Very cool. One thing I wish was better shown: space is close, it's just hard to go up. Our liveable breathable atmosphere is razor thin compared to the size of earth.
In most cases, 100km is less than the distance between sizeable metropolitan areas. It's a day long bike ride. Air runs out less than a bus ride across town. A 15k jog/hike would put you in the stratosphere. Those jet aircraft that seem so high are closer than that. Closer than your friends house or the local stadium probably.
Look at a map or globe with that in mind and everything feels so thin!
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dpq
Amazing work! One minor correction:
> As particles from the sun hit the atmosphere, they excite the atoms in the air. These excited atoms start to glow, creating brilliant displays of light called auroras.
The process is a bit more nuanced than that. The modern mainstream understanding is that the growing pressure of the solar wind makes the tail of the magnetosphere "contract" (sort of pushing it inwards from the sides), which leads to reconnection of magnetic field lines. Once the reconnection occurs, the magnetic field lines that remain bound to the geomagnetic dipole accelerate the particles on them towards the Earth => they slam into the atmosphere, exciting the atoms and generating the aurora.
show comments
daniel_iversen
This was incredible! Couldn't stop scrolling and reading. For a kid of a certain age and curiosity it'll blow their mind! I'm so grateful the creator made this, shame that his "buy me a coffee" isn't a simple PayPal or Apple Pay but you have to put in credit card or bank details!!
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tempestn
TIL it's estimated that over 48 tons of meteors hit the atmosphere every day.
Regarding actual space elevators though, while they're not sci-fi to the extent of something like FTL travel - ie. they're technically not physically impossible - they're still pretty firmly in the realm of sci-fi. We don't have anything close to a cable that could sustain its own weight, let alone that of whatever is being elevated. Plus, how do you stabilize the cable and lifter in the atmosphere?
A space elevator on the moon is much more feasible: less gravity, slow rotation, no atmosphere, less dangerous debris. But it's also much less useful.
show comments
araes
The biplane part (Caproni ca 161) right after the "you should put on a spacesuit" comment got my notice, so I checked. Actually vaguely fascinating that in 1938 the Italians had Mario Pezzi wear an electrically heated pressurized suit [1], an airtight helmet [2][3], and sit inside of a pressure cylinder [4] to fly at 17,083 m (56,047 ft) in a propeller-powered biplane. Seems to have barely been mentioned afterward though, as it's difficult to even find imagery.
Giant Space Bola is much more attractive. It is a 10000 km string with capsules at both ends. It rotates in sync with earth so that the speed at meeting point is the same. You just hop in and end up in space without much effort. Because it is freely floating you can move it around to avoid meteor impacts and other such shit.
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retube
Was hoping would go to geostationary orbit as an actual space elevator would :)
If you like factory games and space elevators, then try Satisfactory!
show comments
isgb
> Space elevators are actually a possible idea being considered by scientists.
> The hard part is making a strong enough cable. And finding enough elevator music...
- We don't have a good ascent mechanism other than rockets - and then we might just use rockets without building an elevator.
- We don't have a good (and safe) descent mechanism.
- Maintenance? Protection from space debris? Protection from oscillations? Ground-protection if the elevator collapses?
This is dyson-sphere level of fiction. We can do back-of-the-napkin calcualtions on how things would work, but the practicalities make it completely impossible or impractical.
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kinduff
I always enjoy Neal's pages. I found planes at high altitude very interesting, didn't know we could fly that high!
show comments
simpaticoder
Given the title "Space Elevator" I was expecting some more information on a hypothetical space elevator cable. Assuming humans can manufacture defect-free nanotubes at any length and can combine them into thicker cables, you could specify at every height a) the cumulative mass of the cable, b) the thickness of the cable at that point, and c) the stress experienced by the cable at that point. You could further break c down into the gravitational vs centripetal forces on the cable at that point.
Space elevators aren't going to happen. Not in Earth's gravity well anyway. Even if you can find a material strong enough (and that's a big "if"), you still have to traverse 50,000km to get from Earth's surface to geosynchronous orbit to get the benefit.
You know what does make way more sense and is way more achievable? Orbital rings [1].
Basically, put some copper wire in space, orbit it at ~8km/s, run a current through it and then you can reset structures on top of it (magnetically) and those structures are fixed to the Earth's surface. You can technically run a cable from 100-150km up to the surface and run a gondola into LEO. This would transform both Earth transport and interplanetary travel. You accelerate something on the inside (Earthside) of the ring at ~2G, like with a maglev train, and you have enough velocity to escape the Solar System.
The rockets at higher altitudes were all in wrong orientation. In reality, they don't fly straight up.
ta1243
What's really interesting is that a space elevator goes to Geostationary orbit by necessity. Getting to 100km vertically doesn't save as much as you might think when it comes to getting into orbit.
To get into a very low earth orbit from an equatorial launch pad at sea level you need about 9.2km/s of Delta-V
To get there from a 100km tall tower, you need about 8km/s of delta-V - about 85%.
Think about how much scrolling there was to get to 100km.
To get to the ISS you'd need to scroll 4 times further. Starlink and Hubble are another 100km beyond that.
You start having radiation problems if you spend too much time above 600km.
Aside from Apollo, the highest a human has been is about 1400km - 14 times more scrolling than this page.
To get to GEO would require scrolling over 25 times further than even that.
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hermitcrab
>Above this altitude is known as the "death zone", because there isn't enough oxygen for human life.
Being pedantic, this should be "there isn't enough oxygen for sustained human life". An acclimatised climber can survive tens of hours.
This type of interactive learning experience reminds me of how fun it was to browse Encarta back in the day. It was full of interesting facts, presented in fun interactive ways. As much as I love that we have Wikipedia today, a static web page with text and limited multimedia is far less engaging and conducive to learning.
I think that Neal Agarwal and Bartosz Ciechanowski should be sponsored by the Wikimedia Foundation to create similar experiences on Wikipedia. That would do so much to facilitate learning for students of all ages.
kmacdough
Super fun!
I do always have to object to comments like "space elevators are possible," "scientists have studied" and "would save money".
It's a fun thought experiment, nothing more (for now). You can do some calculus to estimate the necessary strength-to-weight ratio based on centripetal and gravitational forces. Single carbon fibers seem to meet this optimistic criteria.
But there are many forces left out. Many practicalitites left unconsidered. Why? Because there is no scientific community that believes it's vaguely achievable with near-future technology. It's simply not worth investing the outrageous resources required to do a vaguely useful viability analysis.
moat
That was fantastic.
My biggest surprise (and confusion) was just how high butterflies and bumblebees go.
melenaboija
Holy guacamole, common birds like cranes fly high.
Congrats, first time I noticeably hear my MBP M4 Pro fans and can feel the temperature through the keyboard.
Amazing work, as always. I love neal.fun
Edit: also good to know that paper airplanes have officially beat the SR-71, F-104 or X-43B with altitude record.
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jedberg
I like how the height is measured in metric but the temp is measured in imperial.
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petesergeant
Some huh! moments...
* Jeez, Everest is tall
* They got a plane to 17km in 1938!
* There was a paper airplane flight at 35km
tstrimple
I loved the visuals but space elevators are far more science-fantasy than hard science-fiction. We should move on to sci-fi tech that has more realistic applications.
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nunodonato
Wow, I'm really surprised to see some birds flying that high. Question: How the heck are they able to live normally at such extremely low temperatures?
grishka
I get it that it requires yet-impossible materials to build a space elevator that goes all the way to space, but what if we instead build one that only extends high enough to clear the thickest layers of atmosphere, so rockets could be launched from there for massive fuel savings?
show comments
chasingthewind
I find it curious that the Lockheed Vega is chosen as “Amelia Earhart’s plane” since most people would probably associate her with the Lockheed Electra, the plane she was flying when she disappeared.
It’s analogous to saying that Ernest Shackleton’s ship was the Nimrod…not wrong, just odd.
xrd
My 8 and 10 year old daughters love this site, often choosing it over Roblox during screen time.
This is stunning and perfect.
hshdhdhehd
Perfect. I think it just needs explanation of Karman line. Why is it 100km. What is the meaning?
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ebbi
"Temperatures in the thermosphere can reach 2,500°C, but molecules are so far apart that you wouldn't even feel it."
I don't have a science background. But how does this work? If you can't feel it, how would you measure it?
Space boggles my mind I love it!
lolive
Why not scroll up to 36000 kms, so we can reach the end of the cable?
#iFeelCheated !
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DavidPiper
I found this strangely emotionally affecting. Probably on account of the music, but I was really struck the vastness and loneliness as the elevator went higher and higher (and we're still nowhere close to the moon).
hermitcrab
This is a really nice piece of work.
Question: Why does the Douglas Skyrocket have its undercarriage down at 25km?
Unsolicited feedback: It would be nice to be able to click on an item and see some more information. Perhaps just a hyperlink to a wikipedia entry.
l5870uoo9y
It is appreciated that you can change the temperature unit by clicking on it, and how surprisingly cold and changeable the temperature is as you travel up through the atomic sphere (down to -84C, -119F).
everyone
An actual space elevator would need to be over 357 times longer though right?
Awesome site!
honkostani
I missed that notice at where its says: Here be a near mars atmosphere in temperature, pressure (40 kms up) but not as hostile composition and with less radiation. Thats five Mt Everests high.
cranx
This is cool, but the UX of the arrows should follow the scroll mode of the device. You drag down on an iPhone to scroll up. Following the arrow and dragging up causes nothing to happen
show comments
14
Loved this site. Only thing I could think to add would be the ability to click each item and be taken to a wiki page or some further source of information about the object.
Zobat
Interesting how counter intuitive it felt to scroll up from the "landing spot". Even with the instructions right there on the screen I tried scrolling down at first.
Very cool. One thing I wish was better shown: space is close, it's just hard to go up. Our liveable breathable atmosphere is razor thin compared to the size of earth.
In most cases, 100km is less than the distance between sizeable metropolitan areas. It's a day long bike ride. Air runs out less than a bus ride across town. A 15k jog/hike would put you in the stratosphere. Those jet aircraft that seem so high are closer than that. Closer than your friends house or the local stadium probably.
Look at a map or globe with that in mind and everything feels so thin!
Amazing work! One minor correction:
> As particles from the sun hit the atmosphere, they excite the atoms in the air. These excited atoms start to glow, creating brilliant displays of light called auroras.
The process is a bit more nuanced than that. The modern mainstream understanding is that the growing pressure of the solar wind makes the tail of the magnetosphere "contract" (sort of pushing it inwards from the sides), which leads to reconnection of magnetic field lines. Once the reconnection occurs, the magnetic field lines that remain bound to the geomagnetic dipole accelerate the particles on them towards the Earth => they slam into the atmosphere, exciting the atoms and generating the aurora.
This was incredible! Couldn't stop scrolling and reading. For a kid of a certain age and curiosity it'll blow their mind! I'm so grateful the creator made this, shame that his "buy me a coffee" isn't a simple PayPal or Apple Pay but you have to put in credit card or bank details!!
TIL it's estimated that over 48 tons of meteors hit the atmosphere every day.
Regarding actual space elevators though, while they're not sci-fi to the extent of something like FTL travel - ie. they're technically not physically impossible - they're still pretty firmly in the realm of sci-fi. We don't have anything close to a cable that could sustain its own weight, let alone that of whatever is being elevated. Plus, how do you stabilize the cable and lifter in the atmosphere?
A space elevator on the moon is much more feasible: less gravity, slow rotation, no atmosphere, less dangerous debris. But it's also much less useful.
The biplane part (Caproni ca 161) right after the "you should put on a spacesuit" comment got my notice, so I checked. Actually vaguely fascinating that in 1938 the Italians had Mario Pezzi wear an electrically heated pressurized suit [1], an airtight helmet [2][3], and sit inside of a pressure cylinder [4] to fly at 17,083 m (56,047 ft) in a propeller-powered biplane. Seems to have barely been mentioned afterward though, as it's difficult to even find imagery.
[1] https://en.wikipedia.org/wiki/Mario_Pezzi_(aviator)
[2] https://static.thisdayinaviation.com/wp-content/uploads/tdia...
[3] https://www.enricopezzi.it/fam_pezzi/mario_pezzi/images/MP_1...
[4] https://www.reddit.com/media?url=https%3A%2F%2Fi.redd.it%2F4...
I love this guy.
Re playing this gem https://neal.fun/stimulation-clicker/
I just clicked the temperature thingy in annoyance because I don't use Fahrenheit and to my delight, it just switched to Celcius
A beautifully executed project here, I bought Neal a coffee.
What evolutionary advantage, I wonder, is there to Ruppell's griffon vulture flying at 11400 meters?
edit: units
I love this page and I donated, but I was (naively) expecting it to get to geosynchronous altitude, which is the actual top of a space elevator.
Of course, that would require a page 420 times longer, and I don't know if a browser would even support it.
The other direction:
https://neal.fun/deep-sea/
Giant Space Bola is much more attractive. It is a 10000 km string with capsules at both ends. It rotates in sync with earth so that the speed at meeting point is the same. You just hop in and end up in space without much effort. Because it is freely floating you can move it around to avoid meteor impacts and other such shit.
Was hoping would go to geostationary orbit as an actual space elevator would :)
I watch AC's video on this, it was quite entertaining: https://www.youtube.com/watch?v=Z5aHMB4Tje4
If you like factory games and space elevators, then try Satisfactory!
> Space elevators are actually a possible idea being considered by scientists. > The hard part is making a strong enough cable. And finding enough elevator music...
Most engineers would bring up a lot more issues than just finding a strong cable. Also, most attempts with e.g. carbon nanotubes have been abandoned ages ago https://www.newscientist.com/article/2093356-carbon-nanotube....
- We don't have a good ascent mechanism other than rockets - and then we might just use rockets without building an elevator. - We don't have a good (and safe) descent mechanism. - Maintenance? Protection from space debris? Protection from oscillations? Ground-protection if the elevator collapses?
This is dyson-sphere level of fiction. We can do back-of-the-napkin calcualtions on how things would work, but the practicalities make it completely impossible or impractical.
I always enjoy Neal's pages. I found planes at high altitude very interesting, didn't know we could fly that high!
Given the title "Space Elevator" I was expecting some more information on a hypothetical space elevator cable. Assuming humans can manufacture defect-free nanotubes at any length and can combine them into thicker cables, you could specify at every height a) the cumulative mass of the cable, b) the thickness of the cable at that point, and c) the stress experienced by the cable at that point. You could further break c down into the gravitational vs centripetal forces on the cable at that point.
Previous discussion on 20-apr-2023 https://news.ycombinator.com/item?id=35629972
Space elevators aren't going to happen. Not in Earth's gravity well anyway. Even if you can find a material strong enough (and that's a big "if"), you still have to traverse 50,000km to get from Earth's surface to geosynchronous orbit to get the benefit.
You know what does make way more sense and is way more achievable? Orbital rings [1].
Basically, put some copper wire in space, orbit it at ~8km/s, run a current through it and then you can reset structures on top of it (magnetically) and those structures are fixed to the Earth's surface. You can technically run a cable from 100-150km up to the surface and run a gondola into LEO. This would transform both Earth transport and interplanetary travel. You accelerate something on the inside (Earthside) of the ring at ~2G, like with a maglev train, and you have enough velocity to escape the Solar System.
[1]: https://www.youtube.com/watch?v=LMbI6sk-62E
The rockets at higher altitudes were all in wrong orientation. In reality, they don't fly straight up.
What's really interesting is that a space elevator goes to Geostationary orbit by necessity. Getting to 100km vertically doesn't save as much as you might think when it comes to getting into orbit.
To get into a very low earth orbit from an equatorial launch pad at sea level you need about 9.2km/s of Delta-V
To get there from a 100km tall tower, you need about 8km/s of delta-V - about 85%.
Think about how much scrolling there was to get to 100km.
To get to the ISS you'd need to scroll 4 times further. Starlink and Hubble are another 100km beyond that.
You start having radiation problems if you spend too much time above 600km.
Aside from Apollo, the highest a human has been is about 1400km - 14 times more scrolling than this page.
To get to GEO would require scrolling over 25 times further than even that.
>Above this altitude is known as the "death zone", because there isn't enough oxygen for human life.
Being pedantic, this should be "there isn't enough oxygen for sustained human life". An acclimatised climber can survive tens of hours.
Lovely, as all neal.fun experiments. <3
My favorite is probably https://neal.fun/infinite-craft/
This type of interactive learning experience reminds me of how fun it was to browse Encarta back in the day. It was full of interesting facts, presented in fun interactive ways. As much as I love that we have Wikipedia today, a static web page with text and limited multimedia is far less engaging and conducive to learning.
I think that Neal Agarwal and Bartosz Ciechanowski should be sponsored by the Wikimedia Foundation to create similar experiences on Wikipedia. That would do so much to facilitate learning for students of all ages.
Super fun!
I do always have to object to comments like "space elevators are possible," "scientists have studied" and "would save money".
It's a fun thought experiment, nothing more (for now). You can do some calculus to estimate the necessary strength-to-weight ratio based on centripetal and gravitational forces. Single carbon fibers seem to meet this optimistic criteria.
But there are many forces left out. Many practicalitites left unconsidered. Why? Because there is no scientific community that believes it's vaguely achievable with near-future technology. It's simply not worth investing the outrageous resources required to do a vaguely useful viability analysis.
That was fantastic.
My biggest surprise (and confusion) was just how high butterflies and bumblebees go.
Holy guacamole, common birds like cranes fly high.
https://en.wikipedia.org/wiki/List_of_birds_by_flight_height...
Congrats, first time I noticeably hear my MBP M4 Pro fans and can feel the temperature through the keyboard.
Amazing work, as always. I love neal.fun
Edit: also good to know that paper airplanes have officially beat the SR-71, F-104 or X-43B with altitude record.
I like how the height is measured in metric but the temp is measured in imperial.
Some huh! moments...
* Jeez, Everest is tall
* They got a plane to 17km in 1938!
* There was a paper airplane flight at 35km
I loved the visuals but space elevators are far more science-fantasy than hard science-fiction. We should move on to sci-fi tech that has more realistic applications.
Wow, I'm really surprised to see some birds flying that high. Question: How the heck are they able to live normally at such extremely low temperatures?
I get it that it requires yet-impossible materials to build a space elevator that goes all the way to space, but what if we instead build one that only extends high enough to clear the thickest layers of atmosphere, so rockets could be launched from there for massive fuel savings?
I find it curious that the Lockheed Vega is chosen as “Amelia Earhart’s plane” since most people would probably associate her with the Lockheed Electra, the plane she was flying when she disappeared. It’s analogous to saying that Ernest Shackleton’s ship was the Nimrod…not wrong, just odd.
My 8 and 10 year old daughters love this site, often choosing it over Roblox during screen time.
This is stunning and perfect.
Perfect. I think it just needs explanation of Karman line. Why is it 100km. What is the meaning?
"Temperatures in the thermosphere can reach 2,500°C, but molecules are so far apart that you wouldn't even feel it."
I don't have a science background. But how does this work? If you can't feel it, how would you measure it?
Space boggles my mind I love it!
Why not scroll up to 36000 kms, so we can reach the end of the cable? #iFeelCheated !
I found this strangely emotionally affecting. Probably on account of the music, but I was really struck the vastness and loneliness as the elevator went higher and higher (and we're still nowhere close to the moon).
This is a really nice piece of work.
Question: Why does the Douglas Skyrocket have its undercarriage down at 25km?
Unsolicited feedback: It would be nice to be able to click on an item and see some more information. Perhaps just a hyperlink to a wikipedia entry.
It is appreciated that you can change the temperature unit by clicking on it, and how surprisingly cold and changeable the temperature is as you travel up through the atomic sphere (down to -84C, -119F).
An actual space elevator would need to be over 357 times longer though right?
Awesome site!
I missed that notice at where its says: Here be a near mars atmosphere in temperature, pressure (40 kms up) but not as hostile composition and with less radiation. Thats five Mt Everests high.
This is cool, but the UX of the arrows should follow the scroll mode of the device. You drag down on an iPhone to scroll up. Following the arrow and dragging up causes nothing to happen
Loved this site. Only thing I could think to add would be the ability to click each item and be taken to a wiki page or some further source of information about the object.
Interesting how counter intuitive it felt to scroll up from the "landing spot". Even with the instructions right there on the screen I tried scrolling down at first.