Today, you’ll learn about how cultures across the world often make constellations from the same groups of stars due to the nature of vision and perception, what to do when an animal tries to steal your food during a picnic on the beach, and drones smaller than a red blood cell that can be controlled using only the power of light.
Today, you’ll learn about how cultures across the world often make constellations from the same groups of stars due to the nature of vision and perception, what to do when an animal tries to steal your food during a picnic on the beach, and drones smaller than a red blood cell that can be controlled using only the power of light.
Does your star pattern look like my star pattern?
Staring contests really do work.
Sun doesn’t just give plants life, but drones, too.
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Find episode transcripts here: https://curiosity-daily-4e53644e.simplecast.com/episodes/seeing-stars-seagull-staredown-itsy-bitsy-microdrones
SEEING STARS, SEAGULL STAREDOWN, ITSY BITSY MICRODRONES
Follow Curiosity Daily on your favorite podcast app to get smarter with Calli and Nate — for free! Still curious? Get exclusive science shows, nature documentaries, and more real-life entertainment on discovery+! Go to https://discoveryplus.com/curiosity to start your 7-day free trial. discovery+ is currently only available for US subscribers.
NATE: Hi! You’re about to get smarter in just a few minutes with Curiosity Daily from Discovery. Time flies when you’re learnin’ super cool stuff. I’m Nate.
CALLI: And I’m Calli. If you’re dropping in for the first time, welcome to Curiosity, where we aim to blow your mind by helping you to grow your mind. If you’re a loyal listener, welcome back!
NATE: Today, you’ll learn about how cultures across the world often make constellations from the same groups of stars due to the nature of vision and perception, what to do when an animal tries to steal your food during a picnic on the beach, and drones smaller than a red blood cell that can be controlled using only the power of light.
CALLI: Without further ado, let’s satisfy some curiosity!
[SFX: crickets ambiance]
NATE: What are you looking at?
CALLI: Just checking out the stars. I love finding all of my favorite constellations...
NATE: There’s the Big Dipper. The Belt of Orion... The one that kinda looks like my Aunt Sheila.
CALLI: I don’t think I see that one. But, that brings up a good point. Did you know that the constellations we see are actually based on our vision systems?
NATE: What do you mean? Like, the way human vision works determines how we group stars into constellations? Is that why so many cultures across the world share similar shapes and patterns?
CALLI: Precisely. For a long time scientists thought this was based mostly on almost random groupings of stars. With many cultures identifying them as different and specific to their own traditions. For instance - many of the large shapes in European astronomy aren’t identified across the world. To Europeans, the shapes were just important objects and characters from their religions, mythologies, and even calendars!
NATE: What about the ones across cultures that aren’t as specific?
CALLI: Of course there’s some very obvious bold patterns that nearly everyone sees. Like you said - the Big Dipper, the Belt of Orion. There are actually eighty-eight official constellations according to the International Astronomical Union.
NATE: That does sound very official.
CALLI: And there’s even more beyond those!
NATE: Well there are hundreds of billions of stars.
CALLI: But only about five-thousand are even visible to the naked eye. And we barely ever see more than half of that with good nighttime conditions.
NATE: So what about these other constellations? Would I know any of them?
CALLI: Probably not. They’re called asterisms and have been identified by various cultures throughout history.
NATE: I know the stars are old but how old are we talking when you say “throughout history”?
CALLI: As far back as seventeen thousand years! There have been paintings found in southern France that depict what could be the Pleiades and Orion’s Belt.
NATE: Aunt Sheila’s been up there for a while then... But what did you say earlier about the patterns being based on our vision systems?
CALLI: New research shows that how we group the stars really comes down to the functions of our visual processing. As opposed to a base need for us to assign our cultural beliefs to the star systems up above.
NATE: So it’s basically how our minds see them as opposed to our hearts?
CALLI: That’s a good way to put it. A few researchers ran a study on this idea to try and figure out the reason we see these star patterns. Looking at three different types of vision - low level, mid level, and high level.
NATE: We have different types of vision?
CALLI: Yep! Low-level accounts for us seeing individual stars. Mid-level comes in when we group them together. And high-level would be our interpretation of these groups. The high-level is mostly where we find the differences amongst cultures.
NATE: So the researchers in this study got to stargaze for a living? Ah what a life.
CALLI: It went a little further than stargazing. The team cataloged constellations across twenty-seven cultures in six major regions around the world and found that the groups shared quite a lot of common patterns.
NATE: That makes sense - if the way our brains process what we’re seeing is the same then we’d theoretically all be seeing the same key patterns of stars.
CALLI: Kind of. The psychological element tells us that we’re all seeing the same patterns. The cultural element informs us on the story we assign to their shapes. For example - in western cultures we see "The Big Dipper". But in Scandinavian cultures they see the same patterns of stars and refer to it as "Odin's Wagon." In South Korea, those stars correlate to a cultural story, about placing seven stepping stones in a river to help cross.
NATE: I’m telling you that group right there looks exactly like Sheila, with her beloved border collie Trixie and everything.
CALLI: Hm. Kind of looks more like a house key to me.
NATE: Alright, but if we’re all seeing distinct patterns amongst the thousands of other stars - what makes those specific ones stand out?
CALLI: It’s quite simple really - the two biggest factors are brightness and proximity. The shiniest, closest stars naturally get grouped together.
NATE: Ahhh of course!
CALLI: There’s a few other factors like symmetry as well. But even with just the top two in brightness and closeness - the study found they accounted for many of the recurrences across cultures. Further solidifying their theory that our perception plays a much bigger role in how we map constellations than previously thought.
NATE: That’s so cool that the whole world KIND OF BUT NOT REALLY sees the same patterns when we look up at the sky.
CALLI: The cross section between psychology and astronomy is fascinating when looking at the different ways cultures find meaning in the sky. For some, it’s related to their belief system ...
NATE: And for me, it’s my aunt and her dog. Go figure.
[SFX: Whoosh]
CALLI: Hey Nate. Oh, you brought chips! Nice of you. ... Can I have one? ... Nate. Hello, Nate? ... Are you gonna say anything? ... Is this because I asked for a chip? ... Keep staring. Maybe I’ll take a chip. ... Alright, I’m taking one. You hear me, you weirdo? ... mmm, tasty chip.
NATE: Thank you, Calli.
CALLI: For what? Wait, what are you writing down? What are you doing?
NATE: I’m conducting an experiment.
CALLI: On me?! Using chips!? Disrespectful!
NATE: If it wasn’t chips, it would be something else delicious. I had to know you’d want to eat them. And so I figured why not fried potatoes?
CALLI: Ew, don’t call them that.
NATE: Thinly cut, fried potatoes, known to the layperson as “chips” or “potato chips”...
CALLI: Ugh.
NATE: ... are exactly what the researchers out of Exeter, in the UK, used when studying the effects of the human glare on seagulls out for a snack. Calli, have you ever been in the park, hanging out, and some creature starts working its way over to you, eyeing your snacks?
CALLI: I’ve had my fair share of stare downs with errant squirrels, yes.
NATE: The Exeter team had the same experience and noticed that tensions were actually heating up between the residents of their county Cornwall and the local gull population.
CALLI: A historic rivalry, humans and birds.
NATE: So, hoping to stave off a war, they wanted to see if the seagulls would leave the snacks alone, if the humans did something benign and nonviolent ... like looking at them. Now, let me take a second here to say ... this is the sort of experiment you or I might do on our own. Small-scale, directly related to our daily lives.
CALLI: Totally. I think you’re saying ... science isn’t always about using a multi-billion dollar piece of equipment to discover new, subatomic particles, or a new astrophysical phenomenon.
NATE: Exactly! These researchers were looking for real answers to a real question. And to do it, they developed a scientific experiment.
CALLI: So, what did they do?
NATE: Okay, so herring gulls are basically what you think of when trying to bring to mind a classic seagull. The scientists put potato chips in transparent zipper bags, with weight added, to keep the seagulls from successfully nabbing the chips. Then, they backed up away from the bags, and watched the birds in their peripheral vision. With half of the birds, the scientists kept looking away. With the other half ...?
CALLI: They stared them down like they just insulted their mom.
NATE: For all we know, they may have! But, not really. It was more of just looking at them, in the eyes. And then the experimenters waited for the birds to tap the bag, indicating they were gonna try to eat it or steal it. They waited up to five minutes, and recorded the time if they got a tap.
CALLI: So what happened?
#NATE: Most of the birds actually just took off right away, no matter what. Forty-seven of them. Experimenter looking, not looking, hadn’t even started looking or not looking ...
CALLI: Haha, just gone. No interest. Or, maybe more like, am I on a prank show? I can’t be seen on YouTube right now, I have a job interview coming up.
NATE: Yeah, something like that.
CALLI: So what does that leave?
NATE: The remaining twenty-seven birds. And of them, the ones who were being looked at took an average of twenty-one seconds longer to tap the food.
CALLI: Ah, wow. So, it sounds like the looking had a real effect.
NATE: It’s a small sample, but it would appear that way. Of course, each bird behaved differently. Some appeared to take caution around the human, others barely noticed, if at all. Some didn’t bother with the bag of chips, no matter the circumstances.
CALLI: Those birds are obviously fools who don’t know how to enjoy themselves.
NATE: Absolutely.
CALLI: So, what’s the conclusion here? That the birds can tell the difference between you looking at them and not?
NATE: Yeah! The scientists were surprised to find that staring at the birds gave them pause, in a scientifically significant way. They think what’s going on is that the birds are more likely to think you might attack them if you’re staring at them. They wait you out a bit, and either go for it or decide it’s not worth it.
CALLI: Well, of course. And they’re always waiting for you to turn your back to steal that snack.
NATE: You got it. So next time a bird is approaching, trying to steal your stuff, don’t attack them, just try staring at them. They’re just trying to survive after all. Alright, that’s the story. Want some chips now? ... Wait ... Where did they go?
CALLI: (clearly snacking) I waited till you were distracted, and that’s when I struck.
NATE: You used my love of science against me. Disrespectful!
[SFX: Whoosh]
CALLI: Nate, do you like drones?
NATE: Totally, the footage is so cool. Quick reminder, don't fly them in National Parks!
CALLI: Great, random advice! Have you seen some of those new smaller pocket-sized drones?
NATE: Oh yeah they’re great and they get killer footage.
CALLI: Well what if there was a drone so small, you wouldn’t even be able to see it?
NATE: How small?
CALLI: Researchers have created microdrones that are capable of moving forward, backward, and spinning, all thanks to the power of light. And these drones are smaller than a red blood cell.
NATE: How do you power something with light? Is it like a tiny solar panel?
CALLI: These microdrones use optical recoil. It's the same force that gives comets their tails. Comet tails aren’t from wind resistance.
NATE: Right, space is a vacuum so ... no wind.
CALLI: The tails form as the force of light’s particles act on the comet. We usually don’t notice this recoil since we have so much more mass than these particles, but it can have a big effect on small particles.
NATE: You mean we can use light as a force?
CALLI: Right! Scientists just published a study in the journal Nature Nanotechnology about how they were able to propel micro-sized objects in a water solution with light. They even got precise enough control to move them forward, backward, and make them spin. They had enough control to make them do figure eights. Researchers got the idea for the control by looking at quadcopter drones.
NATE: Ok, but those quadcopters usually use propellers, do these drones have tiny little propellers?
CALLI: Well the “drones” are actually transparent polymer discs, just 2.5 micrometers in diameter, so, about a third the size of a red blood cell. Each of these have four nano-motors made of gold rods embedded on the disc.
NATE: How do they work?
CALLI: These nanomotors have optical antennas, little metallic structures that pick up power from near-infrared polarized light.
NATE: So, step one, pick up light. Why polarized light?
CALLI: Polarized light only vibrates on one plane, which helped the researchers get a bit more control. Different powers of polarized lights can create thrust in the motors that is either clockwise or counter clockwise.
NATE: So they could use the light to make the motors move one way or another?
CALLI: Exactly, and they worked no matter which direction the light source came from. By controlling the four nanomotors, researchers got precise control of the microdrones on a two dimensional water-based surface. They could even get rapid acceleration!
NATE: Tiny drone racing, coming to a microscope near you. But how do you even make something so small?
CALLI: You have to be precise to make such small machines. This is all gonna sound crazy, but ... researchers built nanostructures from something called monocrystalline gold, which they did by cutting with accelerated helium ions.
NATE: My head is spinning.
CALLI: The researchers also used electron beam lithography, like a tiny electron razor blade, to cut out the body of the drones.
NATE: Okay, great. So they’ve made drones about as tiny as you can imagine. What will they do?
CALLI: They say in the future we could optimize them to carry chemical cargo, or manipulate structures on a similar scale. Think, attaching tiny tools to our tiny drones to do work and build on the smallest scale.
NATE: Right, yeah. As technology in general gets smaller, we need to be able to manipulate it and work on it. So, when will they get to work?
CALLI: They’re still making adjustments to get even more control, and they want to add the ability to control how high or low the drones float in a liquid as well, but, I guess ... soon?
NATE: It's amazing that one of the most fundamental things we know, light, not only affects big things like comets, but also might give us control on the smallest scales.
CALLI: A sunny day, and a dedicated scientist. Are there any forces more powerful?
[SFX: Whoosh]
NATE: Let’s recap what we learned today to wrap up. Human visual processing may be the key factor in how we identify different constellation patterns in the sky - giving further explanation as to how different cultures have their own assigned characteristics to the same patterns. This would also explain why Nate keeps seeing his Aunt Sheila right above Orion’s Belt.
CALLI: A team of scientists confirmed suspicions that animals are aware that we are looking at them, and that a good stare might deter them from stealing your snacks. This is especially good news for people who like to picnic on the beach and have seen their sammies fly away in a seagull’s mouth.
NATE: Researchers have created tiny microdrones smaller than a red blood cell. Researchers are able to make the drones move forward, backward, and even rotate, all with the power of light.
NATE: Curiosity Daily is produced by Wheelhouse DNA for Discovery.
CALLI: You can follow our show wherever you get your podcasts and we would love it if you could take a second to leave us a five star review on Apple Podcasts.