As for all the "4,000 MPH crash, everyone dies" crowd, what exactly do you think your chances are of surviving a plane crash? Not an emergency landing, an actual crash. Pretty much 0. So how is this worse?
Edit: Also, if an inductive track system (Inductrack
) was used power failure would not be a problem. The capsule would slowly coast down to a slow speed (1-2MPH) then would drop down onto it's wheels. That sounds a lot safer than what happens if an aircraft losses power.
It would be pretty easy to engineer in many fail safes, segmented tunnel sections with pressure seals could help in the event of a depressurised cabin, and of course there would be emergency oxygen masks available too. Incidentally if a plane depressurises you are equally screwed. True it might not be full vacuum, but the pressure is low enough that without an oxygen mask you will be unconscious in minutes, dead soon after.
The acceleration is a non-issue - as many people have pointed out speed != acceleration. Also you would assume that a group of people smart enough to get something like this to work might just work out what kind of acceleration we can stand comfortably.
Keeping the tube sealed would present a bit of an engineering challenge; it is a lot harder to contain a vacuum than positive pressure. You would obviously need vacuum pumps at intervals along the tunnel, and some kind of airlock system at the entry / exit points.
The tube would have to be able to withstand movements in the earth's surface, thermal expansion and contraction and so on. Also designing the tube for external pressure is tricky, the tube will need to be a lot stronger than if it were pressurised. The cabin will be fine, it is essentially pressurised.
Not impossible to design, just very hard.
Originally Posted by Phaedrus2129
@Everyone: I find OCN's lack of physics education disturbing.
You and me both.Edited by GingerJohn - 5/24/12 at 8:17am