SciShow Tangents - Lasers

Episode Date: February 28, 2023

In all of science, there are very few things conceptually cooler than lasers. A beam of light you can use to blast aliens? Heck yeah! But are lasers actually as cool in reality as they are in science fiction? Probably not! But I guess you'll have to listen to find out 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!And go to https://store.dftba.com/collections/scishow-tangents to buy your very own, genuine SciShow Tangents sticker!A big thank you to Patreon subscribers Garth Riley, Mike A, and Tom Mosner for helping to make the show possible!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[Truth or Fail]Gold-plated bacteriaContact lenses that shoot lasersLead into gold with lasers[Trivia Question]Universal Product Code first scanned in grocery storehttps://www.smithsonianmag.com/innovation/history-bar-code-180956704/[Fact Off]Laser cooking of printed chickenhttps://www.youtube.com/watch?v=jct3f92rIOEhttps://www.scientificamerican.com/article/3-d-printed-chicken-dinner-cooked-by-lasers/Laser lightning rod for deflection/protectionhttps://www.unige.ch/communication/communiques/en/2023/devier-la-foudre-grace-au-paratonnerre-laserhttps://www.nature.com/articles/s41566-022-01139-zhttps://www.nssl.noaa.gov/education/svrwx101/lightning/faq/http://www.usfcam.usf.edu/cam/exhibitions/1998_12_mccollum/supplemental_didactics/21.uman2.pdf[Ask the Science Couch]Long-distance lasers and masers https://www.faa.gov/about/initiatives/lasers/hazardshttps://spie.org/news/12-09-laser-ranging?SSO=1http://ccom.unh.edu/theme/lidarhttps://www.icrar.org/megamaser/https://arxiv.org/abs/2204.02523  [Butt One More Thing]Low-level laser therapy for butt (or any) tendonshttps://www.ncbi.nlm.nih.gov/pmc/articles/PMC8886125/https://my.clevelandclinic.org/health/diseases/22960-gluteal-tendinopathyhttp://www.utahorthopediccenters.com/hip/gluteus-medius-tendinopathy-or-dead-butt-syndrome/

Hello and welcome to SciShow Tangents, it's the lightly competitive science knowledge showcase. I'm your host Hank Green and joining this week as always is our science expert sari riley hello and our resident everyman sam show hi what's up i just did not sleep very much last night i need everybody knowing that going in that there's just there's like 70 percent of hank is in the studio today wow i've turned off all the lights in my office except for one i'm just getting ready for why eddie you're gonna go to sleep after like in your office when this is over i might go to sleep during the podcast no i'm so tired maybe we could all sleep and we

could record an eight-hour podcast of us snoring and it would be like a breakthrough. We'd get in vulture. They'd say, can you believe what they did? Wow. It's cutting edge avant-garde. You guys, what do you want them to do with your body when you're dead? Oh, I want to be either. I think about this a lot.

I want to be either put in one of those fields where people can like science, do science on you and see how the fungus grows on your body. Or I want to just be fed to animals or I want to be put in a tree. But I feel like I heard the putting in the tree thing isn't good. You want to, do you want to get put in a tree? They like plant a tree in you or something. Is that real? Oh yeah. So I can put your body in the ground and put the tree on the body.

They don't like hang you. You're like fertilizer. Yeah. Like just sort of strap you down. So you look like you're sleeping in the ground and put the tree on the body. They don't hang you. You're like fertilizer. Just sort of strap you down so you look like you're sleeping in the tree. What if when the tree grew, my skull was in the tree? That would be cool. Very cool. I hope that that happens for you.

I want to get incinerated by the biggest laser that has ever been made by humans. Hank, I suspect you've asked this question before, because I feel like last time you wanted to be mummified in the Arctic. You're right. I have, and I did. And that is what I actually want. And I feel like I wouldn't know that about you unless we talked about it. Maybe we talked about it outside of a podcast content.

Maybe. Like, what do you want me to do tonight? I bet we've done it before. It's on his Wikipedia. I'm telling you i'm very tired i can't remember things right now i got like four and a half hours of sleep last night and i'm gonna get so many hours tonight i'm gonna get all of them nine o'clock to seven o'clock that's what i'm doing tonight you're not gonna stay up reading your phone until midnight ink

yeah i mean i am you might fall though i fall asleep i mean i might fall, though. I fall asleep, I mean. I might fall just out of sight of the fact. That's where I'm at, where I'm just going to finish the sentences in my head instead of saying them out loud, which makes for great podcast content. Well, Sari, since we've talked about this before, why don't you tell me what you'd like them to do with my body? Yeah. Oh, interesting. do with my body yeah uh oh interesting i think you should live on forever as a skeleton within like a medical classroom or something like that so everyone can say oh yeah this is hank green science communicator oh is that an option can you get to can you get to decide to be a skeleton

it's my body i feel like i should be able to make that decision like i want those dermestid beetles to eat my flesh off and then i want someone to articulate me yeah because then you can still make tiktoks even after your death someone can make tiktoks with you we can put a wig on you and they could just like ai my voice it could just be sari talking through a modulator and should just be like hey what's up it's hank yeah uncle hank's click clack tick tocks all right it's great it's great thank you sari i'm i'm in sam and i think that they should take uh your body and send it to the moon uh so that it can be there for future aliens when they come by. It'd be like, oh, that must have been what they were like. Yeah, they could check out your brain too, maybe.

Cut it open, see. Oh, wow. Oh, she went to MIT, huh? No. They'll be like, oh, she was sad, huh? We can tell just by looking. Every week here on SciShow Tangentsents we get together and try to one up a maze and delight each other with science facts while also trying to stay on topic and

we're playing for glory here or i'm not they are uh but also for hank bucks which i will be awarding as we plan at the end of the episode we'll have a winner and they'll get to brag now as always we're going to introduce this week's topic with the traditional science poem. This week it's from Sam. In popular culture, lasers are so cool. From ray guns to swords to sci-fi multi-tools, they're easy to use, come in lots of fun colors. You can use them to fuse things or blast evil space smugglers. But lasers in real life, let it be understood,

seem to mostly be used to cut things out of balsa wood. They aren't for blowing up aliens or being fired at spaceships.'re taking babies temperatures and etching things into microchips or they're used in a lab by some nerd at mit to accelerate molecules as part of their graduate degree and you probably have to be real smart to make them work and know stuff about physics optics wires and quarks quarks and quarks quarks well that simply can't stand laser should be real fun so i'm putting my foot down and speaking for everyone scientists please do us dumb guys a favor you can make anything else boring but just let us have lasers the most common use of a laser has to be cat toy it has to be number one it is a little bit sad like there's like it's and it's also the same device that's like the cat toy and also for your powerpoint presentation where you're like now point number two here

and you can aim that thing at the wall all day long. It's not going to burn a hole in anything. It's not. Though it is like, don't look at it. Yeah, except your eye may be a little bad.

That's for sure. Yeah. I was so scared of lasers when I was growing up because of that. They were like... We got the powerful boys now. We got some lasers

you have to worry about. Yeah, you don't want to stick your hand under a laser cutter laser. It'll burn you like it'll burn the balsa wood. That's right. Will it? I don't know.

It might be a different thing. It might hit that water and be like, I can't handle this. I'm tougher than a laser. I don't actually know. I wouldn't put my hand under the balsa wood laser when it's making that really cool coaster that you're going to put on your Etsy store. So lasers are fantastic. And I think that we know what they are. Am I right, Sari?

That at least we can draw a pretty sharp line around what a laser is. Yeah, it gets a little blurry, but we sharpen it right back up. Because I got to start with the etymology to show you where the blur is. Oh, I see. Because it's actually laser is a thing. It stands for something. Laser is an acronym, and it wasn't the original acronym. In 1955, the first device that used stimulated emission of radiation was microwave amplification by stimulated emission of radiation,

also known as a maser. And so we had masers. So we had masers first. Yeah, we had masers first. Maser was the original. And then afterward, people were like, hmm, what if we amplified and stimulated emission of radiation using other wavelengths that are not microwave,

specifically stuff in the optical spectrum. Like stuff you can see, visible light. Visible light. And so somewhere around 1957 to 1959, or maybe 1960, there's a hot debate about who first came up with the word laser. Some people were calling them optical masers, which didn't catch on.

Okay, boring, bad. Oh, masers. That's pretty fun. Yeah. So you have oh, masers. Or some guy named Gould was like, what if we just call it a laser? Light amplification by stimulated emission of radiation. Like a maser,er but cooler so we'll

call it a laser and there's a debate i think and one had one term had to win and so laser won out okay you don't have to answer i just want to say a couple of words out loud because there's lots of other wavelengths of electromagnetic radiation so can i have a zazer x-ray amplification by stimulated emission or whatever uh can i have a ultraviolet one that's called a wazer can i have a gamma radiation one that's called a gazer i think you can call them whatever you want, but nowadays, in general parlance, everyone just uses laser for any frequency. Masers or lasers? Some people use masers to say microwave or lower, and anything higher frequency than microwave is a laser. Anything below microwave is a maser.

But some people just generalize and say they're all lasers it's a it's a better word what what in what in like simple terms is a laser this is hard for me to explain because i'm not a physicist but we mentioned in a previous episode i think the mirrors episode there is a um a device called an etalon in optics or a Fabry-Perot infrarometer, which is two mirrors on the ends of a cavity that are parallel to each other. And they're along a tube. So like you imagine a cylinder, there are two mirrors on the end. And waves can pass through the optical cavity, one of those mirrors, only when there are certain frequency. So with a laser or something,

it takes advantage of the fact that some atoms absorb energy and then release photons, and that generates light. And as you input energy into the system it releases photons and those photons start bouncing back and forth and in the mirror which activates more atoms which emit more photons and eventually you have this cascading effect of more and more and more photons being emitted and bouncing back and forth in this little tube.

And then they reach the frequency or they are at the frequency that escapes the mirror. And so you have a bunch of photons of light, very, very aligned because they've just been bouncing back and forth in this little chamber that shoot off into space. And that is my best. it was a little rough like it bounces back and it gets a little bit more photons and they bounce back and they get more photons and they're all sort of aligned because of that because the mirror thing and then how do you let them out eventually is there like a little hole or is it like a partially silvered mirror where some can leak i think one of the mirrors can partially leak i know i really

thought your explanation was going to make them sound more boring but it made them sound even cooler actually yeah i i just remember so this is where my memory is failing i remember the animation on the top of the laser dome was like photons in like a dancing motion and being like one goes that this way and then two go back this way and so that's ingrained in my head uh but then i can't remember the animation for the whole like raising the electron level and then spitting out the photon so that part of the explanation is a little rocky i love that lasers are cool and they got a cool name yeah i'm just like very happy for lasers also sam in your poem i have to call you out on something you said that the smugglers were bad guys but they never well that's true they're they're always good guys that's the

closest thing i could run with colors okay yeah yeah you could have been like awesome great smugglers just great awesome smugglers like han solo yeah i don't know why the smugglers are always good guys because they're anti-authoritarian they're anti-authoritarian yeah and authority in space series is usually even more dystopian than the authority in real life yeah i think next time i go overseas i'm gonna smuggle something But I think you should really respect trade barriers and you shouldn't do smuggling. That's my hardline stance. No smuggling allowed. So thank goodness for a great word with an easy etymology and a definition that definitely

is clear. It never happens, but here we are today. And that means that it's time for the quiz portion of our show, because lasers have been a figment of our creative imaginations for some time, but their uses aren't limited to science fiction. Scientists have been finding very real ways to use lasers to make things that sound made up, but are not. So today I'm going to be telling you a tale of three things made with lasers, and two of them are just plain lies. So tell me which one the true one is. It could be this first one. Using a focused laser beam and mirrors, scientists were able to fabricate gold nanoparticle plated armor that protected

bacterial cells from being engulfed by immune cells. It might be that one, but it might be story number two, where scientists devised a way to make lasers that can work on a thin, flexible substance, which they then turned into a contact lens that can shoot green lasers. That could be it. But it could also be the third one here. Scientists used an optical laser to create extreme heat and pressure so that they could accomplish what alchemists had long tried to achieve. Just on a nanoparticle scale, they were able to convert lead into gold. So it could either be scientists crafting gold-plated armor for bacteria using lasers, scientists making contact lenses that can shoot lasers,

or scientists wielding lasers to turn lead into gold nanoparticles. I would think bacteria is that having gold on a bacteria would be like, oh, I'm safe, but at what cost? Because they gotta be like squishy and flowing around, right? Maybe? Also, why would you want to protect bacteria? I don't know. I feel like the bacteria that's in our gut is fine in there.

Most of them are good guys. Yeah, but they don't need our help. They're fine. They can replicate pretty quick. Yeah, they can just split off another one of themselves and be like run while you still can right they are good at that um what's the second the contact lenses so first of all couldn't be very strong you burn your eyelids off second all, it probably would just be like, if it's just like a faint glow, totally.

I'm sure someone's working on that. So maybe, I mean, maybe that one. I feel like you'd have to pack whatever is in a laser. So like some, something that gets the light,

like that gets the light energy, something that like a crystal or a glass or an optical material that will have its electrons excited and spew out the photons. And I feel like that would be hard to pack into a contact lens. Okay. And I don't know enough about anything to know the last one. That seems plausible, I suppose.

If you shoot something with enough little beams, it'll change into something else. Where are lead and gold on the periodic table? I have no idea am i allowed to look that up or no uh yeah yeah sure i think that they're quite close but i don't i think that that was that's the kind of idea oh yeah 82 so 82 is lead 79 is gold turn lead into gold yeah i think that's possible so i'm just imagining you got a laser beam imagine like your sci-fi narrative but on a very I'm just imagining you got a laser beam. Imagine like your sci-fi narrative, but on a very,

very tiny scale where you got a laser. You go pew, pew. I'm going to knock some neutrons out of you. Pew, pew. Yeah. And then get rich.

And get small to gold. So I think it's the third one. I'm going to go with the first one, actually. All right. Here's the situation. We did use super strong lasers to turn polyethylene plastic into nano diamonds which is maybe even uh you know in terms of like value

creation better than turning lead into gold uh but maybe not because nano diamonds probably aren't that that valuable but we did not we weren't able to knock a bunch of atoms off of lead to make okay that'd be pretty that'd be or protons i should say not atoms that'd be that'd be tricky We weren't able to knock a bunch of atoms off of lead to make gold. That'd be pretty, or protons, I should say, not atoms. That'd be tricky. And a nuclear reaction that I would be, not want to be nearby. But you know, lasers are definitely involved in nuclear reactions. I'm not saying it's impossible.

And Sam, we did use lasers to manipulate the position of golden nanoparticles inside of cells and they're used by scientists to study particular parts of cells and and help them figure out how they work and they wanted to see if they could manipulate and localize those gold nanoparticles with a laser so they infused cells with gold ion solutions to get through that membrane and then they use the laser to manipulate the nanoparticles into the area of the cell they wanted them to be in they were able to use the lasers to push around the gold nanoparticles inside of the cells which is very cool but it is not creating gold-plated armor for bacteria using lasers so in fact in 2018 scientists created super thin membrane lasers that can be charged with blue light so you like charge them up with light and they usually need some kind of solid support to make them stable

but the researchers worked on a way to make a thin sheet with lasers in uh in it that was mounted on a glass substrate and then taking away that substrate so that you could just have the thin membrane and the laser they constructed was about one one-thousandth of a millimeter thick. And then they put their lasers in a contact lens and put them on cow eyeballs that had been previously moved from the cow. So that was like a cow currently. A cow with laser beams.

And they used the blue light to charge up the laser and they saw a laser beam coming off a cow eyeballs. Why'd they do it? I can't really say. I think that they had some ideas that it might be useful for some reasons but like none of them sounded particularly plausible to me it more seemed like hey wouldn't it be cool if we could create cow cyclops from the x-men but cow but a cow yeah so wow i'm sorry neither of you get anything. That's wild. No, that's very cool. Yeah. It sounded so fake.

Yeah, it does sound fake. But scientists will go out, do anything out here. There you go, Sam. Like, here are these scientists trying to make lasers a little bit cooler. Be like, what if we have cows that shoot laser beams from their eye? The picture of the cow eyeball isn't very cool, though. It's just really gross. No, cow eyeballs on their own aren't great.

They also stuck one of the membranes onto one of the researchers' thumbnails, so you could have like a fancy laser finger. Really cool. Really cool. That's great job, guys. Yeah. All right. We're going to take a short break, and then it will be time for the Fact Off. Welcome back, everybody. Get ready for the fact.

Our panelists have brought science facts to present to me in an attempt to blow my mind. And after they have presented their facts, I will me in an attempt to blow my mind. And after they have presented their facts, I will judge them and award Hank Bucks any way I see fit. But to decide who goes first, I have a trivia question for you. In the first half of the 20th century, a man named Joe Woodland was at the beach when he drew up the idea for the barcode in the sand. He was like, this is a great idea. Look at these bars I've drawn in the sand. He was like, this is a great idea. Look at these bars I've drawn in the sand. He'd been thinking about coming up with a code that could be printed on groceries so that stock taking and checkout would be faster. And sitting at that beach, he devised a system inspired by Morse code

that used wide and narrow lines to identify products. That system would later become the basis for the universal product code, which uses lines and lasers to help scan items at stores. code which uses lines and lasers to help scan items at stores what was the first year that an item marked with the upc code was used at checkout oh first half 1951 is my guess wait what was in the? Did you say in the first half or just any time? No, I just said when was it? 1971. The answer, Sam Schultz, is 1974!

Wow, I have a bunch of items that doesn't have UPC codes on it, so that's how I know. It was Wrigley's Juicy Fruit Chewing Gum. Oh, wow. UPC codes on it, so that's how I know. It was Wrigley's Juicy Fruit Chewing Gum. Oh, wow. Yeah. So it was chosen specifically to prove

that the code could be printed on even a very small product. So it wasn't like they had to just buy a special machine that was like, here's the machine we used to scan the gum. Is that what it was like for a while? You've bought one gum. we use to scan the gum. Is that what it was like for a while? You've bought one gum. It's only for the gum.

Yeah. Then everything else is going to tally up by hand, punch it in. But Sarah, the patent for the technology was actually filed in 1949. So if we're going by the patent, you would be closer. But it needed a lot of time before it was actually able to work because the tech had to catch up with it. And they weren't super popular originally, but as larger stores adopted them, they became much more popular. And then the stores kept getting bigger and we needed that support. We needed more stuff.

From the great people at the Universal Product Code place. I don't know. I assume that there's some kind of group that handles this. Guy who's drawing all the new ones, like big bar, little bar, big bar, big bar. Ah, shit, I've already done big bar, big bar. Oh, God. So, Sam, that means you get to decide who goes first. I'm going to go first. I could never live with myself if I said, Sarah, you should go first, and hers was was really good i would just hang up the call yeah having a device

in your home that can instantly produce a fully cooked dinner is a sci-fi staple a la the replicators on star trek or i don't know like the jetsons or something and while we are at the point where we're starting to successfully 3d print certain foods the fully cooked element has so far eluded us like you can 3d print chicken breasts all day long but they're still coming out raw you're gonna need to cook that bad boy and having to cook something isn't very futuristic and it seems that 3d printed food especially meat is also trickier to cook than than regular food in the first place too but in 2022 a research team from columbia university made a massive breakthrough in the field of instant dinners laser cooking what they came up with was the first attempt at a

device that will both print and cook your dinner replicator style well okay so right off the bat this thing isn't like a replicator because instead of raw atoms getting sequenced into any food you want the team starts this process by blending up a bunch of raw chicken breasts and loading it into a 3D printer. Then they print a big old raw chicken nugget. Like I said, cooking 3D printed meat is tricky or at least different, I think, from cooking your traditional straight off the animal meat. Or as the team says in their video about this process, current cooking techniques don't provide the high spatial resolution required to cook 3D printed food, which is just a really weird thing say that is weird to me i'm like really really really do we need high space is that because this is going to be a problem for me if it's if i need to buy a new device to to eat a certain kind of food buckle up buddy so to solve this problem the team shoots their 3d printed chicken with no less

than three different lasers to cook it a blue laser a near infrared laser and a mid-infrared laser so the blue laser penetrates the food to cook the inside of it using a pattern device for optimal chicken cooking then the infrared lasers can be used to brown the outside or to put grill lines on the chicken because why not and the result and the result according to the team laser cooked chicken are more moist apparently and also shrink less than old-fashioned chicken breasts the team had people taste test their 3d printed laser cooked chicken and traditionally cooked non-3d printed chicken and apparently according to them people preferred the laser chicken because of that moisture though the video that the team put out that I referenced earlier

hedged a little bit more by simply stating that the 3D laser chicken was edible and achieved food-safe temperatures. Apparently, some taste... It was no McDonald's chicken nugget. Yeah. That's what they're saying. What is? Apparently, some taste testers said they could taste

the unmistakable metallic tang of laser, which I imagine sort of tastes like how laser printers smell, you know, and they compared it the smell to having fillings put in their teeth. But, you know, I guess that's the one they liked better for some reason. So the team imagines that eventually we'll have like a microwave like device in our homes filled with meat goo that we can push like the chicken breast button. In a couple we'll pull out a moist scientifically perfectly cooked 3d printed chicken breast or at that point i can do anything i want with it i can make a chicken nugget in the shape of the eiffel tower why would i eat a chicken breast if i could if i could eat a chicken have some you know like a chicken ball or a chicken dinosaur well you Well, you're really naming things that already exist with your vast imagination right now, Hank. I forgot dinosaur chicken nuggets are a thing.

Round chicken dinosaur chicken. They're totally a thing. No, they're a ball shape. Okay, it's going to be the shape of a nose. I don't know. Take it again. It's going to be a tree. It's going to be a pig. Some other. I don't know. Took it again. It's going to be a tree. It's going to be a pig.

Some other animals that are cute. A manatee. What if it was, whatever. I'm not going to go on this flight of fancy with you. We wouldn't want to have any fun. I couldn't think of anything, really. So one state of benefit was maximum food customization based on your taste. And the Scientific American article I was reading suggested a burger with alternating medium and well-done sections in a checkerboard pattern.

Because, again, why not? And another benefit, which is actually more cool, is that they can cook the food through plastic packaging. So they think that they could reduce the risk of contamination for stuff like pre-cooked meals you can get at grocery stores. could reduce the risk of contamination for stuff like pre-cooked meals you can get at grocery stores so in conclusion the future is here and it's an unseasoned 3d printed chicken breast cooked by lasers neat i love it if it can write grill lines on there i can also put like a note to my son be like i love you buddy i hope you're enjoying octonauts and if he's eating his chicken breast you could print your own face on it. Being like, oh. What's that?

Oh, it's my dad. Oh, you got one of those microwazers, huh? Yeah, it's instead of mazers, it should have been microwazers. Yeah, that's really good. That's so good. Okay, Sari.

Can you beat microwazers making 3d printing eiffel towers made out of chicken swap ground chicken that's it um i'll try my best so lightning can be really dangerous because many things don't do so well with a sudden blast of high voltage and high amperage current especially living things whose bodies depend on electrical balance or flammable things that can't handle high temperatures without combusting. So in general, this is a little preamble because I decided to make my life hard this episode. Lightning happens because negative charge gathers at the bottom of a cloud of water vapor or dust or something, and the ground's neutral charges are relatively positive. Air isn't super conductive in its everyday form, but when enough charge builds up

and kind of spurts out of the cloud or the ground, it ionizes some air molecules, which makes it more conductive. And eventually all the system hits a breaking point and carves out an easier path for electrons to flow. And when those electrons move all at once, that's a lightning strike. And lightning tends to strike tall things like towers because that height sort of provides a shorter path for the electrons to travel from the cloud to something. And lightning rods are conductive structures

that people intentionally use in this way for some amount of safety and control. So trying to get lightning to connect at a specific tall point and run through a wire to the ground without damaging unsuspecting people or things. But lightning rods, as I

found out, aren't a surefire protection or even particularly great. They only cover about a couple dozen meters in every direction depending on what they're made of. So if lightning is brewing a little too far away from a lightning rod, the strike could easily hit a different part of a building or a bystander.

And you need multiple lightning rods to create a bigger area of protection. And so far, as far as I can tell, we just kind of lived with that risk. But in the summer of 2021 on Santus Mountain in Switzerland, a research team used lasers to help redirect lightning bolts toward a telecommunications tower that's there to help measure this kind of electrical storm stuff. The basic idea is that high-powered lasers

can ionize some air molecules and basically help carve out that path that guides the flow of electrons from the clouds to the lightning rod and vice versa. So to test that, they shot intense short laser pulses based on yttrium aluminum garnet crystals up towards a thunderstorm and

observed what happened with high speed cameras and it turned out that in four times when the laser pulses coincided with lightning strikes the lightning followed the path of the laser for around 50 to 60 meters basically increasing the protection radius of the lightning rod by that much. And besides the fact that this worked, they redirected lightning with lasers, which is a very cool sentence. It's extra cool because using lasers can theoretically work to clear paths for lightning,

even in foggy or other tricky weather conditions, because the photon beams can just blast right through the water droplets and vaporize them so they want to keep experimenting to use lasers to extend lightning rods even further and hopefully develop more protective uh sci-fi future systems against nature's unpredictable electricity so does the laser like does the laser have to be in the place where the where the lightning is coming down or can can the laser be, like, somewhere else? If I'm, like, way over here and there's, like, a big tall building, can I shoot a laser and help the lightning come down at the... Or is it going to, like, follow me? I think it's going to follow the path of the laser.

So the laser has to be where the lightning rods are? Yeah, and be, like... Okay. And it extends it vertically, kind of. This is good news because it means that we can't intentionally make a lightning hit someone. You could plant a laser on them, though, right? Sneak one into there. Yeah, you could plant a yttrium laser on them.

On top of their head, somehow. Give them a hat. Here's your new hat. They're hanging out on a park bench. Yeah. Yeah. Laser shooting off the top of the hat a very powerful laser shooting up some mystery novelist is taking notes right now they're like this is how russia's gonna start

killing spies yeah ultimately i'm like i'm 99 sure that in the future we're gonna be using lasers to like increase the the working distance of a lightning rod seems like why not through that like it's it's working it's good but the like 20 sure that we're gonna have micro lasers that'd be a much bigger impact on my personal life yeah to have to have like a device in my home that just sort of like creates food in any shape or level of doneness i require and as a bonus it shrinks less i love that that was one of those things yeah it's juicy it's juicier it's like yeah because the water is still in there you print out a perfect replica of your own body and you can eat it for dinner.

Come on. You could print out your arm and just be like. I like the idea of printing out like a full sized Hank out of chicken meat and then having a bunch of people over. Just like dip me in the sauces. That would be great. Yeah. Take your finger out. Don't.

That would be really fun actually. Yeah, they'd be like well how big is your micro waser hank like i did it section by section took a long time some of meat hank is quite old it's been around i've gotta give it to sam yeah i didn't think i would but then i kept i kept coming back around to it it's just it's a i mean they're both so good laser guided lightnings are cool but there's just so it's fertile ground there with uh 3d printing meat and using three different kinds of lasers to cook all right that means that it's time to ask the science couch where we've got a listener question for

our couch of finely honed scientific minds. At Sloth Queen asks, what's the longest a laser can shoot? If you shot one into space, would it just go forever? Yeah, that's my kind of feeling as if it's, if you don't hit,

you know, there's like gas and dust in the universe eventually. Oh, yeah. But I feel like infinity. It's still the laser. As long as the time that you have to wait. Is that right, Sari? I think so. But I'll lead up to it with my discoveries of longest laser that just kept escalating as i tried googling different things

because you can't just google how long can a laser shoot you gotta like guess what long distances are so first thing i thought what if you pointed at a friend kind of far away and the thing that i found in this circumstance is that the faa is very vigilant about laser incidents of people on the surface of the earth pointing lasers upwards planes and cruising altitude is generally between 10 and 12 000 meters so a laser shined from the surface of the earth can be quite distracting or blinding to a pilot if it gets up into the airplane and that of course depends on weather conditions so it can definitely go as far as ground to plane and then i was like well okay space on the moon left by apollo astronauts there are

reflecting mirrors on there that have been used continuously since 1969 to study like the earth moon system and how far the moon is away from the earth there are five retro reflector arrays is what they're called and i think any lab or any person can just shine lasers at the moon and measure the distance from the moon to their spot at earth and be like that's neat and so you just shine your laser to where these known mirrors are and it'll and you can like see the laser beam from earth detect it from earth and then i was like okay how far in space can we go and this is the farthest that i found where a powerful radio wave laser called a mega maser so they specifically called it both a laser and a maser in the same sentence uh has been observed by a telescope in south africa this mega maser is about five billion light years from Earth. And so the light from this mega maser has traveled 58,000 billion billion kilometers

from its origin point to Earth, which is basically infinity. Yeah, it can go 5 billion light years. It can go forever. Yeah. If there was aliens, would we be able to see their lasers not not unless they so are we pointed at us yeah so there's a couple there's a couple of problem like reasons they would have had to have pointed them at us at the right moment in their history it would have to be bright enough for our detectors to detect which i don't want those to be tricky i don't think that

we could do that with any of our current lasers. I think there are experiments in laser communication. I don't think we've sent it very far. I think we've mostly used it, like, obviously we're on Earth, so that's the easiest place to test communication is on Earth to satellites or things like that. But there's a whole Wikipedia article about laser communication in space that I kind of glossed over and then was like i want to stick with the mega maser if you want to ask the science couch your question follow us on twitter at scishow tangents we'll tweet up topics for upcoming episodes every week uh there or you can join the scishow tangents

patreon uh and ask us on our discord thank you you to at Fyrigion, Les on Discord, and everybody else who asked us your question for this episode. If you like this show and you want to help us out, hey, it's very easy to do that.

You can go to patreon.com slash scishowtangents. Become a patron of our show and get access to things like our newsletter and our bonus episodes. And a special thanks

to patrons John Pollock and Les Aker. Second, you can leave us a review wherever you listen. That's super helpful, and it helps us know what you like about the show. 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 Sari Reilly. And I've been Sam Schultz. SciShow Tangents is created by all of us and produced by Sam Schultz. Our associate producer is Faith Schmidt. Our editor is Seth Glicksman.

Our story editor is Alex Billow. Our social media organizer is Julia Buzz-Bazio. Our editorial assistant is Deboki Chakravarti. Our sound design is by Joseph Tuna-Medish. Our executive producers are Caitlin Hoffmeister and me, Hank Green. And of course, you couldn't make any of this without our patrons on Patreon.

Thank you. And remember, the mind is not a vessel to be filled, but a fire to be lighted. But one more thing. We've mentioned dead butt syndrome on a previous episode of the pod, but the more technical term for this achy pain is gluteus medius tendinopathy. And that's a fancy way of saying that the tendons that connect your butt muscles to your bones and help you walk are inflamed. There are various ways to rest or stretch to help your butt tendons recover, but one possible treatment

is low-level laser therapy. LLLT involves shining short-wavelength, single-color light to help promote all kinds of biological repair processes, including helping cells proliferate, reducing inflammation, and up-regulating growth factors. How do they get

the lasers into the butt? I don't know! Pew pew! it's only for butt there's for every it's for other parts of your body i think it's for a bunch of things okay you just got a little creative with it yeah i think that they shoot it through the skin yes this is the more practical one my other butt fact option was woman farts during surgery and then catches on fire which was very dubious of an article from a laser yeah they were losing laser on her butthole and then she farted and then they were like it caught on fire but it's dubious because your farts have to have a lot of flammable gas they don't always have that composition usually have that much flammable gas. They don't always have that composition. They don't usually have that much flammable gas.

I mean, there's a little bit, but like what's going to catch on fire? All that stuff's in the... Yes. It's definitely dubious to me. There's not a lot of flammable material left during an operation. They tend to do their best to remove that

and not have it be around. This is not a canon butt fact, everybody. No. It's a non-canon butt fact. Yeah.