Heiwa wrote: But apart from that rocketry actually works in vacuum.
Dear Heiwa,
Apart from that part (which we may just agree to disagree about), it seems we're all pretty much in agreement: rockets simply cannot work in space - and certainly cannot perform the way NASA portrays it.
How droll. Here we are, seemingly entertaining a heated debate - while we're all cool and syntonized as to the fundamental implications of it: NO space travel is possible. It's a bit like a reverse situation of those funny scientists in "A Trip To The Moon" (1902) who first quarreled vigorously with each other - only to eventually nicely collaborate to build their successful, moonbound spaceship...
https://www.youtube.com/watch?v=ku8Cs-ux4UQ
Although we may never be able, for obvious reasons, to collaborate towards building our own spaceship to test our diverging views (as to exactly
why it would not work), I find our debate worthwhile and interesting nonetheless. So let me just summarize in a few paragraphs what, in my view, constitute the primary hurdles for mankind to propel a rocket beyond our atmosphere or, if you will, into the vacuum of space. This will also serve as a response to Hoi's last post - and as a wide tip of my hat to Boethius for having greatly helped my understanding of the problems / physics involved.
- A rocket rising through the atmosphere will nicely proceed upwards in its escape from gravity - as long as certain conditions are maintained: the relative pressures at the rocket's nozzle and the outside atmosphere need to be as equal as possible, in order to obtain maximum 'mileage' / efficiency from the rocket's fuel.
- In fact, NASA clearly states that the
optimal running conditions of their rockets occur only ONCE, at a certain unspecified (mid-range) altitude, when the above-mentioned pressures are identical. This, in perfect accordance with Newton's 3d law - what with its notion of "equal and opposite forces". Clearly, these rockets are designed to work best in our earthly atmosphere - and the atmospheric pressure
IS in fact "the equal and opposite force" which the rocket thrust pushes against. To deny this fact is pure, outlandish and deceptive NASA hogwash-babble. Ironically, it is
NASA itself that claims that their rockets work BEST when those two pressures are equal !
- Aerodynamic drag will of course be a factor in the equation, yet only a minor one - given the pencil-shaped, streamlined vessel. As the atmosphere pressure thins out with altitude, some more speed will probably be gained (out of a given power output) - but this fact would, obviously, have no incidence whatsoever in alleviating the forces needed for the weight of the rocket to escape the pull of gravity.
- Now, as we have previously seen, the atmospheric density range which our spacebound rocket is supposed to operate in, spans from a pressure of 0,001 (the average air density in our atmosphere) to a staggeringly inferior pressure of 0,000000000000000000000001 (the density of space vacuum). Thus, as the rocket climbs ever higher, it will have to
exponentially increase its output/thrust (and, of course, its fuel consumption), in order to keep going - and combating the pull of gravity which, contrary to public belief, does NOT decrease exponentially with altitude.
- The rocket (at a given, high altitude which I cannot pretend to calculate precisely) will eventually be overpowered by the force of the exponentially decreasing outside pressure, its fuel being sucked out into the infinite 'vacuum of space' at stratospheric rate/speed - and faster than you can say
"Houston-we-have-a-prob...---". Much like a champagne bottle popping its cork here on Earth (due to a minimal pressure difference), the rocket fuel will flush out with explosive force. Moreover, this force will expand in ALL directions (a bit like the diffused spray of your garden waterhose nozzle set on 'broad, soft mode') and provide little or no thrust. The rocket, from there on, will be doomed - and plunge back to Earth.
And for those willing to argue that NASA may have found a way to 'pinch' their rocket nozzles, so that the fuel doesn't get sucked out in a flash : well, you can always open a champagne bottle with great care, making the force inside it fizzle slowly out in the atmosphere. But such a subdued, impotent fizzle would hardly provide the necessary energy to propel a rocket away from Earth's gravity, would it?
Only a pinched fart would produce the same amount of 'power'(odor-power, in this case) as a vigorously expelled bowel-gas sample. We all know
that much!
): 