Google X were planning on building a space elevator, but they scrapped the idea because they realised that even they were punching above their weight on this one. Google X decided that carbon nanotubes would be their mode of construction, but no one in the world can build them to anymore than a metre in length at the moment. So they decided to sit back and wait it out.
After reading a bit about space elevators it’s easy to think to yourself “oh… yeah, I guess so…. just build a really long, lightweight, tough tower and it can get up to the satellites, yeah OK, I can picture that”. But when you consider the distances involved, the idea slips solidly back into the fantasy category in your brain next to your super star DJ career. These scientists are talking about 36,000 kilometres of elevator shaft, that’s some trip. 36,000 km isn’t far off the circumference of earth. Imagine building a thin tube that went all the way round earth. Imagine it. Go on. Pretty nuts ain’t it?
The physics involved, as you can imagine, gets pretty dense. Things like this…
![\Delta\left[ \ln (S)\right]{}_{r_1}^{r_0} = \rho/\sigma \cdot \Delta\left[ G \cdot M/r + \omega^2 \cdot r^2/2 \right]{}_{r_1}^{r_0}](https://upload.wikimedia.org/math/b/a/1/ba1dae2ce3c700fe78b53404d2aefea3.png)
,
…and also some of this…
![\Delta\left[ \ln (S)\right] = \rho/\sigma \cdot g_0 \cdot r_0 \cdot ( 1 + x/2 - 3/2 \cdot x^{1/3} )](https://upload.wikimedia.org/math/6/3/7/63768d5eb7a064a9c5a773031dab6ecc.png)
, where 
So… none the wiser? Me neither.
One interesting thing that I could understand about the physics is the gravity vs centrifugal force wrestling match. The parts of the space elevator cable closest to earth will be constantly pulled down thanks to our old pal gravity; the other end of the cable, however, will be constantly pulled outwards because of centrifugal force, like the pulling you experience when you’re on a roundabout down the park. So these two competing forces should, in theory, counteract each other so that it stays put, hovering in mid-air.
Of course, despite not having even nearly made one of these space elevators scientists are already thinking about building them on other planets. Because Mars’ stationary orbit is lower than earth’s and the gravity less strong, we already have the materials needed to build such a thing. We just have to get all the construction workers to Mars first which may be a minor difficulty.
In the far-flung future perhaps we’ll all be able to zip-wire our way to a mini-break on Neptune or get married on one of Jupiter’s less inhospitable moons. But I for one will be sticking firmly with Bognor, there are less blood-thirsty aliens to contend with there. As with most futuristic, forward thinking technology it all comes down to cash. If humans arse it up big time with a massive nuclear disaster maybe we’ll all have to club together to get off this god forsaken rock.
