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In lugnet.space, Jesse Alan Long writes:
> You said in the last letter before this letter that some liquids (referring
> to the reaction to friction of certain particles in outer space) are
> viscious while some solids are very hard and smooth in reaction to friction
> in outer space. If liquids boil in outer space, how is this possible in
> outer space? Do you really mean that gases, not liquids, are very viscious
> with the concept of friction in outer space?
I didn't necessarily mean in space. I was just talking about liquids in
general (on Earth, in an atmosphere).
Clearly if you're trying to push your way through something, a gas is easier
than a liquid, which is easier than a solid. But, this isn't all down to
friction. If you run into a brick wall, that's not friction that stops you
- it's mechanics of a structure. You need to break the bonds in the
structure to cut through it, then force the parts apart. Liquids just have
looser bonds, making it easier to force your way through.
Friction comes into play as you start to move through - it's the rubbing of
the sides of your craft against what it's moving past. That may be gas (in
an atmosphere), liquid (underwater), or solid (snow under the skis of a
sled). This is what is referred to as 'surface drag' in aerodynamics -
friction of the air flowing past. The force of running into the air in
front (along with suction from the turbulence behind you) is know as
'pressure drag', and isn't caused by friction between your craft and the air.
> I also must say that if the rumors (forgive my American dialect of the
> English language) are true about Mir and the condensation of water droplets
> on one of the observation windows, then the whole concept of boiling liquids
> in different environments would be held in serious jeopardy and we may have
> to reorganize our thoughts on condensation, the boiling points of liquids,
> and air pressure in outer space and on our planet.
Yup.
> I do not understand why you say that it would be considered a terrible idea
> for me to use plasma as a heated engine and yet you say that it could be
> guided with electromagnetic fields. Would these electromagnetic fields not
> only stabilize the plasma but also make the plasma increase in speed as
> thrust or would the electromagnetic fields only provide a stable environment
> for the plasma or would neither of these possibilities be true for my space
> craft?
Well, you could. This is what is meant by an 'ion drive'. You super-heat
gas into ionised particles (plasma), then accelerate it backwards. It's
just a bit dangerous. I don't know much more than that, but it's feasible.
It just takes a lot of power for both the heating and the electromagnetic
fields. You'd need to carry your own nuclear power source to run it all,
and all the extra shielding increases the weight of your craft. Voyager
uses a very small nuclear power source on the end of one of its long arms,
but you'd need something much bigger. You'd have to take it up in bits and
build it all in space.
> I have two more questions to ask you, Jason. The first question is would
> Newtonian physics contradict or complement the laws of aerodynamics? If
> there are any contradictions or further explanations from these rules,
> please explain them to me, Jason.
No, they're complementary. It's just that neither completely explains
everything, because airflow is always chaotic. No matter how finely you
analyse it, there's always some tiny error creeps in.
There are further explanations, but I took a degree course at Loughborough
University in the UK, and I don't have them all. Maybe if you took the
course two or three times (to cover all the optional modules), then put in
some post-grad studies you'd have all the answers, but I doubt it. Only
joking - however much you study this, there's always something more you
don't know.
> The second question is what would work
> for an antigravity device for space craft, that is what materials and
> options could we use for space craft? I am glad that the long ordeal about
> the eternal space craft ethical war is almost over in Lugnet.
> Jesse Long
I have no idea. There have been a few reports of some obscure research lab
that claimed to have produced reduced gravity, then immediately retracted
their paper on the subject. Apart from that, there's no progress on
anti-gravity so far.
Jason J Railton
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Message has 1 Reply:
 | | Re: Couldn't resist
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| (...) I understand now in my mind that atoms are what makes the structure of all living organisms and the structure of all living organisms depends on the density and class of materials in the constructuion of space craft. It is obbvious to me that (...) (23 years ago, 2-Jul-01, to lugnet.space, lugnet.off-topic.geek)
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Message is in Reply To:
| | Re: Couldn't resist
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| (...) You said in the last letter before this letter that some liquids (referring to the reaction to friction of certain particles in outer space) are viscious while some solids are very hard and smooth in reaction to friction in outer space. If (...) (23 years ago, 29-Jun-01, to lugnet.space, lugnet.off-topic.geek)
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