SciShow Tangents - Darkness

Episode Date: January 23, 2024

The question plaguing us this episode is, how dark can it really get? Turns out (according to some), not that dark! Unless you're at the bottom of the ocean or floating in the all too-eerie void of de...ep space, you're always gonna have some photons hitting your face. (I'm pretty sure I accidentally stole this rhyme right out of Hank's poem, but you'll just have to listen to know for sure...) SciShow Tangents is on YouTube! Go to www.youtube.com/scishowtangents to check out this episode with the added bonus of seeing our faces! Head to www.patreon.com/SciShowTangents to find out how you can help support SciShow Tangents, and see all the cool perks you’ll get in return, like bonus episodes and a monthly newsletter! A big thank you to Patreon subscribers Garth Riley and Glenn Trewitt for helping to make the show possible!And go to https://store.dftba.com/collections/scishow-tangents to buy some great Tangents merch!Follow us on Twitter @SciShowTangents, where we’ll tweet out topics for upcoming episodes and you can ask the science couch questions! While you're at it, check out the Tangents crew on Twitter: Ceri: @ceriley Sam: @im_sam_schultz Hank: @hankgreen[The Gauntlet]Next December 23rd winter solsticeSOLAR spacecraft went down Reorientation of sun instrument23.5°S latitude alternate nameTapetum lucidum colorHormone in darknessFamous winter solstice sunlight site[Trivia Question]Last December 23rd winter solsticehttps://www.timeanddate.com/calendar/december-solstice.html[Fact Off]Carrots can help you make rhodopsin but not improve night visionhttps://www.sciencefocus.com/the-human-body/do-carrots-help-you-see-in-the-darkhttps://www.sciencefocus.com/the-human-body/do-carrots-really-help-you-see-in-the-darkhttps://pubmed.ncbi.nlm.nih.gov/10484191/https://www.livescience.com/carrots-see-in-the-dark.htmlhttps://www.scientificamerican.com/article/fact-or-fiction-carrots-improve-your-vision/Dogs are more likely to steal food disobediently when it’s dark https://link.springer.com/article/10.1007/s10071-012-0579-6https://www.sciencedaily.com/releases/2013/02/130211090840.htmhttps://researchportal.port.ac.uk/en/persons/juliane-kaminski/publications/[Butt One More Thing]English words for excrement collectors (gong farmer, night soil men) https://www.oed.com/dictionary/night-soil_n?tab=etymologyhttps://www.oed.com/dictionary/gong-farmer_n?tab=meaning_and_use#992848879https://www.atlasobscura.com/articles/when-american-cities-were-full-of-craphttps://ojs.ethnobiology.org/index.php/ebl/article/view/1351/705

Transcript
Discussion (0)
Starting point is 00:00:00 Hello and welcome to SciShow Tangents. It's the lightly competitive science knowledge showcase. I'm your host, Hank Green. And joining me this week, as always, is science expert and Forbes 30 Under 30 education luminary, Sari Reilly! Still 29! And our resident everyman, Sam Schultz. Hey, man. All right. I've never seen this before, but the show flow actually has a suggestion. Is that because we talked about this last time?
Starting point is 00:00:43 Yeah, and you said we should talk about it this time. It's been a long time since the last recording. It's now 2020, whatever it is. Is it 4? 2024? Is that the one that we're in? Yeah, that's the one. As long as you upload this fairly soon. The question is, what is the oldest thing in your
Starting point is 00:01:00 freezer? And I brought this up because I have chicken breast in my freezer that's so old that it moved with me from my old house to my new house for some reason and it's probably like four years old and i'm too afraid you should probably throw away i'm too scared what's gonna happen when it thaws out is it gonna do like indiana jones this is the time of the year to throw away cold stuff because it doesn't melt before it leaves. Yeah.
Starting point is 00:01:26 Sometimes when you throw away stinky stuff, do you think, it's your problem now, garbage man? Because I think about it a lot. Absolutely. Yeah, yeah. But winter is a great time to throw the nasty stuff away. Yeah, for sure. It's so frozen solid. And the garbage man won't even smell it, maybe.
Starting point is 00:01:41 He'll never know until it's too late. I feel like frozen things can't smell bad which has to be wrong but that's how I feel. I mean I agree completely. I feel like yes. I feel like there's a temperature
Starting point is 00:01:53 you can get it to where it definitely doesn't smell anymore. You know like 0.3 above absolute zero there's no smell coming off of that. Oh this would have been
Starting point is 00:02:01 great. All the VOCs are solid rocks. This would have been a great thing to know for our last episode on refrigeration. That's probably why we were talking about it. Sari, what's the oldest thing in your freezer?
Starting point is 00:02:12 There was one point where Sylvia and I were eating a lot of food that we needed a little bread on the side. And so we bought too much of Costco's's like mini non bread packs at one point we had i think three in our freezer and so we still have like one and a half of those packs that are definitely probably got them towards the beginning of moving here so like two a year and a half non's a good one non age as well chicken. Yeah, you could still do it. I think mine, I mean, the actual answer has got to be the ice cubes at the back, right? Yeah, that makes sense. You're never getting to those ice cubes. Like, it's just the ice cube container is made of ice cubes.
Starting point is 00:02:58 And then inside of the ice cube ice cube container, there are the ice cubes that I use. The ice cube container is made of ice cubes. No, so there's the ice cube container. They're the ice cubes that I use. The ice cube container is made of ice cubes. No, so there's the ice cube container that's made of plastic. But inside of that, there is a further ice cube container that is made of ice cubes that are too connected to each other to separate from one another. And on top of that, there are the usable ice cubes. And those ones get rotated through fairly quickly. But the interior ice cube tray that's made of fused together ice cubes those ones have been in there since day one and they deserve to stay there
Starting point is 00:03:30 too i think yeah they're they're just holding on to thermal mass can i still eat this chicken would it be bad i'm sure you could still eat it i think it would taste bad it depends on how i think also how well it was sealed sarah do you think are you worried that maybe he can't eat it safely? No. I don't think so. Okay. I think it would taste bad. But I don't know.
Starting point is 00:03:52 I'm not a food scientist. I'm almost certain it would taste bad. But I'm not certain that it wouldn't do you any harm. It might. So you should Google that first. Or you can just eat it. People have definitely eaten older things stored in less cold places. Uh-huh.
Starting point is 00:04:09 That's true. My favorite topic of all time, bog butter. Bog butter. I love bog butter as a concept. Google says, Eve posts, you may be surprised to learn that you can store raw chicken in the freezer forever according to the USDA. But I don't trust Google anymore because if that's when it pops up, that's an AI. That's AI.
Starting point is 00:04:30 That's like a Markov chain. It's wild to be living in a world where Google has gotten worse for the last 10 years in a row and then got way worse all of a sudden. Yeah. It's like you can't trust what is pulled up as the suggested result so like that could not even be something that the usda said they could just tack those words together according to the usda and it could not be true and that's why you need us here at sasho tangent words coming out of our human mouths.
Starting point is 00:05:08 Yeah, where we really try our best not to lie to you, except for when we lie to each other. Yeah, yeah, yeah. Every week here on SciShow Tangents, we get together to try to one-up a maze and delight each other with science facts while trying to stay on topic. Our panelists are playing for glory and sometimes for hank bucks.
Starting point is 00:05:22 Or not. There's a winner at the end is the important thing. At the end, one of these two jackasses is going to win. The other one's going to feel bad. Now, as always, we're going to introduce this week's topic with the traditional science poem. This week from me. There are only two places that I can imagine where there is nothing to see. Photons have this mysterious way of traveling infinitely,
Starting point is 00:05:46 unless they hit something that absorbs them, which will eventually happen. And if you're far enough underground or sea, well, I think you can imagine. But on the surface, surrounded by space, there's always light out there. A hundred billion trillion stars will be shimmering in the air. You cannot be on the surface of a planet or floating out in space and experience a lack of photons falling on your face. And if they're hitting your face, then they're hitting your eyes too. A couple of EM wave detectors that you made just for you. But what about a place in
Starting point is 00:06:16 space that's very far from ours, where light years of nearly empty space is enough to block the stars? years of nearly empty space is enough to block the stars intergalactic voids are destinations not to be missed you might be fooled to think this a universe where only you exist the topic for the day is darkness do those exist places so far away that there's no light in them yeah i mean i bet if you had like a telescope you could see some stuff uh but unless you like happened to be nearby a wandering star uh they're like if you're in the middle of i think it's called the bloaties void or something and yeah that's the biggest one we know about and it's like space in between galaxies and the way that gravity works is it pulls things out of areas to collect together into this like web of stuff throughout the universe and it leaves these big empty voids and if you were in the middle of one
Starting point is 00:07:11 you'd be so far from any galaxy that you wouldn't be able to see any galaxy because it would be blocked out by all the very very tiny amounts of dust in space that sounds bad yeah i wouldn't i i don't i wouldn't, I don't, I wouldn't want to, it'd be really hard to get there and then also the trip back
Starting point is 00:07:29 would be quite long. There's a bunch of reasons not to go. Yeah, I think whoever's bringing you there is going to leave you there probably. Yeah.
Starting point is 00:07:37 And it's beyond peaceful. It's at the point where going into a sensory deprivation tank or one of those rooms where very little sound it's like, it'll be too eerie to be in the void. It sounds okay. Like sometimes I do want to crawl into a void,
Starting point is 00:07:53 but not that void. There wouldn't be any light to see yourself with either, which is very strange, which I guess is true in a cave. Very bit in a cave with no light. Yeah. Yeah. Uncomfortable. Yeah. Because it's uncomfortable.
Starting point is 00:08:06 Yeah. It's very, like you lose every sense of orientation. Yeah, like you close and open your eyes and it's the exact same. Bad. It's a bad feeling, actually. Yeah, not comforting at all. Is it totally dark in the womb? Good question. I bet some light could get
Starting point is 00:08:26 through. We'll have to ask a baby. We'll have to ask a baby. I feel like your skin is the fact that you can see your veins through your skin and the fact that you can like a baby can kick
Starting point is 00:08:41 and you can see the impression of the foot. The skin is not going to be that that thick there must be some amount this atlantic article says it is dark in the womb but not that dark so whatever that means to you imagine that amount of darkness yeah okay okay darker than outside of the womb potentially depending on where you are so sorry what is darkness you did a really good job i think in your poem just talking about it and i think beyond that we don't really know like darkness refers to a lot of different things when you start getting on the scale of less light like you can have a dark room but you can
Starting point is 00:09:26 your eyes can kind of adjust and you can still kind of see because there's ambient light around or you can have a void in space which is like actually or the inside of a cave which is super super dark we're like nighttime is dark but relative to daytime but we can still see at night and so darkness is yeah spectrum. But there is perfect dark. Like complete darkness does exist. You can't arrive at a place with no visible light. Yes. So there's a wall that you end up with
Starting point is 00:09:55 where it's like zero photons. And that's, you know, the bottom of the ocean. That's another place that doesn't seem comforting at all to me. That seems so close to be that, to be zero light. There's a lot of stuff in the way. Yeah. The only light is from animals, which is very cool. Where did this word come from, Sari?
Starting point is 00:10:12 Dark, yeah. Dark. So much like the mysterious connotations of dark, the origins of dark are also kind of mysterious. It's had similar sounding words for a while like middle english dirk became dark and old english i think also kind of dirk was without light or lacking light or brightness so so the word dark has been around but we've had other words for darkness and for dark things um specifically of germanic origins old high german tarkanin was to conceal and then that became old english like alternate so you had dirk and dark but then you also had
Starting point is 00:10:54 thirk and uh thester which meant darkness which is very weird to me. But the same thing, having little or no light or sinful or obscure. And I don't know why. I think dark went out probably just because it sounds better. This is now me just editorializing. But if you had, can you imagine us walking around and being like, it's sure Thirk outside. It's getting so Thester out here.
Starting point is 00:11:21 We better go outside. Is it Thirk in the womb? it Thurk in the womb? Is it Thurk in the womb? I mean, I like Dirk. That's great. Dirk is pretty fun. These are all good names. Dirk is actually a name.
Starting point is 00:11:39 But I could also see a child being named Thester. That sounds amazing. This can be like our our I was going to say band name but I can't pick pick a genre because I don't know anything like an emo band
Starting point is 00:11:50 with all darkness. We can be we can be Thester and Thirk and Dirk. I think Thester would be more that would be more of a death metal band unfortunately.
Starting point is 00:11:57 Thester does seem kind of death metal-y unless it's like Thester and the Dirks then then who knows. Yeah, it could Dierks. Then who knows? Yeah, it could be. Yeah, then really who knows?
Starting point is 00:12:08 It could be like a swing band or something. One of those 90s. When swing was back in the 90s for a while. Yeah, dark swing. Okay, this is interesting. I like this. All right, now we know what we're talking about. It's time to move on to the quiz portion of our show.
Starting point is 00:12:24 And the quiz portion of our show is today, the gauntlet. My legacy. Yeah. My nemesis. I've never scored positive, I think. So here in the Northern Hemisphere, the days get shorter and shorter through December until we finally hit the winter solstice, which is when we have the longest night of the year. Of course, we should note that while we're having winter solstice in the North, the South is having their summer solstice, which is when we have the longest night of the year. Of course, we should note that
Starting point is 00:12:45 while we're having winter solstice in the north, the south is having their summer solstice. But today we're going to be focusing on the winter solstice, northern hemisphere version, as we put it through the gauntlet. Here's the rules. There is a series of seven questions of decreasing difficulty. I will be directing the questions to you in order from seven to one, asking just one of you at a time. And you can choose whether to answer or pass. If you answer and are correct, you will be given that number of points.
Starting point is 00:13:14 The same number of points as the question. So question number seven gives you seven points. If you're wrong, you will lose that number of points and your opponent can steal for that same point. If they're wrong, they don't lose any points. Why? It's the gauntlets! If you pass, your opponent will get asked
Starting point is 00:13:30 the next question, and they won't get a chance to steal. Just feel like I'm playing Magic the Gathering right now. And then the next question will be a little less difficult, according to Deboki Shrocker-Vardy.
Starting point is 00:13:44 After we've gone through all the questions, we will revisit the past questions. Only this time they cannot be skipped. If you get the answer wrong, you won't lose any points, but your opponent can steal from you. And remember to pay attention to all the questions because you might get some clues to help you out with those harder ones. Are you ready to play? I'm always ready to play the gauntlet. My life is the gauntlet, basically.
Starting point is 00:14:10 Question number seven. We're going to give it to Sam. Does that sound good? Hell yeah. The winter solstice generally falls between December 20th and December 23rd, though it usually occurs either on the 21st or the 22nd. The next solstice on December 20th will be in 2080.
Starting point is 00:14:28 In what century will the next December 23rd winter solstice be? What? I don't know. I don't even want to try to figure this one out, so I pass. That's probably for the best. You have to guess a century, and I don't think that you lose points if you try sari um there's no drawback okay fourth century no i don't think you did
Starting point is 00:14:54 which what year would that be the 2300s yeah that's correct yes that's, that's correct. Yes, that's right. That's right, Sari. Wow. Congratulations. New Year, New Year. Good at the gauntlet. This is wild, but the next December 23rd solstice will be in 2303. We'll all be dead. Yeah. We will all be dead. Maybe.
Starting point is 00:15:19 But our AI modeled counterparts will be podcasting about it. I like that. You know, I was just thinking that maybe instead of my body, I want them to put all my stuff in my casket. Oh. And where would your body go? Science.
Starting point is 00:15:38 What? You want to keep all your stuff from other people getting it? Why? No, not like. Well, look. Look, I don't know if your parents are at the stage yet where they start giving you all their stuff. other people getting it why no not like well look look you i don't know if your parents are at the stage yet where they start giving you all their stuff oh my gosh but nobody wants your stuff my wife's mom has started giving her baby pictures of herself baby albums of
Starting point is 00:15:59 herself you don't want that you don't want rachel baby pictures i think that's adorable i love baby catherine pictures her mom's just done with them she's just like i don't want these anymore what's that all about that's a little bit i have so much stuff i just want i want there to be a place where i get buried but i also want them to be able to see what's up on the inside this is what pharaohs of egypt would do hank you want a pyramid? Yeah, but like, it's like, you know, Pizza John pizza cutters. Yeah, we're building you a pyramid, Hank. That's the bottom line.
Starting point is 00:16:34 But do you want people to see it? Is it like a museum then? No, no, no, no, no. Okay, then definitely pyramid. Yeah, you can't go in the pyramid. Someday somebody will, and they'll say, what's all this crap? They're like
Starting point is 00:16:45 I thought we were digging up a body I wanted bones dang it what's this what's this old pizza cutter and this Minecraft slap bracelet
Starting point is 00:16:53 doing here and then they'll open up the Minecraft slap bracelet and be like no way freaking tape measure amazing this was
Starting point is 00:17:03 this was all worth it they make them out of tape measure. This was all worth it. They make them out of tape measure. The archaeological find of the 22nd century. That's a hundred years from now. Okay. See, that's why I didn't want to guess. That's why I didn't want to guess.
Starting point is 00:17:23 We've forgotten where we've come from. The last tape measure to ever exist. Well, you don't know. You don't know. Yeah, I don't know. Yeah. This might be the last year we make tape measures. Yeah.
Starting point is 00:17:35 Okay, next question in the gauntlet. Sari, for almost a decade, the European Space Agency monitored the sun's activity using an instrument called SOLAR. But that's all capitals, so it stands for something. SOLAR, I don't know what. SOLAR was on board a spacecraft that allowed it to see the sun for about 14 days in a row before the spacecraft's orientation changed and blocked SOLAR's view for a period of up to 25 days. But around the summer and winter solstices, this blackout period was shorter thanks to the position of the sun. How long was solar zoo of the sun blocked
Starting point is 00:18:09 around the winter solstice? Just name a number that's less than 25. Yeah. Well, that's basically what I did with the centuries too, but I'm going to pass. You're going to pass. Oh yeah, because you could lose points. 20, 23.
Starting point is 00:18:25 It's great, Sam, but it's not right. Okay. It's eight days. Eight days is the answer. It was installed in 2008, and it was meant to operate for 18 months, but it performed so well that it wasn't turned off until 2017. Wow. Good job, buddy. But you have a chance to redeem yourself with this one.
Starting point is 00:18:41 have a chance to redeem yourself with this one. In 2012, scientists working on the solar experiment wanted to take advantage of the eight-day blackout period near the solstice to see if they could watch the sun for longer. To accomplish their goal, they would need to reorient the spacecraft that solar was
Starting point is 00:18:57 based on. What was that spacecraft? I don't know. I pass. Understandable choice. The Hubble telescope? That's what I was going to say. No, it was the International Space Station, which is kind of similar.
Starting point is 00:19:14 A similar vibe, you know. Interesting. One of the big famous ones. Uh-huh. I would have assumed that it'd be on one of the spacecraft that went close to the sun, but no. It's just watching from here. All right, Sari, here's question number number four the winter solstice refers to the specific
Starting point is 00:19:29 moment when the sun is directly above the earth at a latitude of approximately 22.5 degrees south what is that latitude better known as oh no it's the tropic of... I got two guesses. Capricorn? Yes! Oh, what? I had the other one in the chamber ready to go. She's just cruising through the gauntlet. It seemed colder.
Starting point is 00:19:59 The Capricorn one is like the winter zodiac sign. Yeah, that kind of feels cool. Cancer seems quite hot. It's a crab crab and the crabs live in the hotter place you live in the beach life yeah yeah what is a capricorn anybody a mermaid goat is it a goat fish a goat fish needs all its hair to stay warm in the north is it just a goat or have i have i have i invented the mermaid part of it? No, it says it's a sea goat. It has the body of a goat and the tail of a fish. It's a capri corn, like a capri sun.
Starting point is 00:20:33 But there's corn inside. That's a fruit juice. It's like a boba tea where you just suck up corn. Come on. I would try it. Like a boba tea with corn?
Starting point is 00:20:48 Corn's good. We're gonna drink them during P4A. Boba tea with corn, but instead of boba tea, it's just Coca-Cola. With corn kernels in it? Yeah! That's coming up soon. I'm excited to try a good old Capri corn. sam and i are hosting a segment
Starting point is 00:21:07 and it'll be right before one of yours hank so uh we can overlap a little with our capricorn projectile vomit that sounds not bad to me i bet it's's going to be fine. I like both of those things. So what can go wrong? Canned corn? It's amazing. I have boba tea straws in my house ready to go. Question number three, which is for Sam.
Starting point is 00:21:34 A group of scientists studying Arctic reindeer wanted to see how seasons affect a reflective surface in the reindeer's eye called the tepetum lucidum, possibly, and that it acts like a mirror that sends light back to the retina, basically giving eyes another chance to capture those photons. They compared the color of this structure in the reindeer's eyes around the summer and winter solstices, finding that the tepetum lucidum were different colors at these periods. What color was it during the winter solstice? Filter out. What color would it be filtering out?
Starting point is 00:22:12 Blue. It's blue. Holy moly, you guys. During the summer solstice, it was gold, which also seems warm. Black seems warm and blue seems cold. Makes sense. Very appropriate. I can't imagine for, I don't know.
Starting point is 00:22:27 I don't know what it's like to be a reindeer. Very few people do. Yeah. And all reindeers, though. Yeah. Sari, question number two. In addition to watching strange eye structures turn blue, scientists have studied the effect of seasonal shifts
Starting point is 00:22:44 on a number of other animals. Various studies have looked at animals during the summer and winter solstices, including hamsters and penguins, goats, and Antarctica-based humans. The methods used in these studies vary, but they all measure a hormone that is produced in response to darkness. What is that hormone? Oh, I used to know know this um shoot is it melatonin there it is okay i thought maybe that you were gonna have a classic nose too much moment there yep yes i had melanin in my head and i was like it's not that it's not it's an m word yep those are different things. Yeah. It's produced by the brain and it helps with keeping timing of our circadian rhythm.
Starting point is 00:23:29 And people often will take it as a supplement to try and fall asleep, which I think probably works to some amount. And for Sam, question number one. While in the modern day, we might acknowledge the solstice by turning around international space stations. Humans have built other magnificent structures that seem to honor the solstice by turning around international space stations, humans have built other magnificent structures that seem to honor the solstice. One famous but mysterious site in England features a set of stones whose opening
Starting point is 00:23:53 lines up with the rays of the sun setting during the winter solstice. What is that structure? Stonehenge? Yeah, that one. One point, baby. That's not... You got other ones too, though.
Starting point is 00:24:09 Alright, now, you might be thinking to yourself, I think that Hank did the gauntlet wrong, and you're right! We broke a couple of rules this time. That's part of the gauntlet. Yeah, that's right. Stop doing it the same every time. It's a living document. But I think that
Starting point is 00:24:29 if we follow the rules of the gauntlet from where we are right now, we didn't have any questions that got passed. I think you're right. They were done. Sam, we came into that with you with a positive four, which is frankly excellent for the gauntlet. But not as good as Ceri's plus 13.
Starting point is 00:24:48 Standing performance. You did a good job. Next up, we're going to take a short break, and then it will be time for the fact talk. Welcome back, everybody. Get ready for the fact-off. Our panelists have brought science facts to present to me in an attempt to blow my mind. After they have presented their facts, I will judge them and award Hank Bucks any way I see fit. To decide who goes first, I have a trivia question. As we established in the gauntlet,
Starting point is 00:25:28 next winter solstice to take place on December 23rd won't happen until the year 2303. But when was the last December 23rd solstice? What is this obsession with the December 23rd? I think it's amazing!
Starting point is 00:25:43 This is the kind of thing that somebody like you would come up to me at a party and say, did you know this? And I would say, I can't even comprehend what you're talking about right now.
Starting point is 00:25:56 It was in 1901. Great guess. Great guess. 1752. Too long ago. Fantastic. Too long ago. Guess. Both of those are right in the range of of when I would have guessed. Oh, my God, Sam. Oh, wow. The answer is 1903. That's right. Okay. You just poo pooed that. But you were the one with the trivia the whole time. After be like after hank tells you that fun fact but you're like i already knew that did you know the last one i've read every newspaper ever printed
Starting point is 00:26:30 and i remember them approximately so that's why i got it that close oh well done sam that means that you get to go first if you don't know jack shit about anything else you know this one thing. Carrots help you see better at night. I assume that I know this because of cartoons. But overall, if you exist in American culture, you have absorbed the information that carrots can help you see good at night.
Starting point is 00:26:57 Basically, have you guys both heard this before? Yes. It's nearly as basic a piece of information as the last December 23rd solstice. Okay, you're right. Or how dark it is in the womb. Not too dark. It's not even really, in my opinion, particularly useful information because we have flashlights nowadays.
Starting point is 00:27:17 Who cares? Did this info come from pre-flashlight caveman times? And more importantly, is it even true? So I'll tackle that last part first. And the answer is sort of. Carrots are full of vitamin A, an essential nutrient that helps a lot of body functions like the immune system, but vitamin A is also vital for eye health. So opsins are a group of light sensitive proteins that hang out in your retina, turning light into signals that are sent to the brain. And vitamin A is an important
Starting point is 00:27:45 ingredient in rhodopsins, which are opsins that are extra sensitive to light and help with low light vision. Vitamin A is also important for keeping your corneas, which are the outermost layer of your eye, healthy. And deficiencies in vitamin A can lead to blindness. So carrots literally do help you see in the dark because they help you see period. But anything with vitamin A in it would do exactly the same. So carrots aren't special. Plus, the thing is that carrots are supposed to help you see better in the dark. And that part is not true. No amount of carrot eating will like supercharge how many rhodopsins that you have.
Starting point is 00:28:18 And one study I saw even correlated high carrot consumption with worse night vision. But the conclusion there was that people with bad night vision were eating more carrots than normal to try to correct it. So then it didn't work. So there you go. Is that for real? Yeah. That's wild.
Starting point is 00:28:35 But as to where this idea came from, it's kind of tricky to suss out. So there's this very romantic story all over the internet that in World War II, the British Royal Air Force purposefully spread the rumor that carrots helped their pilots see better in the dark as a way to hide the top secret radar technology that helped them detect German bombers. They were like, we don't
Starting point is 00:28:55 have new fancy tech. We got carrots. We got some carrots. Yep. But the truth of the matter seems to be that the Germans knew about the radar. That's not like they just had radios that they could listen to and say, oh, they got radar. But there are World War Two era posters where it has like a soldier who's saying like carrots help me see good in the dark. So why do those exist? The other predominant story is that when England was under blockade by German U-boats, they couldn't import food and they had to turn to things that they could grow themselves to eat like carrots. But apparently British people at the time
Starting point is 00:29:28 hated carrots. So the ministry of food, possibly inspired maybe by the Rhodopsin science that I just told you about, turned carrots into a war hero by saying that they helped pilots and soldiers see in the dark and more effectively fight at night. So British people started growing shit loads of carrots, I guess, according to one article, I read 300% more than before the war. And they started making all kinds of food with them, which incidentally led to the resurgence and popularity of carrot cake.
Starting point is 00:29:56 So I guess we all think that carrots make us see better at night because of world war two propaganda. But that answer is very unsatisfying to me because it seems like a huge reach that the Ministry of Food would say, vitamin A helps with your eyes. Carrots have vitamin A. Carrots help our brave boys see in the dark. That's just not very compelling to me, in my opinion.
Starting point is 00:30:16 So I feel like the answer is still out there. We don't know. I mean, that totally compels me. That seems like exactly something that the government would feel like. we need to grow more carrots. Lie. Well, yeah. Lie to the Germans and lie to the people.
Starting point is 00:30:31 Tell them the same lie. That's true. Well, that way the Germans maybe are more likely to believe it if all the normal people believe it too. The normal people. Yes, the citizenry. Yeah. The non-Germans. The locals. I gotcha.
Starting point is 00:30:49 Sam, that is very strange. And also contains some science. Well, a little bit at the beginning there. With the eye stuff. It's social science, Hank. Sari, what you got for us?
Starting point is 00:31:04 Okay, so the three for us? Okay. So the three of us have all lived with dogs at some point in our lives. And you know that thing when a dog knows it's being disobedient, but thinks you won't notice? Like when you're in another room and then you hear a crash and then someone has dragged a pizza box off the counter. And I don't know who could be the criminal here, but certainly not the cute dog with pizza sauce all over their mouth. My goal with this fact is not to anthropomorphize dogs and their gremlin behavior, but there have been a lot of studies
Starting point is 00:31:32 from behavioral psychologists. Gremlin-pomorphized dogs. Yeah. But humans are fascinated by our little dog companions. And so behavioral psychologists have done studies about how domestic dogs understand
Starting point is 00:31:46 when and how humans are paying attention to them. So for example, there are studies where humans put food in front of dogs, tell them not to eat that food, and then maintain eye contact or close their eyes or face another direction or look another direction. And the dogs are less likely to disobey them when there's clear attention and visibility of human eyes. So when they're being watched, they're less likely to disobey them when there's clear attention and visibility of human
Starting point is 00:32:05 eyes. So when they're being watched, they're less likely to disobey. So one psychology researcher who does a lot of her work with dogs, Dr. Julianne Kaminsky, published a study with her team in November 2012, where they did a set of three experiments trying to test dogs' obedience in the darkness. So whether dogs will behave differently with a human in the room when it's dark. And so in one of the three tests, there were 28 dogs included in the data analysis all over one year old, so not puppy puppies. And the four test conditions were complete darkness, the experimenter's face, who is the person telling them not to eat the food, being lit up. How did they get to complete darkness?
Starting point is 00:32:41 Okay, yeah. That's it. Did they go to a cave to the bottom of the ocean or to the middle of the Bootes Void? Where was it? Asterisk.
Starting point is 00:32:52 Less dark than the womb. Like a room with garbage bags, I think, was level. Not Vantablack darkness, etc. The experimenter's face being lit up, the food being lit up, and both the experimenter and the food being lit up. So like, well, okay. And according to their results face being lit up the food being lit up and both the experimenter and the food
Starting point is 00:33:05 being lit up so like and according to their results the dogs took the food more often and more quickly in the total darkness condition than any of the others and they took the food less often and more slowly in the double light condition both by a statistically significant amount and to like avoid conflict um or to like take out confounding variables another one of the experiments they tested 12 dogs in a light or dark room where a human left them with a little food um telling them not to eat it and the dogs took the food in almost all the cases which showed that the dogs aren't avoiding light or dark food in general something about the combination of a human being in the room and the light. And then the third test was similar to the first,
Starting point is 00:33:49 just with different variations of light intensity. So like a brighter light or a farther away light that's dimmer. So basically the overall suggestion of the paper is that dogs may understand that light on the food means that a human can see them eating it, which informs their decision to steal it or not. may understand that light on the food means that a human can see them eating it, which informs their decision to steal it or not. They're more likely to be little gremlins and steal food in the dark. And I think it's very delightful
Starting point is 00:34:15 that scientists are out here designing all these carefully controlled studies to get as much of an objective perspective as possible about what animals do or don't understand about our perception. They're bad boys. They're they know they're like they know mom has bad eyes in the dark and so i'm gonna go over here and go i can hear that yeah i people there's there's a line i feel like and i guess the the way to to solve the existence of the line is just to be like, let's just pretend there isn't. But there is a line past which it's like, the dog does have thoughts.
Starting point is 00:34:53 You know, like the dog is thinking and the dog has a picture of the universe in its head. Of course, because we can't talk to them or ask them, the sort of like objective thing is to be like, well, we can't say that for sure. But like, my dog knows I exist. I don't have a dog. But like, would I had one? Even dogs I don't know. If I'm just walking past them, they know I exist. There's that guy.
Starting point is 00:35:18 That guy's famous. Is that from Dimension 20? is that from dimension 20 but yes we shouldn't anthropomorphize dogs but i do want to dog up homomorphize them like they are beings they're entities they're having their little sneaky thoughts yeah saying i'm gonna i will take the pizza i have two cats and one of them has thoughts and the other one doesn't. I can tell the difference. Nothing in there. So I
Starting point is 00:35:52 get to choose between carrots talking a bigger game than they play or dogs that are more likely to steal food disobediently when they're in the dark. And it's just a cuter fact! And Sari also had a thousand more points than Sam. disobediently when they're in the dark. And it's just a cuter fact. And Sari also had a thousand more points than Sam.
Starting point is 00:36:09 Yeah, that one. So the win for the day goes to Sari Riley. All right. Well, in addition to playing the gauntlet, me, poorly, you guys did great. We also screwed around way too much and we are way over time. So we're going to skip the science couch. If you want science couch questions and answers though,
Starting point is 00:36:29 the Patreon has those, not just recent ones, but you can go down into the archive and get a bunch of us answering science questions. So if you're left feeling like empty because you didn't get the whole episode of tangents, maybe I want you to experience a little bit of that emptiness so you become a patron. That's right. Because we'll have
Starting point is 00:36:48 a whole episode on dark questions that we're answering. And we'll pop this one in there too. And you can listen about how minions peeing and stuff like that. Yeah, we're recording that this week. I'm so excited to watch minions with you guys. Me too. I've never seen a single millisecond of any minions
Starting point is 00:37:04 anything. Me neither. I've never seen a single millisecond of any Minions anything. Me neither. I have no context for it besides the Minions. You've never even seen Despicable Me? No. We don't have kids. And I was just too old. I was too old and cool to see Despicable Me. No, I was old but not
Starting point is 00:37:22 cool. So, it's fun. I can't wait. You guys are going to love it. Despicable Me was 2010. I was in college in 2010, my friend. You don't want to know what I was doing in 2010. You don't want to know what I was doing in 2010. I was studying for school.
Starting point is 00:37:36 I was too busy. Is that your Minion voice? No, the Minions sound like little guys. That's the guy. They sound like this. They say bananas. Hey, bananas. Yeah yeah in that way hey bananas this is why we can't answer the science couch question we're screwing around too much
Starting point is 00:38:00 if you want to if you like this show and you want to help us out first of all you can join our patreon which is a patreon.com slash sideshow tangents a lot of people have done that because it's a good user experience that's gonna be the whole commentary is us just trying to say the little grew lines in our best accent. We're going to get really good at grew impressions by the end of the commentary. Yeah. The Patreon is there. It's always waiting for you and it's just a heck of a fun place to be.
Starting point is 00:38:40 So join us and a special shout out to patron Les Aker for their support. Second, you can leave us a review wherever you listen. We have so many ratings on Spotify, you guys. It feels good. It feels good to see all those ratings. Makes me feel like people like our show, which I think you do. It also helps us know what you like about the show
Starting point is 00:39:00 if you're able to type words in. And finally, if you want to show your love for SciShow Tangents, just tell people about us! Thank you for joining us. I've been Hank Green. I've been Sigrid Riley. And I've been Sam Schultz. SciShow Tangents is created by all of us and produced by Jess Stempert. Our associate producer is Eve Schmidt. Our editor is Seth Glitzman. Our social media organizer is Julia Buzz-Bazile. Our editorial assistant is Tepoki Chakravarti. Our sound design is by Joseph Plunamedish. Our executive producers are Nicole Sweeney and me, Hank Green. And of course, we couldn't make any of this without our patrons on Patreon.
Starting point is 00:39:29 Thank you. And remember, the mind is not a vessel to be filled, but a fire to be lighted. But one more thing. Wherever there are humans, there's also human poop. And in places without sewer systems, the infrastructure to deal with all this waste is currently called fecal sludge management. But there have been plenty of euphemisms for this kind of work throughout human history around the 1300s anyone who cleaned out latrines in the uk was called a gong farmer because gong meant the bathroom and the stuff inside what the gong i'm going to the gong is that what you would say to do what to? To use the gong? What is the... And the stuff inside, what does that mean?
Starting point is 00:40:25 Produce gong. Yeah, you go into the gong to produce gong. I'm going to gong in the gong right now, okay? I'm gonging in here. But around the 1700s, we English speakers switched to using the term nightmen or nightsoilmen because they'd remove the stinky excrement under the cover of darkness, and sometimes it went to farms as fertilizer. While many countries have historically had more robust waste-to-fertilizer systems,
Starting point is 00:40:49 in the UK and US, night soil was more often than not just dumped into the nearest body of water, which was as unsanitary as it sounds. Yeah. Don't do that. Don't gong in the water that you're drinking from. Yeah. It's called a river, not a gong. Not a gong in the water that you're drinking from. Yeah. It's called a river, not a gong. Not a gonger.

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