Could you make an umbrella out of lasers?
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- Опубликовано: 19 фев 2024
- Get a copy of What If? 2 and Randall’s other books at: xkcd.com/books
More serious answers to absurd questions at: what-if.xkcd.com/
Stopping rain from falling on something with an umbrella is boring. What if you tried to stop rain with a laser that targeted and vaporized each incoming droplet before it could come within ten feet of the ground?
Randall Munroe is the author of the New York Times bestsellers What If? 2, How To, What If?, and Thing Explainer; the science question-and-answer blog What If?; and the popular web comic xkcd (xkcd.com). A former NASA roboticist, he left the agency in 2006 to draw comics on the internet full time.
Henry Reich is the creator of MinutePhysics and executive producer of MinuteEarth and MinuteFood and founder of Neptune Studios (the parent company for all three youtube channels).
Credits
Narrated by and based on "What If?" by Randall Munroe
Written & Directed by Henry Reich
Illustration and Video Editing by Lizah van der Aart
Illustration and Animation by Ever Salazar
Music & Sound Effects by Know Art Studios
Laser droplet animation based on footage by:
Physics of Fluids - University of Twente
• 2014 Milton van Dyke W...
/ @poftwente
What If? The Video Series is the official adaptation of the What If? books by Randall Munroe and is produced by Neptune Studios LLC.
©2023 xkcd, inc. 
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I love how most of his answers can be boiled down to "please don't"
Some hypothetical scenarios are best left hypothetical.
Unintentional pun
I wonder what will happen if the power level of the laser is set to “Please Don’t” instead of just “Mega Ultra”…
Well there goes my afternoon plans then.
Like swimming in a nuclear waste cooling pond. 😆 _(One of my favorites.)_
I kind of love Randall doing the objecting lady voices.
It's giving Charlie Brown adults
kinda sounds like Celeste dialogue
I don't even know why but it adds so much!
Now I'm curious if all the little characters (white hat, black hat, etc) have different voices
@@CaTastrophy427Is that like a game or something?
Actual laser engineer over here o/
My job isn't exactly "zapping water droplets with lasers"... But I do zap other "stuff" with lasers, which is then used to squirt droplets... which are then zapped by lasers!
I'm not 100% clear on what my NDA says, but that's probably as close as a description of my job, that I can share on RUclips😅
So about your laser-umbrella-concepts: I would actually do this differently, and more safely for your neighborhood - although the same could probably not be said for the airline pilots flying above you. Instead of aiming the beam parallel to the ground, I'd aim it up, straight into the direction the rain is coming from. And I would also fit a huge defocusing lens (the official jargon would be: "beam expander") on the laser, so the parallel beam, which is normally quite narrow, can expand to have a cross section of about a m².
This would essentially "cook" the droplets slowly as they are falling down to you, since they will all only receive a small portion of the power emitted, but for quite a bit longer than a single "zap". This means they likely won't fragment like you suggest in your video, but boil slowly. Even if they do fragment, your laser beam would be omnipresent to the perspective of the droplet, those fragments will still get blasted until they make it out of the m² thick beam.
As you mentioned in your video, the beam would be going up for a few 100 meters, until pretty much all of the light has collided with a rain drop, perhaps reaching the clouds producing the rain to begin with.
This brings to mind another tantalizing option: Why not evaporate the piece of the cloud that's raining on you? You could feel like God and create your own ray of "monochromatic sunshine" to blast a hole through the cloud.
Looking at the absorption curves for liquid water, I would also suggest using a Near-Infra-Red (NIR) laser, such as a Neodymium YAG laser, which has a wavelength of 1064 nm, giving it an absorption length of about 1mm. perfect for absorbing the power throughout the whole droplet, and not immediately at the surface, which would indeed make it explode.
If you have doubts about my strategy because the raindrops don't fall in a perfect straight line towards you, then I'd counter by suggesting that you could perhaps defocus your laser beam slightly (again with lenses) so you are shining the light in a cone upward, hitting more droplets the further away the beam gets, and therefore creating a larger (no)safe-zone further upward. You may need to increase your power to compensate for spreading out the beam even more though, but I seem to have read more outlandish solutions than that in your books... 😁
Behold! The photothermal flashlight!
By any chance does "stuff" include a certain easily-melted metal?
Basically what I was thinking, diffuse the laser into a upward pointed cone, it doesn't matter if it reaches 100m, cook all the water, or at least splatter it out of your drop zone. Kill them all if you will, but only right above yourself. You would have to have the computer account for the direction of the rain in order to adjust the angle most likely. Though the FAA might come knocking if they found out about this umbrella of yours. It might be an interesting question of vaporizing a hole in the cloud above you, be interested to know if that is at all feasible, I would guess no.
I gotta say, just the statement "I'm not 100% clear on what my NDA says" is kind of a power move
Howdy fellow laser gun engineer 👌👋
For the laser source, may I recommend a phased array of fibre lasers? Waaay easier to aim and focus (or defocus), admittedly a pain in the b*tt to setup, but hey! phasers IRL!
An umbrella diverts water sideways. Splattering the droplets away, instead of evaporating them, is exactly what you would want to do.
except you'd need to splatter them such that you'd guarantee every fragment would fall outside of the area you're wanting to keep dry.
Well, it's not what I want to do. I want to destroy the sky.
@@CaTastrophy427Especially since the thing you're trying to avoid is now "splattering boiling water on yourself" instead of "getting a little bit wet"
@@CaTastrophy427 Not quite; the splatters could be shot again, either vaporizing them, or creating even smaller splatters (which sounds bad, but those would also be falling much more slowly). Also, the splatters tend to shoot out perpendicularly to the incoming laser, so they are mostly going in the right direction.
Splatter enough droplets and you have made yourself an umbrella out of rain.
Out of sheer coincidence, I recently did the exact same research as a joke with some of my friends. We concluded that the whole system (with generators, cooling, targeting, etc.) would cost $8,000,000, weigh roughly 30,000 pounds, chug an entire gallon of gasoline every few seconds, and "protect" 4 m^2 in hurricane weather from the horrors of *liquid* rain. It would also blind everyone.
If only Saudi princes needed to worry about rain you would be set
@@iambicpentakillThey do need to worry about sandstorms.
Obviously, scaling up the technology from the merely absurd goal of vaporizing rainfall to the laughable one of shooting individual grains of sand out of the air is insane. Which is why a prototype of this system has absolutely been mooted for Neom.
Not liquid rain again!
@@Frommermanlmao
@@Frommerman The real problem is to get the sand grain while leaving the spice intact
After hearing the lady's voice I can't wait to see him doing Hat Guy saying, "What if we tried more power", during the laser pointers at the moon one.
To this day that one is my favourite What If. Hopefully it makes it into the videos at some point.
*dying bird noises*
@@Zarethorne i hope so too
Yes to more power. I so hope that one gets a video!
I love that one
2:31 "...how far will it go before it hits a drop? This is a pretty easy question to answer; it's the same as asking how far you can see in the rain."
The simplicity of this brought me joy.
"Why is my house on fire again" is a killer line.
The 'again' is doing a lot of heavy lifting here
It's just the northern lights.
The rain should put the fire out… oh. Oh, gosh.
@@julianparsons3027 THE RAIN IS ON FIRE, TOO!!!
@@Kylora2112 Hears the song "I set fire to the rain" in my head! Maybee this is what that song is actually about? Trying to ignite rain with lasers! :)
Finally, an xkcd video that doesn't end ion a world-ending apocalypse
Yet, there goes the neighborhood.
Nah, just the neighborhood and maybe a significant part of the surrounding city, assuming the laser beams can travel far enough to set that on fire. Also, all that superheated steam might get interesting. To say nothing of the power requirements.
@@pariahzero Within a few videos we may be able to work it down to the destruction of a mere room.
Yeah, I found the video a bit short as well.
The baseball one only had a *city* ending apocalypse...
Another important question: How loud would it be to instantly vaporize a drop of water with a laser? Sudden conversion of a raindrop to gas has got to create a shockwave that would be *loud*. Repeat that with as many raindrops in close proximity over the user's head and it's got to be... unpleasant.
Depends where you are. You know that wonderful sound of raindrops on a tent when you're inside it? Well, it would sound like that - 20 miles away.
@@ianmason.how do you know?
@@mrosskne Extrapolation from hearing heavy small arms fire at a distance.
I imagine it would sound similarly to pouring some water into a ripping hot pan: a loud hiss. Sure, x100 and constantly noise, but no shockwave.
@@johnwostenberg840 the thing is: a hiss is the tiniest fraction of the drop converting to steam - and slowly. If the entire drop converts to steam nearly instantly, the phase change would not be unlike the solid to gas phase change of gunpowder, which is a bang.
I enjoy that the last power setting on the laser is "please don't"
I like how it's "why is my house on fire AGAIN?", because it has happened more than once
If it's not the guy with the laser cannon on his roof, it's the guy with the rocket car or the guy with the lava moat.
Not surprising given who his next-door neighbor is.
maby its the guy with the aー10 canon backward on his car
probably from the aftermath of pitching a baseball at near light speed. the lore deepens
It's not an expensive neighbourhood to move into. In fact, you can probably get the land for free, and the construction company may well give you discount from the first 5 houses you order from them.
The character voices are absolutely delightful
I never considered what the stick figures in xkcd sounded like, but I am reading all his comics in this voice from here on out
Funny, I really dislike them
Swiveling lasers to target raindrops is about what they did at CMU to make rain-removing headlights. They replaced the single bulb of the headlight with a projector with a million pixels. It would turn off the pixels that would hit raindrops, letting the remaining light go much, much farther. They had high-speed cameras to find the raindrops, and then calculated where they would be when the pixel was ready to fire a few ms later. This apparently really worked, but needed massive computer power. That's a mere matter of hardware design...
This sounds like a monumental waste of computing power if you ask me..
@@rrai1999 Actually doing it, sure. Figuring out how it's done is almost certain to eventually be useful for something more practical eventually though.
can we talk about that very well-done rotoscoped water droplet animation at 1:34, it looks very nice
So what you're saying is we should use microwaves as an umbrella instead?
i find xkcd's "voice of reason" character quite charming lol. It's voiced like a pleasant version of Charlie Brown's teacher - the trombone "wah-wah" voice :)
She has a canonical name (Megan)
I have to think there's another layer of problem here. Let's say you vaporize the falling water above you and remove the kinetic energy of the drop in the process. You now have a tiny amount of steam, which I would expect to rise. But it's rising into a shower of relatively cold water, which will cause it to condense and join the rain falling on you. So now you have more liquid water falling on you than before, increasing your power requirement. Yes, the condensed steam shouldn't take as much energy to re-evaporate, but you still have to hit it quickly.
The water it warms would need less energy, though. Thermodynamically, it would all still work out
@@samriches9145 I expect there would be an equilibrium but it should be a higher power requirement than you would expect for the natural rainfall.
Hot vapor expands... in all directions. Sure, you'll have a little getting in the way, but if you're only protecting a human-size area of ground, the vast majority of steam will quickly expand out to the sides. I expect the complication to be very minor.
The lasers splattering droplets rather than evaporating them might help for the umbrella actually. You don't need to turn the droplets to mist to stay dry, you can simply deflect them so they land somewhere else than on you. That probably takes a lot less energy. Deflection rather than evaporation is how a boring umbrella works after all.
This is exactly my thought! I wanted more analysis of targeting systems that would splatter the drops in the right directions to stop them from hitting you since I'd wonder if there is a better way than just hitting them from below.
@@lordtadhg This actually feels like something that might be possible to analyse without too much difficulty. When the laser hits the side of a drop, it causes the tiny spot it hits to evaporate very quickly, and the reaction force from that steam rushing away pushes (and deforms) the rest of the drop in the other direction. This is called ablation and is pretty well studied for lasers so it shouldn't be too hard to get a heuristic relation between laser power and force caused. The amount of force required to deflect the drop is very easy kinematics to approximate. So the final result can't be too hard to get a rough handle on.
The problem is if you platter the droplets into smaller droplets, you are now going to have to deal with the smaller droplets, which then splatter into even smaller droplets, some of which will be directed back to the original droplet location and repeat until uou fonally vaporize the water.
And I am pretty confident you arent get droplets nearly a metre.
@@88porpoise but the new smaller droplets aren't in the same place as the original one. They're clear moving sideways in the video, and at a considerable speed. If you hit them when they're reasonably high above you, it only takes a very small nudge to get them to miss you.
@@QuantumHistorian It may have a fairly high velocity initially but it will lose that velocity extremely quickly due to air resistance and gravity will have it heading back down onto your head.
It will also depend to an extent what direction the laser is firing, if it is mostly upward it is going to be much less effective than if it is mostly horizontal (which has its own issue with outside droplets blocking the laser).
It would have probably been an interesting analysis, but I would bet a lot of money that it isn't going to come close to changing the conclusion.
Not to mention that lasers aren't exactly known for their power efficiency. I used to wotk with 10 watt lasers that required a literal refrigerator to watercool them.
You're doing this in the rain! It's a free water cooling system 😎 (as long as you aren't firing your lasers straight up)
I'm curious if this was a long time ago or just a different type of laser then I'm used to. I do live event lighting and I've worked with 30w lasers that arent that much bigger then a shoebox and can run for hours outdoors in the summer or in a hot venue constantly without any heat problems.
@@marlowcowan5343 Yeah, it was a 20 years old system. Also the task requires stability of power. But modern systems for the same task run fine with air cooling. Still their power consumption is still well over the wattage of the produced laser beam.
@@QualityGarbage The fact they need cooling at all proves they're not very power efficient.
@@QualityGarbage - The cooling from the nearby rain could only _begin_ to be helpful if the lasers were at least 50% efficient (i.e., you only need to dissipate
from now on i'm going to imagine every xkcd stick figure talking like an animal crossing character. thank you dearly for this.
Just wanna pop in and say: I found your channel yesterday and am already a fan of your videos. I just love your style, from the ridiculous topics, to the drawing style and mumbled sound effects... awesome. Definitely looking forward to more!
His channel is pretty new, but Randal Munroe's webcomic xkcd has been around for decades and is genuinely hilarious. I can't link in a comment, but google it!
If you didn't know: there is a whole series of online comics by the same author. While the comics don't generally deal with blowing up the world, they are fun to read if you are into science / technology.
Google "xlcd" if you are interested.
Also, there are traditional books that cover the exact same topics as these videos.
If you haven't yet, you should go to his website where all these videos originated from. Once you get through those, buy (or take out from your local library) his two books which also have more thought experiments like this!
@@Donkringel Yes! His books are also SO fun, and the What If blog has hundreds of entries.
@@Donkringelno, just get the books for free from any of the many PDF pirate sites
Yay new xkcd video!
Kid you not, I just got done watching a video about Michael superbacker and that whole air-umbrella fiasco, and then THIS (at-time) 3-minute old video is the top of my feed when I click home, like a logical hyperextension... Almost feels like the universe itself is curating content
Next video: Can we make an umbrella out of... Water?
@@eross.carmona7235 Sure, if you freeze it
You are the chosen one. BUILD THE LASER UMBRELLA
Help! You’ve discovered the secret! We are the only two real humans left in existence and the simulation is crafted for us. Do not mention outside of this comment chain or *they* might activate
@semanticks I may have no relevant knowledge or qualifications, but since when has Destiny ever called for such minor minutae like that?
0:29 that sound 👌👌😂😂
OMG it's so awesome to see my question animated 😁 This was a lot of fun to watch and it made my day the same way it did way back when you took the time to answer it on WhatIf. Thanks so much
Xkcd: It’s totally impractical.
Styropyro: Hold my beer...
I was looking for this comment
Idunno when someone made a laser flyswatter that was the very first thing I'd ever seen styropyro terrified by.
This is the best show ever. Someone get this man a million dollar budget.
Not that that would necessarily help, it is just that good already.
NO. Do not give this guy any budget.
We don't want practical demonstrations of any of these videos.
@@ChiefArug Woah, don't include me in that "we", I'm totally down for going out in a blaze of science! I mean, sure, some of them are less of a "blaze" and more of a slow burn (such as everyone suddenly being on Rhode Island), but that'd still be a heck of a story for the afterlife.
@@JarieSuicune Exactly! We could make this the new Mythbusters
Im all for giving Randall and MinuteEarth a million dollars, but not to increase the budget for these videos. The low quality 5 minute stick figure drawings are what make it
Damn, I miss Minute physics. Glad we got xkcd.
Well, looking at the credits it seems like Henry, the minutephysics guy, pretty much runs this whole operation, right?
The recent Styropyro video was making use of a 2kW laser. 5 of those with the line optics pointing straight up and oscillating back and forth may feasibly evaporate / splatter away all droplets in a m2.
Unfortunately, rain doesn't fall straight down (or straight wherever the wind is blowing it) except on super super clear days. Often, the wind will whisk the rain around enough that you'd need to clear a *really* wide cylinder of area to have no rain touch you on the ground.
I absolutely adore the side characters with voices, I think it adds a lot, when done in moderation (like you did here)
We need the “what if you made the periodic table out of bricks of the elements?” one. That’s was fantastic and remains my favorite.❤
“DO. NOT. BUILD. ROW. SEVEN.” -xkcd
Though honestly, stopping after row 1 is probably a good idea. By the time you reach row 2, you're already dealing with elemental fluorine...
2:22 As a physicist, I'm very amused by how much weight the sentence "...you wouldn't have any direct problems with relativity..." is carrying. And the incredibly weighty assumption that there is an asterist with a footnote of someone doing a quick back of the envelope calculation to make sure that was at least approximately true. (Using slew rates and so on.)
I remember as a kid asking this is a different way. I wondered why cars didn't have microwave/laser transmitters on the front to melt snow and ice. Then learned to do the math and found you'd need a couple nuclear reactors per vehicle to power something like that.
Randall has actually done an article on this exact question! I don't remember the title exactly, but 'xkcd what if microwave snow' should give you it. He came to very much the same conclusion as you did.
or just a heating coil running through the car.
@@mrosskne That would help get snow and ice off of the car, but wouldn't be fast enough to let a car move at speed through snow. He was looking for a microwave snowplow, not an electric ice scraper. 😁
Amazing! It is great to see all the explanations finally getting turned into videos. I have spent many a day perusing xkcd, all the books, and all the other Randall content. Keep it up! You are doing some amazing work!
Great to see What If? on RUclips! Also, the sound effects are hilarious and add a new layer of fun to an already funny thing. Great work!
Why i need a umbrella made of laser when i have my 20€ umbrella for years and it works pretty.
*Randall doesn't destroy the world in a What If? episode
*Randall destroys a town in a What If? episode
Progress!
I soent most of my teenage years reading and re-reading your What If? books, and I just found this channel at 21. Crazy how the world works, time to binge watch!
Watched all of these last night and am happy to watch another! Perfect timing! :D
We need to get Styropyro on this
0:23
"The idea of stopping rain with a lazer is a thing we are currently talking about"
"Fine"
MY GOD, THAT IS SO WEIRD TO SAY
"Did you ever hear the strategy of Darth Bane the Dry? I thought not. It's not a story Randall would tell you."
What I love most about these videos is that you manage first totally break expectations and the one up yourself ...every time. 🙂
These videos are super helpful, especialy when I need to turn pluto into plutonium, water droplets into plasma, or try to hit a baseball at .9c.
Now what would happen if I fill the solar system with soup up to jupiter? Or build a peanut butter tower 1 billion stories up?
Short answer for the soup, and for XKCD readers no surprise, a black hole.
Yeah, but it takes much less energy to turn the drop into a bunch droplets, _travelling away from the device._ So really the laser umbrella should only do that
But the questioner asked for the drops to be vaporized
That last panel really got me. Just one simple word adding so much. Which word? You have to look through the video again to know.
Again? AGAIN!
I bought and read these books years ago. Now I get to hear the author excitedly run through these concepts, and I’m not disappointed.
Ok Will Wheaton did a great job on the audio book but can we have Randall do a few chapters for what if three?
Okay, but what if it's just about keeping a specific area dry rather than vaporize all the water falling on that area? Vaporizing some of the water would create a nice pocket of steam that would presumably expand and push nearby falling water away from the area to be protected. That should reduce the energy and targeting requirements.
At that point you'd just get an airjet that blasts water away from a certain radius, like that one proposed tech umbrella idea.
Sure, but that's not a laser.@@TH3W0LF100
This is what I was thinking, If a small amount of laser force would destroy the drop... That is the whole point, we don't need it vaporized just moved.
And that was when the idea for Mythbusters 2030 was born. Featuring all the questions you didn't know you needed answered about high energy physics. XKCD could be the voice over.
i cannot believe that I am lucky enough to be alive the same time these videos are being uploaded. I was already lucky enough to coexist with xkcd. What a world. What a timeline.
It seems much more important to develop a laser snow shovel, whether that is vaporizing snow on the ground or vaporizing it to prevent it from reaching the ground.
"Why is my house on fire again?"
*PEWPEWPEW*
"Dunno..."
Again?
so what I'm hearing is that it IS possible...
RUclips stop watching this. Fix the damn ads
@@nabilbudiman271 this, but it's not like the community manager can do anything
Yeah, by vaporizing yourself.
You know the rules, and so do I...
Hey when the site arbitrarily decides to not let my comments get posted, can you change it to tell me why? Rather than just letting me think the comment successfully posted, but the site quietly deletes it before anyone else sees it, discarding paragraphs of text and sometimes up to an hour of research?
Imbababababimmm
I've already read all of these, and I'm still happy to watch a video on it anyway! That's how you know your content's good!
The biggest revelation for me in this video: Randall Monroe has a top-notch narrator's voice.
I'm a big enough XKCD fan to be here, but not big enough to have ever watched Randall lecture. When the narration started my first thought was, "Oh, they hired a pro instead of DIY. Kind of a shame in a way".
1:19 "But it gets worse" - ongoing What If theme XD
I love watching those topics being made into videos. Please keep it up!
Man, I'm always happy to go back and read this very excellent tubobleg, but there's something very special about these updated videos.
I love all the little sound effects you make!
A great thing about these what if questions is finding how feasible the solution can be (yeah, I know i'm stretching the definition of feasible), like we're all rooting for this cool contraption to actually be possible. Makes it very fun to think about. Great idea to make this into a youtube channel!
Ohhh this is right up my alley and I am so happy I stumbled on this amazing channel. You are going to blow up!😊
Oh hey! I needed to use your book "what if?" for my high school earth science class and I feel absolutely in love with the absurd questions and humorous artwork. I even made a little video of my own that's lost on a thumb drive somewhere where I tried to use nuclear blast to propel a ping pong ball at several times the speed of light. Anyway, love your stuff, keep doing it so I find another one of your videos in two years!
I LOVE these videos! Thank you so much
I love this channel and i know how long it take to animate and edit this stuff but i still always feel like they are too short/ like i come away with more questions than i wanted. I mean ik thats how science works but still
Fascinating! I learned something today that I didn't think I needed to know!
Thank you for that! Awesome video by the way, I love the fun narration style!
Super excited for this fun analysis video! Thanks so much for uploading! Looking forward to more like this from you! Might comment more later!
Hearing these out loud, and as a video is such a joy
Thank you for making videos. They bring great joy to my life
genuinely brightened my mood after watching that video thanks
Love the sound effects X)
Its a shame i found his channel so early, because now I've seen all his videos and have to wait for the next one
All I needed was 31 seconds to figure out this is an absolute gem of a channel.
Love it, love it, love it.
Judt found the channel and it only has a handful of videos :c noooo.
love the work you do
I just love this channel
I love the amusement in the final line, because yeah, perhaps firing lasers off wildly isn't the best idea haha
The sound effects are particularly on point in this one
Fun analysis video! Thanks for uploading!
It appears I cannot get enough What If. I read the site at first, then got the books, and now I'm watching the videos. I'm pretty sure if this were released in scratch'n'sniff format I'd buy it.
"A thing we are currently talking about" "*Sigh* fine.
I think the convection of such hot air, against air as cold as that which surrounds rain, would make it a lot less like an autoclave. It'd be more like sitting next to a heating element in a pool, vs in a hot water cylinder. The hot fluid will quickly flow away from you, being replaced with fresh cold fluid.
Could you imagine a city full of laser umbrellas? “You’ll put your eye out, kid”-A Christmas Story.
This is video is so well done.
Thank you
so glad i found this, thank you!
Additionally, when it rains, the atmosphere is already saturated with moisture. Creating more "moisture" in the form of water vapour or steam isn't going to magically erase the water from existence. If anything you'd just create an additional raincloud right above where the laser was focused on targeting.
I've been reading XKCD for years and only now has Randall given me the idea of every character in every comic talking like a trumpet
What I'm thinking is, a laser at your location, waffling about randomly above you at extremely high intensities, possibly synched to dubstep. The exploding steam itself will serve a gaseous deflector. You're looking to change the momentum of the water droplets around it, not vaporize them entirely. And for those worried about the micro-droplets it creates, that's just going to end up as general humidity in the air. A poor man's version would just be a giant compressed air nozzle, it would do something similar. 10kW actually isn't that much power at all, this is actually doable for a laser, as long as there's no avian friends or aviators above you as you harpoon the atmosphere with deadly intensity.
I thought the same. Could have used a Randy Johnson reference with the avian friends here.
These make me inordinately happy when they pop up in my feed...
This reminds me of the late David Jones' Daedalus column in New Scientist. I am sure he did an article about using. ultrasonic waves to "shape" water droplets so they would fall away from a central point instead of straight down. I think he proposed a massive machine to cover an area the size of a cricket pitch so that play could continue uninterrupted during a rain shower.
Where has this been all my life?
Instant subscribe!
I can't put into words how much I love these
Reading the title, I thought of that sonic umbrella that deflects the rain.
I know light has momentum, that's how the light sail works. So I thought this video would be about deflecting the raindrops rather than vaporising them.
But after watching the video I suspect that any noticeable momentum imparted would require astronomically ridiculous power.
I was expecting some talk of "firing it upward in a cone shape"
like presumably that could eliminate all the rain right above you.
an EUV lithography machine turns droplets of molten tin raveling at over 200 miles per hour into plasma at a rate of 50,000 droplets per second. The first laser "pre-pulse" shapes the droplet into a flat shape and the second full power laser burst turns the molten tin into plasma (emitting EUV light). A droplet is 0.05 ml and one square meter of 0.5 in/hr rain is 71 droplets per second. So that machine can vaporize the rain falling on 704 sq. m. of area. Also, power to turn tin into plasma is less than power to turn rain into steam.
Animating previous questions has tickled my fancy today. The smile I got while watching this actually hurt.
Thank you for answering a question I didn't know I wanted the answer to.
Holy moly, when did this channel pop up? This is great
We have a hypothesis, now someone call styropyro
Another thing about why it would just splatter water instead of vaporizing the entire drop is that energy as heat doesn't travel instantaneously. The water molecules on the surface always react first thus causing a rapid expansion that separates other water molecules in the drop before it can absorb the energy from the laser.
the little sounds the stick figures make are adorable and all that i will hear now when i read xkcd.