compactifies the Earth into a black hole, then I'm inside the black hole already. But you know, if you happen to be on a trip to the space station when the Earth turns into a black hole, then I guess you can ask the question like, can you be around it safely? Nearby? I mean, let's make this realistic, right.
Right, Yeah, let's pretend that you're part of this earth, Daniel. Let's stove into that fantasy.
And you hear it in the question, this idea that black holes suck stuff in. And it's true that black holes have strong gravity, but they're not like vacuum cleaners. You know, they just pull on stuff the way everything else with gravity pulls on stuff. The Earth pulls on you right now, and that doesn't change just because it's turned into a black hole. So, for example, if you're standing on the surface of the Earth, you feel it's gravity. If then underneath you the whole Earth turns into a peanut sized black hole, that doesn't change the force of gravity you feel because it's the same amount of mass pulling on you with the same gravity.
Right like, nothing would change basically except that you would maybe just loose the ground under you.
You would lose the ground under you. And so now, if you want to avoid falling into the black hole, I prefer the phrase falling in rather than getting sucked in, because it tells us about the gravity that's happening there. You need to go into orbit around the black hole. The reason you don't fall to the center of the Earth now is because the Earth is holding you up. If that's not the case, then you need some other way to avoid falling into the center of this new black hole, and that would be to go into orbit. Basically, you need to be moving fast enough that you keep missing the Earth as you fall. That's what an orbit is.
I see, so we would feel the same gravitational force, which means we would fall into the peanut sized black hole if the Earth certainly turn into a black hole. And so it's not a matter of distance because I guess technically you would feel the force from this black hole anywhere in the universe. Right.
Technically speaking, you do feel it anywhere in the universe because gravity is infinite in extent. I mean, it falls off like one over distance squared, so it drops off pretty quickly. But yeah, in principle, we feel gravity from Andromeda. That's why that neighboring galaxy is coming towards us and we're shooting towards it. We feel gravity from things that are infinitely far away, that's true, but the value of that is pretty small. And so as you get closer to something, it's gravity gets much much stronger because it increases like one over are squared.
Right, So like technically we are getting pulled into all the black holes in the universe right now, Like every black hole in the universe, for which they might be an infinite amount or trillions, we're getting sucked into them as we speak, right.
Yeah, they are tugging on us. But they're being defeated by the gravity of the Earth, of course, and the Earth being pretty massive and pretty close is overpowering it. Think for example, about the Sun. The Sun is so much more massive than the Earth. Why is it that you don't fall into the Sun right now? Because the Earth, even though it's much much smaller mass, is much closer to you. So it's winning the gravitational time of war and keeping you on the surface.
Right But technically we are me and the Earth. We are still falling into the Sun. It's just like, as you say, we're in orbit, we have some kind of velocity in a different direction than the direction of the Sun, and so that's why really we're not falling into the Sun exactly.
We have just the right velocity in just the right direction to be in a stable orbit around the Sun. So you can avoid falling into something if you orbit around it. And in fact, a lot of stuff orbits around black holes. If you think about like the picture you have in your mind of a black hole, it's this black sphere, but it's surrounded by a disk of swirling stuff, and you might wonder, well, why is that stuff there? Why isn't it just immediately falling into the black hole. And the answer is that it's spinning. It has rotational velocity, and that helps it avoid falling in immediately. So you can stay in orbit around a black hole for quite a while until you lose that velocity by bouncing off of other stuff, and then you fall into it.
Right, So I guess technically, if the Earth turned into a black hole, mmm, you would get sucked in even as you're standing there now. Well. But also maybe if you're relatively far away, like at the distance of the Moon or something, you would fall in unless you can get into an orbit.
Yeah, that's right. If you were on the Moon, for example, you'd already be in the Moon's orbit, and so you just stay on the Moon and the Moon would keep orbiting around the black hole. If you're on the surface of the Earth, however, you're probably not moving fast enough to stay in orbit.
I see. So the trick to avoiding falling into the black peanut hole is to start running really.
Fast, yeah, exactly, or get out of spaceship. And how fast you have to go to be in orbit depends on how far away you are from the black hole. The closer you are, the faster you have to be moving, and the further way you are, the slower you can move and be in a stable orbit.
All right, So then I guess the answer to the question is really that it's not about being far away. It's about having some sort of speed that lets you be in an orbit around the black hole.
Yeah, precisely. And if you were, for example, at one hundred kilometers away from the black hole, which is pretty close, you'd have to go like sixty thousand meters per second to avoid falling in. And if you were at one kilometer it'd be ten times that speed. And if you were just like one meter away from this peanut sized black hole, you'd have to go like twenty million meters per second.
Wow, which is a you be toasted, right, because you can hankle around that fast around something that small, can you?
Certainly you could. You could be a meter away, you could be whipping around really really fast. It'd be hard to accelerate to that speed without like crushing your internal organs. But you know, even that speed, though it sounds fast, is a pretty small fraction of the speed of light. So in principle you could actually go that fast.
Right.
What about here on the surface of the Earth. How fast would you need to be going, Like, if I'm in the highway going at you know, seventy miles per hour, Am I safe if the Earth suddenly turned into a black hole?
Yeah? So if you're at the surface of the Earth, which is six million meters from the center of the Earth, then you need a velocity of about seventy nine hundred meters per second to avoid falling into the surface of the Earth.
All right, that sounds not in the millions. How does that translate into miles per hour?
That's like seventeen thousand miles per hour, So it's definitely faster than you're moving right now. If you're just standing still on the surface of the Earth, then you know the Earth goes around one time per day obviously, then you're moving at like four hundred and sixty meters per second, so you're moving a lot slower than you would have to be if you wanted to avoid falling into a black hole at the center of the Earth.
Okay, so then the answer then would be it would all fall in, as you like to say, unless you just happened to be breaking some sort of crazy speed record on land.
Yeah, or you had access to some really powerful rocket or spaceship or something.
Oh, I see, you could activate it as soon as you hear news that the Earth turned into a black hole. You could activate your jet pack and then fly away.
If I had a jetpack and I saw the Earth sort of crumbling beneath me into a black hole, then yeah, I would turn that thing off. That's why you have it.
Oh, I see, I would have given it to my kids first, But you know that's just me. No, I'm just kidding.
First, put the mask on yourself. Then help the child nest uf. Isn't that what they say?
All right? Well back, and fortunately I don't think you have to worry about that, right. I don't think the Earth is in danger of turning into a black hole anytime.
Soon, unless Beckham has some evil plans to grow up and compactify the Earth into a black hole, and we've just aided them.
Well, why they need to grow up? They could be a child genius evil genius. Well here's ho hoping you're not Beckham. But thanks for asking the question. All right, Well, let's get into our two other questions for today, one about entropy and time and the other one about radioburse. But first, let's take a quick break.
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Or right. We're answering listener questions today on the podcast, and our next question comes from Dave, who is from Germany. Here's day's question.
What I would like to know is In one of your podcasts, Daniel explained that when space is generated, each increment of space is containing its own newly generated increment of energy, and I understand that energy when it's existing, that it can be converted. Now, normally, when energy is converted, as to my understanding, there's also entropy generated. I wonder what happens with this entropy. Far as I know, entropy and time are the only two physical components which move forward in time, or rather are generated and only in one direction. So are there any connections between entropy and time? And if there's a connection between entropy and time, what a time freeze when there's no more entropy to be generated in our universe?
All right, Thank you, Dave from Germany. It's kind of a complicated question here. I think he's asking whether, you know, I think we've talked about how energy is generated when new space is created in the universe, and so there's maybe some entropy associated with that energy. And so what's going to happen, you know, at the end of time, when maybe the universe is not expanding or we run out of entropy. What do you think he's asking?
I think he's got a lot of fun questions. I do think he had more questions sort of generated in his mind as he was asking his initial question, And I think that makes sense because a lot of these things are connected. I think the heart of the question is probably about how the expansion of space is connected to the end of the universe, you know, like, is the expansion of space dooming us to a certain eventual fate of the universe m.
And I guess specifically he was asking, like, when the universe expands, is entropy increasing as well?
Yeah, that's a really cool question because you know, we've talked about how the expansion of space breaks something else which we always thought was fundamental and ironclad rule of the universe that energy is conserved. And you know, energy is conserved but only when space is static. Remember that a lot of these conservation laws come from symmetries that come from assumptions that we can make about the universe, and one of them is that space is static, and so energy is only conserved when that holds, and if the universe is expanding, that doesn't hold anymore. So it makes sense to also ask, like what else gets broken when space expands, when the universe is creating more space.
So is entropy being created with new space in the universe?
I wouldn't say created, right. Entropy is not something that like you create. It's not a physical thing. It's like a calculation that we can do to evaluate a situation, say what is the entropy of this? You know, you can like run the numbers and say what's the entropy of this situation versus that situation? I don't think of entropy as like a physical thing that's actually made. But you can ask the question when space expands, when new space is being created, does entropy go up or down?
I see, is it being created or not? I'm just kidding. I guess so is entropy increasing when space increases as well? That's the question.
Yeah, and it makes absolute sense, and I think the answer has to be yes, and not just because of the second law of thermodynamics that says that you know, entropy always goes up, but because of the nature of entropy, right. Entropy is a really slippery concept, and I think a lot of people think of entropy as like the amount of disorder or a disorganization sort of in the universe, the amount of stuff is sort of mixed up.
It's a messy topic.
And that's a helpful way to think about it, sort of approximately. But what entropy actually is is sort of a measurement of our ignorance about what's going on at the smallest level. To calculate entropy, you have to make like a statement about something macroscopically, like it's temperature or its volume or something you know macroscopically that we can see and measure and then compare that to what we know about it microscopically. So entropy is related to the number of different ways you can make microscopic arrangements that are consistent with your macroscopic statements than about things like temperature. So it's like a measure of like how much we don't know about the microscopic states.
Right, It's almost like, you know, the messier things are, the more different ways that the messiness can be. But if you want something really neat and ordered, you only have so many options.
Yeah, It's like if you have a bunch of coins and I tell you all the coins are heads, Well, then I've told you exactly how every coin has to be. They all have to be heads. It's only one way for that to happen.
Right, that's low interpy.
Right, Yeah, that's low entropy exactly. But if then I tell you, well, half the coins are heads, then now you have a lot of different ways to arrange all those coins. As long as half of them are heads, you're free to decide for this coin and for that coin, whether it's heads or tails. So there's a lot of ways to arrange the coins to satisfy my sort of macroscopic statement that half of them are heads, and so that means it's high entropy because there's a lot of configurations, and the second law of thermodynamics is nothing more than that. It's just saying things that have high entropy are more likely to happen because there are more ways for it to happen.
And usually that happens with time, right.
And usually that happens with time, Like.
The more time passes, the more the things that are likely are likely to happen.
Yeah, exactly. It's a foundational idea in quantum mechanics that every possible state microscopically is equivalently likely. But if more of those states represent the same thing macroscopically, like they're close to a fifty to fifty split heads and tails, then they're more likely to happen because they're just more of those possible outcome comes. It's like if you roll a huge handful of dying, you add up all the numbers, you're much more likely to get something near the middle of the possible outcomes than the very maximum value or the very minimum value, just because there's more ways to get that outcome, and there's only one way to get the maximum and one way to get the minimum. So it's really just a statement of probability.
So then does that mean that as you get more space in the universe, there's kind of more ways for things to be arranged, and therefore entropy it just naturally increases.
Yep, that's exactly what happens. The more ways you have for things to be arranged under the hood, the more entropy you have, and the more space means more micro states, more micro states means more entropy. Mmm.
I see all right, So then is that what is causing enterping the universe to increase or is it just helping entropy increase in the universe.
Entropy would be increasing even without dark energy. If space was not expanding, then entropy would be increasing anyway, just because that's where the second Laft or reinemic says that if you start from a low entropy configuration unlikely arrangement of your micro states, you're going to end up in a more likely arrangement as time goes on. So even if space was not increasing because there was no expansion, entropy would still be gradually going up. But as you say, it's helped by the fact that space is expanding, and so there's more stuff to get mixed up, and so entropy is increasing that way as well.
I see, so entropy is accelerating in the universe because of dark energy, which is the expansion of the universe.
Mm hmmmm. And he asked another sort of fun question there because he was talking about energy conversion. You know, every time you turn one kind of energy into another kind of energy, it's never perfectly efficient. A little bit leaks out as heat, and that also is an increase in entropy. But it's really the same thing because heat spreading out is really just like more micro states sharing in the wealth of the energy, and it's spreading out. It's more likely for energy to be spread out than for it to be compact. But he's talking about how when you convert one kind of energy into another, entropy goes up, and he's wondering about, like the actual process of creation of space itself, does that like leak heat out into the universe.
What I guess, if you're creating space, you're creating energy, and if you're creating energy, you're heating things up.
Yeah, it's a really fun question. I've never really thought about that before the problem is that we don't have any idea for what that process is. Like, we know that the expansion of the universe is accelerating, and that means space is being stretched and created, but we don't really know what the mechanism is for that to happen. We don't have an explanation for that. Some people think it might come from negative pressure from quantum zero point energy and all the fields that are in space, but if you do the calculation, that doesn't actually work. It doesn't explain what we see. So we observe that space is being created, but we don't know what's doing it. So we have no concept for this mechanism. We don't know if it actually involves an energy conversion from some other so of external energy we haven't been aware of, or if it's actual creation of energy itself. Hmm, I see, So we're too clueless to really answer that question. Sorry, Dave.
Well, if there's entropy being generated by dark energy, can I call it dark entropy?
You can call it whatever you like.
I think I'm going to reserve that for my new sci fi novel, Dark Entropy.
That is a cool title, actually mysterious and chaotic.
Yeah, there you go, all right, And then there was a sort of an appended question at the end here about whether you know at the end of time or at the universe keeps expanding and expanding and entropy keeps increasing, does that mean that time is going to end or freeze?
Yeah, everybody wants to know the answer to that question, Dave, and unfortunately nobody does. Right. We just don't know what the future of dark energy is. Will it continue to pull stuff apart and write everything out and increase the entropy of the universe till an eventual heat death. We just don't know, because again we don't know what the mechan and we don't know if it will continue. Remember that dark energy has not been persistent in our universe. While we think the cosmological constant might be constant because it's called the cosmological constant, dark energy itself only took over around five billion years ago to create this accelerated expansion, so we don't know why it turned on around. Then, we don't know if it's going to keep going, if it's going to stop, if it's going to turn around and shrink the universe back down to some other crazy dense state. So we just really don't know. We can't predict because we don't understand this mechanism at all.
All right, So then I guess the question is stay tuned and or we have no idea.
Sorry, Dave, we have no idea, stay tuned. We may still have no idea in a billion years.
This is going to be messy either way. All right, Well, thank you Dave. That answers that question. And so let's get into our last question of the episode from Robin, and it's about radioburse. But first, let's take another quick break.
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All right. We're answering listener questions today on the podcast, and our last question comes from Robin from Oregon, and she has a question about the National Radio Quiet Zone.
Hello, Daniel and Jorge, this is Robin Marx in cobrag Gorgon. I just got done listening to your show about fast radio bursts and it got me thinking about the National Radio Quiet Zone. In Green Bank, West Virginia, where basically nothing electronic is allowed. No microwaves, no sel phone, no Wi Fi. I thought it would make a great episode on your podcast.
What do you think?
All right, thank you, Robin. That sounds like a great place to visit for a vacation. No cell phones, no electronics. I mean, you probably go a little crazy the first couple of days, but maybe you would reach some sort of zen state afterwards.
Yeah. It's an amazing sort of spot in the country where they've really tried to keep things quiet so that astronomers can listen to the skies and not be crowded out by all the crazy radio signals that humans generate.
So this is an actual place in the United States, in West Virginia.
This is an actual place in West Virginia. The most powerful radio telescope in our hemisphere and the largest steerable radio telescope is now the Green Bank Observatory in West Virginia, exactly. And you know, this thing is listening to the sky, and it's listening to the sky not in terms of sound, of course, but in terms of a special frequency of light we call radio waves. And if you want to listen to the sky. You have to make sure you're not drowned out by basically light pollution from other sources of radio emissions.
And I guess all of our cell phones, most of our electronics, they use these radio frequencies.
They do, they use these radio frequencies. We're constantly beaming radio waves around the world for radio right If you're listening to us on the radio right now, then we have been transmitted to you using this kind of electromagnetic radiation whose frequency puts it in the radio band. And not just our cell phones and not just our radio towers, but a lot of our electronics accidentally sort of incidentally generate radio noise.
Well, this is interesting. How big is this National Radio Cuisment? Is it like a federal thing or how do people all agree in a larger space to not use their cell phones?
It is a federal thing. It was created in nineteen fifty eight. It's this big rectangle of land. It's about one hundred miles on a side, and so it's really pretty spacious. And it surrounds this Green Bank Observatory in West Virginia.
Cool.
And you said it was created in nineteen fifty eight. Did we have radios? I guess we had radios and TV but no cell phones back then.
No cell phones. But these days also they try to restrict Wi Fi usage that also operates in the similar frequencies.
All right, forget it. I mean I can go on a vacation with those cell phones, but Wi Fi.
Yeah, So they try to be as quiet as possible, and they actually drive around with this truck listening for radio signals, trying to catch people like emitting in their radio what and yeah, they do. They drive this patrol truck around listening for emitters because some people just aren't aware. Like if you have an old microwave oven that's poorly shielded, it can generate a lot of radio noise.
I see. But then if they find somebody, how do they radio it in to come take them away. They can't.
They can't. They just politely knock on the door and ask those folks to stop using it. It's not heavily enforced, like you can get a fifty dollars fine for emitting you in the quiet zone. But they mostly just try to work with people and help them understand the importance of radio astronomy and what they're trying to do.
That would be an expensive phone call if it costs you fifty bucks.
And this is a real concern. This this hilarious story from Australia where they also have a big radio telescope where they saw these weird signals and you know, they're listening for messages from outer space and they saw this bizarre signal they couldn't understand until they finally tracked it down after more than a decade to be the microwave in the breakroom where the grad students hang out.
What they couldn't figure out why this signal always lasted the same amount as a popcorn sitting on the microwave.
Yeah, basically grad students eating frozen burritos created a false signal of extraterrestrials.
I guess these telescopes are pretty sensitive, right, Like you're trying to detect really weak signals from space.
Exactly, we are trying to listen to really quiet signals. Remember, the power of a signal falls very quickly with the distance. You know, if you shout from the top of a mountain, then people can hear you if they're close by, but as they get further and further away, it's harder and harder to hear that shout it falls with the distance squared, and so the message, for example, from an alien civilization could come with a very small amount of energy by the time it gets here.
M I see.
It's like I think you were telling me once, it's like the energy of a falling snowflake.
Yes, it's a very very gentle ripple in the electromagnetic fields. And that's why this dish is huge. This thing is as tall as the Washington Monument. It's got two acres of area on the dish.
What.
Yeah, Also, it's kind of beautiful. You should check out a Google image of this thing.
Is it bigger than like the Arasibo?
It's not bigger, unfortunately, but it is steerable, right. Aricibo is sort of built into the ground. This thing is above ground, but they can turn it so they can point it in various directions and that helps them understand like the location or the source of a signal.
WHOA, I guess One question is why aren't there more of these radio quiet zones? Like you know, I've been to Hawaiian the tusc find me for using my cell phone up there.
Well, they don't have radio telescopes in a way. Most of those are optical telescopes. So this is a special kind of telescope that's listening for radio, and so it's mostly sensitive to radio noise, and radio telescopes aren't as common as optical telescopes. It's a sort of special branch of astronomy, I see, and it's a really exciting one. I mean, there's lots of really interesting things you can learn about the universe just by listening to the sky in the radio.
You know.
This is how we discovered, for example, that the center of our galaxy had a black hole because people heard this weird signal from the center of the galaxy and they thought, what's that? What could be there making this weird pulse?
Wow?
Then we pointed one of these telescopes to the center of the galaxy.
Yeah, that's how we figured it out. Radio astronomy, the whole field was sort of invented accidentally. There's an engineer at Bell Labs who was asked to figure out, like, could we beam signals using radio waves across the Atlantic? How much interference is there? So he just built a huge radio antenna to sort of listen for the amount of noise. He was more worried about thunderstorms. But then he heard this weird signal and he discovered, hold on a second, this isn't even coming from Earth. It's coming from somewhere else. And that's when radio astronomy was born. We realized that the stars were sending us information in another frequency and nobody had been listening.
Interesting, I guess that the universe is sending us signals in all frequencies.
Really, that's why we listened. In the radio and the X ray and the optical, we look at gamma rays, we look at every sort of kind of frequency, because different parts of the universe glow at different frequencies of light. Right. The hotter you are, the higher your temperature, and the more energetic, the higher the frequency you emit of your radiation. So radio waves come from sort of cooler, quieter stuff. But it's also very powerful. It's very good at seeing dark stuff that you can't otherwise see, like huge clouds of gas and dust that aren't glowing in the visible light.
Right, And sometimes when you see those photos of like giant space nebula or giant clusters of stuff out there in space, and you see as all these colors, that's really what it is, right, like they sort of manipulate the signals from all these different frequencies and they assign colors to them.
Yeah, a lot of times they do a color map. Right. They take things which are invisible to your eyes. Right, you can't see radio waves even when they hit your eyeballs, you can't see them, and then they shift their frequency so that you can see it. They map it into the visible spectrum.
All right. So then this National Radio Aquiretsment can anyone go visit? Is it open to the public or do you have to like sign in or get permission. No.
It's a huge area of land, so it includes like cities. People live there, Like people's homes are in this area. It's not a closed off region. People live there. But there's no radio signals. Right, there's no radio stations, you can't use cell phones, you're not supposed to have Wi Fi.
There's like whole towns with no cell phone or Wi Fi signals.
Yeah, there's like a whole mountain resort there that has like you know, landlines and phone booths and all sorts of quaint stuff. Wait, what's a phone booth? It's this thing I see on Doctor Who I don't really know what Superman. And some people like to live there, like some folks feel hyper sensitive to electromagnetic radiation, you know, they don't like to live near sources of it. And so if you're that kind of person, then this is made for you. Or if you're a radio astronomer.
Wow, I wonder if people are happier there, do you know what I mean? Like, I feel like maybe my life was a little happier before this sort of constant source of noise in my pocket.
All those email beings that you don't pay attention.
To, all these things that you know I have to ignore.
I don't know. And it's a great place to do radio astronomy, but it might also be a good place to do a psychology study of the effects of modern communication. I'm sure somebody's looked into that. Interesting.
Unfortunately, most of the people who live there are physicists. So you know that diracs the happiness question down.
It definitely skews the sample for sure.
Wouldn't be a scientific study. All right, Well, thank you Robin for that question. It was a fun topic to explore. I had had no idea about this National Radio Quiet Zone and was Virginia.
That's right, So if you are driving through it, please don't blast your stereo or turn on your Wi Fi or open up your phone, because those astronomers want to hear the message from the aliens when it comes and not your silly emails.
Yeah, all right, well those are our three questions for today. And once again, it's amazing, first of all that people are listening to this podcast. Thank you so much for being there for us. And it's amazing the range of questions we get from people from all over the world.
That's right, and remember that science is just people asking their personal questions about the universe. So keep asking your questions. Think to yourself, if I could get the answer to one question about the universe, what would be my one question. And if you know what that question is and you don't know the answer, hey right to us. Maybe we can help you figure it out.
May we'll ask a questions right back at you, avoid answering it like we did some questions today.
And then we'll run away to the radio free zone and avoid your email.
Sounds like a good deal, all right, Well, thank you for joining us. Hope you enjoyed that. See you next time.
Thanks for listening, and remember that Daniel and Jorge Explain the Universe is a production of iHeartRadio. For more podcasts from iHeartRadio, visit the iHeartRadio app, Apple Podcasts, or wherever you listen to your favorite shows. When you pop a piece of cheese into your mouth, you're probably not thinking about the environmental impact. But the people in the dairy industry are. That's why they're working hard every day to find new ways to reduce waste, conserve natural resources, and drive down greenhouse gas emissions. House US dairy tackling greenhouse gases. Many farms use anaerobic digestors to turn the methane from manure into renewable energy that can power farms, towns, and electric cars. Visit us dairy dot COM's Last Sustainability to learn more.
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California from the California Office of Traffic Safety and Caltrans Hey, their.
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