Документ взят из кэша поисковой машины. Адрес оригинального документа : http://www.mso.anu.edu.au/pfrancis/roleplay/greenhouse.doc Дата изменения: Tue Mar 21 09:07:13 2000 Дата индексирования: Tue Oct 2 04:23:25 2012 Кодировка: Поисковые слова: reflection nebula

Planetary Climate Exercise: Carbon Dioxide Cycle

You are biologists, and your special field of expertise is carbon dioxide
(CO2). Carbon dioxide is vital to all plant growth as it is used in
photosynthesis, and you have been researching where it comes from and where
it goes to.
You have been experimenting with growing exotic fruits near volcanos. All
volcanos emit large amounts of carbon dioxide: the more active, the better.
In the course of an adventure-filled few years, you have perfected fragrant
'Popocatapetl Peaches' from the vast volcanoes of central Mexico, giant
'Kiwi KucumbersTM' from the North Island of New Zealand, and the
hallucinogenic 'Fuji Fungi' from Japan, currently banned in Australia
following some unfortunate incidents at raves in Melbourne. But your
proudest research triumph has been, without a doubt, the prize-winning
'Chateau Vesuvius' 1993 vintage.
In the process of your research, however, you became somewhat perplexed. So
much carbon dioxide is being emitted by the world's volcanoes that you
would expect that the Earth's atmosphere would be much thicker than it is,
and mainly composed on CO2, rather than the nitrogen and oxygen that are
its biggest constituents. Where has all the carbon dioxide emitted by all
the world's volcanoes since the Earth formed gone?
After exhaustive (and exhausting) research, you have discovered that carbon
dioxide is very soluble in water: most of the CO2 produced by volcanoes is
dissolved in the sea. You have taken samples of water from all the world's
oceans: when you boil the samples, the carbon dioxide is released and can
easily be measured. The remainder of the CO2 seems to be in the form of
carbonate rocks such as limestone and marble. This is harder to measure,
but if you heat the rock samples to 200(c, the rocks release their carbon
dioxide and you can measure it. Your next venture involves genetically
engineered coconut palms on carbonate rocks buried by lava on a small
Caribbean island.

Planetary Climate Exercise: Coal Experts

You are a team of top researchers from the Fossil Fuels Institute, funded
by the coal, gas and oil industries. Because of this funding, you have
better labs and more accurate equipment than almost anyone else at this
conference: you drive nicer cars, live in bigger houses, and can
investigate more difficult scientific problems.
You have been doing research on ways to spot bushfires at a very early
stage: long before they are dangerous. If you can do this, many of these
fires can be put out before they hurt anybody.
Many gas pipelines, coal mines and oil fields are in regions threatened by
bushfires: that is why your employers are paying for this research. You
hope, however, that your research will be of great use to many other
people: it could save a lot of people's lives.
Whenever anything gets hot, it emits infra-red radiation. People are quite
hot, for example, and their skin constantly shines with infra-red
radiation: this is how people buried in earthquakes are found and rescued.
Bushfires are hotter still, so they will emit very intense infra-red
radiation.
You plan to use a satellite to scan Australia several times a day with an
infra-red camera. All the bright spots will be potential bushfires.
Unfortunately, there are a few problems. Infra-red radiation penetrates
clouds quite well, so you can see fires all the time. But it doesn't
penetrate water vapour very well: if a fire breaks out in a very humid
region, all the infra-red radiation is absorbed by the water vapour, and
you don't see anything. Infra-red is also blocked by carbon dioxide, so it
is hard to spot bushfires near big power-stations, because of all the
carbon dioxide they emit when burning coal.
Before you left for this conference, your boss called you in to remind you:
you work for the fossil fuel industry, so if you hear of any scientific
results that suggest that fossil fuels are dangerous, try and suppress
these results. If the conference comes up with a result harmful to your
employers, you can kiss your jobs goodbye.

Planetary Climate Exercise: Heat Balance

You work for a top secret government lab, studying space warfare. Indeed,
the lab is so secret that when you retire, all memory of it will be wiped
from your brain, and replaced with fake memories of a life as turnip
farmers.
The big problem in space warfare is not in destroying enemy spacecraft:
your colleages in the laser section down the corridor have got plenty of
ways of doing that. No: the problem is finding the enemy in the first
place, especially if they are in black-painted, radar-absorbing stealthy
spacecraft.
The way you figure it, any spacecraft is going be be receiving lots of
heat. Firstly, any motors, engines, machines, nuclear reactors, laser guns
or cosmonauts on board will generate heat. Secondly, visible light
radiation from the Sun will be constantly hitting the spacecraft, and the
energy from this solar radiation (which is in the form of visible light)
will be absorbed by the object.
If all this heat is being added to an object in space, it will
continuously heat up, unless it can get rid of the heat in some way. On
Earth, a cool breeze or a spray of water could cool it down, but in the
vacuum of space, there is nothing suitable around. The only option for
getting rid of heat energy in space is to radiate it. Luckily, every
object radiates infra-red heat radiation all the time: you are all doing it
as you sit there reading this. So is the conference hall, the grass, trees
and buildings outside.
So: every object in space will have to radiate infra-red radiation. The
hotter it is, the more it will radiate. If it cannot radiate infra-red
radiation, for whatever reason, it will just go on getting hotter and
hotter, until eventually it is so hot that the infra-red radiation leaks
out.
As it happens, you are currently using this knowledge to build infra-red
sensitive cameras. This should enable you to spot most enemy spaceships. If
they don't try and keep the infra-red radiation in, they will stand out
like a sore thumb against the cold darkness of space. If they do try and
bottle up their infra-red radiation, by using lots of insulation, the
spacecraft will just get hotter and hotter until the cosmonauts inside
start frying! But don't tell any of your colleagues too much about this
work: you never know who might be a French spy.

Planetary Climate Exercise: Spectroscopy Experts

You are astronomers, unlike most of the others at this rather strange
conference. In fact, you are experts at one of the most difficult
astronomical problems: measuring the chemical composition of something you
cannot even touch. You point your telescopes at distant objects, and by a
very detailed study of the wavelengths of the light that you see, you can
sometimes determine the chemistry of something far out in space. Strange
but true!
You've recently been turning your telescopes on Venus. The data looked
quite boring at first: the atmosphere was mostly made of lots and lots of
carbon dioxide (CO2), with a few clouds of sulphuric acid droplets to add
variety. When you looked more closely, however, some rather surprising
evidence came to light. You detected absolutely no water on Venus. However,
you do detect some rare isotopes, which are normally found only where water
is present.
How come these isotopes are present, but no water? You suspect that the
water must have escaped from Venus or been destroyed, leaving behind only
these tiny traces of isotopes to show that it was once there. You calculate
that, once upon a time, Venus must have had oceans. But where did they go?
What went wrong?


Planetary Climate Exercise: Atmospheric Transmission

You all grew up downwind from a tannery, and as a result, you have
dedicated your lives to the downfall of companies that pollute the
atmosphere. You spend many of your weekends climbing smokestacks to plant
Greenpeace banners on top, or chaining yourselves to factory railings.
On weekdays, you work for a government research institution, trying to
invent ways of testing the air over factories to see if companies are
breaking anti-pollution laws. The problem is: imagine you suspect that a
company is pumping out noxious chemicals. You could get a warrant and go
and inspect them, but by the time you do all the paperwork, they might have
switched off the offending process. What is needed it a way of seeing what
it in their fumes, from outside the factory gates.
You have figured out a brilliant way of doing this. You set up a bright
light, emitting lots of visible light radiation and infra-red radiation, on
one side of the factory. Then you set up a detector on the other side, and
you see which types of light make it through all the polluted air.
To make this process work, you need to know which pollutants absorb which
types of light. You have spent years shining beams of various sorts of
radiation through test-tubes full of strange gas mixtures. And after years
of dogged work, you have concluded that gasses fall into four distinct
categories.
1. Completely Transparent: Many substances, including Nitrogen, Oxygen,
Ozone, Xenon, Hydrogen and Helium, are transparent to both visible light
radiation and infra-red radiation.
2. Completely Opaque: Some substances, particularly small droplets of
water, of sulphuric acid, and of hydrochloric acid, block both visible
light and infra-red radiation equally.
3. Visible Light Blockers: Any tiny solid particles, such as diesel fumes,
interstellar dust, smoke from burning forests or cities, or tiny dust
grains picked up in dust storms, are rather good at blocking visible
light radiation, but are poor at blocking infra-red radiation.
4. Infra-red Blockers: A variety of molecular gasses, including water
vapor, Methane, and Carbon Dioxide, block infra-red radiation but not
visible light radiation.

So far, you have used this technique to prove that a large local
manufacturer of hot water systems was using illicit methane-based paints to
clean their pipes: infra-red radiation was being severely blocked as it
passed over their factory, while visible light radiation was making it
through unscathed. You are now working on a visible light based sensor to
test that diesel truck engines are correctly tuned up, and not emitting too
many tiny solid particles of incompletely burnt fuel. Unless the truck
companies persuade the government to shut down your research program.

Planetary Climate Exercise: Water Cycle

You are physicists employed by a company that builds water heaters and
showers. You have built up a worldwide reputation for your expertise in the
properties of hot water at different temperatures.
At temperatures of around 20(C, water just sits there. Small amounts of
water vapor evaporate from the surface, but nothing very significant.
Unless you add perfume, that is: perfume evaporates even at 20( C, a
feature that led to the success of your 'smell-good rose-petal
washbasinTM'.
If the temperature rises, more and more water vapor evaporates. The
increase is dramatic: even small increases in temperature can dramatically
increase evaporation rates (think of how much faster your washing dries on
the line when the temperature is 20( C rather than 10( C!). You used this
fact in your hot-air blowing auto-dry towel-free shower: a best-seller in
Japan.
When the temperature rises above 100( C, of course (or slightly higher
temperatures if the pressure is higher than that at sea-level on Earth),
water will boil, and will all turn into vapor. Water vapor is normally
stable: it lasts for ever, as long as the temperature remains high. Unless
it is exposed to strong ultra-violet (UV) light, that is. The one blemish
on your otherwise brilliant research career was the combined Jacuzzi and
sunbed you produced a few years back: as the water vapor steamed off the
surface of the water, the UV light from the tanning lamps (designed to
mimic the healthy rays from the Sun) broke it down into hydrogen and
oxygen. The oxygen would make people euphoric and sleepy, while the
hydrogen built up until any spark (say from the off switch) caused it to
explode. Your company is still recovering from all the lawsuits.