Daniel and Jorge Explain the UniverseJoin Daniel and Jorge as they respond to 4 questions from listeners, just like you!
Learn more about your ad-choices at https://www.iheartpodcastnetwork.com
See omnystudio.com/listener for privacy information.
If you love iPhone, you'll love Apple Card. It's the credit card designed for iPhone. It gives you unlimited daily cash back that can earn four point four zero percent annual percentage yield. When you open a high Yield savings account through Apple Card, apply for Applecard in the wallet app subject to credit approval. Savings is available to Apple Card owners subject to eligibility. Apple Card and Savings by Goldman Sachs Bank USA, Salt Lake City Branch, Member FDIC terms and more at applecard dot Com. 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. How is US Dairy tackling greenhouse gases? Many farms use anaerobic digesters 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.
As a United Explorer Card, you can earn fifty thousand bonus miles plus look Forward to extraordinary travel rewards, including a free checked bag, two times the miles on United purchases and two times the miles on dining and at hotels. Become an explorer and seek out unforgettable places while enjoying rewards everywhere you travel. Cards issued by JP Morgan Chase Bank NA Member FDIC subject to credit approval offer, subject to change terms apply.
Hey, Jorge, you know how we end most of our podcast episodes by asking people to submit questions?
Yeah, the people actually sibm in questions.
Yeah. Do you know that a lot of people actually write.
In Oh, and how are the questions? Oh? My god?
The questions are awesome. They reflect like people's real desire to understand things about the universe.
Well, you read all of them, you know.
I'll admit I love the questions so much that I actually read and answer all of them. But some of the quest questions are so fun and I think other people probably share the same questions that I'll ask those people to record themselves asking the question and send it in so we can do a whole podcast episode just about some listener questions.
So somebody get to write asking why they couldn't understand this episode.
Not if we do a good job explaining it?
What's that? What kind of question would you have, Daniel?
If you were a listener, if I was listening to my own podcast, I would be like, who is that guy with my voice? And how did he get a podcast? What question would you ask?
Orgy?
I would probably ask, how do we get more people to listen to this podcast? Hey, I'm Jorgey and I'm Daniel, and welcome to our podcast Daniel and Jorgey Explain the Universe or more accurdly, Today, Daniel and Jorge answer questions about the universe.
That's right or explain the universe inside your mind?
That's right. Every week, twice a week, we are beaming information and explanations about the incredible mystery that is the universe straight through your ears and into your brain.
And we try to make it fun. We try to make it engaging. We try to make sure that you can actually understand what we're talking about. We don't want to impress you with fancy words. We want to impress you with the incredible majesty and wonder that is this universe we find ourselves in.
Yeah, and sometimes you know, we don't get all the information out there or some people don't quite understand everything that we covered and we were able to cover in the podcast, and so people still have questions.
Yeah, or sometimes we'll explain one thing and it inspires another question, make somebody wonder, oh what about this or what about that? And often I think Jorge does an amazing job of anticipating those questions. A lot of people have written in saying Jorge asks the questions I have in my mind. So kudos to you, Jorge for the great follow ups and for asking the right questions.
It feels like a backhanded compliment.
No, it's not backhanded at all. It's a great compliment. You're a good science communicator. You understand what is clear and what is not. But sometimes there's a question rattling around in somebody's head that they just really need an answer to, and so they write in and ask us.
Yeah. So today on the podcast will be answering listener questions.
That means questions from people like you. If you're listening to this and you have questions, you could hear your own voice next time. Write to us at Questions at Daniel and Jorge dot com with your questions about the universe, or life or whatever's going on around you.
Where you can also reach out to us on Twitter, Instagram, or Facebook. Right, do you check all of those, right, Daniel?
I do. I respond to Twitter questions and Facebook questions and all that kind of stuff. So, yeah, engage with us. We're eager to hear from you.
Yeah, you can ask us about the universe, about how rude we are.
How engaging we are to each other.
What our favorite fruit is?
Everybody knows. Nobody has a question about what your favorite fruit is right now, everybody knows it's papayas clearly.
I feel like I don't know you, Daniel. I feel like you.
Don't know I think I think bananas are clearly your favorite fruit. But I wonder, like, is that the favorite fruit to say? I mean to eat? Sure, but what about saying like, isn't papaya more fun word than banana?
More fun than banana?
Yeah, it's just fun about the word papaya.
I think you need to go out into the street and ask people this question.
No, here's another question, what's your favorite fruit to draw? Like, as a cartoonist, that's a fun fruit to draw because papaya is just kind of a blob.
I feel like if I say banana, people are going to infer something from.
That, that's a dangerous.
Or if papaya, people might also infer something from that. So let's just stay clear out of cartooning plus fruits.
All right, All right, too bad. Well I'm still curious. You can tell me offline later.
Well, so today we're going to be answering four questions from all over the universe, or at least all over the planet Earth.
That's right, And so here's the first question. It comes from Alessandra from Italy, and he wants to know about how we see so far into space.
Hi, guys, it's Alessandro from Italy. I really enjoy your podcast, and I'm curious to know how can we see so far through the space without being hidden by das Nebula and Adela Martin. Thank you, and I will enjoy your answer.
Well, Alessandra certainly sounds Italian. He didn't have to tell us where he was from.
He Yeah, he's a beautiful accent. Yeah, it is the language of love or is that French?
Although I feel like Italian shouldn't just be heard, it should be seen. Right, there's a I'm sure there's some hand gestures that he couldn't capture in that.
In that save it for the YouTube podcast.
That's right, that's right. But it's a great question.
Yeah, it's an interesting question. How can we see so far out through space without being obscured or blocked by nebula and other clouds of dust and stuff that's out there. How is it that we're able to see these stars there are billions and billions of light years away without anything blocking our view.
Yeah, Like, is it lucky that we can see so far? Is it coincidence, you know, or is there some reason for it? I think first, let's just take a moment to appreciate that view. You know. We say, like, if you stand at the top of a mountain and you can see hundreds of miles, it seems like a great view. But we don't often realize or consider the fact that the view above our heads, the one's out into the night sky, is the best view we will ever see. You know. It's sort of a It can give you vertigo, just to imagine that you're standing on the tip of a rock, you know, that rock being Earth, and staring out billions of miles across this ocean of space to these other tiny little pricks. Yea. So it's really pretty incredible, not just the space is vast, but that you can see so far through it, right.
Right, Yeah, Because like if you stand up top of mountain, you can't see out there forever. Right, Like, if you look at the next mountain, it's going to look a little bit hazy, and if you look at the mountain behind it, it's going to look even hazier. And so I think the question is how is it that we can see with such crystal clarity out there into space?
Right And it's a great question, and you know the answer is that mostly space is transparent, right, transparent to light because what mostly what we're doing is we're seeing with light, and so light can pass through space without interacting. And that's what we mean by being transparent. We mean that a particle like a photon, a piece of light can fly through it without being effective, without being changed.
So it's not that I mean there is stuff out there. It's not like space is completely empty, but you're saying that we can see really far because the stuff that's there doesn't necessarily block the light.
That's right, exactly. Transparent doesn't mean non existent, right, There is stuff out there in space, but mostly the light can pass through it, just the way the light can pass through the window in your living room, right, mostly unaffected. Now, the window is not completely transparent, just like as you said, the air is not completely transparent, but it's mostly transparent. And so there can be stuff there, but as long as the particles don't interact, then they fly through and you can observe them on the other side basically unchanged.
Okay, so but what's out there in space that could be blocking or be but isn't it?
Yeah, And so there actually are some things that block our view. So mostly space is empty, you know, from the point of view of light, like there's just nothing there. There are little particles, but mostly it's empty. And the reason that we can see light from other stars is that there just isn't much stuff between us and them. But sometimes that's not true. So, for example, closer to the center of the galaxy, there are these really big nebulas of gas and dust, and we can't see through them with normal light, the kind of visible light that we're used to seeing with our eyes. And so, for example, if you want to study the center of the gas, you have to find other ways to do it because you can't see it with visible light.
Oh, I see. So the dust and gas out there do block or view, but most of it is concentrated in certain spots, like the center of galaxies.
Yeah, exactly, And so if you want to look out away from the center of the galaxy to nearby stars, there's not a whole lot between us and them. The thing that mostly blocks review is our atmosphere, right, our atmosphere interferes with light, and that's probably most of the stuff that's going to do that. So that's why we sometimes launch telescopes in a space so we can get a clear view of what's coming at us from far far away.
So if the Earth just happened to be like if our solar system just happened to be inside of a nebula, we would be totally blind to the outside universe.
Yeah, that's right. If we happen to be embedded inside a gas cloud or dust cloud, absolutely, And remember our sun probably was born in a gas cloud or a dust cloud. Most of those places are stellar nurseries, those where stars are born and eventually though all that stuff coalesces and it doesn't just hang out a cold US is into stars, and planets, and that's you know, the ancient history of our solar system.
So we really are sort of likely to have such a good view, right because we could have been born in like a we our planet could have been in the middle of a of a the eculumn of Los Angeles, right.
Yeah, we could be. But I think that most of the time gravity will do its job, and by the time the planets are formed and life has evolved, et cetera, that gravity will have done its job and cleared out that space will pulled it together into other objects, you know, planets and stars or whatever.
Oh, it concentrates all the gas. Yeah, I see, it makes stars, which clears the view.
Yeah. And you know, it's no coincidence that the kind of light that we can see, that our eyes can pick up is also the kind of light that can pass through space. Because that light comes from the Sun. It has to pass through space to get to us, right, and then it has to survive the atmosphere. And so the kind of light that we can that is around on Earth is the kind of light that we've evolved to see. So obviously it can get here from the Sun, and so it has to be able to pass through space for us to see it.
Right. But what's kind of cool too is that just because there is a gas or a nebula in front of us, it doesn't mean that we can't see through it, because if we other kinds of light do go through that kind of stuff.
That's right. When we say visible light, we mean light of certain frequencies, you know, red, green, blue, all those other colors that we can see. But light has lots of other frequencies.
Right.
You can wiggle more quickly into the ultraviolet, you can wiggle more slowly down into the infrared, or really slowly down into the radio waves. So we don't usually call those light, you know, they call them a radio waves or gamma rays or whatever, depending on the frequency, but they really are just still electromagnetic radiation. They are another form of light, and depending on the wavelength, they have different properties. Some of them can pass right through gas and dust. So, for example, radio waves, which are really long frequencies compared to visible light, it can pass through gas and dust and we can use that to see into the center of the galaxy.
Yeah, that's pretty cool. It's like having X ray vision.
Yeah, exactly, And we can actually use X rays. Also, X rays do also pass through gas and dusts. Right now, some of these things, like X rays, they won't penetrate our atmosphere, So if you want to see that, you have to have something really high in the atmosphere, like on a balloon, or maybe even into space, like an X ray telescope in space to see that.
That's interesting. Huh. You have to go up. You have to fly up like Superman to have X ray vision. Mm hmmmm.
And these days we even have other ways to see the universe that are not just light, like we can see the universe through neutrinos. There's some weird stuff out there that just makes neutrinos and neutrinos pass through almost everything, so they're a really good way to see really really far away. And then recently we develop this ability to see gravitational waves, and this is not even stuff, right. Gravitational waves are the ripples in space itself, so they can pass through basically everything matter.
I am all right, So that's the answer. The answer is the question was how can we see so far through space without being blocked by nebula and other stuff, And the answer is that there isn't that much stuff out there space is pretty empty, and even the stuff that's out there doesn't really block our view.
Yeah, and we have other ways to see through the stuff that does block our view.
And if we were blocked by nebula and other stuff, eventually all of that stuff would have turned into stars or moved around.
Yeah. Just wait a few billion years and you know, and the view will change.
Yeah. Yeah, just hang out, Just hang out.
You don't need to graduate anytime soon, do you your PhD thesist? Just wait a few bill No big deal, no.
BIGI all right, thank you Alissander from Italy. That was a great question. And before we go on, let's take a quick break.
With big wireless providers. What you see is never what you get. Somewhere between the store and your first month's bill, the price you thought you were paying magically skyrockets. With Mintmobile, you'll never have to worry about gotcha's ever again. When mint Mobile says fifteen dollars a month for a three month plan, they really mean it. I've used mint Mobile and the call quality is always so crisp and so clear. I can recommend it to you, So say bye bye to your overpriced wireless plans. Jaw dropping monthly bills and unexpected overages. You can use your own phone with any mint Mobile plan and bring your phone number along with your existing contacts. So dit your overpriced wireless with mint Mobiles deal and get three months a premium wireless service for fifteen bucks a month. To get this new customer offer and your new three month premium wireless plan for just fifteen bucks a month, go to mintmobile dot com slash universe. That's mintmobile dot com slash universe. Cut your wireless bill to fifteen bucks a month At mintmobile dot com slash universe. Forty five dollars upfront payment required equivalent to fifteen dollars per month new customers on first three month plan only speeds slower about forty gigabytes On unlimited plan. Additional taxi spees and restrictions apply. See mint mobile for details.
AI might be the most important new computer technology ever. It's storming every industry and literally billions of dollars are being invested, so buckle up. The problem is that AI needs a lot of speed and processing power, so how do you compete without cost spiraling out of control. It's time to upgrade to the next generation of the Cloud Oracle Cloud Infrastructure or OCI. OCI is a single platform for your infrastructure, database, application development, and AI needs. OCI has four to eight times the bandwidth of other clouds, offers one consistent price instead of variable regional pricing, and of course nobody does data better than Oracle. So now you can train your AI models at twice the speed and less than half the cost of other clouds. If you want to do more and spend less, like Uber eight by eight and Data Bricks Mosaic, take a free test drive of OCI at Oracle dot com slash Strategic. That's Oracle dot com slash Strategic Oracle dot com slash Strategic.
If you love iPhone, you'll love Apple Card. It's the credit card designed for iPhone. It gives you unlimited daily cash back that can earn four point four zero percent annual percentage yield. When you open a high Yield savings account through Apple. Apply for Apple Card in the wallet app, subject to credit approval. Savings is available to Apple Card owners subject to eligibility. Apple Card and Savings by Goldman Sachs Bank USA, Salt Lake City Branch Member FDICE terms and more at applecard dot com.
All right, we're answering listener questions today and the next question we have here is from Shelley from Australia, from down Under and.
Shelley, Shelley asks a really awesome question and a lot of people wanted the answer to.
She's questioning whether whether you have a real job or not?
Daniel, and I'm grave enough to play this question on the podcast.
Here we go, Hi, Daniel and Joge. I'm Shelley from Brisbane, Australia. And what I would like to know is how does physics actually work? How do you come up with a theory and then create an experiment to test that theory? What does a physicist actually do every day? You get up, you get your hoffee, you got work, and then what how do you go from a theory to an experiment then to an explanation.
Now I love that question. I love when she says And then.
What my question is, is Shelley your wife, Daniel, or is she sending a question? Is she wondering what do you do all day?
No?
But it's hilarious because that's what I do. I get up, I drink coffee, and then I go to work and then I go, Okay, now what.
I do today. So that's that's pretty much the answer. The question is the answer.
No, that's the two sides of academic freedom. You know, as a professor, you basically get to do whatever you like. On the other hand, nobody tells you what to do, so you have to come up with stuff to do yourself. Right, So every day you answer that question today what. Yeah, it's a great question. It sort of goes to the heart of you know, how is science done?
Right. I think she's maybe wondering, like, what's your day to day like, like she probably knows that there is this general process, but at any point, how do you decide what to do?
Yeah, so you know, day to day, of course, you get up, you get your coffee, then you start entering the three hundred emails that came in while CERN was awake in Geneva nine time zones ahead and I was sleeping. And then when you get through all that, you get to start to think about sort of the higher level science, right, And she asked a questions, you know, how do you go from theory to experiment? Like how do you come up with an experiment? And I think that's a really interesting question because a lot of times that is the way it works, Like a theorist comes up with an idea saying like I think maybe there's this new particle, or I think maybe there are black holes out there, and then it's a job of the experimentalist to figure out the answer. Right, is that correct or not? Do these things really exist or not?
But there's sort of a step before that, right where you I mean, I mean, you have to know what's going on in the field. You can't just posit these things out of the blue. You sort of have to know. You have to read what everyone else has done and what everyone else is doing, and you kind of have to try to ask a quest nobody else's answered.
Yeah, that's certainly true, although I get a lot of crackpot ideas from homegrown theorists that haven't yet done that, you know. But yeah, you want to come up with an idea. You want to come up with an idea that's new.
Like maybe the difference between a professional physicist is that you spend your life on it, right, You go to conferences, you talk to people, you know what's going on.
Yeah, you definitely have to know how things are done and you know what questions have been answered in that perspective. You can sort of think of science like a conversation. You know, we're trying to figure out what is the universe? How does it work? And you want to say something relevant, and so you have to think of, like, what is the question at hand? What is it we're trying to figure out right now? And how can I test it? And that's the bit about being an experimentalist. I'm an experimentalist. And you know what does the job actually involve, Well, it involves coming up with a way to ask a question of nature that will reveal the answer. You know, some theorist says, I think it's a new particle, the squiggly on. Well, then you can't just ask nature the question does quiggly On exist or not? It's not like nature some oracle, right that just answers whatever question you want. You have to trap it. You have to trick it, you have to corner it. You have to come up with an experiment. You can do something that a physical thing you can build that will tell you whether this thing exists. Because you know, if you do your experiment and the data is this, then you know the answer is yes, this is quiggly on. If you do the experiment and the data comes out differently, then you know the answer is not as quigly on.
Right.
But that's not trivial, right. That requires some cleverness. You have to think about the right way to sort of corner nature and make make it tell you whether this thing exists by revealing the answer in your experiment.
And part of that has to do with the null hypothesis. Right, like this idea then where you you sort of assume that this quiggly on doesn't exist, and you run some experiments and if you see something that clearly shows you that the quigli not existing is not quite likely, then that means you have something.
Yeah, exactly. We need conclusive evidence. We need to see data that couldn't have been produced if the squigglyon didn't exist, right, They could only be produced if the squigglyon existed. We need something that's in that sense unique, right. It has to be necessary and sufficient. And so often what we do is in my particular case, because I'm a particle physicist, is you know, we're colliding protons together, and if we want to ask the question does the squiggly on exist? And we think, well, what would the squiggly on look like in our data, how did it appear? You know, would it leaves splashes of energy over here? Would it leaves traces of its motion over there? And then we sort of look for those telltale signs. But then we have to think about what else could look like that. Is there anything else that could mimic it, anything else that could look like this SQUIGGLYI on but not actually be the squiggly on. So a lot of the experimental work that I actually do involves that kind of statistics, like figure out a way to look for this thing in a way that nothing else could mimic.
Yeah, And then but it also works the other way around, like somebody maybe did an experiment to look at something else and they found something weird, and so that doesn't fit the theory, and so then theories have to come up with an explanation for the data.
Yeah, And in my view, this doesn't happen enough. And I think a lot of people, especially in particle physics, think that it always starts theorist has an idea for a new particle, experimentalists just go check to see if that's true. Right, And there's actually a really lively debate right now about how do we do this in particle physics because the theorists predicted, oh, super symmetric particles will appear at the Large Hadron Collider, and then we didn't find them. And some people think, oh, that's a failure. But I think that experimentalists can be explorers that we don't have to just answer the question does this new particle exist? We can go out and look for weird stuff. Right, let's just see what's out there, you know, the way like when you land on Mars, you don't ask the question are there purple cats and dogs there? You just walk around and look to see if there's some new kind of life that will blow your mind. So, yeah, you're absolutely right. Sometimes an experimentalist find something weird, something that can't be explained with our current understanding, forces us to come up with a new theory when that can explain that. Yeah, and those those are the greatest moments in science.
If you ask me, okay cool, So okay, that's okay cool. So that's what you do, and then it's like eleven am, and then then what do you do?
Then it's time for my nap? Right then I do this awesome podcast with this cartoonist.
Yeah, I have no moral stand to criticize a lazy lifestyle or work life. But I think that's the kind of the general answer is that, you know, it's it's like a it's a conversation, right, Like you're it's not just you in a room trying to come up with ideas and theories and experiments. It's like you're conferring with other people. You're reading other people's work. You're you're trying to, you know, come up get clues from other people's results and things like that. Right, It's it's sort of a conversation and it's a process.
Yeah, And it has to be a conversation because science it's just people. Right. If you do some science and nobody reads it, then you haven't really pushed human understanding forward at all. Right, So you have to do something people are interested in so that they will listen and they will change sort of the common understanding. It'll move forward the wavefront of human thought.
Yeah, yeah, all right, Shelley from Australia. That's your answer, basically, coffee, coffee, coffee fuel, Yeah exactly. All right. Our next listener question comes from Alex from Connecticut.
Here we go, Hey, guys, this is Alex from Connecticut and I'm wondering if there's anywhere in the universe where dark matter is not present. Thanks, give up the good work.
Alex sounds pretty excited about his question.
He has a great trader voice. He should do movie Traders.
In a world where dark matter is not present everywhere. This is a great question because we've talked about how dark matter is. There's much more dark matter in the universe than normal matter, so it's a very natural question to wonder, like, is it feeling the universe is invisible? But is it? Is it everywhere?
Yeah? I mean there's not a little bit of dark matter out there. There's five times more dark matter than like all the stars and gas and clouds and planets out there.
Right, Yeah, exactly, It's a huge amount, and so it's very natural to ask where is it? And the answer to his question is yes, there are lots of places in the universe without dark matter, because it turns out that dark matter and normal matter basically follow the same distributions. That is, you can tell where the dark matter is just by looking for the non dark matter.
So who's following who, who's the stalker, and who's the celebrity.
It's, you know, something of a dance right there. We know about dark matter only because if it's gravitational effect on stuff, right, and so gravity affects dark matter and normal matter, and the two pull on each other, and so it's something of a dance as they tug on each other. And that's why they're linked together. That's why dark matter and normal matter are in the same places, because they're gravitationally attracted to each other. Now, because there's more dark matter than normal matter, you could probably say the normal matter is following the dark matter.
So invite. That's the only way that dark matter can interact with our matter, right that we know of is gravity.
So far that we know, it's the only way it can interact with our matter. It might have some interactions with itself that we don't know about, but to interact with our matter, to see it to affect our you know, the things that we can test and observe, gravity is the only way for us to probe that. And you know, people really interestingly people do simulations of the universe without dark matter. They're like, what would have happened if there wasn't dark matter? And things just don't coalesce as.
Quickly you run the universe, but you run it without dark matter, and yeah, get totally different results.
Yeah, this is amazing, Right, you can stimulate the whole universe. It's pretty incredible. And they ask, you, know, what would the universe look like under various scenarios, And that's really important because it helps them understand what was the various fraction of things in the very beginning and how sensitive are we do that? Like it was any configuration mostly going to give you galaxies and stars and planets or is it really sensitive? And it turns out that if you didn't have dark matter, then it takes a lot longer for stuff to clump. Right, The only reason we have stars and galaxies and planets is because gravity's gathered this stuff together. Turns out it's gotten a huge boost from all the dark matter helping it to pull it together. And without that dark matter would take billions more years to get all this structure. So we wouldn't even be around without the dark matter. So pretty much dark matter follows normal matter and helps out.
Yeah, so pretty much. When you look out into the universe and you see what for all the shiny stuff is like stars and planets in light that's kind of pretty much where dark matter is also.
Roughly that's correct. But if you look at the for example, a galaxy, there's a huge blob of dark matter also at the center of the galaxy. But then there's a we call it a halo. It extends beyond where the visible galaxy is, but mostly it's a blob centered at the visible galaxy.
Right right. I think the question is like a you wouldn't see, for example, like between here and Andromeda. You wouldn't see a giant blob of dark matter just floating by itself, would you.
You might probably not, though, yeah, probably not. But it's possible for dark matter normal matter to get separated, like in the Bullet cluster. You know, some of the dark matter and the normal matter got separated because of big collision, and the normal matter interacts with itself and the dark matter passes through. As far as we know, so there could be blobs of dark matter, but it's not like it's evenly distributed, right, So there's lots of places where we think there probably isn't any dark matter.
Okay, all right, So the answer to Alex's question is, yes, there are probably many places in the universe without dark matter. Dark matter clumps together in specific locations.
That's exactly right. This is one case we can give a very crisp answer. Yes, that's the TLDR Yes, alex yes cool.
Before we keep going, let's take a short break.
When you pop a piece of cheese into your mouth or enjoy a rich spoonful of Greek yogurt, you're probably not thinking about the environmental impact of each and every bite. But the people in the dairy industry are. US Dairy has set themselves some ambitious sustainability goals, including being greenhouse gas neutral by twenty to fifty. 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. Take water, for example, most dairy farms reuse water up to four times the same water cools the milk, cleans equipment, washes the barn, and irrigates the crops. How is US dairy tackling greenhouse gases? Many farms use anaerobic digestors that turn the methane from maneuver into renewable energy that can power farms, towns, and electric cars. So the next time you grab a slice of pizza or lick an ice cream cone. Know that dairy farmers and processors around the country are using the latest practices and innovations to provide the nutrient intents dairy products we love with less of an impact. Visit usdairy dot com slash sustainability to learn more.
There are children, friends, and families walking, riding on paths and roads every day. Remember they're real people with loved ones who need them to get home safely. Protect our cyclists and pedestrians because they're people too. Go safely California from the California Office of Traffic Safety and Caltrans.
Hey there, fellow globetrotters and destination dreamers. If you're anything like us, you'd note that life's too short for boring toasters and towels. That's why we decided to ditch the traditional wedding registry and went with honeyfund dot Com. Imagine your friends and family chipping in to send you on a dreamy, exotic honeymoon. Practical check, meaningful, double check. Plus, it's fee free and so fun for wedding guests to shop. So why get more stuff when you can have unforgettable experiences? Join the revolution at honey fund dot com and start your adventure today.
All right, and so our last question today comes to us all the way from Iran. So far as I'm from, Iran has a pretty interesting question about the shape of galaxies.
Yeah, here he is.
Hi, guys, my name is fire Zom. I'm from Iran. After listening to your episodes about the galactic collision and the gravity, I have a question to ask why all the galaxies and solar systems in the universe are disc shaped? I mean, if the gravity extends through all the dimensions the same, why they are planar?
Yeah, this is a great question too, right, yea. You look at the sky, you look at these galaxies, you look at the Solar system, and they all seem organized in these discs.
Yeah, they look like flat blobs, right, not like perfectly spherical blobs, but like flat blobs right.
Yeah, exactly, They're mostly flat and they're not spherical yet exactly. And so it's a very natural question. It's a totally typical thing to see out there in the universe.
Like if you look at all the models us of our Solar system, they look like hula hoops, right, one inside of the other. Why doesn't it look like, you know, like the model, the old model of the atom, where the hula hoops are in all kinds of directions. Why are the orbits of all the planets sort of pretty much in the same plane or at the same level.
Yeah, exactly. It's a great question because you could imagine otherwise, maybe the plants would all be zigging zagging around in lots of different directions, right, Yeah, even if they each have their own circle, they could be they could be all sorts of different directions.
Yeah.
The short answer to your question is angular momentum, right that This conserved quantity. Is that something you just can't get rid of. If an object, if a cluster objects, has angular momentum, it just can't get rid of it. But let's dig into that just for a moment. Let's just think about momentum at first. If you have like a rock in space and you push it, then that rock is going to go on forever unless something stops it, right, if it runs into something or whatever. Otherwise it will go on forever. And that's because it has momentum. And in our universe, momentum is conserved. Why is it conserved, We don't know, but we know that it is, and so things keep going if you push them. There's another kind of momentum which is about spinning. It's called angular momentum. You start something spinning, it'll keep spinning right right unless something stops it.
Right, And you're saying this applies to like the Earth going around the Sun. That's spinning around the Sun, and it's hard to not spin right like, it's hard to suddenly stop and go straight into the Sun.
Yeah, the only way for that to happen is for something from the outside to come and like bang into the Earth, and that could change. That could stop the Earth from going around the Sun, or stop the Earth from spinning. If you want to stop your anger momentum, you need to have something from the outside. But a closed system like the Earth and the Sun or the galaxy or whatever can't just stop spinning. That angle momentum can't just disappear. It has to has to be transferred somewhere or balanced out by the opposite moment mentum somewhere else, right, Like two objects flying through space can stop if they bang into each other right right, in the same way, two things spinning opposite directions could both stop spinning if they touch, and their angler momentum cancels out.
Right, and things kind of have anger momentum because they didn't start from rest. You know, like if you put two stones out in space, they're just gonna and there's nothing else around them. The two stones are just going to fly straight into each other. But if you if they're going at different speeds, then they're going to start circling each other as they get closer to the other.
Right exactly exactly, And so you can imagine sort of the history of our solar system or a galaxy, depending what you're thinking about. And started as a big cloud, right, a big chaotic cloud, everything shooting in random directions, and it might feel like, well, everything just sort of cancels itself out, But there's one place where you can draw line through it, and turns out that everything is orbiting around that, right. That's called the center of rotation. And it's sort of like if you're holding up a stick, right, this one place that balances the stick where it'll be pulled on by gravity the same amount on both sides. The same way you find this big cloud, there's some line you can draw through it around which everything is rotating.
Yeah, and that that point is where basically the center of the galaxy or the center of the Solar system is going to form, right.
Yes, exactly, and so everything is rotating around that and then gravity does its thing. It pulls things together as much as it can, and so but it can't shrink everything down too much because it's spinning, right, and the spinning keeps it sort of fluffed out, but only in the direction perpendicular to that line, to that rotational axis. So along that rotational axis, gravity can swish things down as much as it wants, right, there's nothing preventing it. But around that axis things have to keep spinning, and that spinning keeps them from getting too close to the center. The same way, like the reason that the Moon doesn't fall to the Earth is because it has velocity, right, it's spinning around us, and so angler momentum can't go away and has to go somewhere, and it keeps the stuff from falling too far into that central axis. So that's why everything becomes a disk.
Yeah, And that's kind of why all the hula hoops sort of merge. Right, Like, let's say the Earth is on a hula hoop orbit around the Sun, right, so we're on a disk in a circle, are and an oval, And like, let's say that there was another planet that was also going around the Sun, but it was going in a totally different hula hoop, like totally maybe perpendicular to ours. And I think the idea is that, you know, the attraction between our planet and that other planet, it's not going to make us go closer to the Sun or like destroy our orbit, but it is going to make the hula hoops sort of merge together, right.
I think over a long period of time, Yeah, they would both come to orbit in another plane that's sort of like the average between the two, because the rotational center would be some axis that's perpendicular to that new plane. Yeah, this is the kind of thing it's easier to describe in front of a chalkboard.
We'll use the chalkboard of the mind. That's kind of the idea is that everyone at at the beginning, everyone's rotating and going in their own orbits. But over time, all these orbits sort of align with each other. And so that's why galaxies and solar systems they all look like flat disks.
Yeah, exactly, the direction perpendicular to that disc. Things can pull together, and collisions and attraction all that stuff helps balance it all out and pull.
It together flattens it.
But along that disc it can't get too close in because of angler momentum. It has to keep spinning, and that spinning keeps it from falling in towards the center. Yeah.
So like gravity just squishes in one direction, but it's can't squish it in the other directions because that's where the spinning is happening.
Yeah, And his question was really interesting because he asked about the dimensions, And you're right that gravity works in all these dimensions, right, But because we have angler momentum, and anglermentum is defined along a plane two dimensions, it makes it sort of asymmetric, right, that it doesn't get treated the same way. One really fun exercise is to think about, like what would physics be like in four dimensions or in five dimensions? That can kind of blow your mind. But if we had like a four dimensional space, then you would actually have two different axes of angular momentum that would be conserved, and so things would look even crazier.
Wow, what would you call that?
A blob?
Blob?
And this is why I'm not on the Physics Naming Committee.
All right, cool. So, and the idea is that gravity does work in all directions, but it has trouble bringing things together in the direction where they're spinning. Yeah exactly, And so but it can bring things together in the direction they're not spinning. And so that's why maybe things start out in as a big blog, but then they eventually get squished down and they pick kind of the average spin direction.
Yeah exactly. So gravity is the great flattener of the universe.
The great flatter the great squisher.
It squisher.
Yeah, you just renaming squish t.
Yeah, there you go. You got Newton, You've got Einstein, and then you got Cham. What was Cham's contribution to theory of gravity? Oh, a better name? That definitely definitely is up there.
And then when I break into quantum physics will be the squishiton.
I'm gonna go devise an experiment to look for the squishitar.
That's right, I'm gonna call it to squishiton, and then go get some coffee and then I'm done.
Boom, there's my day.
Yeah, and then what then what? All right?
So those were awesome questions. I love your questions. You might think I'm gonna send him a question he's never gonna answer. I will surprise you. Send us a question, you'll get an answer. You might even hear your voice on this podcast eventually.
Yeah, and if you're Daniel's wife and have also a question about his lifestyle or habits.
Just interrupt me anytime, anytime.
He'll probably answer that question without interrupting you. That might even work.
Out podcast with an audience of one.
Well, thanks for joining us once again and again. If you have questions, please send it to us at questions at Daniel Andhorhead dot com.
Thanks for listening and thanks for asking questions.
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 Daniel Andorge dot com. 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 you as dairy dot COM's Last Sustainability to learn more.
There are children, friends, and families walking, riding on passing the roads every day. Remember they're real people with loved ones who need them to get home safely. Protect our cyclists and pedestrians because they're people too. Go safely California from the California Office of Traffic Safety and Caltrans Hey.
Their fellow globetrotters and destination dreamers. If you're anything like us, you'd note that life's too short for boring toasters and towels. That's why we decided to ditch the traditional wedding registry and went with honeyfund dot Com. Imagine your friends and family chipping in to send you on a dreamy, exotic honeymoon. Practical check, meaningful, double check. Plus it's fee free and so fun for wedding guests to shop. So why get more stuff when you can have unforgettable experiences? Join the revolution at honey fu n D dot com and start your adventure today.
