Nothing is more real than nothing
Samuel Beckett (1951)
Hi all,
what a great discussion and subject this is. Thumbs up to all contributors. I will try to shed my light on it and hopefully spark (unscientific pun intended) the discussion up again.
I started off reading the discussion on lux' and Heiwa's critical side to Boethius' attempts to convince the audience of his points. But, I have to say (and throw away another
myth of mankind), he is right.
The crucial part is the quote above.
Space is not only a vacuum (the pressure discussion for the past 31 interesting and great pages), it is also absolutely stone cold. There's nothing.
Both P (pressure) and T (temperature) are nearly zero. At least, that's what most of the sciences agree upon, hopefully also the science unspoiled by NASA.
The ideal gas law P * V = n * R * T describes the key factors.
P = almost 0
T = almost 0
R = non existent (no gases in a vaccuum, only solids with such low T)
V = almost infinite (floating molecules into space)
n = ?
Boethius is right the rocket will not bring any thrust as there is no pressure law possible.
The comparison of simon on the water-powered funicular is great. The thrust produced by water in air is comparable to the thrust of hot air (rocket fuel) in a vacuum. It simply doesn't produce thrust.
But the Temperature is far more important. Remembering basic physics and chemistry in secondary education I recall that "molecules hardly move at near-zero temperatures".
Even if solar radiation causes temperatures to be higher on anything up there (a rocket, etc.) so on the sun-faced side of spacecraft and that heat can be transferred via conduction outside (the metal can) and convected inside (the pressurized cabin), there will always be a "shadow" side.
Material properties depend on temperature and at these extremely incredibly low temperatures everything becomes a solid and must become enormously fragile and break up in individual molecules.
As Boethius described the behaviour of the escaping "gas", like that is the interaction with the whole "solid" spacecraft with near-zero space as well.
What would happen?
- Assuming the rocket gets enough thrust (E) and acceleration (a) to withstand Earth's gravity (g)
- The rocket would reach lower and lower temperatures the higher it goes ( P -> 0, T -> 0, rho -> 0)
- I do not know the temperature profile of the supra-atmospheric region, but with less and less air particles (rho), less and less heat (E, T) can be trapped
- There has to be a limit as to where the rocket can travel based on both Temperature (material behaviour) and Pressure (thrust)
- From there, and where this line actually is would be something to investigate, the rocket would simply fall back to Earth as there is no thrust to be produced to withstand the gravity
Even if the thrust would be no problem, at a certain temperature level everything desintegrates. It will break down in molecules, "floating" away in
the vast nothingness of space.
And that is without counting the most enormous all-destructive types of radiation (E, lots of E) in space. If we don't know even 1% of
our own oceans, how can we think we understand space? We have no way of going there and measuring which other kinds of unimaginable radiation is out there.
This makes space travel impossible and life on Earth comfortable. No alien could ever visit us in that ridiculous Star Trek spacecraft.
This is my thesis, and I realise I did not supply any links to the various points, but most of them are discussed in the previous pages anyway. Later on I will try to build the case better, but for now, this is my thought.
Selene
I have not the smallest molecule of faith in aerial navigation other than ballooning
William Thompson (Lord Kelvin) (1896)
That just made my day! 
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