What if you built a billion-story building?
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- Опубликовано: 10 фев 2025
- 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/
This question came from Keira, who at age four and a half wanted to build a billion-story building. Actually, it came from Keira’s dad, who wanted to help Keira appreciate how big and difficult such a project would be.
Credits
*******
Randall Munroe | Narrator
Henry Reich | Writer & Director
Lizah van der Aart | Illustration and Video Editing
Ever Salazar | Chief Chaos Controller
Know Art Studios | Music & Sound Effects
What If? The Video Series is the official adaptation of the What If? books by Randall Munroe and is produced by Neptune Studios LLC.
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 LLC (the parent company for all three youtube channels).
©2025 xkcd, inc.
Love that the the list of high building problems including “finding a good name”, then at the end calling it a Keira-skyscraper after the girl who asked the question
Can we build one from the poles of earth?
I didn’t realize that, that’s sweet
I bet in 40-50 years someone will name a really massive building that after this video. Randall have a way of infecting future engineers etc with these ideas.
@@Aarush.A.S it's still spinning so I assume it would twist itself apart
@@Aarush.A.Sdon’t think that would matter because. Centrifugal forces would no longer keep it from crushing itself. Secondly you would and twisting forces that would be vastly different at altitudes because of wind shear, and lastly the earth precession on its axis and changes so you couldn’t stay on the pole unless the building can move. Even one centimeter at that distance would cause the same side issues in no time flat.
It takes five minutes for the elevator to come in the morning in a thirty-story building. A billion stories? I’d never leave.
Oh hey, it's that guy!
Chocolate Rain
Going down 30 stories does not sounds that bad. The question is can you go faster down that you would waiting and going for elevator. On the other hand going up 30 stories sounds terrible. :D
It would probably be more sensible to just build service and commercial levels in a large enough building, basically making a skinny arcology.
RPE: Rocket propelled elevator
I love how you made the tone of the video more simple for Keira to understand. Loved it!!!
It is sweet, but keep in mind, that those questions were submitted a decade or so ago. On his website you can see the answer to this particular question was uploaded on the 24th of april 2014. So Keira is now presumbaly 15.5 Years old. Now that I think about, the original answer was written in this simple tone for that exact reason. Wellp, it's still interesting to think about that so much time has passed since she asked her dad the question :D
@@Valle_nicThat sounds like code for "welp, I'm getting old!"
Yes I love it
"Pretty close to impossible to build"
So you're telling me there's a chance
yeah that wording was a mistake 😂 In the ears of a small child that's just "quitter talk". Should've stuck with "impossible" :D
For us now, no. For the future civilizations, they'll deal with that shit
i mean, space elevator is a theorized megastructure; even if it's impossible & impractical on Earth, it may be possible & practical on smaller planets like Mars which has weaker gravity, hence a lower geostationary orbit altitude & a shorter space elevator (with a shorter tether)
@@americantoastman7296 But it technically isn't impossible though, there's a chance in the distant future when technology is advanced enough. It's close to 0% but not 0%
Ok, first we'll need a team...
The original question for this was posted to What If on April 29th, 2014.
If we assume that the question was answered around the same time that it was submitted, Keira would be about 15 now. In the U.S., she is likely a freshman or sophomore in high school.
I hope this earnest response set her on a path of curiosity and learning. And if she starts applying for colleges in the next few years, she has a fun fact to add to her application.
Maybe Keira finds out, how to build a space elevator. Not as spectacular as the billion story building, though...
Dang! That took a while!
This video was on the top floor of the Keira Skyscraper. That's why it took so long to get to RUclips
In 3 years Keira will be on onlyfans
For some reason, Randall switched peanut butter in the original answer to Jell-O ("jelly" for those of you outside the US) in the video. Otherwise it's pretty much the same.
It's a nice touch that Randall also simplified the wording down a bit for this one, compared to the usual articles, which might be more technical/jargonistic by comparison.
Makes sense, since it's for Keira, who's 4.5.
To be fair, this article was written on the blog in 2014, so probably not 4.5 anymore. Which is why Randall said "was" at the beginning of the video. But I think it's good to do anyway for the sake of other kids who might have this question!
He kinda forgets halfway through though. At the beginning: "So you know Jell-O?" By the end: "geosynchronous satellites," "centrifugal forces"
She’s around 15 now (the blog post came out before the first _What if_ book)
Would it be faster to use an Up Goer 5 to get to the top?
@@thesledgehammerblog The Up Goer would have to be mounted on rails, along the side of the Skyscraper., so that it rotates alongside the Skyscraper. It would have to rotate 180 degrees to slow down, so you didn't go flying past your destination.
Anything past ~55000 km would be unreachable: the TWR of the S-IVB would be insufficient for slowing down.
Phineas and Ferb could build that in an afternoon
MOM!!! Phineas is trying to build the tallest building in the universe!!
Of course they would. And then one of Doof's schemes would take it away
i know what were going to do today ferb
@@brentallen8653 just as mom gets there to see it, the bolts holding the skyscraper to the ground come loose and the whole thing goes into orbit.
@@kody1965 Because the float-inator made it float; it was built because he was annoyed by the buildings and shot the wrong building because of a Platypus engineer.
"Barad-dûr-licious" was awesone! 🤣
0:02 "What if you built a billion-story building......UNDERGROUND"
You'd come out the other side and still crash into the moon
@@GeezSus
Turns out, it wouldn't be that much different than in the first example.
@@GeezSus Nice solid foundations though
Poles of the earth
Each story would be about half an inch and that's not including the materials of each floor/ceiling.
This was originally published on the What If? website in April of 2014, so Keira's now 15 years old. To my knowledge, she has not yet built a billion story skyscraper (source: probably would have noticed).
It was really, really, sweet of you guys to call the final one a Keira skyscraper. Great way to inspire the next gen of science lovers!
E
love that the tone of this is "please, Keira, we're begging you not to build the Keira Skyscraper"
Oh funny to see you here. Your voice sounds a little similar to Randall's & Henry's voices to me, so you all occupy adjacent spaces in my mind.
3:41 Everything on the "roof" would experience 1.62 g of "artificial gravity" (centrifugal force) directed away from Earth. This is tolerable by humans, but the hand-drawn folks inside the "roof sphere" would have to watch the view while standing "upside down": with their feet away from Earth.
I thought it would be more tbh
Thanks for doing the math
I came up with 1.98g myself
let see.... so you need to calculate the height of a floor and the rotation speed of the earth... and actually now that i think about it... where its build should have a impact on this.. since its completely different results if its on the rotational axis or at a 90 degree angle from it...
on a side note i have no interest in trying to calculate the results but just thought to point out that you would need to know where it is placed on earth to calculate the correct centrifugal force
@@anticlaassic Yeah because geostationary is only 36000km, which is basically 80x closer. But at geostationary orbit, the pull from earth’s gravity is 32x weaker so centrifugal force doesn’t need to be that high. Which is why at the top where earth gravity is negligible, centrifugal force is still managable
@Necrotechian Good point about the placement. If it were not on the equator, centrifugal forces would result in massive bending moments in the building.
Let's be honest. We've all been Keira's age. Even if someone rationally explained why the "genius" ideas we thought of at that age are for all intents and purposes impossible, that didn't stop us from attempting our idea anyway.
That little girl probably wants to build a billion-story building even more now.
You have to try to do the impossible every once in a while, just to see where the line REALLY sits.
And that’s a good thing. As a teacher, I feel a lot of the job is to get students to understand how complex the real world is, without putting them off trying to improve it.
Aim high, for every arrow feels the pull of the earth.
She'd be something like 15 now, as other people have said. That only makes me hope even more she still wants that billion storey skyscraper and is studying to make it happen.
E
"Stacking 10 mega-mega-mega skyscrapers on top of each other to get one Keira-skyscraper."
Hu... Nice touch.
E
The original question for this was posted on What If on April 29th of 2014.
If we assume that the question was answered around the same time it was submitted, Keira would be around 15 years old. In the United States, she is probably a freshman or sophomore in high school.
I hope this sincere response sets her on a path of curiosity and learning. And if she starts applying to colleges in the next few years, she'll have a fun fact to include on her application.
0:50 HIGH BUILDING PROBLEMS
- ACROPHOBIA
- EFFICIENT HEATING
- WIND
- GETTING ELEVATOR MUSIC THAT IS LONG ENOUGH
- FINDING GOOD NAME
- TRASH CHUTE
The humour of this channel is unmatched 😅
We're pretty high above the sun too. Nobody's talking about acrophobia from being so high. It's all relative.
Ok so like what if the ocean got turned into Jello??? 0:24
Bouncy water
We‘d all die screaming from environmental collapse and a sudden 99% reduction in earth water supply, and the food pyramid collapse, and the dying plancton still responsible for a majority of oxygen production on earth i belive, starvation from food shipments no longer being able to move, several thousand idiot trying to walk on it and sinking like lead, dead submarine crews…
Shall I go on elaborating why this is
*A TERRIBLE IDEAD*
It may be a slight inconvenience
Fish die from being trapped in Jello.
Jiggle jiggle jiggle jiggle Jiggle jiggle jiggle jiggle Jiggle jiggle jiggle jiggle
As a parent, I appreciate the toned down explanation. You didnt need to make it kid friendly, but you did and I love it. Great job!
Ah, waiting in elevator lines for mega mega mega mega long time. Not to mention that the food delivery would be quite cold when it reaches my top floor penthouse.
Then let's build a device, that makes the pizza during delivery.
Considering technological advancements required to build a billion floor skyscraper, we'd have settlements on the Moon by now. It would be closer to order pizza from the Moon.
@nilsadelsbach8556 Pizza oven inside the elevator, there ya go
Yeah, humanity will have to somehow find a way to put kitchens on other than the ground floor of buildings.
That's what minions are for.
It's so sweet the language is more accessible for the asker. I love it.
E
Dude I just bought What If 2 and was reading this question's answer and then you upload a video with an easier explanation. Idk how you knew but thanks.
I love how this takes the imaginative ideas of kids in such a fun and scientific way.
0:51 - I loved seeing "Trash chute" on the list. I once lived on the 20th floor of a 30 floor high rise, which had a trash chute. I loved throwing things down the trash chute. Especially medium sized pizza boxes, which made a cool sound going down, and glass jars, which made a cool crashing sound at the bottom.
1:28 oh my goodness what is that plane doing there
THEY HIT THE PENTAGON
Sometimes there’s just planes in the air, unrelated to 9/11
@@Taukingur sounds like a conspiracy theory to me idk
A second plane has hit the mega-mega skyscrapers
did we forget
"Getting elevator music that's long enough"
Dream Theater to the rescue!!
Octavarium would be a great skyscraper name too!
Inna godda da vida *baby*!
@@pileofstuff On a 24 hour loop!🤪
@@pileofstuffwoah, small world, fancy seeing you here! love your videos :3
I'm imagining "The Girl From Ipanema" on an endless loop...
This is such a fascinating concept! I love exploring 'What If' scenarios like this-it's amazing how science and imagination can come together in these discussions.
I like how even though the answer to the question is “ it’s not really doable”. The video still ends on a sweet note of “it would be pretty cool though”.
i mean having a gravity defying mega structure that rivals the orbit of the moon WOULD be pretty cool on its own already!
This channel is perfect, it makes a 4 minute video feel like an interesting 40 minute lecture
You did this under the assumption that I put my Kiera skyscraper at the equator, which is silly of course. What if I put it at the poles instead? Then no centrifugal force, right?
I wouldn't say "none" because there's some wobble no matter what in absolute terms. And even a little wobble is colossal at the end of such a long rod.
I could watch nothing but this channel for a whole year and be content.
The view on the Roof would be not only increadible, but also to die for, concerning the centrifugal force that presses you against the top of it :P
At 2:42 the animation is a little misleading tbh, the centrifugal force would get bigger when the building is attached to earth, but in case of satellite it would decrease with the distance.
That’s no skyscraper, that’s a barely even a space elevator anymore😂
It's an intergalactic space elevator, since you can now chuck stuff out of the Milky Way.
Me looking at the xkcd channel last night : Hmmm I haven't seen an xkcd video in a while, did I not get notified? awww, nope...
Me this morning : He does care about about!!!
Wow I was literally watching one of your videos just now, how is this question more bizarre than the others already
bizzare?
The other videos in question:
*Everyone dies, when does the last light go out?*
*Let's drain the ocean why not*
*Let's melt the entire moon with laser pointers so strong they will probably melt everything around them aswell*
I think filling the solar system with soup was weirder, but this is a fun one.
0:31 "Barad-Dûr-licious!" Nothing like starting the day with a fresh xkcd video and a fresh LOTR pun.
the universal trade center
1:29 perfectly aligns with this
Boys, where can a man find an interstellar void craft around here?
The question is purely hypothetical…
dilithium plasma can't melt tritanium beams.
Can we build it on the north pole? No centrifugal force there, rightr? Maybe it twists a bit
If you build it on the north or south pole, you need to figure out how to make it not collapse from its own weight. If you build it even a little bit off, the centrifugal force will pull the building to the side, which sounds even worse to me.
After a certain height, the rotation at ground level would be faster than the rotation at the top and the building would twist apart. I'm not going to do the math. The rotational spin of the Earth is actually pretty slow (one rotation in 24 hours) so you might get decently high, but it will happen well before you get to one billion stories.
It's so cute to me how this feels like an explanation actually tailored to Keira and her abilities (while still being completely accurate and very fun)
I have a REALLY good idea!! Y’know how warm air rises and cold air descends, what if warm air descended and cold air went up? How would hot air balloons work, etc?
That is rather interesting
Generating cold is way harder than generating heat, so a cold air balloon would simply not exist. I doubt a single ice cube could even cool down enough air to lift itself up, unlike how a candle can lift itself in the normal world.
The way you explained everything specifically for Kiera to understand is so adorable and considerate of you. Naming the billion-story building after her is extremely sweet, too.
The Keira skyscraper made its debut a long time ago in a manga called Blame
That thing doesn't really scrape skies anymore, because the "sky" is arguably beneath it. So can we even still call it a "skyscraper"?
A starscraper
"pretty close to impossible" so you mean there *is* a slight sliver of possibility
With enough human will, anything is possible
"So you're telling me, there's a chance?"
A former colleague of mine used to work on the upper floors of the HSBC tower in Canary Wharf. Part of the hiring process then (~20+ years ago) was to ask candidates if they struggled with motion sickness due to the swaying of the building in high winds.
Just binged What If?, What If? 2, and How To, this year. First 3 additions to be Goodreads, they were great. Love seeing the individual questions/things in video. Hope you're working on another book! Been following your webcomic for over a decade.
"Getting elevator music that's long enough" Can't argue with that logic lol
We could just do a Taylor Swift 10 year version.
You could build it so high that the centrifugal force would be as strong as the gravity on the surface, but in the opposite direction.
I think I saw structures like that in fiction.
Better yet, at the billionth floor, you would most likely instantly be smooshed into a fine red paste from the centripetal force…
What about building it from the poles ??
The fact that our magical impossible tower would get by our space junk is why I feel depressed in the morning. That we would have dreamed it up, and made the trash that would bring it down, is also why I feel content in the evening. Remembering we will do it eventually is what wakes me up at night.
But what if it was a center for ants?!
How big would a billion floor antscraper be? I’m guessing still pretty big, a billion of anything is pretty big. So even if each “floor” was only a handful of mm tall, it would add up fast!
Edit: Basic math says it would be at least 1000km tall still! Woah… and that’s only 1mm per floor! So an actual antscraper with a billion floors would be like 4-5000km tall! That’s still on the small side too, if it was bullet ants or a more luxurious center for ants, it could be upwards of 20,000km high! Wooooah… you’d have ants hanging out at nearly twice the height of commercial flights! It would be poking just past the stratosphere layer boundary I think.. I gotta actually look into this. Because I think I’m still under sizing for the biggest ants and I might have my atmospheric layer heights wrong. It’s crazy that I’m measuring an anthill in atmospheric layers… hahaha wow. Science is so cool.
The Simple English script for the benefit of Keira - nice building name, by the way! - reminds me of XKCD 1133, 'Up Goer Five', where NASA's Saturn 5 was described using only the most used 1000 English words.
There is a whole book from him using only the most common 1000 words, it is amazing!
You liked 1133? I've got good news for you. Just google "Thing explainer"
You liked XKCD 1133? I've got good news: Just google "Thing explainer"
To build a billion story building, you need to utilize galvanized square steel and borrow screws from your aunt
I love how Randall actually tried to put into perspective just how tall a billion floor tall skyscraper would actually be.
Since that'd be very tough for a fully grown adult to comprehend, let alone a young child.
The real lesson I get from this is space elevators will likely never happen.
Don’t show this video to Trump
🤣
I showed it to trump, he said okay
With his penchant for exaggeration* he'd probably say he already has one.
(*Lying)
Wait actually do, please do do that, that would bankrupt the US economy which is a good thing
Showed it to musk, he diverted all funds to build this for his spacecraft. X-tower, the everything tower. Won't need any other building ever again
1:15 If anyone is curious, as floors are added to this (ridiculously tall) building, you'd obviously need more elevators to carry all the people up and down the building. But the amount of floor space you lose to any added elevator, increases with the height of said elevator. (And I say added elevator, as obviously, not every single elevator needs to go to the top floor.)
This is for 2 reasons. If we say the elevator shaft takes up 10 m^2, then if it goes through 20 floors instead of 10, then it takes up 200 m^2 of floor space, instead of just 100 m^2. And each elevator you add also has to travel further, reducing their throughput too, so they can't support as many new floors. Though unless you go to _extreme heights,_ adding a floor still gives you more floor space than the elevators would eat up.
The latter effect of the elevators reducing in throughput as they get taller, can be reduced or even eliminated by dedicated express elevators or having multiple carriages in the same shaft respectively. Though again, this only really applies to extremely tall buildings. I've seen some people try to argue that elevators eat up all the added floor space on buildings that are only a _few_ floors tall. Which is just a ridiculous claim if you bother to think about it for more than a few seconds.
That was very sweet, talking directly to the person who asked your question.
Don't think we've got tall enough buildings to need it, but I've always thought of why not doing elevators like a train system.
Each car has motorized cogs/gears etc to move itself, goes up one shaft, moves over, then down another with multiple cars on the same route/loop.
Have some shafts be the "express" ones that stop every 15 floors or so, and some be the "local" shafts that go to every floor.
With the multiple cars in the same shaft you wouldn't need so many shafts, "just" more cars.
You'd get bunch ups, but I'm sure you could work with subway folks on how to deal with that.
Higher cost, higher maintenance, but just a thought.
I love this... puts a smile on my face... :)
Follow up question for you. How long would it take the worlds fastest elevator to reach the top of the keira skyscraper?
The fastest elevator is about 45mph. If this skyscraper is 10x the distance to the moon the time comes out to just under 6 years.
1:20 I love the swimming pool on the moon reference
A bit of a nitpick, but there's no such thing as centrifugal force that pushes you outwards. It's just inertia doing weird stuff.
The fact that it's not a real force doesn't make it any less useful to talk about it. If you want to convince everyone to give it a different name, one that doesn't include the word "force", then go ahead.
Watching this video reminded me of the early Genesis lyrics for "Get 'em out by Friday":
"This is an announcement from Genetic Control
It is my sad duty to inform you of a four foot restriction on
Humanoid height.
I hear the directors of Genetic Control have been buying all the
Properties that have recently been sold, taking risks oh so bold
It's said now that people will be shorter in height
They can fit twice as many in the same building site"
Perhaps the solution for Keira is that we just need people to be 1 micron tall, then our Billion Story Skyscraper could be 1.5km in height.
But what about building the thing on the poles? You can save yourself all of this centrifugue hussle
The Earth does have wobble, so the top of any Mega building is going to be moving in a circle, getting faster as the distance from the Earth increases. At some point, the upper end of the building would be moving in a circle larger than the Earth's circumference.
If the North Pole melts, there won't be anywhere to put it. And youre probably not gonna get a construction crew to Antarctica, though that does seem like a rather trivial problem in comparison to the rest
It would need to be on the south pole, since there's no land under the north pole, just sea ice, and you'd then need to deal with building the base in snow-desert/blizzard conditions, as well as glacier-proof the base (otherwise it'd slowly migrate or get crushed by the glaciers)
@@okami7dreco786 Given the height, the amount of water is actually a trivial percentage, so in relative terms, a non-factor at the North Pole.
I do actually wonder what other interesting forces such a height would introduce. To what degree is it orbiting the Sun along with the earth? Completely different set of issues.
xkcd what if damage tier list
Whelp, there goes the planet:
Magnitude 15 earthquake
Earth grows 1 cm growth every second (eventually)
Point national ignition machine lasers at the moon
Whelp, there goes humanity:
When would the last light go out
The earth stops spinning
Whelp, there goes society (society has been disrupted but humanity survives):
The oceans drain (dutchpunk dystopia)/mars ocean
Everybody jumps at once
Whelp, there goes the neighbourhood:
Lightspeed baseball pitch
Trevor’s lightning
Billion story building but it collapses
Will kill somebody:
1 nanosecond inside the sun
No rules Nascar
Submarine spaceship
Swimming in a nuclear power plant
Billion-story building (assuming it's strong enough to not collapse. the higher story inhabitants would still die from being in space)
Could kill (or hurt) somebody:
Swimming in a nuclear power plant (no guards)
Laser umbrella
Half empty glass
Just this once everybody lives!:
No rules nascar (except the driver must survive)
1 nanosecond on the surface of the sun
Pool on the moon
Printing wikipedia
Point hubble telescope at earth
Point laserpointers at the moon
Magnitude -15 earthquake
At "BARAD-DÛR-LICIOUS", I had to pause for a minute to finish laughing.
Amazing. This is my favourite ever one. Great job Randall!
Love how the words and tone of this video are meant to be understood by a 5 year old, but it still remaind interesting for everyone
you missed how radiation would barbeque people
The view from the roof would also be the view from the basement because the restorative acceleration on the upper floors points inward & so you would walk down the stairs to get to the "roof"
We just have to convince the International Bureau of Weights and Measures (or whoever's in charge of this sort of thing) to re-define a "story" to be way, way smaller than it currently is so that we can technically define a regular-sized building as 1 billion stories high.
The kiera skyscraper gives a whole new meaning to " I whip my hair back and forth"
Reminds me of that one episode from Phineas and Ferb...
ive been binge watching your videos i love you
0:41 Loved the half life 2 citadel reference
3:24 But wouldn't the angular velocity of the building slow down due to conservation of angular momentum?
That billion-story skyscraper would also sufficiently redistribute Earth's mass outward that its rotation would slow.
you see, if the building is tall enough, trash will not go down the trash chute, it will go up. well, most of it. there's also a portion of the trash chute in the middle where the trash wouldn't go anywhere, neither up nor down, without outside help.
Thanks Randall, Henry, Lizah, Ever, and Know Art Studios
In A Keira skyscraper, you'd need space rockets to go from the bottom to the top
Even planes wouldn't be fast enough to make people happy
1:45 technically, 100 skyscrapers stacked would not be a megaskyscraper, it would be a hectoskyscraper. The mega-mega-skyscraper mentioned at 1:54 would likewise not quite live up to its name, but it WOULD contain 1.0 megafloors. Which is cool.
1:02 Elevators are not really an issue anymore check out Thyssen Krupps "Multi" it is basically a MagLev Train style Elevator which kann go vertical and horizontal, basically you could have 2 shafts serve a whole building having multiple carts going up in one shaft and down in another and upon reaching their floor moving sideways out of the way into a parking position.
A Type III Kardashev-scale civilization is able to capture all the energy emitted within its galaxy, which is just enough resources to build one Keira-skyscraper.
You're a good sport, I'm glad you made this video
The "Keira-skyscraper" is such a cute name!
I like how the entire premise of this video is to just absolutely demolish a 4 year old's dreams of becoming an architect 😅
One thing that confuses me about using centrifugal force here is that assumes we're making the skyscraper on the equator. You could set an arbitrarily extreme latitude such that the average weight of the skyscraper is 0, and in this case the issue would be down to internal stresses in the material. Would these stresses beat out the stress on the base of the skyscraper? Well, the centrifugal force scales linearly with height, so the net force on the base of the tower (equal to the entire weight of the falling half of the skyscraper) should equal the net force on the orbit point of the skyscraper (though this point would be experiencing shear forces equal to the falling and flying weights, instead of compression forces).
One neat consequence of this is that while the tower would start thick and thin out as it goes up, it would actually thicken once again as the tower reaches the orbit point, as that is the other point that experiences the most stress and material at that height is close enough to free fall to not add to the total weight of the tower.
Of course, if you can manage this, you have a very good space elevator, and it would have been cheaper to just build it shorter at the equator.
That is a lovely update to the original post.
I’ve got 2 questions now
If you have a skyscraper that goes the 10th of the way to the moon, does that counteract the whole “crushed by its own weight” thing?
What about a giant pyramid?
If you topped it off there you've basically created a space elevator.
Sou‘d need to go a bit further and add a counterweight, then you‘d have a tension structure which can usually be built much taller than a compression structure. You‘d still need wicked strong materials tho
HE KNEW I WAS LOOKING FOR A NEW XKCD VIDEO YESTERDAY
This gives me an idea. If we built the skyscraper tall enough, could we get the top floor moving at the speed of light? How many floors would that be? I'm giving you the budget of every carbon molecule in the galaxy to make nanotubes out of.
I wish he would have mentioned that there have been popular ideas to build a space elevator to make it cheaper and easier to go between the earth and the moon.
Elevators could be replaced by high volume automatic catapults, but the limiting factor so far has been our inability to catch the catapultees. I say that the technology exist now to build well coordinated robotic arms, installed in every floor, that would overcome this limitation.
You should make videos more often!
I also expected a mention to the need of a crane that is even taller than the skyscraper we are building to be able to build the skyscraper at the end. :D
So, a building around space elevator?
Structural engineer here. One thing you forgot to mention about elevators is that after a certain length, the cables will snap under it's own weight.
I love that this is answering a small child’s question.
extraordinary homepage pull 🙏 i love your content,