On Feb 1, 4:53 pm, mad_casual <ademloo...@gmail.com> wrote:
> On Feb 1, 10:16 am, Cathal Garvey <cathalgar...@gmail.com> wrote:
>
> > Work can only be extracted from a gradient of energy, not merely energy
> > itself.
>
> ...in a closed system using only chemistry. Terraforming another
> planet is about as open and 'not strictly chemical' as any of our
> systems currently get.
I don't understand the context of this statement, though if you aren't
using nuclear transformation you are most definitely using strictly
chemical transformations to terraform (aside perhaps from physical
transformation - moving materials from another source).
> I realize we're talking about simple astrophysics, but I appreciate
> the advanced thermodynamics lesson. You're taking the issue out of
> context. If I wired a radio beacon to a wind turbine and set one on
> the surface of Mars and floated the other on the atmosphere of Venus,
> which one would I get more broadcasts from more frequently? Sure,
> you'd have to engineer a balloon(ish) device to keep it afloat, but
> that's easier than making it 90X more sensitive to "wind". Considering
> we did the former and have yet to perform the latter...
I would hope the balloon is anchored, as it wouldn't do much floating
in the air - and for that matter it would be wiser to just make it on
the ground as a windmill on a balloon will still suffer during changes
of wind direction based on the distance it is able to travel before
getting anchored again.
> Once again, taking the systems under question out of context (liquid
> water, hah!). If I have a cold glass with a sliver of ice at the
> bottom and a 700 degree crock pot with 10X the amount of water in the
> form of steam, which system has more potential energy to yield?
If taken alone, the 10x volume would have more in a nuclear sense -
they are both equally nothing in a thermodynamic sense unless you can
mix them, in which case they are both limited by the smaller volume
(since they are the same substance).
> Think of it in more complex and less 'already solved' (maybe biased)
> terms; you're in a -20 freezer with a jacket on, 4 liters of liquid
> water, and a plant you want to keep alive. At the far end of the
> freezer is an LED-like lamp that produces plenty of broad spectrum
> light but doesn't heat the room appreciably. About 2/3 of the way
> between you and the LED lamp is a solar panel/oven device that stays
> at 700 degrees with a small pot of boiling water on top. About as far
> from from you as you are from the heater is a mostly frozen glass
> that's less than 1/3 full of water. Survive as long as you can. To me,
> the answer is figure out how to regulate the heater, the plant, and
> your own metabolism to last until the "LED lamp" goes out and ignore
> the frozen glass of water.
That's not more a more complex set of terms - the only energy to be
extracted exists by moving material between the heat and cold
sources. For example, in your previous suggestion of using the
surface of the planet as the cold spot (assuming that it isn't already
heated heavily, which is unlikely) - there is a reason we can use
underground pipes of hot/cold water for heating and cooling homes and
why basements stay cold in the summer and warm in the winter - the
Earth makes a very good insulator, as do most uneven mixtures of solid
materials - if it were different we would be boiled in lava or there
would be no molten core to the Earth. In the case of Venus, radiating
the heat into space is likely the only option. Venus does have an
extremely slow rotation (over a hundred earth days to a day) - so
hugging the hot/cold area would likely be the only meaningful way to
extract energy without enormous reservoirs to store it and control the
release at approximately 50% of the total change happening naturally
(assuming zero losses and accounting for the differences in
temperature at different parts of the day-night cycle following a
sinusoidal pattern). Ultimately following the horizon would be energy-
intensive in itself, and even to utilize it as wind you would need to
chase it, root your position until the wind stops, then catch back up,
or make a power grid circling the equator and only actually attain
power from a portion of it at a time (still needing to be rooted to
the ground to turn the windmills). And frankly, if it requires
thinking in terms that don't make sense so as to confuse yourself in
such a manner that you can't understand the implications, it doesn't
make them solvable, just that your bong is probably empty.
> When we're talking about interplanetary travel, what's the difference?
> Are you as surprised as I am by alien invasion movies where the aliens
> travel across the Universe only to get their asses handed to them by
> humans who have "mastered" flight? Aliens couldn't be that stupid,
> right?
Changing subjects doesn't change the underlying principles that govern
both. If you don't have a gradient you can't extract the energy
because it is for all intents and purposes, just potential energy.
Personally I believe a focus on developing nuclear technologies will
yield better results than trying to harness anything chemical or
physical in nature, as there is an incredible amount of energy
condensed in any bit of matter that if unleashed in full could heat
and instill a gradient between itself and the surrounding matter -
being able to "burn" dirt or any other matter into electromagnetic
waves would be the apex of energy generation that is likely to arise
from current foreseeable technological trends. In the long term, if
we become nomadic aliens to foreign worlds, it will likely be for the
purpose of attaining matter to burn in such a manner - unless we
figure out how to condense it from background radiation in a less
cumbersome way - but beyond that I can't see how the alien invasion
comment even remotely plays into the thread. On a separate note
though, if you want a good story about stupid aliens, check out The
Gods Themselves.
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