Daniel and Kelly’s Extraordinary Universe - Listener Questions 31: Photons, aliens, and baseball

Episode Date: October 25, 2022

Daniel and Jorge answer questions from listeners like you! Send your questions to [e-mail]  See omnystudio.com/listener for privacy information.

This is an I-Heart podcast. December 29th, 1975, LaGuardia Airport. The holiday rush, parents hauling luggage, kids gripping their new Christmas toys. Then, everything changed. There's been a bombing at the TWA terminal. Just a chaotic, chaotic scene. In its wake, a new kind of enemy emerged, terrorism. 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. My boyfriend's professor is way too friendly, and now I'm seriously suspicious. Wait a minute, Sam. Maybe her boyfriend's just looking for extra credit. Well, Dakota, luckily, it's back to school week on the OK Storytime podcast, so we'll find out soon. This person writes, my boyfriend's been hanging out with his young professor a lot. He doesn't think it's a problem, but I don't trust her. Now he's insisting we get to know each other, but I just want her gone.

Hold up. Isn't that against school policy? That seems inappropriate. Maybe find out how it ends by listening to the OK Storytime podcast and the IHeart Radio app, Apple Podcasts, or wherever you get your podcasts. Get fired up, y'all. Season two of Good Game with Sarah Spain is underway. We just welcomed one of my favorite people, an incomparable soccer icon, Megan Rapino, to the show. And we had a blast. Take a listen. Sue and I were like riding the line. Bikes the other day. And we're like,

we're like, people write bikes because it's fun. We got more incredible guests like Megan in store, plus news of the day and more. So make sure you listen to Good Game with Sarah Spain on the IHeart Radio app, Apple Podcasts, or wherever you get your podcasts. Brought to you by Novartis,

founding partner of IHeart Women's Sports Network. Tune in to All the Smoke Podcast, where Matt and Stacks sit down with former first lady, Michelle Obama. Folks, find it hard. hard to hate up close. And when you get to know people and you're sitting in their kitchen tables and they're talking like we're talking. You know, you hear our story, how we grew up, how Barack grew up. And you get a chance for people to unpack and get beyond race.

All the Smoke featuring Michelle Obama. To hear this podcast and more, open your free iHeartRadio app. Search all the smoke and listen now. Hey Daniel, I have a question. Do you have to be really good at math to be a physicist? Well, you know, it depends a bit. On what? Whether you want to be a good physicist or a bad physicist? Actually, I think that the most evil physicists are probably the ones that are best at math. Do you say that because you're not good at math? I say that because I'm not an evil physicist.

That's what all evil physicists say. That's my answer to that question. But to answer your other question, I think it depends a little bit on the kind of math you have to do. What do you mean? Like complex or simple? Well, you know, for example, I have no trouble doing calculations and boosts and rotations in special relativity, but I mess up time zones at least once a week. Yeah, those time zones can be super complicated. You have to like add numbers and subtract numbers. That's crazy. Sometimes you have to subtract different numbers based on where you live and where they live. It's crazy, man. Yeah, I know. There's like 24 time zones. That's a lot for one simple brain to handle.

Too much for me. Does Not Compute. Beano, hey, we're late for our recording. Hi, I'm Jorge M. Cartoonist and the co-author of Frequently Asked Questions About the Universe. Hi, I'm Daniel. I'm a particle physicist and a professor at UC Irvine, and the thing that's preventing me from having a far-flung, evil empire is the time zones. Oh, man, you're like Lex Luthor with a special weakness? Like, all we have to do is, what, schedule or meeting with you?

And you'll be defeated. Exactly. I'll show up at the wrong time and get frustrated and my plans would just fall apart. And a SWAT team will be waiting for you to arrest you. But, you know, it's more complicated than you make it sound because it's not just that there are 24 time zones around the globe and that my team is actually spread out over several of them. but the time zones shift independently.

There's two weeks of the year when Europe doesn't have daylight saving time and we do. And then there's some states in the U.S. that do and don't. It's a nightmare. Well, they have this new thing called computers, Daniel, that will do all of these calculations for you. I don't know if you are up on this technology, but all you have to do is typing your local time zone on the computer and will tell you what time it is in other parts of the planet. That's a good idea. We should use computers to help with physics.

I don't think anybody ever thought of that before. I'm going to get right on that. You don't even need AI or anything. You just need I. But anyways, welcome to our podcast, Daniel and Jorge Explain the Universe, a production of iHeartRadio. In which we tried to translate things much more complicated than the local time in Geneva. We want to understand the very nature of the universe itself. If you dig down into the firmament of human knowledge, can we penetrate even below that to understand the actual bedrock foundation of the universe?

Can we take it all apart and understand the very basic pieces of reality and translate those into our minds so we can play with them, contemplate them, and understand why the universe is the way that it is and not some other way? We ask all those big and hard and difficult questions on the podcast, and sometimes we even answer a few of them. Yeah, because life seems pretty normal, pretty sensical on an everyday basis, but as you drill down into the universe and you look out into the cosmos, things get a little bit complicated. Even time itself is more complicated than most people think. It's relative and it's different depending on where you are in the universe, not just here on Earth. And the way the universe works at the smallest scales and in the vicinity of black holes is very different from the way the universe seems to work in our normal everyday lives. So we're forced to try to translate this unknown, unfamiliar universe into rules that we do find familiar.

And along the way, we use mathematics as a bridge to guide us into the depths of the unknown truth. Because the way we familiarize ourselves with the universe is by asking questions, wondering how it all works, how can it all make sense, and what kind of math do I need to know to predict what's going to happen? And we ask questions about the universe because we are curious people, and we know that you ask questions about the universe because you are all curious people. And we want to encourage that we love to hear your questions. We want you not just to listen to us blah, blah, blah, blah about the nature of the universe, but to ask your own questions, to make sure the ideas we are talking about are really clicking together in your mind that you can do more than just listen

along and nod but that you can take these ideas and apply them to new situations and if that doesn't quite work we want you to reach out and send us an email to questions at danielanhorpe dot com so we can help straighten it out for you yeah because everybody has questions and sometimes the questions you might have about the universe are the same questions that leading edge physicists have about what's going on that's right like what time is it right now in geneva yeah i guess technically You're a leading-edge physicist and you don't know what time it is, so it's cutting-edge research to look at your watch, Daniel. It's the very forefront of human knowledge. Am I the only one here because I'm late for this meeting or am I early for this meeting or is this even the right month for this meeting?

Well, maybe you should upgrade from using, you know, sand clocks or sundials to know what time it is. I know you like to be like OG physicists, but, you know, those computers nowadays are pretty good. Yeah, they are pretty good. But I think I need even more basic help than that. I've shown them for flights at the wrong day. I've shown up for flights at the wrong airport. I've landed the wrong airport. You know, sometimes I think there's even a limit to what computers can do to help somebody.

And you say I'm the one that's always late. Sounds like you're the one with a bigger problem here. Well, I'm just glad you're here at the right time. At the same time as me. It's one of the deepest questions in the universe. Does Daniel actually know what he's doing and where he's supposed to be? We do get questions from listeners and we love to answer them here on the podcast. because we get some pretty amazing questions.

Our listeners are pretty awesome, pretty curious. And also they sort of know their stuff, right? They really do. I got a lot of really sophisticated and well-thought-out questions. So if you're out there and you've been listening to the podcast for several years and you have burning questions about the universe, don't be shy. Please write to us. We really do want to hear from you and you really will hear back from us.

Write to questions at danielanhorpe.com. So today we have three awesome questions from listeners and they range from how do you see photons, what color photons are, and also what are the ingredients for life? Or the not ingredients for not life, I guess. It's kind of a complex question. It's also involving baseball. So to the end the podcast, we'll be tackling. Listener questions 31, which somehow is coming after listener questions 32. Who says we have to do listener questions in order anyway, man? Or you say we traveled somehow back in time, Daniel? Yeah, that's a much simpler explanation than Daniel got confused and scheduled these out of order. We've gone back in time to answer ancient listener

questions. Did you schedule it the wrong time zone or something? Or are we like 32 time zones back? Any number bigger than 30 is basically infinity. You know, I like dealing with very small things and very small numbers of things. There's a reason we don't have 30 quarks in the standard model. You know, we just lose track. Boy, we pay you to be a physicist. I'm starting to think maybe we should should see some bonifas or have you do a test or something. Maybe I should just rely on the computer to organize these podcasts. I thought you did. Don't you have an Excel spreadsheet with the numbers and stuff?

Are you saying there's a user error here? It is possible to make mistakes in Excel. That's true. But this is the 30, I guess technically 32nd time we answer listener questions, even though this is the 31st episode, right? This is the second time. We've said it's the 32nd time. And we love answering listener questions.

So let's jump right into it. Today's first question comes from Sam, who has a question about how we see photons. Hello, Daniel and Jorge, and thank you for your wonderful podcast. And especially thank you for being so accessible to answer listener questions. I have a follow-up question

to a recent listener's question. In that podcast, there was discussion about photons and their speed around black holes. The discussion made references to things like two observers of a photon's movements and seeing photons moving away from us. I understand that we infer the direction, velocity, and composition of objects

based on the information conveyed by the stream of photons that I receive, which I, or my instruments used to construct the details of that object. But I was confused about the discussion and idea of two observers seeing the same photon or seeing a photon moving away, as I didn't know how that information could be sent by a photon

and to two observers at the same time. Thanks again for helping me and others better understand this weird universe. All right, awesome question. Thank you, Sam. And I guess it's a follow-up question to a question we had in an other episode. But is it from an episode we did in the future or in the past? It's an episode we haven't yet done in the past. And so Sam is psychic?

Maybe Sam is just many time zones ahead of us somehow in Geneva. Oh, right. Is he in Denmark or something? They're pretty smart in Denver. They are pretty smart. They can see the future. But I guess this question has to do with this thought experiment we talked about in an episode before about how do you tell if photons change their path around a black hole? Yeah, we were talking about photons having different speeds than just the speed of light.

And if you were far away from a black hole, for example, you could see photons get bent around a black hole. You could see them crawl out of the gravitational well very, very slowly. And we had a whole conversation about how the speed of light for photons is really just a speed of. light locally and that far away photons might have all sorts of weird different speeds. It's a really complicated topic in general relativity. Right. I think the experiment was that, you know, you have a black hole out there in space and there are two photons kind of flying near it, you know, one near it or one less near it, they're

going to do different things. And I think Sam's question is like, how do we know what those photons are doing if they're moving away from us or they're moving perpendicular to us? Like, how do you see a photon moving if it's not, you know, hitting your eyeball? Yeah, so it's a really great question because Sam is thinking like, how do you actually do this experiment? Is this something physicists are just thinking about or is this something you could actually measure in the universe, which is a really important thing to do because physics is more than just like thinking about things. It's also about going out there in the universe and making measurements. Many times we've thought the universe worked one way and then went out there to confirm it and discovered, oops, nope, the universe works a different way.

So definitely doing experiments and making measurements, a vital part of learning about the universe. Yeah. So I guess maybe let's break it down, Daniel. Like if you have a photon out there flying through space, how do you actually see it if you can't see it? Your mental picture of a photon is probably misleading. You're imagining like some pulse of light that flows through the universe. Maybe it flies past you. And you might even be thinking about it like glowing. That you could see a photon fly by you because in the end it's light, right? You can see light.

Well, the truth is that you can only see photons that actually hit your eyeballs. Like if you're in a dark room and a photon flies right in front of your nose but doesn't hit your eyeball, you can't see it. It's invisible to you. you would never know that it's there. You mean, it's not like a laser beam in a Star Wars movie, right? Like a laser gun shot, right? You won't see a stream of light flying past you. Exactly.

Like in those spy movies when they have to do a dance through a room full of laser beams and not interrupt any of them. The reason you see those laser beams is because they're reflecting off dust in the air. Or if they're really intense, maybe they're even ionizing the air so the air glows. But in a vacuum, if the photon is moving unobstructed in front of you, you wouldn't see it. It would just pass right in front of you and be totally invisible. Right. And also in the case of the laser that you can see, it's like it's shooting a whole bunch of photons and some of them are hitting the dust particles or the smoke particles in the air

and then bouncing into your eyeballs. But the other ones are just going right through, right? Exactly. And in the more realistic spy movies, the lasers are invisible and they throw a handful of sawdust into the air to make the lasers visible again. So the point is that you can't actually see photons unless they hit your eyeball or some detector. So he's absolutely right that a photon passing by a black hole and getting bent and shot off in another direction, you couldn't literally see that with your eyeballs. Right, in a vacuum.

Although didn't we talk about one, some special materials or some special situations where like a photon makes like a wake or something? We did talk about the really amazing experiments that show that the human eyeball can see a single photon. And they do this by splitting a photon in two. There are special materials that will take a photon and like split it into two of lower energy. And so then you can see one while the other one is like undisturbed.

But that's not technically the same thing. So a single photon traveling out there in the vacuum, you can't actually see it go pass unless it hits your eyeball. Exactly. Or unless you have a friend whose eyeball it hits and then they tell you about it. So then you couldn't see a photon traveling away from you either, right? Yeah, exactly. You shoot a laser beam out into the universe.

You're not going to see that beam unless it hits something and bounce. is back, right? If it hits dust or smoke in front of you, you'll see where it is. Like at night, if you shine a flashlight up at the sky, you can see the beam a little bit if it's reflecting off of dust, but mostly it's invisible. The aliens on Alpha Centauri that receive your photons, they can see it eventually, but you can't see the photons unless they've hit something and come back to you. Right. So then in these thought experiments where you shoot a photon at a black hole, in theory, the photon will slow down, right? As it approaches the black hole and moves slower than the speed of light to you, but you won't actually

be able to see it doing that, right? So to be very precise and specific, if you're just a single observer and you're shooting that photon towards black hole, then Sam is exactly right. You won't see it. But this is a thought experiment, and we do this in physics all the time. We try to imagine what might happen in various scenarios. In those thought experiments, we're often skipping an implied step. If we were to actually do that experiment, it would look different. We would set up detectors everywhere or we would have huge teams of observers in lots of different places so they could see stuff. That's kind of boring and a lot of work. So we don't talk about that step when we set up the thought experiment. But Sam's exactly right that in order to actually

detect those photons to do that experiment, you would have to have more than just the one observer. You'd have to have whole teams of observers and careful rules about how they synchronize and communicate that information. Yeah, you have to figure out what time zones they're in. I mean, that would just be impossible for physicists. You just sit there in the Zoom waiting. right, all by yourself for somebody to send you the details. We're never going to get this paper out. Right. I think what you're saying is that in order to see what happens to a photon that flies near a black hole, you would have to maybe put a detector near the black hole or something, right?

And measure how long it takes for the photon to get to that detector. Yeah, exactly. And this is true in lots of thought experiments we do about special relativity. Lots of examples of people going near the speed of light and measuring their time and looking at each other's times. You often have to have like whole teams of observers to actually conduct those experiments in real life. So we've thought about how that might work and we've proven ourselves that technically it's possible to make these observations if you have the right team. So we don't usually talk about that part in the thought experiment because it's like the boring details

you would actually have to organize to make things work. Right. I think maybe what Sam is getting at is that in the thought experiment, you talk about what happens to one photon as it goes near a black hole. It would slow down. But maybe in a real life experiment, it wouldn't just be one photon. Like you shoot maybe two photons at the same time and one of them you would measure. halfway through and the other one you would measure in another point you know what I mean like you you would need more than one photon you can't just know what's going to happen or what is happening to one photon yeah sometimes you can measure what happens to just one photon although a lot of these experiments you want to know

what would happen in various circumstances so you're right you would need multiple photons and anyway you'd want to replicate your experiments and make multiple measurements so practically speaking that's exactly right you'd want a stream of photons so sometimes you want to separate them so you know which photon is which. Like an experiment where we're figuring out if the human eye can see a single photon, it's very important to know when one photon arrives at the eye, so you can know if it arrived and if the person saw a real photon or just made of a flash. So sometimes you want them to be well separated. Right. So I guess that's the answer to the question then is that you can't see a

photon moving away from you, but you could set up a detector ahead of you to catch that photon, right? And then that way you would know what happened to that photon. And you can imagine filling the universe with detectors or with assistants you know to take note of things and later synchronize them against your clocks and so if you add that sort of implicitly to all the thought experiments you can think more concretely about how you would actually do these things right but unfortunately that's boring and a lot of work which um apparently physicists are not willing to do because then you have to get out of your couch i guess well you have to organize it and everybody shows up at the wrong time and so like yeah yeah and then so it's probably

Practically impossible. Exactly. At least one physicist's answer. Maybe you should try a harder working one to see what they say. That sounds like a good idea. That means the work is on you, Sam. All right. Well, let's get to some of these other questions about the ingredients of life

in maybe other planets and also about the red shifting of photons. 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, chaotic.

seen 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. My boyfriend's professor is way too friendly, and now I'm seriously suspicious. Well, wait a minute, Sam, maybe her boyfriend's just looking for extra credit. Well, Dakota, it's back to school week on the OK Storytime podcast, so we'll find out soon.

This person writes, my boyfriend has been hanging out with his young professor a lot. He doesn't think it's a problem, but I don't trust her. Now, he's insisting we get to know each other, but I just want her gone. Now, hold up. Isn't that against school policy? That sounds totally inappropriate. According to this person, this is her boyfriend's former professor, and they're the same age. And it's even more likely that they're cheating.

He insists there's nothing between them. I mean, do you believe him? Well, he's certainly trying to get this person to believe him because he now wants them both to meet. So, do we find out if this person's boyfriend really cheated with his professor or not? To hear the explosive finale, listen to the OK Storytime podcast on the IHeart Radio app, Apple Podcasts, or wherever you get your podcast. 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. Do this. Pull that. Turn this. It's just... I can do it in my eyes closed. I'm Manny. I'm Noah. This is Devon. And on our new show, no such thing. We get to the bottom of questions like these. Join us as we can. 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. Listen to no such thing on the iHeart radio app, Apple Podcasts, or wherever you get your podcasts. Your entire identity has been fabricated. Your beloved brother goes missing without a trace. You discover the depths of your

mother's illness, the way it is echoed and reverberated throughout your life, impacting your very legacy. Hi, I'm Danny Shapiro, and these are just a few of the profound and powerful stories I'll be mining on our 12th season of Family Secrets. With over 37 million downloads, we continue to be moved and inspired by our guests and our guests. their courageously told stories. I can't wait to share 10 powerful new episodes with you, stories of tangled up identities,

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All right, we are answering listener questions here today, and we have some awesome questions here from people about the ingredients of life and also the color of photons. Our next question is from Christian. Hi there, Daniel and Jorge. I just wanted to start off by saying I love your podcast. I've been watching baseball lately, and that's inspired my question. So in baseball, we see a lot of teams do what's called recreation in the aggregate.

So they maybe lose a good player or a great player, and they try to recreate that player's effect with multiple good players. So my question is this, you're the GM of the universe. For whatever reason, we lose the crucial elements of life, water, carbon, oxygen, et cetera. Maybe they're traded to the Mets, whatever. How would you, as GM of the universe, recreate these crucial elements in the aggregate? Are these elements so unique that no other elements or combination of elements could recreate their effect. What qualities in particular make these elements so conducive to life and why might

they be unique? Thanks again for taking the time to review my question and go twins. All right. Awesome question from Christian. Although he made a crucial mistake in that question. What's that? He assumed we followed sports. We can't answer your question, Christian, because we have no idea what you're talking about. Sorry. Yeah. Next question. No, I'm just kidding. I did see the movie Moneyball, so I think I'm sort of qualified to answer this question. That's right. Jorge did his homework. That's right. Yeah. And in this case, the GM is Brad Pitt, right? Exactly. Is Brad Pitt going to also play you in the movie about your life?

Yeah. I should play Brad Pitt in this movie. Right. Yeah. That's definitely happening. Yeah. Yeah. So this is an interesting question. It's almost like fantasy football mixed with physics. Or would you say it's fantasy physics? It's more like fantasy chemistry, yeah. But it's really interesting question about like how life might operate without the basic building blocks that we use. And it's not just a fantasy, you know, biochemists have been thinking about this for a while.

Is the recipe of life that we have here on Earth the only possible recipe? Are we being narrow-minded when we look for biosignatures on other planets that are similar to the ones on our planets? Shouldn't we be thinking about other ways life might evolve so that we can anticipate it and look for it more effectively in other places? I think it's a really cool thing to think about.

Yeah, and so I guess specifically his question is like if you're the general manager of the universe, I guess, or Earth, and you're trying to make life, and you have these ingredients, water, carbon, oxygen, but somebody took away one of your ingredients, or they got traded to, I don't know, another universe or another planet. Could you find a way to replace these elements to still make life? Yeah, you know, I know that baseball fanatics are pretty fanatic,

but he's basically putting the GM at the God level of the universe here. Hmm, yeah, godly manager. I guess baseball is Christian's religion. But it's a really interesting question, whether you could make life with other fundamental bits of biochemistry. And Christian specifically asked about carbon and water and oxygen. And he's right. Those are essential bits in our kind of life. And so it's fun to think about whether you could build life without them.

Right. And I guess specifically, like, you know, we should go through each one. Like if you took out carbon, could you still find something to replace it or a set of other molecules or atoms to replace it to make life? Yeah. And so to answer that, you have to think about like, well, why do we use carbon? Why is life carbon based? What is the utility of carbon? If you're going to replace it, what are the kind of thing you're going to look for? And carbon is pretty ubiquitous in life. I mean, what we call organic molecules are the ones that have carbon in them, right? And there's a reason for that because carbon is very flexible. The way that its electrons are organized means that it can build all sorts of really interesting bonds. It's like that really useful Lego brick that you can attach other stuff to. And so you can make all sorts of really interesting molecules and complicated molecules that can swap around a lot. And so it allows for us to build really complex things like DNA that can store a lot of information. And it allows us to create really complicated metabolisms, right? To move energy around and create the processes that we need for life. So it's really at the foundation of all the

biochemistry of life as we know it. Interesting, right? Is it true that all life as we know it uses carbon? Like do we know of any life that doesn't use carbon? We do not. absolutely not. We've never seen any life on Earth that doesn't use carbon. And you're saying it's because carbon has something unique about it. What is it that's unique about it? Like it has its electrons or the right number of electron orbitals or the orbitals are in a special position. What is it about carbon? Yeah. So the chemical properties of any element are determined by like how many electrons it has and how many empty slots it has in its outermost ring. And carbon has just the right number that it makes it easy to like stick them together to make these bonds in a useful way and also

to stick other things onto it. So you can stick like iron and magnesium and zinc and nitrogen onto these like chains of carbons. Carbon is useful because you can stick a couple of carbons together and still have room for another one and another one. So it can make these very long chains and then you can have like other elements stuck onto the side. It's not limited in that way. Other elements like xenon, for example, all their orbitals are just full. So they don't like to interact with anything. And yet other elements, you can stick them together in a couple of ways, but they're sort of limited because the number of the electrons they have free in their outer orbital. So carbon is just like a very versatile element? Right. It's versatile, but is there something unique about it that lets you make complex molecules?

Like can you make complex molecules out of something else? Or just not as well, you're saying? So it is possible, actually. If you look through the periodic table, there are other elements that have similar behaviors. Silicon is the most famous example. It could also build really long chains of itself so you can get big complex molecules, molecules that can like carry a lot of biological information.

And so it's been famously proposed that life elsewhere in the universe might be made out of silicon instead of carbon. It's like an alternative. You know, it's like Duplo bricks instead of Lego bricks. Ooh, the knockoff. But I guess what's the difference between carbon and silicon? Do they have the same number of electrons?

Do they have different, you know, orbitals or atomic weight? Well, Carmen is much. further down on the periodic table, right? It's element number six, where silicon is 14. And so you might think, oh, well, that makes carbon much more common in the universe and therefore much more just likely to be useful for life. And it's true that carbon is much more common in the universe because remember where these elements come from, they come from fusion at the hearts of stars. You start with just hydrogen from the big bang. You stick it together. You get helium in the hearts of really, really hot stars. You can make carbon. You build from there to make the heavier

elements. So in the broader universe, carbon is much more common. There's like 10 times as much carbon in the universe as there is silicon. But actually, here on Earth, silicon is 900 times more common in the Earth's crust than carbon. So we're actually sort of drowning in silicon here on Earth, but of course our life is made out of carbon. So that sort of suggests that like carbon is much more useful. It's much easier way to start life than silicon is, even though silicon is much more common here on Earth. You're saying silicon has a higher atomic weight, like it's heavier. It has more protons and the nucleus. And does it also have more electrons in its orbit? Yeah, the neutral atom will have the same number of protons and electrons. So carbon has six protons and silicon has

14 protons, which means it also has 14 electrons. But wouldn't having more electrons give you more ways to like interact or form bonds with other atoms? It's not just the number of electrons in total, right? It depends on the number of electrons mostly in the outer layer, because those are the ones that do the interacting. When you click elements together, you do it by having their outer shells interact. Electrons don't really go deeper into the lower shells. It really just has to do with how many you have free in the outer shells that let you click these things together like Lego bricks. Right. And Silicon can't form bonds with other important atoms, right? That's one of its problems. Yeah. So carbon is really cool because it can easily make bonds with like phosphorus and

sulfur and metals. And while silicon can make long chains of itself, it's not as good at connecting with these other kinds of things. And so like oxygen and nitrogen and phosphorus, it's not so easy to build like biochemical molecules with all these other little bits in it out of silicon than carbon. So from that perspective, carbon is a better choice for making a diversity of chemical combinations. I see. I think you're saying that it's still possible to make life with silicon,

but maybe because it's not as versatile, you couldn't maybe do as many neat tricks with your molecules as you could with carbon, which maybe would make it harder to kind of evolve life, I imagine. It might make it harder. There's certainly fewer things you can do with silicon than carbon,

though actually being prevented from like latching onto all these weird other things can also protect life, right? If, for example, the basic building blocks of your life can't grab onto heavy metals, magnesium, and zinc, then you're sort of shielded from some of those impurities because they don't engage with your biochemistry. So like silicon-based life might be more protected

from heavy metals, for example, whereas we find like mercury and lead poisonous in our biochemistry. So there's sort of a pro-anacom there. And as you said, there's much more silicon here on Earth than carbon, and yet life chose carbon as its building box. Yeah, exactly. And so even though there's more carbon in the universe, Here on Earth, we don't have like an average scoop of the universe stuff, right?

Hydrogen is the most common thing in the universe by far, but we don't have very much hydrogen here on Earth because it was mostly gobbled up by the sun and by Jupiter. So the process that formed the Earth didn't get like an equal sampling of everything. And especially here on the crust, there's a lot more silicon. We think that the carbon-based molecules were more volatile and it sort of like boiled away early on. And so you're right. even though we have more silicon than carbon, we ended up making life out of carbon. And that's just, you know, one example.

We don't know if that's typical, if it's common, if everywhere life will start from carbon, it might be unusual. It might be like a single flash in the pan. So is carbon super unique to make life? Or can physicists and chemists imagine using another atom to make life? Like I know silicon, maybe it's not a great candidate, but are there others? There are not a lot of other great candidates. In terms of replacements for carbon, it's basically silicon or nothing.

Oh, wow. So if there is life out there in the universe, it's probably carbon too, right? Probably carbon or silicon or weirder than anything we have imagined so far, which could be very unlikely or very, very common. What do you mean weirder? Like it uses, I don't know, titanium. Well, we're starting from some assumptions that the biochemical processes and information storage that's part of our life will be necessary for other kinds of life. And maybe that's not true. And so maybe there's a completely different way to organize self-sustaining information, you know, loops of plasma currents inside of stars that can just be made out of hydrogen, for example, where the complexity comes from, you know, the structure of the plasma instead of the structure

of the atoms that you're making out of heavier elements. We don't know what we haven't yet imagined about the ways that life can be. Right, right. I wonder if like all life in the universe being made out of carbon means that we're more likely to be eaten by aliens. We're more likely to be edible to aliens. Yeah, absolutely. That's what I mean. Are we, I mean, we're all, you know, tasty to each other, perhaps. All right, well, let's tackle some of the other ingredients of life.

What if we had all of the ingredients of life except another one of these crucial ones, water? Like, what would happen if we didn't have water? Yeah, it's a great question. And maybe not a necessary one because remember that, like, water is everywhere in the universe. It's not like water is that hard to find. I know on space operas, they're always talking about finding water and selling water. But, you know, we have like whole planets of water out there. Neptune and Uranus, they're called ice giants for a reason.

There really is a lot of water out there in the universe. But anyway, it's fun to think about where life might start if there isn't much water around. You know, for example, there are moons of Jupiter and Saturn that have oceans that could be like made out of other kinds of liquids. Ammonia, for example, or methane. And so it's fun to think about whether or not you could have life that uses other solvents. the role of water in life basically is to dissolve stuff so that things can slosh around and exchange it's hard to have life if everything is like a solid crystal because then it can't like exchange information and transfer energy you need some flow some movement so that energy

and information can sort of move around and make things happen it's like you need it as a medium right not just for life to like develop in and for like books to move around in but also like inside of our bodies you need water so that you can circulate stuff right and i i can move from one place to the other. Yeah, you need these basic processes to happen. And so you need some kind of flow. Just like if you have a party, but nobody's talking to each other, then nothing's really going on. And so to get the party started, you need some way for these bits and pieces to interact.

And the best way we know is to dissolve them all in water. And then they can just sort of slosh around when they bump into each other, good stuff happens. And so people have thought about whether this is possible in other kinds of chemicals. And one fun alternative is ammonia. Ammonia is also fairly common in the universe. And like water, it's liquid over a large temperature range and can also dissolve a wide variety of compounds. Wait, so do all life on Earth, as we know it, use water as its basis?

Do we know of any other life that doesn't use water? We don't know of any life that doesn't use water. It's all water based. And you know, the basic cell has water inside of it. Life basically is a bag of water with other stuff dissolved into it. But haven't they found bacteria in like, you know, sulfur pools and, you know, at the bottom of volcanoes and things like that? They have found bacteria basically everywhere, but they are all little bags of water. Okay. So then ammonia is interesting because it's also a liquid.

And what's the chemical formula for ammonia? Ammonia is NH3. So it's nitrogen and three hydrogens. And, you know, there's plenty of hydrogen out there in the universe. And nitrogen is also not that rare, although it's not as common as oxygen. But there's plenty of ammonia out there in the universe. Okay. So then out of all the liquids out there that could form the basis of life, why is ammonia a better or a candidate than everything else,

but maybe not as good as water? Well, it's a good candidate because it has some of the same properties as water, meaning that it's liquid in a large temperature range. For life to happen in ammonia, you need ammonia to be liquid, to be liquid. So for this to be likely, you want it to not have to have very special circumstances. And so like water has 100 Celsius degrees in which, it's liquid, ammonia also has a pretty broad range. It's liquid from negative 78 to negative 33C. But there are other liquids that are liquid over a wide range. What makes ammonia special?

Well, ammonia can dissolve a bunch of stuff. Also, ammonia has a large heat of vaporization. That means if you have like a lake of the stuff, it's harder for it to just like evaporate into the atmosphere. And we think that probably life formed in like lakes and oceans, maybe brackish water, where like waves were lapping up and mixing stuff around. So you need sort of like stable pools of this liquid for life to form. And ammonia, like water, has this large heat of vaporization. Takes a lot of energy to evaporate it into the atmosphere. Interesting. Why is that? Why does water and ammonia have this property? So it's getting deep into chemistry territory, which is not my expertise. But I think it has to do with the intermolecular forces, basically how

hard is it to pull these things apart? Each of these atoms are pretty stable, but they're also a little bit sticky. When they get near each other, they like to clump together. And so this just depends on like how much energy it takes to pull the individual molecules apart to change it from a liquid into a gas. And that depends on the details of the chemical structure. Yeah, I guess if you had like a large lake of alcohol, it would just evaporate pretty quickly. Exactly. So for different chemicals, either you need a lot of energy to evaporate them or not very much. And so for ammonia, you have a fairly large heat of vaporization, though not as big as for water. So water is sort of better at forming big, stable pools than ammonia is.

All right. So ammonia, it might be a good replacement for water, but life on earth didn't use ammonia. Why aren't there any ammonia-based life forms on Earth? Well, again, we don't know if it's just luck, but water does have some advantages that ammonia doesn't have. For example, ice floats on liquid water. When you freeze water, it actually grows in volume, so its density drops, which is why lakes, for example, in the winter, freeze from the time.

top down. The liquid water can stay underneath and like fishes and microbes and whatever can sometimes survive through the winter under the ice, whereas that would be trickier if they froze all at once, for example. And so this very strange property of water allows it to float on liquid water. And that doesn't happen for ammonia, for example. Also, water is stable in the presence of oxygen. A lot of things out there when you put them near oxygen, they can combust, right? They can burn or they can oxidize. But water is actually stable in the presence of oxygen because it's actually the product of combustion. If you take hydrogen and oxygen together and you light a match, you get water. And so water is stable in the presence of oxygen, which is nice if you want to have

oxygen in your atmosphere and not have it be on fire all the time. Right. Also, I imagine water is much more abundant here on Earth, right? Like we don't have large lakes of ammonia, but we do have a whole ocean of water. We certainly have a lot more water than ammonia. Though in other places, in the solar system, there are lakes of ammonia or methane, for example. Is it also sort of a property of its solvent properties, you know, like maybe, like if you try to grow something in kerosene, it would just dissolve and die? Is it water like soluble, but not too soluble? They're both really good at being solvents, but one disadvantage for ammonia is that it's liquid at lower temperatures, right? Like negative 70 to negative 33C. That means if you have

life that's ammonia-based, it's going to move slower. It's going to evolve more slowly. Like the whole time scale for things to happen is going to be slower just because things are colder. So water-based life might just like outpace and out-race ammonia-based life. Interesting. So it is possible for life out there in the universe to be ammonia-based. If there's a planet where there's no water, but there are oceans of ammonia, maybe life could develop there. Yeah, it seems like it's totally possible. Yeah. And so they would be drinking a glass full of ammonia every day. They might think that water stinks, right?

Maybe they use it to clean. All right, the last ingredient that Christian mentioned was oxygen. Do if you lose oxygen, can you still have life? And it seems like oxygen is part of water, too. So I guess the questions are kind of related. Yeah, I suppose so. Oxygen is a part of water. There's not a part of ammonia.

But when you think about oxygen life, you're mostly thinking about breathing oxygen, like atmospheric oxygen, O2, that's in the atmosphere that you pass through your lungs and that many, many things on Earth rely on. And we often think about oxygen is like a biosignature. We're looking on other planets to see if there's maybe life in their atmosphere. We're checking out to see if there's oxygen there. Like you're saying if we had maybe water and carbon, but not a lot of oxygen gas, could you still have life? Or what would you use to replace oxygen? Yeah. And it turns out you actually don't need oxygen. And we didn't have oxygen here on earth when life evolved. Oxygen itself is a product of photosynthesis. So life started here on earth

when there was no oxygen in the atmosphere. It was anaerobic to begin with. Right. There are bacterias that grow without any oxygen, right? Yeah, like the bacteria in your gut are mostly anaerobic microbes because there isn't a whole lot of oxygen in there. Right. But eventually life produce oxygen and that's what we require right now. So what is oxygen good for then? So oxygen was originally a waste product, right? Microbes learned to do photosynthesis and oxygen is the byproduct of photosynthesis. It's just like they're garbage. And it turns out that some kinds of metabolisms that involve oxygen are much more efficient than the anaerobic ways. And so a bunch of other microbes figured out how to take advantage of that waste product and use

it to make themselves more efficient. So it's sort of like supercharges life's metabolisms. And that's just like a lesson about microbes. Microbes will always figure out. out how to use someone else's garbage and turn it into their food. It sounds like it supercharges life. So could you have complex life or life as we know it without oxygen? We don't know. We didn't have a lot of atmospheric oxygen on Earth until about 850 million years ago. And that's also about when things started to get much more complicated. So it's possible that you sort of need oxygen or something similar to supercharge your metabolism and allow things to get complicated. Or it's possible that it would have done it without oxygen. We only really have this one experiment so we don't

know. If we didn't have it, could you replace it or, you know, if we didn't have those bacteria making it and you want it to supercharge life, there's something else you could use? Oxygen is pretty special because it's so reactive and it's very good at like accepting electrons at the end of this metabolism cycle, but there are other things you can do. People think that like sulfur, for example, could also serve as part of the like respiration process for alien life, though nothing really is as good as oxygen. Right. It probably won't smell as good either. We're talking about aliens, sipping ammonia, and smelling like sulfur. Smelling like raw eggs. All right, well, I think that answers Christian's question, which is that if you lose anyone in your life team, it'd be pretty

hard to replace them. It seems like you could try, but you probably won't win the World Series. We don't know if you'll be as competitive. But then again, we're just looking at the one example we have here and we don't know if this is the one lucky time that the twins actually win the World Series or this is a pretty typical example out there. In the meantime, we'll just assume Christian looks like Brad Pitt. Or maybe Christian is Brad Pitt. All right, let's get to our last question of the day, but first, let's take another quick break. 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.

My boyfriend's professor is way too friendly, and now I'm seeing. seriously suspicious. Well, wait a minute, Sam, maybe her boyfriend's just looking for extra credit. Well, Dakota, it's back to school week on the OK Storytime podcast, so we'll find out soon. This person writes, my boyfriend has been hanging out with his young professor a lot. He doesn't think it's a problem, but I don't trust her. Now, he's insisting we get to know each other, but I just want her gone. Now, hold up. Isn't that against school policy? That sounds totally inappropriate. Well, according to this person, this is her boyfriend's former professor and they're the same age. And it's even more likely that they're cheating. He insists there's nothing between.

them. I mean, do you believe him? Well, he's certainly trying to get this person to believe him because he now wants them both to meet. So, do we find out if this person's boyfriend really cheated with his professor or not? To hear the explosive finale, listen to the OK Storytime podcast on the IHeart Radio app, Apple Podcasts, or wherever you get your podcast. 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, until 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 run right.

I'm looking at this thing. Listen to no such thing on the Iheart radio app, Apple Podcasts, or wherever you get your podcasts. Hey, sis. What if I could promise you you never had to listen to a condescending finance bro? Tell you how to manage your money again. Welcome to Brown Ambition. This is the hard part when you pay down those credit cards. If you haven't gotten to the bottom of why you were racking up credit or turning to

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advice, listen to Brown Ambition on the IHeart Radio app, Apple Podcasts, or wherever you get your podcast. Okay, we are answering listener questions and we've answered awesome questions about how do you see photons moving away? And all. Also, what would happen if you lose some of the ingredients for life here on Earth? Now, our last question here is about the red shifting of light. And it comes from Josh. Hi, Daniel and Jorge. I had a question about red shifted photons.

I was just wondering how we can always tell the difference between a photon that's been red shifted versus it just started out more red. If you could dig into that, that'd be great. Thanks and keep up the good work. All right. Awesome question here from Josh. I think his question is, how do you tell what color a photon was originally? Like, was it made a certain color or if it was stretched to a certain color? And the answer is that we can't.

All we can do is measure the energy of a photon. Measure its wavelength or its frequency. Those are all equivalent. Those determine how much energy it has. So when a photon arrives on our sensors, we measure its energy. And then we can say, oh, this photon has a certain frequency or a certain wavelength. And that's technically all we can know just from the. photon itself. From context, from where it came from, from all the neighboring photons it arrives

with, we might be able to deduce something about its history, but directly all we can ever measure is the photon's current energy. We can't ever really measure its past energy. Really? So there's no difference between a photon that's been stretched to be red and one that was made red. Yeah, quantum particles are very simple in some way. They have a list of properties and that's it. And two photons that have the same energy and are going the same direction are identical, right? There's no difference to them. They don't even really have an identity. You can't, like, say, this one's Fred photon and that one's Maria photon.

Really no difference. They're just like ripples in the larger field that they're all part of anyway. Isn't there another, I don't know, a component to a photon that might be able to tell you something? Like, you know, if I take a photon and I stretch it so that it's red, won't I lose some overall energy or something? supposed to maybe making a red photon that's really energetic. Then you could say, oh, this one's really energetic. This one's low energy. Maybe this one was stretched.

Well, the energy determines the color. And so two photons that are like the same redness have the same energy. So you can't tell if one of them earlier had more energy and then got stretched to lower energy. And you might wonder, like, where's that energy going? Energy doesn't go anywhere. I mean, a photon gets redshifted. It's because of the relative velocity between you and the source. So it really just sort of like depends on the frame of reference.

It doesn't really go anywhere. Well, maybe we should talk a little bit first then about what it means to redshift something and what are the different ways it can happen because I think it can happen in two ways, right? Whether the source of light is moving away from you or you're moving away from the source of light, then the photon is going to look redder. It can also happen because of the stretching of space, right? Yeah, there are two different ways to redshift a photon. If an object that shoots light at you is moving away from you,

really, really fast, then the wavelength of that light is stretched out. And so it gets redder. Remember, the light always travels at the same speed. So if somebody's in a galaxy far, far away, and they're moving away from you really quickly, and they shoot a blue laser at you, then it's still going to arrive here at the speed of light. It always travels at the speed of light, but it changes the wavelength. So it gets red shifted. This is a handy way to measure the velocity of things that are far away that we can't otherwise measure.

If we can measure their red shift, then we know how fast they are going relative. to us. But you're right, there's a second way that photons can get stretched out. And that's if space itself is expanding. So not just things moving through space, but space itself making more of itself bubbling up from within to stretch itself out. And we think that's happening in the universe. The whole universe is expanding and that expansion is accelerating. And so photons moving through the universe get stretched out. A great example is the cosmic microwave background radiation. We measure these at very, very long wavelengths, very, very red light. But originally, when it was generated, it was generated by a very hot plasma, thousands and thousands

of degrees. So it was very short wavelength. But over the timeline of the universe, those photons have gotten stretched out to very, very long wavelengths. It's interesting to think that the color of a photon depends on your perspective in a way, right? Like, I can make a photon on here, and I put a lot of energy into it, so it's really blue. But depending on how you catch it, you're going to think, or it's a different color. You might think, oh, this is super low energy if you catch it while on the run. It feels weird because energy feels like a fundamental thing, and people say it's conserved. And so it feels weird to think like different people could measure different energy.

There's an important difference between something being conserved and something being invariant. Something invariant means that everybody measures the same thing. Everybody always measures the speed of light to be the same. But you don't always measure energy to be the same. Say you're running past me and I throw a ball. I see the ball moving really, really fast. It has a lot of energy, I say.

But if the ball is moving at the same speed you are, then it has no velocity relative to you. And you say, no, the ball is at rest. It has no energy. So you don't even need relativity to disagree about the energy to things have. Yeah, that's super trippy. But I think what you're saying is that, you know, if you just catch a photon out in space and you see that it's red,

there's no way for you to know just looking at the photon, whether it started out as red or if it started out as blue or if it was blue and it turned red, there's like no way for you to know if you don't know anything about where it came from. That's right. So you get a photon from another galaxy. It's got a specific frequency. You don't know what frequency you would see it at if you were in the rest frame of the galaxy. You just can't tell. Right. But if you know something about where it came from or you have more of them coming from the same source, you could maybe deduce whether they were made at a certain frequency or not. Exactly, because this is something we do all the time. We look at a whole galaxy and we say, oh, the light from here is redshifted. So if we can't tell from an individual photon, how can you tell the redshift of a galaxy? The answer is, as you say, you look at all of them at once because a galaxy emits photons at certain frequencies. It's filled with specific gases, hydrogen and helium and neon, whatever, and each of those gases emit only at certain frequencies.

Because remember, they're all quantum objects and they have electrons whizzing around them. and those electrons like to go up or down energy levels. And those energy levels are sort of like floors in a building. The elevator stops at one or at five or at seven. It doesn't stop at like floor 4.72. And so the electrons give off photons of very specific energies. If you have a bunch of hydrogen gas and it's hot and glowing, it's going to glow its specific frequencies.

So if you look at the energy of the photons you're getting from a big blob of gas, you can tell, is it hydrogen, is it helium, is it neon based on the energies of those photons. But if it was just missing one frequency, right? Like if the source only had one element in it, then it would be hard to tell. It's only when you have, you know, complex things like stars that, you know, have multiple elements in it that you can sort of identify the light, right? You can actually do it with just hydrogen because hydrogen has multiple levels. It has a whole set of energy levels. So hydrogen gas emits not just one frequency, but many.

So what you do is you look at the spectrum you see and you compare it to what you expect. You say, oh, this looks like hydrogen, but it's been shifted over. over a little bit. So hydrogen has its own fingerprint. Helium has its own fingerprint. Neon has its own fingerprint. So you can actually tell all of these things apart. And you can not only measure the red shift, you can also measure the elemental compositions. You can tell how much helium there is and how much hydrogen there is and how much water vapor there is by where those peaks are. You wouldn't get confused between like hydrogen and helium because the two are different. Yeah, the two are different. Even if they're shifted. Because they're all shifted together

typically, right? The hydrogen and the helium in that galaxy are all moving at the same speed relative to you, mostly. This is actually also the way we measure the rotations of galaxies. We look at like one side of the galaxy versus the other. We see different shifts, which tells us that the galaxy is rotating in a certain way because parts of it are moving towards us and parts of it are moving away from us. Right. But I guess I mean, if we had a whole galaxy of just hydrogen and another whole galaxy of just helium, would you be able to tell the two apart? Or would you be confused with like, oh, maybe this is hydrogen but shifted to helium or maybe this is helium shifted to hydrogen. Well, our voices would all sound really weird if the whole universe was just helium,

right? So that's clue number one. But also clue number two, scientifically, they do have a different spectrum, right? Helium and hydrogen have different spectrum. They have different energy levels because this is a different charge in the nucleus. So the solutions to the Schrodinger equation are different. So the gaps between the energy levels in helium are different than in hydrogen. So there's no way to take helium and like redshift it to make it look like high. All right. So then you wouldn't need to know where it came from or would you? I mean, once you get the light and you see these fingerprints and you instantly know whether it was redshifted or not. Yeah, exactly. Because there's no other way to make those fingerprints. There's no gas in the universe that emits light like hydrogen redshifted with a Z of 4. Right. So once you see that spectrum, you're like, well, this has to be hydrogen and it has to be redshifted a certain amount. There's no other way to make this pattern of light. Right. But to see, I guess to see those fingerprints, you need a whole bunch of photons of different. frequencies, right? You need your source to emit a whole range of frequencies. Whereas if you just got a whole bunch of photons at one frequency, there's no way you could tell they were redshifted.

Or even if you got like a weird sampling of different photons at different frequencies, there's no way for you to know. You would have to assume it came from, you know, stars or a galaxy. Yes, not information you can get from one photon. It doesn't carry its own personal history around. It's only from a whole collection of photons that you can tell what the redshift was of the source. So if like an alien in another galaxy shot a laser at you that they manufactured artificially, there would be no way for you to tell whether it was redshifted, right? Yeah, exactly. We wouldn't be able to tell what the original frequency was and what the shift of the frequency was, assuming that they could make a laser of arbitrary frequency. Right, which they're aliens, so probably yes, right?

You're giving the aliens a lot of credit here. I mean, I'm assuming they're still bound by the laws of physics, right? Right. You're assuming they're in the right time zone to shoot you the laser in, then they know what they're doing. Maybe that's going to save us, right? Maybe they want to vaporize us, but they use the wrong time zone. And so they actually vaporize Geneva instead of us.

Yeah, they get rid of the Danish. What are we going to have for breakfast without the Danish? Yeah. And then we'd all be drinking ammonia. And, you know, in Denmark, of course, they don't call Danish's Danish's. They just call them breakfast? No. They call them Vienna bread, actually.

Vienna bread? Wow, what do they call in Vienna? I don't know. I've never been to Vienna. I got the time zone. wrong i was supposed to go but i missed my flight somebody from vienna right in and please educate us that's right and is the danish is the pastry redshifted or not if you eat it in denmark or vienna i don't know is it blueberry shifted or is it raspberry shifted deep questions all right well i think that answer is

josh's question is that you you can't tell the difference if you just look at a photon if it's redshifted or not but if you get a whole bunch of photons and you assume they come from you know natural sources, then you could deduce whether it was redshifted or not. Exactly. And it's a great question because it's really good to think about like, how do we actually know what we know? Are we sure we're not being confused about what we're looking at? Basically, the light has to be organic. Otherwise, you can't tell. Well, it has to be natural at least. Farm raised, you know, cage-free light. Then you can tell. That's right. No pesticides, please, in our astronomy.

All right. Well, I think that answers all of our questions here today. Thank you, everyone who sent in their questions. We love getting questions. We really do. It's not just something we say. Please do write to us to questions at danielanhorpe.com. We love hearing from you. Yeah. We might even pick the question to answer on the podcast. Even if you are a twins fan. I don't even know where the twins are from. Are they from the Twin Cities? Minnesota, man. What is it hockey or basketball? I think it's lacrosse. Yeah, it's lacrosse. It looks like lacrosse, depending on your point of view. All right, well, we hope you enjoyed that. Thanks for joining us. See you next time.

Thanks for listening, and remember that Daniel and Jorge Explain the Universe is a production of IHeartRadio. For more podcasts from IHeartRadio, visit the IHeartRadio app, Apple Podcasts, or wherever you listen to your favorite shows. December 29th, 1975, LaGuardia Airport. The holiday rush, parents hauling luggage, kids gripping their new Christmas toys. Then, everything changed. There's been a bombing at the TWA terminal. Just a chaotic, chaotic scene. In its wake, a new kind of enemy emerged, terrorism.

Listen to the new season of Law and Order Criminal Justice System. the IHeart Radio app, Apple Podcasts, or wherever you get your podcasts. My boyfriend's professor is way too friendly, and now I'm seriously suspicious. Wait a minute, Sam. Maybe her boyfriend's just looking for extra credit. Well, Dakota, luckily, it's back to school week on the OK Storytime podcast, so we'll find out soon. This person writes, my boyfriend's been hanging out with his young professor a lot. He doesn't think it's a problem, but I don't trust her. Now he's insisting we get to know each other, but I just want her gone.

Oh, hold up. Isn't that against school polo? See, that seems inappropriate. Maybe find out how it ends by listening to the OK Storytime podcast and the IHeart Radio app, Apple Podcasts, or wherever you get your podcasts. Get fired up, y'all. Season two of Good Game with Sarah Spain is underway. We just welcomed one of my favorite people, an incomparable soccer icon, Megan Rapino, to the show, and we had a blast.

Take a listen. Sue and I were like riding the lime bikes the other day, and we're like, Wee! People ride bikes because it's true. We got more incredible guests like Megan in store, plus news of the day and more. So make sure you listen to Good Game with Sarah Spain on the IHeart Radio app, Apple Podcasts, or wherever you get your podcasts. Brought to you by Novartis, founding partner of IHeart Women's Sports Network. This is an IHeart podcast.