To quote Toy Story:&quot;That&#x27;s not flying, that&#x27;s just... falling with style!&quot;Accelerate upwards fast enough, you can so to speak fall upwards for a short while before you fall back down again...

I always enjoy Neal&#x27;s pages. I found planes at high altitude very interesting, didn&#x27;t know we could fly that high!

Earlier this year, we were treated to an exceptional photo of one: <a href="https:&#x2F;&#x2F;www.smithsonianmag.com&#x2F;smart-news&#x2F;mysterious-red-sprite-appears-in-nasa-astronaut-photo-from-the-space-station-what-is-this-strange-electrical-flare-180986946&#x2F;" rel="nofollow">https:&#x2F;&#x2F;www.smithsonianmag.com&#x2F;smart-news&#x2F;mysterious-red-spr...</a>

It was enjoyable and informative.Learned that sprites can be 50km long!!

I don&#x27;t like to input Cc details into random sites whose main business is processing said transactions.

But xx% of some amount is still better than 100% of $0. And the pure convenience of using PayPal, Apple Pay or things like Ko-Fi will probably result in more net donations.

PayPal doesn&#x27;t cost significantly more than what a small online place can get from other payment processors. It&#x27;s something like 3% + $0.50. That&#x27;s also not much more than what a small business can usually get for in person credit cards.This site does use buymeacoffee.com, which appears to be a dedicated payment platform. Its transaction fee is apparently 5%, which is steeper, but better for these small donations because of the lack of a fixed fee.

&gt; Apple Pay take a significant cut of the transactionI don&#x27;t think this is true&gt; Apple Pay does not cause additional fees for users and merchants.[1][1]<a href="https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Apple_Pay#Cost" rel="nofollow">https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Apple_Pay#Cost</a>

PayPal and Apple pay take a significant cut of the transaction. CC is a lot less and bank is mostly free of TX fees.
Most users don&#x27;t know&#x2F;don&#x27;t care, so given the option, they will likely take it and funnel their donations to conglomerates.

I&#x27;ve never heard of link, so it&#x27;s the difference between a random website and a well established brand. Not that hard to understand why someone might be hesitant to put in their cc details.

How do you pay with PayPal if not putting in your credit card or bank details? link is a pretty well-known online wallet and much simpler to use than PayPal.

This was incredible! Couldn&#x27;t stop scrolling and reading. For a kid of a certain age and curiosity it&#x27;ll blow their mind! I&#x27;m so grateful the creator made this, shame that his &quot;buy me a coffee&quot; isn&#x27;t a simple PayPal or Apple Pay but you have to put in credit card or bank details!!

Excellent! My wrist started to hurt 0.01% of the way to the moon.

Its development is really interesting, in that it was more a proof of a scientific paper to start with. Anyway one of their tweets from September 2024 indicates they&#x27;re working on a sequel, despite their publisher (Annapurna, owned by Megan Ellison, daughter of Larry Ellison) having had some issues around then.

they are working on a new game. Outer Wilds doesn&#x27;t need a sequel, leave it be, its perfect as it is ::)

I was really disappointed not to see a sequel. No new games from the developers since.

The atmosphere of this reminded me of the game Outer Wilds

Thing is, you&#x27;re going to invest massive amounts of R&amp;D in something that might be impossible, when you could invest in actually building stuff in space so you only need to shoot humans out there.

Space elevator was the perfect application for carbon nanotubes according my professor few decades ago. I wish humanity could unite for such project and enter space exploration phase. But I feel it will stay sci-fi forever.

I don&#x27;t see it. Why worry about a weaponized space elevator when stealth bombers, cruise missiles and ICBMs exist?If the power building the space elevator wants to bomb you, you&#x27;re going to get bombed.

The problem with space elevator is not only the lack of material today, but also the fact that such elevator is an ultimate and very fragile weapons platform, you basically get stones up the well and then drop them on the enemy. Meaning that any authoritarian country would destroy it even before it is ever built. And sturdy enough space elevator after it&#x27;s break at any high point would start falling down on the planes in a loop, eventually flattening everything in its path when higher portions reach supersonic speeds. So unfortunately there is low chance it will be built, unless we sort out stuff on the planet first.

A space elevator is kind of like a vertical mass driver, so just build one of those along the surface of the moon with modest acceleration, survivable by passengers.Rotating cables (&quot;rotavators&quot;) on the moon seem much more practical than full space elevators.<a href="https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Momentum_exchange_tether#Rotovator" rel="nofollow">https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Momentum_exchange_tether#Rotov...</a>

Ah, good catch. Stand corrected on that one.

&gt; A space elevator on the moon is much more feasible: less gravity, slow rotationThe slow rotation is a minus, it means you&#x27;ve got to string the tether up to L1 instead of &quot;just&quot; up to geo&#x2F;luna-stationary orbit. A lunar space elevator needs to be at least 56000 km long, more than 20000 km longer than the one to earth.&gt; But it&#x27;s also much less useful.Yeah, especially because all the things that make lunar space elevators a little more attainable also make lunar mass drivers a lot more attainable. Why ride in an elevator for a week if you also can just be fired from a cannon?

If you somehow manage to get magnetic fields involved, so you are not afraid of friction with the cable itself, at 1.3 max apparent acceleration&#x2F;deceleration (after a turnover) and including earth’s gravity you get 116min to geostationary.If you account for various inefficiencies like taking it slow in the lower atmosphere 
Ant whatnot, it still should be in the matter of hours. So totally feasible and even comfortable.

#1 is one of the things they typically get wrong in stories.Climbing the cable is a nightmare, especially as it gets thicker as you go up. Thus do not climb the cable! Rather, when the cable is built a whole bunch of anchors are built into it. You are not climbing the cable, you are climbing a track on the side of the cable. The cable&#x27;s job is to support the track plus any load on it.

Almost all discussions around space elevators focus on the cable itself, how to manufacture and deploy it, and completely forget about the issues that would arise afterwards:1) How do you attach the climber to the cable without affecting its structural integrity? By squeezing it really hard? A material that&#x27;s optimized for longitudinal tension strength is probably not very tolerant of lateral compression.2) How do you provide power to the climber? A regular electric cable can&#x27;t support its own weight, so either you have to attach it to the climbing cable, or you have to make it from the same material.3) Is it even worth it? The climber needs to cover a distance of ~36,000 km, so even at 200 km&#x2F;h it takes 7.5 days from the bottom to geosynchronous orbit. How many climbers and what payload can the cable support at the same time? Refer to issue #1 regarding limits in speed and mass per climber.The throughput in tonnes&#x2F;day is absolutely abysmal in relation to the immense upfront infrastructure cost per elevator. Compare this to SpaceX&#x27;s Starship, which is getting closer and closer to fully reusable 100 tonnes to orbit in minutes. Space elevators will stay science fiction forever, not because they&#x27;re infeasible, but because they&#x27;re useless.

Well if it&#x27;s contingent to having massive amounts of unobtainium and subject to unsolvable engineering reality check conundrums then it&#x27;s just as unlikely as an Alcubierre drive which &quot;only&quot; needs exotic matter that allows negative energy.

A terrorist attack on a space elevator happens to figure in the first episode of the TV series Foundation.<a href="https:&#x2F;&#x2F;foundation.fandom.com&#x2F;wiki&#x2F;Bombing_of_the_Star_Bridge" rel="nofollow">https:&#x2F;&#x2F;foundation.fandom.com&#x2F;wiki&#x2F;Bombing_of_the_Star_Bridg...</a>It’s about as devastating as you would expect.

The issue of the line falling back to earth is solved by putting the base of the elevator on water. If the top part of the elevator was cut of you could even detonate charges along the line to make sure all pieces fall into water.

I&#x27;m wondering if it&#x27;s one of those paradoxes where by the time we are technologically capable of building one, we won&#x27;t actually need it.

While a space elevator doesn&#x27;t contradict any fundamental limits of physics, that doesn&#x27;t mean it&#x27;s actually possible to build one. There is no reason to be certain that it&#x27;s actually possible to create a material that has the required characteristics in terms of tensile strength to support it&#x27;s own weight, plus the weight of the elevator, plus the weight of all the additional cabling. It also has to endure the huge temperature differences that it will experience along its length and from day to night and from season to season.This is especially true considering that you don&#x27;t need something that barely holds - you need something that you know will hold up to many times more weight than it needs to, so that it can be safe: the potential energy such a thing would store would be enough to dig into hundreds of meters of rock all around the world, if it ever crashed. So, you have to ensure there is no realistic chance of it ever crashing. It also has to be highly non-fragile in other ways, so that a madman with a bomb or a freak collision with an airplane or a meteor (especially likely in the thin upper layers of the atmosphere) won&#x27;t bring it all down.This combination of properties may well be completely impossible to actually achieve in a material. Even if there is no obvious basic law of physics that it would break, that doesn&#x27;t mean that it wouldn&#x27;t break other, harder to touch, derived laws.

thing is we do have materials strong enough, because as it turns out the issue with strength is in flaws between indivual molecules in any given material, not so much the type of material, and very small amples with perfect molecular bonds are plenty strong, but getting consistent perfect molecular bonds is the challenge,
 and if this can be done, other technologys ,such as vacume ballons
will be possible, such as flying citys to go with the space rlevators

There are designs for untethered structures in orbit that could function with current technology, e.g. <a href="https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Skyhook_(structure)" rel="nofollow">https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Skyhook_(structure)</a>

I think most plans envisage a large mass (such as a captured asteroid) in geostationary orbit to anchor the top of the elevator cable.

Tension, not compression.  Doesn&#x27;t matter how floppy it is.

Have you ever tried to balance a string on its end? It gets harder, the longer the string is. There aren’t any other physics than that.

&gt; while they&#x27;re not sci-fi to the extent of something like FTL travel - ie. they&#x27;re technically not physically impossibleOn Earth.Zylon or M5 [1] could build an elevator on Mars. Kevlar on the Moon.To drive this home, it’s estimated we could build a lunar space elevator for less than what Bechtel fleeced NASA for a mobile SLS launcher [2][3].[1] <a href="https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;M5_fiber" rel="nofollow">https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;M5_fiber</a>[2] <a href="https:&#x2F;&#x2F;opsjournal.org&#x2F;DocumentLibrary&#x2F;Uploads&#x2F;The_Lunar_Space_Elevator_a_Near_Term_Mea%20(1).pdf" rel="nofollow">https:&#x2F;&#x2F;opsjournal.org&#x2F;DocumentLibrary&#x2F;Uploads&#x2F;The_Lunar_Spa...</a>[3] <a href="https:&#x2F;&#x2F;oig.nasa.gov&#x2F;wp-content&#x2F;uploads&#x2F;2024&#x2F;02&#x2F;IG-22-012.pdf" rel="nofollow">https:&#x2F;&#x2F;oig.nasa.gov&#x2F;wp-content&#x2F;uploads&#x2F;2024&#x2F;02&#x2F;IG-22-012.pd...</a>

TIL it&#x27;s estimated that over 48 tons of meteors hit the atmosphere every day.Regarding actual space elevators though, while they&#x27;re not sci-fi to the extent of something like FTL travel - ie. they&#x27;re technically not physically impossible - they&#x27;re still pretty firmly in the realm of sci-fi. We don&#x27;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&#x27;s also much less useful.

Ditto, although you&#x27;d have to scroll about 357 times further.I suppose it could be livened up by including the orbits of things, but there would still be lots and lots of empty space.

The thing is, the same author has already done that.<a href="https:&#x2F;&#x2F;neal.fun&#x2F;size-of-space&#x2F;" rel="nofollow">https:&#x2F;&#x2F;neal.fun&#x2F;size-of-space&#x2F;</a>

Such a lost opportunity, was hoping for another &quot;space is massive&quot; experience like already done in similar interactive maps.

Would be boring and space elevators are just for fun. They aren&#x27;t a real idea.

Was hoping would go to geostationary orbit as an actual space elevator would :)

Grateful it wasn&#x27;t as long as Infinite Paperclips or Cookie Clicker, but still worth it. Great site!

Careful folks! This escalates quickly. Do not use xdotool on this.

Thanks, I spent my lunch hour completing it without cheating. Amazing!

Thanks! I found a funny hack: DVD logos generate stimulation per bounce, so ... let them fly for a few seconds, then resize window to small size and back. Lot of bounces as the logos get caught by the moving edge :).

I love this guy.Re playing this gem <a href="https:&#x2F;&#x2F;neal.fun&#x2F;stimulation-clicker&#x2F;" rel="nofollow">https:&#x2F;&#x2F;neal.fun&#x2F;stimulation-clicker&#x2F;</a>

I did the same. I eyed it suspiciously and thought to myself, &quot;This site is really well designed. Do you think if I...&quot; and it did switch! The obvious interaction was implemented! Rare these days.

Doesn&#x27;t work on the the &quot;meters&quot; display, though!

Unfortunately that doesn&#x27;t change the &quot;mph&quot; in the info boxes.

I just clicked the temperature thingy in annoyance because I don&#x27;t use Fahrenheit and to my delight, it just switched to Celcius

I just looked at it in the dev console in a chrome based browser and I think it is already pretty optimized. It runs very smooth on my device (Thinkpad T480).

the website feels heavy, can we optimize this further?? (not a web dev)

but every behaviour has a cost. In cast of flight altitude its energy and distance to food, water, mating zones.

Not every behavior has an evolutionary advantage.If anything, &quot;evolution&quot; filters out disadvantages (eg: can&#x27;t survive because your neck&#x27;s too short and that pesky giraffe is eating all the leaves you could reach).Evolution kills what doesn&#x27;t work.

I prefer to call them &quot;footsies&quot; or, sometimes &quot;feet&quot;.

&gt; Feets are actually just fineNon-SI legacy units have been grandfathered in and &#x27;accepted for common use&#x27;, but ICAO recommends that SI units should be used[1] (eventually). China and quite the majority of the ex-USSR, for instance, use metre flight levels[2].There have been at least two aviation accidents and incidents relating to unit mis-conversions. This is two too many. As an SI absolutist, everyone should switch to SI or units purely derived from SI (so domain-specific stuff like parsecs, electronvolts, and binary prefixes, if appropriately symbolled are OK). It is an internationally-recognised, and nearly universal standard that permeates every aspect of human lives.[1]: <a href="https:&#x2F;&#x2F;aerosavvy.com&#x2F;wp-content&#x2F;uploads&#x2F;2014&#x2F;08&#x2F;an05_cons.pdf" rel="nofollow">https:&#x2F;&#x2F;aerosavvy.com&#x2F;wp-content&#x2F;uploads&#x2F;2014&#x2F;08&#x2F;an05_cons.p...</a>[2]: <a href="https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Flight_level#People&#x27;s_Republic_of_China_and_Mongolia" rel="nofollow">https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Flight_level#People&#x27;s_Republic...</a>

Feets are actually just fine in anything related to aviation.

Wikipedia [1] implies it&#x27;s to give them an incredibly large field of vision to spot prey, though the source it cites [2] seems less certain about that[1] <a href="https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;List_of_birds_by_flight_heightshttps:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;List_of_birds_by_flight_heights" rel="nofollow">https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;List_of_birds_by_flight_height...</a>[2] <a href="https:&#x2F;&#x2F;web.archive.org&#x2F;web&#x2F;20131011012320&#x2F;http:&#x2F;&#x2F;blogs.bu.edu&#x2F;bioaerial2012&#x2F;2012&#x2F;09&#x2F;26&#x2F;the-ruppells-griffon-vulture-the-highest-recorded-flying-bird" rel="nofollow">https:&#x2F;&#x2F;web.archive.org&#x2F;web&#x2F;20131011012320&#x2F;http:&#x2F;&#x2F;blogs.bu.e...</a>

A beautifully executed project here, I bought Neal a coffee.What evolutionary advantage, I wonder, is there to Ruppell&#x27;s griffon vulture flying at 11400 meters?edit: units

The rockets at higher altitudes were all in wrong orientation. In reality, they don&#x27;t fly straight up.

I think those technologies are mentioned throughout the book - just at a much larger scale in the second part.

Did you read Seveneves by Neal Stephenson? In the second part of the book, they use this and related technologies.

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.

There are other presentations by this guy are long. I don&#x27;t consider the space and the things we put between LEO and GEO to be boring.

I think the idea behind this was less to showcase an actual space elevator and more to showcase what&#x27;s going on at different altitudes. And above the Kármán line it would have become pretty boring, especially if you want to go up to GEO and beyond where the counterweight of a space elevator would be located - the Kármán line is at only 0.28% of the way to GEO. Using a logarithmic scale would have maybe helped, but not sure...

Incomplete. Where&#x27;s the LEO, GEO, the counterweight?

Only for Earth. We already have materials that can do it on the Moon (Zylon, for example), though not with great tether-to-payload ratios (200:1 or more), and Mars isn&#x27;t too huge of a stretch (huge like the mass of the tether, which would be in the thousands to one tether-to-payload ratio. Shipping 50,000 tons of Zylon to Mars is a different beast)

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.

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).

Some huh! moments...* Jeez, Everest is tall* They got a plane to 17km in 1938!* There was a paper airplane flight at 35km

An actual space elevator would need to be over 357 times longer though right?Awesome site!

Zero. By the time you get to GEO your are connected to a station which is in Geostationary orbit. Your 35 hour ascent at say 1000km&#x2F;h will have accelerated you sideways to the required 3km&#x2F;second with a sidewards acceleration of 0.002g throughout the trip.Of course you would be looking at a constant acceleration, not just a 1000km&#x2F;hour trip. You&#x27;d probably be able to do the journey in a couple of hours with a reasonable acceleration and a rotating cabin (say 1.1g, meaning acceleration would slowly increase from about 0.1g at the surface, then after the flip point you&#x27;d decelerate at 1.1g). Even then sideways acceleration wouldn&#x27;t be noticable (and your cabin could gimbal to just add it to vertical acceleration)That&#x27;s the other crazy thing. A space elevator takes forever at elevator, or car, or even plane speeds. But with constant acceleration&#x2F;decelleration you can have a trip in airplane style seats with cabin crew serving you caviar &#x2F;&#x2F; scratchcards (depending on class of cabin). Your peak vertical speed would be in the region of 8km&#x2F;second - way above Earth&#x27;s escape velocity, but you wouldn&#x27;t even notice the acceleration&#x2F;deceleration. You&#x27;d slow down in under 15 minutes.Or you wouldn&#x27;t and you&#x27;d depart Earth at 8km&#x2F;s, twice the escape velocity.(If you really wanted a fast departure you&#x27;d accelerate at say 1.2g and get upto 30km&#x2F;s, twice the speed of New Horizons. 1.2g would probably mean you&#x27;d have the seatbelt on for the whole 40 minute trip)You could launch cargo to Mars at say 5G, which would get it there in between 10 and 45 days depending where it is. Obviously you&#x27;d have a problem slowing down when you got there.

How much delta V would be needed to reach, say, a circular orbit from GEO altitude?

What&#x27;s really interesting is that a space elevator goes to Geostationary orbit by necessity. Getting to 100km vertically doesn&#x27;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&#x2F;s of Delta-VTo get there from a 100km tall tower, you need about 8km&#x2F;s of delta-V - about 85%.Think about how much scrolling there was to get to 100km.To get to the ISS you&#x27;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.

Neal also made one:<a href="https:&#x2F;&#x2F;neal.fun&#x2F;size-of-space&#x2F;" rel="nofollow">https:&#x2F;&#x2F;neal.fun&#x2F;size-of-space&#x2F;</a>

And &quot;up&quot;, but shown sideways, and on a different scale: <a href="https:&#x2F;&#x2F;joshworth.com&#x2F;dev&#x2F;pixelspace&#x2F;pixelspace_solarsystem.html" rel="nofollow">https:&#x2F;&#x2F;joshworth.com&#x2F;dev&#x2F;pixelspace&#x2F;pixelspace_solarsystem....</a> &quot;If the Moon were only 1 pixel&quot;

I&#x27;m here to find this one, thank you!

The other direction:<a href="https:&#x2F;&#x2F;neal.fun&#x2F;deep-sea&#x2F;" rel="nofollow">https:&#x2F;&#x2F;neal.fun&#x2F;deep-sea&#x2F;</a>

Too far away to scroll: <a href="https:&#x2F;&#x2F;www.whereisroadster.com&#x2F;" rel="nofollow">https:&#x2F;&#x2F;www.whereisroadster.com&#x2F;</a>

Wow, I&#x27;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?

Amazing work as always. Paired with Wikipedia it makes for a very productive day.

Previous discussion on 20-apr-2023 <a href="https:&#x2F;&#x2F;news.ycombinator.com&#x2F;item?id=35629972">https:&#x2F;&#x2F;news.ycombinator.com&#x2F;item?id=35629972</a>

How on Earth do we know the maximal altitude for a pterodactyl?

Right.  So the solar wind provides the energy that drives the aurora, but it&#x27;s more indirect than just &quot;solar wind particles hit the atmosphere&quot;.  Instead, the solar wind is injecting energy into the magnetic field of the magnetosphere, and when reconnection occurs some of this magnetic energy is dumped into particles in the magnetosphere, some of which can then strike the atmosphere.

I feel that way about galactic center filaments. They just scream &quot;this region of space is not safe&quot; in the most awe-inspiring way to me. 150-lightyear-long, magnetically powered, speed-of-light tornados. And there&#x27;s hundreds of them.<a href="https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Galactic_Center_filament" rel="nofollow">https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Galactic_Center_filament</a><a href="https:&#x2F;&#x2F;science.nasa.gov&#x2F;asset&#x2F;webb&#x2F;milky-way-center-meerkat-and-webb&#x2F;" rel="nofollow">https:&#x2F;&#x2F;science.nasa.gov&#x2F;asset&#x2F;webb&#x2F;milky-way-center-meerkat...</a>

These are cool. I wonder how much they screw with satellites etc.? How predictable are they? It seems like it&#x27;s just a deadly, mostly-invisible wall of energy flying around at unbelievable speeds!

Any discussion of aurora which do not mention space tornados: <a href="https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Space_tornado" rel="nofollow">https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Space_tornado</a>Is inherently incomplete. Not necessarily because they&#x27;re needed to explain it, but they do need to be brought up at any time possible because they&#x27;re cool.

Amazing work! One minor correction:&gt; 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 &quot;contract&quot; (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 =&gt; they slam into the atmosphere, exciting the atoms and generating the aurora.

No, thank you. Don&#x27;t want any existential crisis today!

Neat! It would be amazing to see how the pressure changes with altitude in addition to the temperature.

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.

It&#x27;s my understanding that the Karman Line the conventionally accepted &quot;edge&quot; where you leave the atmosphere and enter outer space, but many call this out as a fairly arbitrary point, arguing that there is no measurable boundary. Useful as a point of reference for positioning, though. Neal possibly just used it as a marker but chose to not define it for this reason.

It&#x27;s an arbitrary number, which is a good enough measure to distinguish an aircraft from a spacecraft.Kármán said that it&#x27;s about this height where the aerodynamic lift and inertia being dominant are reversed.<a href="https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;K%C3%A1rm%C3%A1n_line" rel="nofollow">https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;K%C3%A1rm%C3%A1n_line</a>

Perfect. I think it just needs explanation of Karman line. Why is it 100km. What is the meaning?

Lovely, as all neal.fun experiments. &lt;3My favorite is probably <a href="https:&#x2F;&#x2F;neal.fun&#x2F;infinite-craft&#x2F;" rel="nofollow">https:&#x2F;&#x2F;neal.fun&#x2F;infinite-craft&#x2F;</a>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.

WARNING: This guy&#x27;s site is a trap for people with ADHD&#x2F;OCD -- the ease at which I was sucked into every link on his site made me nope the heck out.Beautiful work though.

&gt; just clear the atmosphereBut for what purpose? You just want to float around in a elevator carriage, aren&#x27;t you going somewhere when you go with a space elevator?

There&#x27;s a big difference between &quot;clear of the atmosphere&quot; or &quot;100km up&quot; and &quot;in orbit&quot;. Orbit is more about velocity than altitude.

I think it could but does not necessarily have to reach a station. The elevator just has to clear the atmosphere, right? As they say: once you&#x27;re in orbit, you&#x27;re halfway to anywhere.

Oh no, I scrolled all that way and didn&#x27;t even reach some destination! Where does this space elevator go? No one knows! Would have been bit more satisfying if it ended up at a space station or something, as I think that&#x27;s the purpose of the space elevator idea in the first place :)

Yes, absolutely but I found it funny anyway!

I dunno, by that rationale you could argue that Tesla Roadsters have officially beaten the X-43B&#x27;s altitude record, couldn&#x27;t you?

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.funEdit: also good to know that paper airplanes have officially beat the SR-71, F-104 or X-43B with altitude record.

Came here to ask the same thing. Hoping you get a response from an expert. I was vaguely under the impression they were mostly gliders... maybe it&#x27;s something to do with thermals?

Scientists created a detailed virtual reconstruction of pterodactyl’s body and then feed it to computer simulation to estimate flight speed, endurance and altitude.

How do we know how high pterodactyls were flying?

My 8 and 10 year old daughters love this site, often choosing it over Roblox during screen time.This is stunning and perfect.

Wow, I just discovered Ruppell&#x27;s Griffon Vultures from this. What a fascinating bird with high flying capabilities!

&gt; Temperatures can reach &lt;something very high&gt; but the molecules are spread sobfar apart you wouldn&#x27;t feel it.Conceptually I get, it&#x27;s like being in a cold room that showers hot sparks on you from above occasionally......but I feel that the definition of temperature has been abused here slightly

It&#x27;s purely out of principle because in a proper cookie popup rejecting everything should take the same amount of clicks that accepting everything doesI do understand that this is one those generic ones (I saw it many times) which the original creator of the website just slapped on.

Did you know if you open a page in a private browser window, once you close that page all the cookies vanish? It&#x27;s even better than a button which might not even work.

I didn&#x27;t take a look cause I didn&#x27;t see &quot;reject all cookies&quot; button in the cookie popup

This is just lovely. I, for one, have bought Neal a coffee!

Space elevator is not something which stands on the ground and grows up. It is something which lives on geostationary orbit and grows down from it to the Earth. If you cut the lower 1 meter of it, the rest will hang......that is, until a satellite will hit the cable above. Space elevator is built in the equatorial plane, all satellites cross it, so eventually every satellite is going to collide with the cable. For this reason the space elevator is incompatible with existing spaceflight, that&#x27;s why even with nanotubes it&#x27;s unlikely to be built.

The sound mixing is so smooth. Is it a simple fade with the right choice of melodies or is there more to it?

That space elevator music 100% made my day, thank you!

The material is actually not a problem, if you consider active structures. 
<a href="https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Active_structure" rel="nofollow">https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Active_structure</a>
<a href="https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Space_fountain" rel="nofollow">https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Space_fountain</a>Then again, when doing mega structures, a launch loop is more plausible.

This presents a considerable risk of splitting English into several languages, none of them intelligible with the others.

Related and recommended: Greg Egan “Phoresis” a sci-fi novel of two twin planets in extreme proximity to each other. (I think I read it in one of his anthologies.)

To get to the Kármán line (100k) a mountain with a 60 degree slope would require a base of 115km. A cone with 115km diameter base has a volume of 3.5×10^5 km^3. Which is 3.5x10^14 m^3, which is about 10^15 kg of rock. So it is going to take you a while!

All we have to do is make the global religion require bringing a rock to a specific location; after long enough we’ll have a mountain so high it extends out of the atmosphere!

A version of this also happens in the first season of Foundation, the Apple TV series based on Asimov&#x27;s novels.

A fictional representation of a thing exaggerated for dramatic effect and to create plot tension shouldn&#x27;t really convince you of many things at all. They&#x27;re rarely accurate portrayals.

In adition to being fictional, what would happen on Mars does not reflect what would happen on Earth as the Martian atmosphere is so much thinner than ours.

Kim Stanley Robinson&#x27;s description of a Martian space elevator falling and wrapping twice around the entire planet convinced me that they aren&#x27;t a good idea.<a href="https:&#x2F;&#x2F;www.kimstanleyrobinson.info&#x2F;content&#x2F;clarke" rel="nofollow">https:&#x2F;&#x2F;www.kimstanleyrobinson.info&#x2F;content&#x2F;clarke</a>

Really great book (and series). Though it&#x27;s not &quot;hard sci-fi&quot; by any means, the technology feels real enough to keep my brain from focusing on the holes and enjoy the fun philosophical and ethical problems that Scalzi comes up with

In John Scalzi&#x27;s Old Man&#x27;s War, there is a discussion of how the more advanced society that they&#x27;re interacting with deliberately put a space elevator on Earth, not because it was the easiest or cheapest solution, but as a sort of constant reminder of just how much more technologically sophisticated they were.

Doesn’t the weight of the cable itself let alone any payload preclude this from becoming real based on all plausible material science

A space elevator doesnt just take you to the karman line (like in the OP website), to get to orbit, you&#x27;d need to get up to geostationary height. That&#x27;s 22,000 miles.What&#x27;s the best way to pull yourself directly vertical along a cable for 22,000 miles?What&#x27;s the best way to descend 22,000 miles quickly, but also with a braking mechanism that isn&#x27;t going to require a heat shield?Some sort of slow cable car going at 10mph even is going to take 2200 hours... 1000mph is going to take 22 hours still. That&#x27;s a full day to orbit even going REALLY fast. And getting up to 1000mph vertically, for a sustained 22 hours... that&#x27;s not an easy feat.And if the goal is just to get up past the karman line and use the elevator as a stage 1 for a rocket launch and detaching from the elevator while suborbital is fine, then it&#x27;s a one way trip, and still need to re-enter the old fashion way.The scale of space makes all of the problems far more complicated (edit: not just the cable strength issue, but traversing the cable)

Isn&#x27;t the entire point of the space elevator to be the ascent&#x2F;descent mechanism?Once you have the cable up, you can grab onto it and pull yourself up.

Skyhooks may allow for much easier access to space within the limits of likely practical carbon nanotube based structures. A rotating tether that orbits the planet could be timed to &#x27;catch and throw&#x27; supersonic aircraft into space. Lots of engineering still required, but potentially actually feasible compared to space elevators.

Most engineers would bring up a lot more issues than just finding a strong cable.He did. The elevator music!

Impractical on Earth given existing technology, but there are a lot of bodies in the solar system which have enough gravity to make them worth while but where they&#x27;re small enough that the materials needed are ones we have right now.  The Moon in particular.

I think a space elevator on the Moon would be more practical, pointing towards earth.  The gravity force is smaller, so existing materials could work.  There&#x27;s not as much of an atmosphere to deal with.  It would go past the L1 point between earth and the moon.  It could be extended from the poles, where it&#x27;s most likely where bases might exist.

&gt; Space elevators are actually a possible idea being considered by scientists. 
&gt; 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 <a href="https:&#x2F;&#x2F;www.newscientist.com&#x2F;article&#x2F;2093356-carbon-nanotubes-too-weak-to-get-a-space-elevator-off-the-ground&#x2F;" rel="nofollow">https:&#x2F;&#x2F;www.newscientist.com&#x2F;article&#x2F;2093356-carbon-nanotube...</a>.- We don&#x27;t have a good ascent mechanism other than rockets - and then we might just use rockets without building an elevator.
- We don&#x27;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 like the white text on white backgroud. Makes very easy to read

Interesting how counter intuitive it felt to scroll up from the &quot;landing spot&quot;. Even with the instructions right there on the screen I tried scrolling down at first.

does anyone have the link to the money one ? scale of a billion ?

&gt; Going fast enough sideways so you stay up there is the tricky bit.nah, thats the simple part. getting up there efficiently is the difficulty. once we&#x27;re up, its just a matter of force over time to create a nice orbit.The faster you go, the more friction you face, and the more heat and vibration your equipment must endure.Going slower reduce friction and stress but use more energy just negating gravity. Slow rocket is inefficient rocket.So we wanna leave the atmosphere as soon as possible, but not so fast that the rocket melts or engines collapse. Prefferably just below the sound barrier.once we&#x27;re up, its pretty chill... until you wanna go down again. Slow rocket is alive rocket.

Which is another part of why a space elevator is nifty - by definition it extends out to a distance where you are going fast-enough-sideways.Now, I have no idea how practical it is to build one (Angela Collier has a video saying it&#x27;s kinda ridiculous), but it&#x27;s a cool idea.<a href="https:&#x2F;&#x2F;www.youtube.com&#x2F;watch?v=Z5aHMB4Tje4" rel="nofollow">https:&#x2F;&#x2F;www.youtube.com&#x2F;watch?v=Z5aHMB4Tje4</a>Also since rockets have moved away from hydrolox, it would be nice to have a greener launching system.

This is where Douglas Adams was right, of course:&gt; There is an art, it says, or rather, a knack to flying. The knack lies in learning how to throw yourself at the ground and miss.You&#x27;re not going sideways - you&#x27;re actively falling continuously, but somehow missing the ground for the entire length of your orbit.

There&#x27;s an XKCD for that: <a href="https:&#x2F;&#x2F;what-if.xkcd.com&#x2F;58&#x2F;" rel="nofollow">https:&#x2F;&#x2F;what-if.xkcd.com&#x2F;58&#x2F;</a>

&gt; Going up is the comparatively easy part, it&#x27;s not exactly rocket science.Some would argue is quite literally rocket science, even if suborbital rockets are much simpler, like they can just burn solid fuel.

&gt; it&#x27;s just hard to go upGoing up is the comparatively easy part, it&#x27;s not exactly rocket science. Going fast enough sideways so you stay up there is the tricky bit.

If memory serves well, Frenchmen solved the problem of going up in two ways, and the one you quote seems like a lot of hot air to me. I mean, if you follow that line of thought, the literature says an American would get to the Moon in 19 days or so.The other French method included two dogs, a bunch of chicken, and a very large cannon, which had quite a bit more showmanship.

&gt; it&#x27;s just hard to go up.Eh. Going up is easy. A Frenchman, a sheep, duck, and rooster solved the whole ‘up’ thing over two centuries ago.But going DOWN? That’s far more difficult. What wonders may lie beneath our feet: vast caverns, ore, underground oceans… hard to get to though.

True statement, but disclaimer: your friends may be closer if you live in a European city without American suburban sprawl...

That&#x27;s a fascinating comparison, never seen it visualized like that before.

That didn&#x27;t sound right to me, and so I checked it as follows:Estimate for a standard classroom globe at 13&quot; in diameter (I&#x27;m seeing a rnage of 12-14 inches as typical). I&#x27;m reporting in inches because that is what came up first and most of the globes are for sale in the US. Mixing units here, but, it works out.But, in meters, the diameter of the Earth is 12,742,000 m on average. if we use the &#x27;Karman line&#x27; as defining the edge of what the atmosphere is, that is 100,000 meters. Solving for X ... (13&quot; &#x2F; 12742000 m)=(X &#x2F; 100,000 m). gives us an atmosphere thickness of approximately 0.1&quot;. -----Paper glued to the globe would have a thickness of maybe, 0.004&quot; (thin paper) to 0.012&quot; (like a card stock paper).... so that analogy is off by an order of magnitude or more.Even if you use the mesosphere as the definition for the top of the atmosphere, that is still 85,000 meters and thus similar.People can check the numbers I used.* Perhaps the analogy should go more like: the thickness of the cardboard sphere the globe is made out of is about the thickness of the atmosphere. Because, having completely destroyed a globe once in my youth, I remember the cardboard shell being approximately a tenth of an inch thick. But, that&#x27;s maybe not a great reference for the analogy because not everyone has cut apart a classroom globe....

I wonder how standard this globe size is. My mental one is the one we had at home that was about 15&quot; in diameter I&#x27;d guess.Another comment talks about atmosphere being a 1 mm layer on a grapefruit... so definition of atmosphere extents might be different in these two anecdotes.(edit: I submitted this comment two minutes after another comment did the math on the globe&#x2F;paper layer version...)

And the bumps for the mountains on that globe (assuming you had a fancy one) were gross exaggerations:<a href="https:&#x2F;&#x2F;dahosek.substack.com&#x2F;p&#x2F;one-million-stories" rel="nofollow">https:&#x2F;&#x2F;dahosek.substack.com&#x2F;p&#x2F;one-million-stories</a>

For a standard globe that you might see in a classroom, the Earth&#x27;s atmosphere is about as thick as the paper glued to the outside that displays the map.

I didn’t think that sounded right but went and did the math and you’re actually round up to .2%. It’s .156%. And that’s already a mind numbingly scary place to be.

As a follow-up to this, even though water makes up 70% of the Earth&#x27;s surface, it&#x27;s only 0.02% of the Earth&#x27;s mass.

We live at human scale within a thin slice of a planet-sized environment.On the planetary scale, humans are tiny. We&#x27;re more or less equivalent to bacteria.Our entire civilisation is a skin rash.

Likewise, it is crazy to me when I realised how thin our oceans are. I used to think of them as super deep (I mean, they are) but even the Mariana trench is a mere 0.2% of the Earth&#x27;s radius. Average ocean depth is more like 0.05%.

It isn&#x27;t even necessarily _that_ hard to go up. It&#x27;s just hard to go up _and reach orbital velocity_.

&gt; Our liveable breathable atmosphere is razor thin compared to the size of earth.If earth were a grapefruit, our atmosphere would be ~1mm thick!

The most important feature of a launch site is having no populated areas downrange. Kilimanjaro would have Mombasa downrange.I don&#x27;t know of any launch sites significantly above sea-level, the marginal performance increase wouldn&#x27;t be worth the logistical nightmare. It&#x27;s easier to fly up a 747 than build a launch facility on top of a mountain.

Sounds like the plot of The Dabare Snake Launcher: <a href="https:&#x2F;&#x2F;www.amazon.com&#x2F;Dabare-Snake-Launcher-Joelle-Presby&#x2F;dp&#x2F;1982192259" rel="nofollow">https:&#x2F;&#x2F;www.amazon.com&#x2F;Dabare-Snake-Launcher-Joelle-Presby&#x2F;d...</a>

In a parallel universe where Africa is covered by world powers, Mount Kilimanjaro would make a pretty good launch facility. Reduced rocket equation needs for being nearly 3 miles high. If you start in thinner atmosphere you need less fuel to punch through it. You’re also higher when you hit Max Q.This is essentially what Scaled Composites and Virgin Galactic were trying to do with their cargo plane system, only you don’t have to worry about the ignition timing because you’re not in free fall.

Very cool. One thing I wish was better shown: space is close, it&#x27;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&#x27;s a day long bike ride. Air runs out less than a bus ride across town. A 15k jog&#x2F;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!

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.

Doomscrolling isn&#x27;t supposed to feel so right...

I really wanted to enjoy Satisfactory, but I really struggled with building a factory in first person perspective.Factorio, Dyson Sphere Program, Captain of Industry...loved them all. Satisfactory? Just wasn&#x27;t for me.

I watch AC&#x27;s video on this, it was quite entertaining: <a href="https:&#x2F;&#x2F;www.youtube.com&#x2F;watch?v=Z5aHMB4Tje4" rel="nofollow">https:&#x2F;&#x2F;www.youtube.com&#x2F;watch?v=Z5aHMB4Tje4</a>If you like factory games and space elevators, then try Satisfactory!

I have a feeling engineers said the same about going to the moon under Kennedy.

No engineer actually thinks a space elevator is possible. It would be a silly waste of resources.

Seems like even before we do an elevator, we should get _something_ tethered to the ground to be in space. Like... anything! That&#x27;d be a huge accomplishment.

Different species will have different &#x27;death zones&#x27;. I&#x27;m not sure any bird would stay at that height for 10s of hours though.

I was wondering about this, because the link shows a bunch of birds in the &quot;death zone&quot;.

&gt;Above this altitude is known as the &quot;death zone&quot;, because there isn&#x27;t enough oxygen for human life.Being pedantic, this should be &quot;there isn&#x27;t enough oxygen for sustained human life&quot;. An acclimatised climber can survive tens of hours.

Space elevators aren&#x27;t going to happen. Not in Earth&#x27;s gravity well anyway. Even if you can find a material strong enough (and that&#x27;s a big &quot;if&quot;), you still have to traverse 50,000km to get from Earth&#x27;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&#x2F;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&#x27;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]: <a href="https:&#x2F;&#x2F;www.youtube.com&#x2F;watch?v=LMbI6sk-62E" rel="nofollow">https:&#x2F;&#x2F;www.youtube.com&#x2F;watch?v=LMbI6sk-62E</a>

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.

Because space elevators aren&#x27;t actually possible so it doesn&#x27;t really matter.

Why not scroll up to 36000 kms, so we can reach the end of the cable?
#iFeelCheated !

This. Took me a while to realize you have to scroll down, not up.

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

Deep links would _kill_ on this. I&#x27;d love to be able to link someone to the Blackbird. (25,700 meters)

Just came to say that this is so cool. Great work.

I mean the idea isn&#x27;t actually real or practical. It&#x27;s a thought experiment that makes for some fun calculus. No one&#x27;s actually going to try and build one.

Counterweight or just more cable.  IIRC it&#x27;s 170k (miles?  kilometers?) if you use no counterweight.  And note how fast that outer end is moving, it can throw things pretty hard.

actually geosync isn&#x27;t the top.  You need to extend beyond that &amp; have a counterweight that balances the weight of everything below the point of geosynchronous orbit.  Otherwise it would fall down.

From the same site, there&#x27;s the Size of Space page:&lt;<a href="https:&#x2F;&#x2F;neal.fun&#x2F;size-of-space&#x2F;" rel="nofollow">https:&#x2F;&#x2F;neal.fun&#x2F;size-of-space&#x2F;</a>&gt;There are a few sites which let you scroll through the solar system, from the Sun or Earth IIRC. Here&#x27;s one:&lt;<a href="https:&#x2F;&#x2F;onotherplanets.com&#x2F;solarwalk" rel="nofollow">https:&#x2F;&#x2F;onotherplanets.com&#x2F;solarwalk</a>&gt;Ah, and &quot;If the Moon Were Only One Pixel&quot;, which is what I&#x27;d had in mind, shared by @stared &lt;<a href="https:&#x2F;&#x2F;news.ycombinator.com&#x2F;item?id=45641839">https:&#x2F;&#x2F;news.ycombinator.com&#x2F;item?id=45641839</a>&gt;:&lt;<a href="https:&#x2F;&#x2F;joshworth.com&#x2F;dev&#x2F;pixelspace&#x2F;pixelspace_solarsystem.html" rel="nofollow">https:&#x2F;&#x2F;joshworth.com&#x2F;dev&#x2F;pixelspace&#x2F;pixelspace_solarsystem....</a>&gt; (2014)(HN discussions: &lt;<a href="https:&#x2F;&#x2F;news.ycombinator.com&#x2F;item?id=44266828">https:&#x2F;&#x2F;news.ycombinator.com&#x2F;item?id=44266828</a>&gt; (4 months ago), &lt;<a href="https:&#x2F;&#x2F;news.ycombinator.com&#x2F;item?id=21735528">https:&#x2F;&#x2F;news.ycombinator.com&#x2F;item?id=21735528</a>&gt; (6 years ago) &lt;<a href="https:&#x2F;&#x2F;news.ycombinator.com&#x2F;item?id=32936581">https:&#x2F;&#x2F;news.ycombinator.com&#x2F;item?id=32936581</a>&gt; (3 years ago).

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&#x27;t know if a browser would even support it.

That was fantastic.My biggest surprise (and confusion) was just how high butterflies and bumblebees go.

&gt; On June 21, 1972, Jean Boulet of France piloted an Aérospatiale SA 315B Lama helicopter to an absolute altitude record of 12.440 kilometres (40,814 ft).[68] At that extreme altitude, the engine flamed out and Boulet had to land the helicopter by breaking another record: the longest successful autorotation in history.[69]I just had to look that up. Absolutely incredible.

Given the title &quot;Space Elevator&quot; 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.

Super fun!I do always have to object to comments like &quot;space elevators are possible,&quot; &quot;scientists have studied&quot; and &quot;would save money&quot;.It&#x27;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&#x27;s vaguely achievable with near-future technology. It&#x27;s simply not worth investing the outrageous resources required to do a vaguely useful viability analysis.

I like looking at these, but does why does it have to redline my cpu?

You can click on it to change to Celsius!

I like how the height is measured in metric but the temp is measured in imperial.

Holy guacamole, common birds like cranes fly high.<a href="https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;List_of_birds_by_flight_heights" rel="nofollow">https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;List_of_birds_by_flight_height...</a>

The biplane part (Caproni ca 161) right after the &quot;you should put on a spacesuit&quot; 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&#x27;s difficult to even find imagery.[1] <a href="https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Mario_Pezzi_(aviator)" rel="nofollow">https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Mario_Pezzi_(aviator)</a>[2] <a href="https:&#x2F;&#x2F;static.thisdayinaviation.com&#x2F;wp-content&#x2F;uploads&#x2F;tdia&#x2F;2013&#x2F;10&#x2F;PEZZI-Mario-full-pressure-suit.jpg" rel="nofollow">https:&#x2F;&#x2F;static.thisdayinaviation.com&#x2F;wp-content&#x2F;uploads&#x2F;tdia...</a>[3] <a href="https:&#x2F;&#x2F;www.enricopezzi.it&#x2F;fam_pezzi&#x2F;mario_pezzi&#x2F;images&#x2F;MP_1937%20C161_01w.jpg" rel="nofollow">https:&#x2F;&#x2F;www.enricopezzi.it&#x2F;fam_pezzi&#x2F;mario_pezzi&#x2F;images&#x2F;MP_1...</a>[4] <a href="https:&#x2F;&#x2F;www.reddit.com&#x2F;media?url=https%3A%2F%2Fi.redd.it%2F40xmdzpd1ft71.jpg" rel="nofollow">https:&#x2F;&#x2F;www.reddit.com&#x2F;media?url=https%3A%2F%2Fi.redd.it%2F4...</a>

I honestly expected to be scrolling for a couple of days to reach geostationary orbit.

We can&#x27;t practically build a tower that tall. A space elevator would work by hanging off a counterweight (possibly more space elevator cable) which means it needs to go past geostationary orbit.

The space elevator would need to be strong enough to lift a rocket. Though, maybe without all that extra fuel they could be much smaller and lighter.

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?