Via File 770, I noticed this:
Firm Floats Plan to Hang Colossal Skyscraper From an Asteroid
Click through to see the amazing artist’s rendition of how this might look.
Don’t expect it to go up anytime soon, but a New York City-based design firm has floated a mind-bending plan for the erection of a skyscraper it bills as “the world’s tallest building ever.”
Dubbed Analemma, the fanciful tower wouldn’t be built on the ground, but suspended in air by cables from an asteroid repositioned into geosynchronous Earth orbit just for the purpose.
Over the course of each day, the floating skyscraper would trace a figure-eight path over our planet’s surface, according to plans posted online by Clouds Architecture Office. It would swing between the northern and southern hemispheres, returning to the same point once every 24 hours.
The speed of the tower relative to the ground would vary depending upon which part of the figure eight it was tracing, with the slowest speeds at the top and bottom of each loop, the plans say. The asteroid’s orbit would be calibrated so that the slowest part of the tower’s path would occur over New York City.
That’s … mind-boggling, both in itself and for the statement it would make. (LOOK, WE ARE IN THE FUTURE!)
a) I trust planes could avoid this structure?
b) Birds would be okay, I guess? It’s hard to see how anything could accidentally hit a thing as large as this.
c) Wow, talk about totally being safe from earthquakes and stuff, maybe they should hang one up over California?
d) The concern expressed in the article, that people who live in a tower literally separated from the Earth would feel disconnected and psychologically separate, I don’t know, could be. It would depend on how easy it is to go back and forth, probably.
e) This is just … really cool.
The future, we are in it.
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It’s a phenomenal PR stunt, but it’s not actually feasible. Assuming a theoretically perfect single crystal of nested fullerene carbon nanotubes, at 300GPA tensile strength, and density of 2g/cm^3. (The strongest ever observed is only 60GPA.)
That corresponds to a weight limit of 300e9/1e4/10/1000 = 3000 tonne/cm^2 at ground level. (In comparison, 3000tonne is 1/100 the eight of WTC1.) That’s incredibly strong, but the thing needs to hold it’s own weight out to geosynchronous orbit, at 24000km. The weight of a 1cm cable, 1km long is 200kg. So the thickness of the strand needs to double every 60km, out to a radius of where the gravity is significantly offset by distance and velocity. (The actual calculation is a fairly tricky integral. Fortunately, the answer is in Wikipedia.) The result at geosynchronous orbit is 22000cm^2, or 2.2 square meters. Not bad! Unfortunately, the building ways 100x more than our initial area can hold, so the actual area at geosynchronous orbit is 220 square meters, a cable roughly 16m thick, and 18,000,000m long. That’s something like 20 megatons of carbon. Wikipedia estimates the cost of building a space elevator–with only 12,000kg capacity–to be around $10 billion–and that’s optimistic, neglecting R&D costs. This thing is 50x bigger, and even more optimistic (assuming perfect cable and no engineering safety factor.) And if the thing ever fell to earth, it would do more damage than 100 HBombs.
TL;DR
No one is going to build a quarter trillion dollar building. But they might build a space elevator some day.
Good heaves, Pete. Math and physics rains all over the coolest ideas.
Well, then, I’ll hope for a space elevator.
I particularly like the parachuting to the ground option.
I do hope a good SF writer decides to make use of the idea.