Daniel and Kelly’s Extraordinary Universe - Listener Questions 4

Episode Date: June 18, 2019

Daniel and Jorge answer questions from listeners, like you! Learn more about your ad-choices at https://www.iheartpodcastnetwork.comSee omnystudio.com/listener for privacy information.

This is an I-Heart podcast. I was diagnosed with cancer on Friday and cancer-free the next Friday. No chemo, no radiation, none of that. On a recent episode of Culture Raises Us podcast, I sat down with Warren Campbell, Grammy-winning producer, pastor, and music executive to talk about the beats, the business, and the legacy behind some of the biggest names in gospel, R&B, and hip-hop. Professionally, I started at Deadwell Records. From Mary Mary to Jennifer Hudson, we get into the soul of the music and the purpose that

drives it. Listen to Culture raises us on the IHeart Radio app, Apple Podcasts, or wherever you get your podcasts. Why are TSA rules so confusing? You got a hood of you. I'll take it all! I'm Manny. I'm Noah. This is Devin. And we're best friends and journalists with a new podcast called No Such Thing,

where we get to the bottom of questions like that. Why are you screaming at me? I can't expect what to do. Now, if the rule was the same, go off on me. I deserve it. You know, lock him up. Listen to No Such Thing on the IHeart Radio app, Apple Podcasts, or wherever you get your podcasts. No such thing. Betrayal Weekly is back for season two with brand new stories.

The detective comes driving up fast and just like screeches right in the parking lot. I swear I'm not crazy, but I think he poisoned me. I feel trapped. My breathing changes. I realize, wow, like he is not a mentor. He's pretty much a monster. But these aren't just stories of destruction. They're stories of survival.

I'm going to tell my story, and I'm going to hold my head up. Listen to Betrayal Weekly on the IHeart Radio app, Apple Podcasts, or wherever you get your podcasts. Hey, Daniel, what's been in our inbox lately? Well, we get the usual stuff, people with minor corrections, people with. with cosmic questions, people asking me to send them special stuff for Father's Day. So you said people were asking about Father's Day? Yeah, some people write in, I like this because they're not actually fans of our show, but their dad or their mom is a fan of the show,

and they want us to send a special Father's Day or Mother's Day message to their parent who listens. So it's like young, cool, hip people saying, hey, my dad likes your show, and I have no ideas for any Father's Day's gifts. So do we charge for these, or? We don't charge for these because we're in nice, guys. And we like helping people, and we're also fathers. And so I want to give a special shout out to Paul Truslow, whose daughter Caitlin asked us to give you a special Father's Day message. So happy Father's Day, Paul. And Roll Tide, I'm supposed to say also.

Hi, I'm Jorge. I'm a cartoonist and the creator of Ph.D. Comics. Hi, I'm Daniel Weitzen. I'm a particle physicist by day and a podcaster by any other time. Now, welcome to our podcast. Daniel and Jorge Explain the Universe, a production of I-Hard Radio. In which we really do honestly try to answer questions about physics. Questions that we have, questions that you have, questions that we just randomly float into our minds some days. Yeah, and if you actually send us a question, either at questions, at danielanhorpe.com or any one of our social media channels like instagram or twitter or Facebook we will actually get to your question and maybe even talk about it on the podcast

that's right because when you have a question probably other people have the same question and that's the wonderful thing about having people suggest questions because sometimes there's an angle to something that we haven't thought of because we come out from a scientific perspective and seeing it from the point of view, the audience helps us really explain these things, really get down and untangle all those mysteries that you have in your mind. Because our goal is at the end of this, that you have a crystal clear picture of what's going on in this universe. And if you send us a question that stumps Daniel, you'll actually get a prize, right, Daniel?

Yeah, banana cake. Oh, no, it's a podcast, it has to be audio. So the sound of Jorge eating a banana cake that Daniel made. How about that? Some reader shows give you your phone message. They'll record your voicemail message. We will record one of the hosts eating bananas. What could be better than that?

Yeah, well, hey, that could be a good ringtone, right? That could be a good ringtone. Hey, I got a call coming in. How do you know? It sounds like somebody's eating in your pocket. Yeah, that's right. If you're the kind of person who doesn't like people leaving your voicemails, this is the contest for you.

Right here. That's right. That's right. No, seriously, I would love to get a question that stumps me. I do get questions. A lot of times I get questions. I've never heard before, and that's a wonderful experience because, you know, there's a standard of those questions people ask, but then there's a question I'd never even thought

to ask before, and that's wonderful because it gives me a little view into the mind of the questioner. I have to think, what did they understand or what was going on in their head that inspired this question so that I can then figure out how to guide them from there to a clear picture of what's actually happening, and that's the challenge of teaching, and that's what I really love about it. So these are questions you hadn't even thought anyone could ask or would ask. Yeah, I'll give you an example. I give demonstrations at elementary schools sometimes,

and we use, like, liquid nitrogen and all sorts of stuff to, you know, one time we froze a banana and shattered it on the ground, and the kids thought that was cool. And afterwards, we're open for questions. Wait, wait, wait. You shattered a banana? That's right. Some bananas were harmed in the making of this podcast.

I have to admit. Oh, man. My heart is bleeding, Daniel. But afterwards, we were open for questions, and some kid raises his hand, and he says, if lightsabers were real, would they be made of liquid nitrogen? And I thought, I have no idea how to answer that question. Like, where do you even begin? You rolled your eye.

You're like, obviously, they're made out of khyber crystals. What? Do your research. I had not done my research on fictional universes and how science might work in that fictional universe, but I love that he connected two things he found amazing. Liquid nitrogen and lightsabers and thought maybe these are the same things. And actually, we get a lot of emails like that. They're like, hey, today you guys talked about the mystery of, you know, dark matter.

Maybe that's the same thing as this other mystery. Like after our time episode, a lot of people wrote in and said, maybe dark energy is just mistaken how we observe time and time doesn't just move forward constantly. It's sort of stutter steps and that's dark energy. People love to connect two mysteries and try to solve them at once. So, you know, that little boy in the class, he really exemplified the kinds of questions that listeners ask. We're all just little Star Wars fans inside.

That's right. That's right. Yeah. Well, today we are answering your questions on the podcast. Today's episode is about... Listener questions, part four, right? Or are we up to part pie? Are we sort of... Is this version pie?

I think our podcasts are integer numbered, yeah. So this would be number four. It'd be awesome to have 0.14 of a podcast, but I'm not sure how do you pull that off? All right, so today we have three interesting questions from listeners from all across the world, right? Or at least the United States. I think some of them are international. They don't always tell us where they come from, but based on the accent, I don't think all of these come from the southwest of the United States. Which seems to be a big hotbed for fans over our show.

No, it was just random. Last time I happened to pick three questions, which all, like, came from the South. That was totally just random. But today we have three pretty cool questions from listeners. One is about gravity, another one about dark matter, and the other one is about the nuclear of atom. Like, how do they stay together? And why don't we all just explode into balls of nuclear explosions? Maybe we will. You'll find out on today's episode.

I think people might already know the answer. but teaser, you're okay for the next couple of seconds. You'll survive long enough to hear the end of this episode at the very least. And then you can then explode if you, like, from knowledge. Do you think anybody has ever perished while listening to our episode? That just dark thought just entered my head. Oh, my God. Let's cut that out and not getting to that.

Can you imagine being the last thing anybody ever heard in their life? Oh, wow. Foray, making a joke about bananas. It blew their mind. It just expanded their idea of what a joke could be, and it just overwhelmed their neural network. Yeah, I don't know if that means the joke was amazing, so good that they couldn't take it,

or they're just like, you know what, I'm done after that. I've no hope. I can't take anymore. If people get paid to say those kinds of jokes, then I'm out of here. There's no reason to go on. That's right. Goodbye, cruel, unfunny world.

Well, help neither of these things happen to you, our dear listeners. But our first question comes from Florence, from Texas, and she has a question about how gravity could keep the Earth in orbit. Here's what you had to say. I have a question about gravity. You've described it before as the weakest force, and you said, in fact, that it's so weak that when you're picking up an object with a magnet,

you're overpowering the entire Earth's gravity. So that's pretty weak. My problem is when I start thinking about the objects in a Kuiper Belt, they're 30 to 50 astronomical units away, and that's billions and billions of miles. And yet the sun's gravity is still able to keep them in orbit. And that just gives me the impression that gravity is really strong, not weak. So those two thoughts really don't go together. Would you help me with that?

All right. Thank you, Florence, from Texas. So that's a pretty interesting question, right, Daniel? Is that we often mention on the show that gravity is the weakest force, and it's actually super duper, duper weak. but at the same time I think maybe a lot of listeners are thinking but wait if gravity is so weak

how is it keeping the earth going around in orbit and other planets and Jupiter and how is it such an amazing and incredible force in the universe? It is an amazing and incredible force in the universe and you're right to wonder about that because as you look out into the night sky you think about

all the structures in the universe the solar system with the planets going around the sun and even the galaxy and the structures of galaxies and the supercluster all of that is determined by gravity, right? So gravity seems to have a huge role in organizing the way the universe works, right? And the way we discovered dark matter was through gravity.

And so if you just looked at it, you'd say, well, gravity is one of the most important forces because it shapes the whole universe. So then to hear somebody say, actually, gravity is the weakest force in the universe. That does seem like a strong contradiction, right? It doesn't make sense in your mind because how can it be the weakest force

and also be the thing that shapes everything else. Right. It's kind of like the organizing force in the universe, right? It organizes planets into solar systems and solar systems into galaxies and galaxies into clusters. Like if we didn't have gravity, everything would just fly away and fly apart. Yeah, that's right.

We wouldn't have any of the good stuff that we have without gravity. So we own a big thanks to gravity. And I like the way you said it. It sort of organizes things. I think that's one of the big ideas to understand how gravity can play such a big role. roll and be so weak. It's sort of like the way you make a big mess in your house and then you come back home and your mom is organized the living room or whatever, right? Some mysterious forces

organized it while you were gone. Your mom still cleans your house. That's pretty good. Noah, your mom cleans my house, Jorge. She doesn't clean yours. She flies from Panama every week and cleans your house. And she doesn't even call me. Oh, my God. Maybe because I don't celebrate Mother's Day. Yeah, exactly. Well, you should have sent her a banana cake. No, but the point I wanted to make, the actual physics point, not a joke, is that gravity is a force that's sort of left over. Like all the other forces in the universe, electromagnetism, the strong force, the weak force, all these forces are so powerful that they get kind of naturally balanced. Like there's no electrostatic force or electromagnetic force between the earth and the sun. Why? Because if there were, it would be incredibly powerful and it would balance itself. The way like lightning, is a balancing of the electrons between the earth and the sky, right? Anytime there's any imbalance, there's a huge bolt of lightning to balance these things out. And so as a result, there is no electromagnetic force

between these huge celestial objects. And so gravity can't be balanced, though. It's the one force that cannot be neutralized because it only has mass. There's no negative mass to balance it out. So after all the other forces have made their big mess, gravity is sort of left to pick up the pieces. It's the only thing left on the playing field.

Right. Well, I think it's important to maybe mention that when we say it's the weakest force, it's a relative assessment, right? Like we're not saying gravity is weak. It's just weak relative to the electromagnetic force. Oh, I'm saying it. No, I'm saying the gravity is super weak. It's embarrassing.

It's puny. It's pathetic. But only because you know other forces that are stronger. But if you didn't know the other forces, you'd be like, oh, my God, gravity is what keeps the Earth from going around the Sun. and the Earth is pretty big. So it's like a huge force. You just know that in comparison, it's kind of wimpy.

I guess so. I mean, I think in comparison is really the only metric we have. It's also important to recognize how much weaker it is. Like if you took electrons, for example, and you asked, like, what is the force of their electrostatic repulsion compared to their gravitational attraction, then the difference is like 10 with 33 zeros after it? So, you know, millions, billions, trillions, quadrillions, you run out of numbers really quick. It's a huge difference.

It's like a completely different scale. Right. So you're saying if I have an electron and maybe a proton, they're both being attracted by two forces, gravity and electromagneticism. But you're saying the electromagnetism is 32 orders of magnitude stronger than the gravitational force between them. Yeah, exactly. They're totally different scales, exactly. Electromagnetism, I mean, is a gadillion. What's the word for

32 zeros? It's banana aliens. There you go. Banana is a cake zillion. It's so much bigger. You don't even really want to describe them in the same level. It's like, you know, the mass of the earth versus the mass of a penny or something,

you know? You don't call a penny a celestial object because it isn't, right? It's so tiny. You just sort of round it up into the earth. Anyway, the reason that gravity can still play on the field at all is that these other forces are so strong that they balance each other out.

And gravity, you can't do that, right? Like we were talking about one electron, another electron, they repel each other. Whereas an electron or proton, they attract each other, right? Gravity only makes attractive forces. Everything with mass feels gravity and it attracts itself. There's no way to have repulsive gravity.

We did a whole podcast episode about anti-gravity. As far as we know, it's not possible. So there's no way to balance gravity out after everybody else has done their stuff and been neutralized, gravity is left over, and so then it gets to organize the universe. Yeah, I was thinking maybe an interesting picture is to imagine a proton in the sun

and then imagine a proton and an electron on Earth. It's not that there's no electromagnetic force between that proton and this proton and electron. It's just that the proton in the sun is pulling the electron towards the sun, but it's also pushing the proton away from the sun, with the exact same force. So our pair of proton and electron

here on Earth just doesn't feel any electromagnetic force with that proton in the sun. But it does feel gravity. Yeah, exactly. And there's lots of protons and electrons in the sun, and so they all work, they all arrange themselves in such a way that there's effectively no net force. And there's

no way to arrange the protons to get no net gravitational force. There's just no way to do that. But I think it's interesting to think about it's not that there's no force, it's just that there's no net force, you know, like it is pushing and pulling us electrometanically, the sun,

but it all just sort of cancels out. Yeah, yeah, like it's pushing on a proton and it's pushing on an electron the opposite direction. Right, but because our proton and the electron are holding on together, they're not going anywhere. Yeah, that's a fine way to think about it. And I think the other thing to recognize is that

gravity is really, really weak, but the sun is really, really, really big. like really, really, really, really big. So it can have a pretty strong gravitational effect on the Earth, even though gravity is weak, because it just has so much mass, right? And so, yeah, gravity is weak, but the sun is so big that those two factors kind of cancel each other out, and it becomes an important force.

Yeah, the weakness accumulates. Exactly. You have, like, a billion people all whispering your name, it's going to add up to a huge scream, right? And that's the way it is with gravity. All those protons in the sun are, giving a tiny little tug on the protons and electrons on Earth

gravitationally, but there's so many protons in the sun that it's enough to pull a whole planet around in a circle, right? It's not a small amount of force to keep the Earth in orbit, right? It's a huge force that keeps Earth in orbit. Oh man, you just gave me a new nightmare to imagine a billion people whispering

my name. Whoa! That is so bizarre. That is kind of creepy, actually. Yeah. I don't know where that came from. Okay, let's all whisper Paul's name for Father's name. For Father's Day. Do you think he'll sense a disturbance in the force when that happens?

Everybody listens to me to this right now. I go, Paul, Paul, Paul, Paul, happy Father's Day, Paul. Happy Father's Day. Your daughter's awesome. Cool. All right, that's Florence's question. about gravity. And so the answer, Florence, is that gravity is weak, but it's also happening on such a large scale that it does, it is enough to pool planets and keep galaxies together. That's right. And after all the other forces have done their business, gravity's left over to organize the universe because it can't be balanced out.

All right. Well, that's one question. And we'll get to the two other questions we have today about dark matter and atomic nuclei. But first, let's take a quick break. December 29th, 1975, LaGuardia Airport. The holiday rush, parents hauling luggage, kids gripping their new Christmas toys. Then, at 6.33 p.m., everything changed. There's been a bombing at the TWA terminal. Apparently the explosion actually impelled metal glass. The injured were being loaded into ambulances, just a chaotic, chaotic scene.

In its wake, a new kind of enemy emerged, and it was here to stay. Terrorism. Law and order, criminal justice system is back. In season two, we're turning our focus to a threat that hides in plain sight. That's harder to predict and even harder to stop. Listen to the new season of Law and Order Criminal Justice System on the IHeart Radio app, Apple Podcasts, or wherever you get your podcasts. I don't write songs. God write songs. I take dictation. I didn't even know you've been a pastor for over 10 years. I think culture is any space that you live in that develops you.

On a recent episode of Culture Raises Us podcast, I sat down with Warren Campbell, Grammy-winning producer, pastor, and music executive. to talk about the beats, the business, and the legacy behind some of the biggest names in gospel, R&B, and hip-hop. This is like watching Michael Jackson talk about thoroughly before it happened. Was there a particular moment where you realize just how instrumental music culture was to shaping all of our global ecosystem? I was eight years old, and the Motown 25 special came on. And all the great Motown artists, Marvin, Stevie Wonder, Temptations, Diana Ross. From Mary Mary to Jennifer Hudson, we get it. into the soul of the music and the purpose that drives it.

Listen to Culture raises us on the IHeart Radio app, Apple Podcasts, or wherever you get your podcasts. Imagine that you're on an airplane and all of a sudden you hear this. Attention passengers. The pilot is having an emergency and we need someone, anyone, to land this plane. Think you could do it? It turns out that nearly 50% of men think that they could land the plane with the help of air traffic control.

And they're saying like, okay, pull this. Let's do this, pull that, turn this. It's just... I can do my eyes close. I'm Mani. I'm Noah. This is Devin. And on our new show, No Such Thing, we get to the bottom of questions like these.

Join us as we talk to the leading expert on overconfidence. Those who lack expertise lack the expertise they need to recognize that they lack expertise. And then, as we try the whole thing out for real. Wait, what? Oh, that's the run right. I'm looking at this thing. See? Listen to no such.

thing on the iHeart radio app, Apple Podcasts, or wherever you get your podcasts. Our second question of the day comes from Margie, who has a question about dark matter. Hey, Daniel and Jorge, this is Margie. My question is, how does dark matter influence the movement of the planets in the solar system? Does it make them all orbit at the same speed? And if so, how all right that's a pretty interesting question um we've talked a lot about dark matter in this podcast and how it's there it's all around us it's in the center of um galaxies right all over the galaxy and it's constantly pulling on everything and helping galaxies stay together yeah this is a wonderful question because this is a kind of question that shows me that people are doing physics

in their mind right this says you've learned how dark matter influences how galaxies rotate like we discovered dark matter because we saw the galaxies were spinning too fast, so they need more gravity to hold them together. So that means that dark matter makes enough gravity to be like noticeable about how things spin, right? So then a natural physics thing to do is to say, okay, I have my new understanding, let me apply it to something else. Does that make sense? And this listener obviously thought, well, if there's dark matter enough to affect the galaxy spinning,

why can't we notice it here on Earth? Like, why can't we do that same measurement and see like, hey, the Earth is going around the sun too fast? Can't we detect the dark matter in our solar system by looking at how the Earth orbits the sun, the same way we look at how the sun orbits the center of the galaxy? It's really a genius question. Oh, I see. The question is,

is the Earth going around the sun faster than it should be if dark matter didn't exist? Yeah, because imagine, for example, that there wasn't just the sun in the center of the solar system. Imagine there were five suns, but you can only see the one of them, right? and the other ones were made of dark matter. What would happen in that case? In that case, there'd be a much stronger gravitational force

than you would expect from one sun, and for the Earth to stay in its orbit, it would have to go much, much faster. And so you would see a discrepancy. You would measure the speed at which the Earth was orbiting the sun, and you'd say, huh, it's going way too fast. What's keeping it together, right? What's keeping it in the solar system?

Why isn't it just flying off? And then you would deduce the presence of all those dark suns, right? So this listener is like, well, can we see the dark matter? Because we've said on this podcast several times that dark matter is everywhere. It's not just out there. It's here. It's in this room. It's on your planet.

It's hanging out in that bunch of bananas you just ate. It's everywhere. So why can't we see it in our solar system? Right. Well, I guess question number one is, is there dark matter in our solar system? And then question number two is, does it influence the orbit of planets? So, Daniel, is there dark matter here in our solar system? We think so.

Now, we don't know 100% for sure. The reason is that gravity is pretty weak, right, as we talked about recently. And so it's hard to get a sense for exactly where dark matter is, because the only way that we can see it is through its gravitational effects. And so we can see its effects sort of like on a galaxy-sized scale. But it's really hard to get a very clear map of where the dark matter is. But we think it probably is. We think it's probably distributed pretty evenly through the galaxy.

There's a blob in the very center, and it sort of just falls off gradually. So we suspect... Like, we would see it as a haze just permeating everything. Exactly. And, you know, a deep question about dark matter is like, is it just a smooth haze or are there structures? It's stuff happening. Is there like life forms in dark matter?

We really don't know because we haven't been able to see it with enough resolution because the only way we've ever been able to probe it is through gravity. And that's a, it's, you know, real frustration for us as scientists. It's like most of the matter in the universe is there. It's right in front of us. We can't see it. We can't tell if it's doing anything interesting or just sort of, of a smooth haze.

Right. And so the question is, if we are kind of in a bath of dark matter right now, which we could be or could not be, maybe we're like in a bubble of non-dark matter? Is that possible? We might be in a little gap? It's possible, right? But I think the most sensible and the simplest assumption is just that dark matter is smooth. And as you say, we're in a bath of dark matter.

I think that makes the most sense. It's the most likely explanation. Okay. So in that case, if we are bathing in dark matter, would it affect the orbit of the planets? So the short answer is yes, but not on a noticeable way. And the reason is that the solar system is not big enough, right? Like if you take the density of dark matter, and we expect that this is about like one proton's worth of dark matter about every three cubic centimeters. So there's not actually that much dark matter spread out over the universe, right?

Like if you sort of look at your thumb, there's probably only one proton's worth of dark matter in it. Yeah, if you take all the dark matter and you spread out. it out evenly through space, then you end up with about one proton per thumb. I like the thumb as a unit of volume, yeah. One dark matter proton per thumb. Thumbs up. Yeah, and you might be thinking, hold on, isn't there supposed to be more dark matter than normal matter? And there is, but there's five times as much, but here we're sort of spreading it evenly

through space so we can imagine how it might affect the solar system. But we actually don't sort of know that, right? Like it could be all concentrated in my thumb, or it could just be kind of this haze that's covering everything. Yes, it could all be concentrated in your thumb. No, there's some limits. I mean, if dark matter was really, really clumpy and it was all concentrated in your thumb, that would be a huge amount of mass, and we would definitely notice that. Your thumb would be attracting stuff to it all the time, like a crazy weird magnet. My thumb is pretty attractive. Well, do you hitchhike a lot? Does your thumb stop a lot of cars? Yeah, no. I get compliments about my thumb all the time.

I don't believe that for a second. I don't believe that for a second. You're like, I've seen your thumb, Jorge. It's nothing special. Next time we're in a random situation, I'm going to ask somebody to comment on your thumb. We'll just see what they say. All right, let's do it.

If you take one proton's worth of dark matter per thumb and you add that all up inside the solar system, it adds up to a lot. It's like 10 to the 10 kilograms of dark matter in the solar system. And that might seem like, oh my gosh, that's a huge amount, 10 to the 10. but it's small compared to the sun, which is like 10 to the 30 kilograms.

So dark matter, if you spread it out evenly, there's not enough of it in our solar system to influence gravity on top of what the sun is already doing. So you're saying, like, our solar system is a, it's kind of a concentrated part of the universe where there's a lot of mass here, as opposed to, like, in the empty gas between solar systems. And so you're saying, like, here in our neighborhood,

there is just a lot more of the regular stuff than there is dark matter. So dark matter is kind of negligible right here where we are. Exactly. Dark matter is negligible for the gravitational effects of the Earth and the Sun. Exactly right. Because mostly the Sun is a concentrated blob of normal matter, and we don't think the dark matter has been concentrated in that same way.

Not only is it negligible, but it's also kind of spread out evenly all around us, right? So it would be sort of maybe tugging us in all directions at the same time and maybe not really affecting the orbit? It would be tugging us in all directions, but physics, says that if you're moving in an orbit, you're affected by the mass of all the stuff that's a smaller radius than your orbit. And actually, it doesn't matter how that's distributed inside that radius. If it's like, you know, like if the sun was a point particle or the sun was its normal size or twice its size, if it doesn't change its mass, the physics says that it

doesn't affect how the force of gravity acts on that body. It all integrates out to be the same thing. So the dark matter outside of our orbit just cannot affect our orbit. That's right. It's Sort of like that episode we talked about where you jump into the center of the Earth, you're only affected by the mass of the Earth that has a smaller radius than you do. Everything else outside of you cancels out because there's always one bit tugging you here and another bit tugging you the other direction. And the stuff with a smaller orbit adds up to give you an overall tug that's the same as if you just put a particle with the mass of that stuff at the center of mass of it,

which would be the center of the Earth. So in this case, you would still be affected by dark matter. And we are, like the orbit of the Earth is affected by the dark matter in the solar system. But it's, you know, one part in 10 to the 20, so it's not measurable. So you're saying that we do sort of have like an equivalent of a dark sun in the middle of our solar system affecting our orbit. It's just very small. That's right. Dark matter is changing our lives.

It makes our years shorter by one part in 10 to the 20 because it speeds up the Earth because of its additional gravity. But it's, you know, it's not something we can measure. On the galaxy scale, though, you can. And the reason it affects things on the galaxy scale, the reason that you can detect it at all is that galaxies are just so much bigger than solar systems. And so they add up to a huge amount of dark matter compared to the mass of a sun.

Like the stuff in between solar systems adds up. But maybe the stuff within a solar system doesn't add up too much. Exactly. So when you're calculating the force of gravity on the sun as it rotates around the center of the galaxy, it's influenced by everything that has a radius smaller than it's compared to the center of the galaxy. And that's a huge amount of dark matter.

Well, I think that's probably why I was late to the recording of this podcast. It was, you know, dark matter shortening my ear. That's right. Well, you used up your one, you know, one in ten to the twentieth of a year, so you need another excuse next time. No, no, it built over my entire life and leading up to me being late to this podcast. It's not that you were finishing that one last piece of banana cream cake. No, no, I finished that yesterday. All right, so that's Margie's question about whether dark matter affects the orbit of the planets in our solar system.

And the answer is yes. We kind of do have a dark matter sun or a dark matter mass in our solar system, making everything just a little bit faster, go faster around the solar system. But it's really not measurable. And without seeing how galaxy spin, I don't think we ever would have discovered dark matter just by looking at the orbit of the Earth. All right. Thank you, Margie. And so we'll get to our last question from Prida

when we get back from a quick break. December 29th, 1975, LaGuardia Airport. The holiday rush, parents hauling luggage, kids gripping their new Christmas toys. Then, at 6.33 p.m., everything changed. There's been a bombing at the TWA terminal. Apparently, the explosion actually impelled metal, glass. The injured were being loaded into ambulances, just a chaotic, chaotic scene.

In its wake, a new kind of enemy emerged, and it was here to stay. Terrorism. Law and order, criminal justice system is back. In season two, we're turning our focus to a threat that hides in plain sight. It's harder to predict and even harder to stop. Listen to the new season of Law and Order Criminal Justice System on the IHeart Radio app, Apple Podcasts, or wherever you get your podcasts. I don't write songs.

God write songs. I take dictation. I didn't even know you've been a pastor for over 10 years. I think culture is any space that you live in that develops you. On a recent episode of Culture Raises Us podcast, I sat down with Warren, Campbell, Grammy-winning producer, pastor, and music executive to talk about the beats, the business, and the legacy behind some of the biggest names in gospel, R&B, and hip-hop. This is like watching Michael Jackson talk about thoroughly before it happened.

Was there a particular moment where you realize just how instrumental music culture was to shaping all of our global ecosystem? I was eight years old, and the Motown 25 special came on. And all the great Motown artists, Marvin, Stevie Wonder, Temptations. from mary mary to jennifer hudson we get into the soul of the music and the purpose that drives it listen to culture raises us on the iheart radio app apple podcasts or wherever you get your podcasts imagine that you're on an airplane and all of a sudden you hear this attention passengers the pilot is having an emergency and we need someone anyone to land this plane think you could do it it turns out that nearly 50% of men think that they could land the plane with the help of air air traffic control. And they're saying like, okay, pull this. Do this, pull that, turn this.

It's just, I can do it my eyes close. I'm Mani. I'm Noah. This is Devin. And on our new show, no such thing. We get to the bottom of questions like these. Join us as we talk to the leading expert on overconfidence. Those who lack expertise lack the expertise they need to recognize that they lack expertise.

And then as we try the whole thing out for real. Wait, what? Oh, that's the wrong. I'm looking at this thing. Listen to No Such Thing on the I Heart Radio app, Apple Podcasts, or wherever you get your podcasts. All right, our last question of this episode comes from Prida, and she has a question about why the nucleus is stable.

I imagine the nucleus of an atom, right? What else could it be about the nucleus of what? of the cell. The nucleus of a banana? I don't know. This is a physics podcast, man. So here's a Prida's question. My name is Prito.

And my question is, why is the nucleus of an atom even stable? The nucleus of atom has protons, which are positively charged. They're supposed to ripple each other. And they're not supposed to stay together. Please explain. Why does this happen? All right. So Prida wants to know how a nucleus can be stable, like, because the nucleus,

and the nuclei of atoms are made up of protons, mostly, right, and neutrons, but a lot of protons, and all the protons are positively charged. So they should be repelling each other with the electromagnetic force. Yeah. So how can they all stay together? How is it that you and I are here, Daniel? Yeah, I love that we're talking about forces and force balancing in all these questions today. This is a great question, right?

And they all are positive and they are pushing away from each other. So what holds it together? Yeah, that's a really positive thing, I think. Yeah. And kind of negative, too. Well, I'm kind of neutral on the topic. But I was wondering whether people knew about this. Like, is this a common question?

Do people have an idea? So actually, yesterday, when my kids were watching a movie, I walked around a mall here in Irvine, and I asked people if they knew what kept the nucleus together. And I got some interesting answers. Cool. So here's what people had to say. Do you know why the nucleus stays together? Like, what keeps it together if it's all positive charges?

Opposite force on the outside or neutrons. What holds an atom together, huh? Right. I'm sure I learned that in physics long ago, but I can't remember. I don't know about that one. I don't know. More electrons. They stay together because the more protons there are, the heavier the atomic weight.

So what do you think? Now we're getting random people on the street. to answer listener questions. Eventually, we don't even need to be here anymore, right? Yeah, we should just crowdsource this podcast. Just go in the mall and be like, hey, here's a question. We'll give you 20 bucks to talk about it for 40 minutes. Exactly.

That's our retirement plan. No, this one was interesting enough, and I really was curious about what people knew, so I thought, we don't often do this for listener questions, but I did the man-of-the-street interviews for this one. Well, I'm surprised that people kind of knew a little bit of what you were talking about, right? They were like, oh, you mean like the oven atom? And they sort of understood the question, because it's not an easy question to get your head around, right?

No, it's not an easy question. It's not a simple answer. But you're right. People understood the question, and that was cool. So I think it is a common question. And all these people, after I asked them, they're like, wait, tell me, what is the answer? You can't just walk away after asking me that question. I have to know now.

It's like inspire this burning desire in them to understand why their nuclei were not flying apart. Do you try to, when you're roaming the malls looking for people, do you try to always hit like the, you know, the dad or the mom just waiting for their kids or their spouse who's shopping? I try to ask people who are on their phone board, yeah. I don't interrupt people in conversation or people who look like they're going somewhere. I look for somebody who's, like, sitting there on their phone, obviously waiting for somebody to, like, try on pants or something.

So they don't, they don't, I don't want to interrupt somebody's day. You're going to the dressing room, you're like, hey, I have a physics question for you. Friendly neighborhood physicist. Physicist arrested at local mall. And then I ask people in the next cell when I get arrested. All right, so let's ask you the question. So how is it that protons stick together inside the nuclei of atoms? Yeah, well, to answer this question,

you need to understand a little bit about how protons and neutrons are held together. Because protons and neutrons, remember, are not fundamental particles, but they're made of quarks. So there's up quarks and down quarks. And those particles are held together by a different force, called the strong nuclear force. And it's called the strong nuclear force because it's super-duper-strong.

It's much, much stronger than electromagnetism, which, of course, puts gravity to shame. So the strong nuclear force is the strongest, most powerful force we've ever discovered. And that's what holds the protons together.

Yeah, it's the reason the protons and the neutrons they're bound states of this force. So there's quarks inside the proton and quarks inside the neutron, and they're exchanging gluons all the time. This is a particle called a gluon, which holds the corks together into a proton and into a neutron.

So that's what holds the protons and neutrons together, but what keeps the protons from repelling each other? Yeah, so the strong nuclear force, which holds them together, it's very short range. Like it's super powerful, but it doesn't go very far. But it extends a little bit of ways past the edge of the proton. And so what happens is that there's a little bit of the strong nuclear force left over between the corks inside the proton and neutron to attract the protein,

and neutrons to each other. So even this little extra bit of the strong nuclear force is enough to overcome the repulsion of the protons because they have the same charge. Oh, really? I never thought about that. Is that how you explain it? Is that the force that's keeping the protons together

is also the force that keeps a proton stuck to another proton because it sort of leaks outside of the proton. Yeah, essentially it's like the quarks in one proton are talking a little bit with the quarks in the neighboring proton or the neighboring neutron. And to them, the fact that there's like an overall positive charge in protons and not in neutrons is irrelevant because those forces are so weak compared to the strong nuclear force. The strong nuclear force doesn't care about your electromagnetic charge, right?

Yeah, exactly. It doesn't care at all. And the quarks do have electromagnetic charges. And actually, they're really weird that like two-thirds charges and minus one-thirds charge, they're pretty strange. But the forces are much weaker than the strong nuclear force. So the strong nuclear force sort of leaks out of the proton and into the next neutron and into that next neutron, and that's how they tie themselves together. There's enough leftover after you make the proton or the neutron to tie it to the next one. How can there be any leftover?

I mean, if the proton is stable, right, like it likes being held together, how can it have any leftover, you know, attraction? Doesn't it all just cancel out within the proton? how can you have some leftover to attract more protons? No, you're right. And it would if all the corks inside the proton were like right on top of each other. But they're not. They're like all sloshing around.

So if you're like on one side of the proton, you're a little bit closer to one of the corks than the other two. And so the force from that one little cork is enough to have like a little bit of leftover charge. So actually maybe two protons being stuck together makes them weaker inside, right? Each one is maybe just a little bit weaker because they're stuck to each other. You can think of it's sort of the way atoms form molecules, right?

And atom is electrically neutral, right? Because the protons and the electrons, right, are balanced. But how do atoms form molecules? They're bonds between the electrons because the electrons, you know, they talk to each other. One, like, jumps from here to there and they exchange photons and stuff. And so this is like protons getting stuck together by those extra little bits of leftover forces. So it's the strong nuclear force that's so much more powerful than electromagnetism that even a little extra left over bits can overpower the protons pushing away from each other.

This strikes me as a little bit as a nuclear infidelity, you know? Like you got three quarts being perfectly happy in a bond to make a proton. But then one of them is like, hey, look at that. There's some other quartz over there in that other trio, menagerie of protons. I'm a little bit attracted to them too. And so that's what brings the two things together, right? Yeah, quarks feel a lot of love, right? They're happy to share their love with quarks,

even inside other protons and neutrons. And there's sort of a limit to how much you can do this because these forces are very short range. And so the bigger the nucleus gets than the weaker, the sort of the stability of the nucleus. If you try to make a nucleus that's too big, than like the protons on opposite sides of the nucleus, they'll feel the electrostatic repulsion,

but they won't be close enough to feel the strong nuclear force anymore. And that's why heavier elements are less stable and more likely decay radioactively. That's why we use uranium, like uranium-235, to do radioactive fission and not like helium or lithium. Put enough protons together, they bunch up, and at some point the nuclear force, the strong force isn't enough. They start to repel each other.

Exactly, because the strong force drops very quickly with distance. And so if you're far enough away from the proton, then you don't feel it. Then it's like all the corks are on top of each other. And so that's why there's like a maximum size you can make to a nucleus because the strong force, which holds it together, is a very short range. And when the nucleus gets sort of bigger than that range, then it can't do the job anymore. It's like, you know, you try to hold a bunch of balloons, right? Imagine trying to hold a huge pile of balloons.

There's a maximum number you can hold until you need somebody else to come over and grab a bunch of them. So then the nucleus splits into two, right? And that's what happens in radioactive decay. All right. So then that's the answer to the question. The nucleus stays together. Even though the protons are, are repelling each other, they're trying to push each other apart.

There is another force that leaks out from inside of each proton that then sort of links up the two protons together. And that force is stronger than the electromagnetic repulsion. Exactly. That's what holds them together. And that's what holds us together with you listeners. the force of these questions. You guys have all these questions

bouncing around in your head and you send them to us and we love thinking about them. We love talking about them and we love trying to explain them to you. And really it's this love of the universe and this desire to ask questions and this hunger to get the answers

that brings us all together. All right, well thank you so much to Florence, Margie, and Prida for sending in their questions and thanks to all of you who are sending us questions as well. We enjoy reading them and it kind of makes our day to hear from you guys.

Absolutely. Please don't stop sending questions. Questions at danielanhorpe.com. All right. And that's our podcast. We hope you enjoyed those questions. And stay tuned for more amazing facts and questions and interesting perspectives about the universe. And stay tuned for the sound of Jorge enjoying a banana cake. That's right. One of you lucky people will win this prize. Lucky, unlucky. We're not sure, but somebody's going to win it. Positive and negative. See you next time. If you still have a question after listening to all these explanations, please drop us a line we'd love to hear from you.

You can find us at Facebook, Twitter, and Instagram at Daniel and Jorge, that's one word, or email us at Feedback at Danielandhorpe.com. 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. Culture eats strategy for breakfast, right? On a recent episode of Culture Raises Us, I was joined by Valicia Butterfield,

media founder, political strategist, and tech powerhouse for a powerful conversation on storytelling, impact, and the intersections of culture and leadership. I am a free black woman. From the Obama White House to Google to the Grammys, Valicia's journey is a masterclass in shifting culture and using your voice to spark change. Listen to Culture raises us on the IHeart Radio app, Apple Podcasts, or wherever you get your podcasts.

Why are TSA rules so confusing? You got a hood of you. I'll take it all! I'm Mani. I'm Noah. This is Devin. And we're best friends and journalists with a new podcast called No Such Thing, where we get to the bottom of questions like that.

Why are you screaming at me? I can't expect what to do. Now, if the rule was the same, go off on me. I deserve it. You know, lock him up. Listen to No Such Thing on the IHeart Radio app, Apple Podcasts, or wherever you get your podcast. No such thing. I'm Dr. Joy Hardin Bradford, host of the Therapy for Black Girls podcast.

I know how overwhelming it can feel if flying makes you anxious. In session 418 of the Therapy for Black Girls podcast, Dr. Angela Nealbornett and I discuss flightings. What is not a norm is to allow it to prevent you from doing the things that you want to do, the things that you were meant to do. Listen to therapy for black girls on the IHeart Radio app, Apple Podcasts, or wherever you get your podcast. This is an IHeart podcast.