JohnD wrote:That video used Carl Sagan's voice, but would he have approved of it's physics content?
1/ Jumping off a high cliff on a low gravity body. Yes, you float down as shown. But gravity is gravity and mass is mass. If your fall was as far as shown, you would still be travelling quite fast at the bottom, with no means of slowing down. Death, from impact or vacuum, unless of course, you had a jet pack.
I don't see a problem here. This form of recreation has been discussed in many places. Given the very low surface gravity of small bodies, it is completely possible to jump from cliffs if they are not too high (a kilometer, perhaps) and still arrive at the bottom with a low enough velocity to land on just your legs. And of course, we don't know what other arresting devices might be provided.
2/ Those blimps, apparently on Mars. Bigger crew/cargo quarters than an Earthbound dirigible, but the envelopes are the same/smaller, in an atmosphere with a density equivalent to the Earth's, 35 kilometers high. They just wouldn't take off, even if 'filled' with vacuum.
There may be some artistic license there, although to be fair, we can't really tell the true size of the blimp, and we don't know anything about the density of the structures hanging off it. It isn't certain that something like that couldn't work on Mars.
3/ And what was that 'star ship on a rail'? At first I though it was on a space elevator built from the Moon - good idea! Less garvity to start with, but it morphed into something in deep space.
It is a space elevator. I think you're confusing what was at the bottom- a lit up lunar base- with deep space.
Wanderers
