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Background Briefing for Students



This exercise is designed to teach you about the Earth's place in space,
and how it affects conditions on Earth. It is also designed as a social
mixer: you will be spending a lot of time together, often working in
groups: this will give you a chance to meet your classmates.

Educational theory shows that people learn best not by sitting quietly and
listening, but by actively doing things and thinking subjects through for
themselves. In this exercise, you will have to work out the Earth's place
in space for yourself! It took the ancient astronomers five thousand years
to do this: you have one hour. But on the other hand, you have an unfair
advantage: you know the answers!
I'd like you to imagine that you are aliens, living in the city of Mog, on
a strange and distant world that just happens to be just like the Earth.
Except for one thing: on the world of Mog, the weather is always cloudy:
and I mean always: the clouds have never broken in all of history (just
like on Venus). The inhabitants of Mog have never seen the sky. You have a
quite advanced technology, but know nothing of astronomy. The city of Mog
stands in the centre of a vast, perfectly flat plain.
So what do you know about your world? It is obviously flat (the concept of
a spherical world came from astronomy). Every day, the clouds start to
glow, and the temperature rises. About 12 hours later, the clouds stop
glowing: night falls. On Earth we always associate day and night with
movement, as we see the sun crossing the sky: in Mog, this idea would never
occur to them. They believe that the Great God has a light switch, which
she switches off and on to make day and night. When the switch is on, the
clouds are lit up from the other side, or start to glow in some mysterious
fashion.
You have no conception of North, South, East or West, as that comes from
astronomy. You do have seasons: during summer the day lasts longer than
during the winter. Presumably the Great God just leaves the light of the
sky switched on for longer.

You should divide yourselves up into groups of three: introduce yourself to
your group partners if you don't already know them. One person from each
group should then come down to the front and pick up a briefing paper for
your group.
I'd like you to pretend that you are a conference of maverick Mog
scientists, gathered together to discuss some strange new evidence that may
overturn this commonsense view of your world. It will be hard: you'll need
a cast iron case to persuade people that everything they've believed for
millennia is wrong. Furthermore, you have to persuade the inquisition to
let your heresy pass unpunished.
You should start off by reading your own group's briefing paper. Try and
figure out an explanation for its puzzle. Think about what other evidence
might support your theories. Then go out and exchange information with the
other groups. None of you have anything like enough information by
yourselves: you'll have to combine all your knowledge to come up with a
compelling story.


Explorers


You are intrepid explorers: the most successful that Mog has ever known.
For months or years at a time, you have ventured far out across the endless
plains, leaving all settlement far behind, living off a monotonous diet of
wurtleberries and snarks. You have discovered hitherto unknown rivers,
oceans, mountains and forests, and many plants and animals unknown to
science. But your strangest discovery concerns none of these.
Two summers ago, you were exploring far from home, in the direction
opposite to the Mountains of Ming. You had traveled for many months to get
there. One summer's evening, relaxing beside your campfire while toasting
strips of snark-skin, you noticed that night came remarkably late. And
morning came remarkably early: you hardly had time to sleep! In mid-summer
in Mog, the Great God turns the lights of heaven off about 7pm: he always
has, and everyone knows that he always will. But on that remarkable day,
darkness started around 8pm.
At first, you suspected that your clocks were fast. After all, clocks are
delicate and bulky things, which do not travel well: all those pendulums
make them very inconvenient and cantankerous. But dawn arrived at 4am; an
hour earlier that it is supposed to in mid summer. Furthermore, both the
clocks in your party agreed very accurately with each other. When you
returned home, your clocks were in agreement with the great clocks of the
national academy.
You stayed at that campsite for a week, checking this extraordinary result.
Every day started an hour early and ended an hour late. Had the great God
decided to light up the whole world for longer in summer? You hurried home
to Mog to find out. But strangely, when you reached home, nobody had
noticed anything unusual. Back here in Mog, the length of the day had been
exactly normal, throughout the summer.
Your discovery created a sensation in scientific circles! How could the
Great God light up some parts of the world longer than other parts? That
would have to mean that she uses different lights to light up different
parts of the world! If true, this would be of fundamental importance to
theology. But it all seems pretty improbable: it would be so much simpler
if there were only one light for the whole world.
Most scientists seem to think that you've stuffed up your measurements
somehow. Perhaps, they say, you were drunk, mad from loneliness, or perhaps
this is all a practical joke. A party of rival explorers set out last year
to test your result, and reported that the length of the day at your
campsite in mid spring was exactly normal for the time of year. They've
been laughing at you ever since they came back. The government has cut off
your funding, research students avoid you, and you are all working in the
local supermarket to make ends meet.
But you are still convinced that your observations were correct. The day
was longer down there. You don't understand it, you cannot explain it, but
it was true. That's why you've come to this meeting: perhaps the other
people's experiences will help make sense of yours.

Telegraph Engineers


You are telegraph engineers: for years now you have been building a network
of telegraphs, linking Mog to its surrounding cities. You are practical, no-
nonsense people, with a firm commitment to the bottom line! You don't waste
your time worrying about obscure, impractical issues of theology: you leave
that to the priests. Until now, that is.
You have recently completed the greatest piece of telegraph engineering
that the world of Mog has ever seen: a telegraph linking Mog to the
incredibly distant seaside city of Zing. No other telegraph line in the
world extends one tenth so far: it is at least fifty day's ride to get to
Zing.
The grand opening was scheduled for three hours after dawn. The high
priestess of Mog was scheduled to send a blessing to the loyal citizens of
Zing. Excitement was so great that crowds started to gather around the
telegraph station in Zing at dawn. As the time of the great ceremony
approached, the gathering crowd was surprised by a strange loud tapping
noise coming from the telegraph station. You rushed inside, and were
dumbfounded to see the telegraph tapping out the message from the high
priestess: half an hour early!
What had gone wrong? As signals passed up and down the telegraph, it turned
out that the priestess thought she was on time: she'd sent the signal
exactly three hours after dawn. The people of Zing were also correct: the
signal did arrive in Zing only two and a half hours after dawn. You double-
and triple-checked: every signal from Mog seemed to arrive in Zing half an
hour before it was sent! Likewise, signals from Zing arrived in Mog half an
hour late.
How could this bizarre stuff-up be explained to your superiors? Your
company scientists admitted that the physics of telegraph wires was a new
field and poorly understood: they suspect that some hitherto unsuspected
effect makes signals travel forward or backwards in time on long telegraph
lines. They are trying to raise the money from the Mog Research Council
(MRC) to build some more enormously long telegraph lines to test this
theory.
Some maverick scientists and philosophers, however, have come up with a
much more radical theory. They feel that telegraph signals that travel
through time is a pretty far-fetched explanation, and one that could lead
to all sorts of paradoxes. These radicals note that, throughout the world,
people set their clocks by dawn and dusk. Perhaps, they hypothesised, dawn
and dusk occur half an hour later in Zing! Pretty extreme heretical stuff
this: to say that the great god switches the light in the sky on and off at
different times in different places. This must mean that there are many
lights in the sky, not just one.
You don't know what to believe. You'd rather just get back to earning a
steady wage building telegraph lines. But this mystery keeps preying on
your minds: that's why you are here at this conference full of weirdo
heretics. Perhaps together, you can work out what is going on.



Smuggler's Guild


You shouldn't admit this to anyone else here, but you are smugglers. You
grow the highly illegal mung-mung berries in your remote and secret camps
high up in the mountains of Ming, and then smuggle them into Mog to sell to
decadent nobles (mung-mung berry juice is an extremely potent aphrodisiac).
This is a very lucrative trade, and you all live lives of great wealth and
comfort (between smuggling expeditions).
Unfortunately (since a certain unfortunate practical joke involving spiking
the Chief Inquisitor's milk with mung-mung berry juice just before the
annual parade), the army are cracking down on smuggling. Every night, a
huge patrol of soldiers marches out of one of the city's four gates and
sets an ambush for any approaching smugglers.
What you need is some way to warn approaching smugglers of which gate the
soldiers are guarding. You tried waving lamps from the city towers but the
guards always saw your lamp wavers and arrested them.
Luckily, your research department came up with something very sneaky. It is
a powerful lamp, connected to an amazing set of huge lenses, which focus
the light into an incredibly tight beam. This beam of light is only one
centimetre wide: nobody outside the beam can see anything! The lamp is set
up just above eye level (3 metres high) in an old house outside the walls,
beaming the tight beam of light towards the waiting smugglers. The soldiers
walk under the beam without ever knowing it is there. The smugglers,
however, carry a mirror on top of a 3 metre pole: by placing the mirror in
the beam they can reflect the light down to their eyes and read signals.
Unfortunately, after months of successful use, the system nearly failed
last month. Due to increased army patrols, the smugglers were much further
away from the city than usual when they tried to read the signal, but they
couldn't find the beam of light. Eventually, you discovered that the beam
was still there, but three centimetres high (ie. 3.03 metres above the dead-
flat plain). At first, you through that the beam wasn't quite horizontal,
but exhaustive tests showed that it was exactly horizontal. Why then was
the beam high? Several nights of test showed a curious fact: the further
you went from the city, the higher the beam went.
Near the city, it was exactly 3 metres high, but as you went further and
further away it got higher and higher off the ground. By the time you could
barely see the highest towers of the city, the beam was nearly 10 metres
off the ground! This seems to happen whichever direction you point you
special lamp.
Being curious people, with inquiring minds, you decided to come along to
this meeting to try and see if this strange fact could be explained. You
have two possible ideas. Perhaps something in the air makes light curve
slightly upwards. Alternatively, perhaps the great plain around Mog isn't
really flat, but Mog is on a very slight hill. However, this seems hard to
believe: during wet weather the plain around Mog becomes a huge swamp, but
the water doesn't flow away from the city (it just sits around until it
evaporates).



Commercial Scientists


You all work for the research division of an enormous trading company. You
work on tight deadlines to solve practical problems for the company: over
the years, the research division has been responsible for doubling the
company's profits. You are very popular with the shareholders!
Recently, the sales manager came to you with a curious problem. She was
involved in selling selenium, an incredibly expensive and valuable metal
used in medicines for acne. In the selenium trade, it is vitally important
to weigh out them metal accurately: if you sell even a microgram too much
or too little, the cost can be horrendous. Selenium traders use by far the
most accurate scales ever constructed to weigh out the metal.
This sales manager had noticed that the scales seemed to work differently
in different places. Scales that worked perfectly in Mog gave measurements
slightly too low when trading with the cave-dwelling Zingars. When trading
with the selenium miners of Wang, the scales seemed to give measurements
slightly too high.
This problem was first brought to your attention five years ago, and you
have spent a fortune trying to fix it. At first, you thought that changes
in temperature might be causing the problem, but even when measurements
were made at the same temperatures, the tiny differences persisted. Then
you worried about the effects of wind or humidity, but even when you
suspended the scales in a vacuum, the differences persisted.
In the end, you have been forced towards a radical conclusion: the weight
of the selenium (and of any other substance you tried) changes from place
to place! When you are underground, objects weigh less. When you are on the
surface at Wang, objects weigh more. You've now traveled all over,
measuring how much things weigh, and you've come up with a startling
conclusion. Heavy objects seem to attract your scales. When you are in the
mines, all the rock over your heads seems to pull the scales upwards,
partially counteracting the weight of the metal. At Wang, all the heavy
metals in the rocks below you seem to suck you scales downwards even harder
than usual.
This mysterious effect even seems to work sideways. You've taken your most
sensitive instruments close to the great mountain wall of the Ming Massif,
and the huge volume of rock seemed to pull your scales sideways, towards
it.
What is this mysterious force that seems to suck objects towards large,
heavy objects? Could it have anything to do with the other mysteries to be
discussed at this conference? That's what you've come here to decide.



Clock Makers


You are craftspeople: heirs to a ten thousand-year tradition of fine clock-
building in Mog. Each of you spent long years of slave labour during your
apprenticeships before reaching the status of master clock-makers. Each of
you is internationally famous for the precision and beauty of the clocks
you have made, and each of you has large groups of poor overworked
apprentices slaving for you.
Five years ago, you decided to work together to try to build the ultimate
clock: one more accurate than ever seen before. You goal was to achieve the
fantastic accuracy of one minute per year!
You achieved your goal last year. Your `magno-temporimetre' is the marvel
of the age and sits in a special room in the Queen's Palace. People come
from all parts of the world to marvel at its fine construction and
intricate workings.
Clocks are normally set by dawn and dusk every day: yours is the first
clock accurate enough not to need this. Indeed, you have been measuring the
time of dawn and dusk every day for the last year, both to check the
accuracy of your clock and to settle an age-old theological debate.
The debate is this: everybody knows that the Great God turns the light of
the sky on for longer in summer and shorter in winter. However, over the
year as a whole, is the total amount of daylight (the time for which the
light of the sky is on) greater or less than the total amount of darkness?
Orthodoxy says that light must always defeat darkness, but certain
scurrilous heretics maintain that the period of darkness is actually
greater.
You can now answer this age-old problem: it turns out that, averaged over
the year, the periods of day and night are exactly equal! The longer days
of summer exactly cancel out the longer nights of winter. Wonderful are the
ways of the Great God!
If this wasn't enough of a theological conundrum, you discovered another
amazing fact. You measured the times of dawn and dusk precisely. Half way
between these times is mid-day. Remarkably, the interval between one midday
and the next is always exactly the same, year round. The times of dawn and
dusk may change with the seasons, but mid-day (and mid-night) are
incredibly regular and unvarying throughout the seasons.
Your discoveries have triggered furious theological debate (and several
executions by the inquisition). Why does the Great God switch on and off
the light of the sky in this precise way? Surely, there is some important
moral message for the Great God's humble worshipers in all this.
That's why you've come to this conference: to see if they can help you
understand these strange patterns. However, looking at all the weird,
almost heretical people around you, you are beginning to think that you may
have made a mistake!



Central Bank Officials


You work for the Mog Treasury, in the anti-forgery office. The population
of Mog is full of disgustingly dishonest people, many of whom try and make
their evil living by forging banknotes. Your job is to stop them.
It is a hard job. Every time you come up with some new and clever way of
detecting forgeries, the criminal scum improve their forgeries! You've
tried making the patterns on the notes more complex but to no avail: they
soon copy your best efforts.
But now you reckon you have the forgers licked. You've invented a marvelous
device which you call a 'Photometer': a machine that measures precisely how
much light falls on its glass eye. You shine a beam of light at the
Photometer and measure precisely how bright it is. You then put a banknote
over the glass eye. If 22% of the light still gets through, you know the
note is genuine. The forgeries use different papers and different inks:
some of them let more light through and some let less, but they almost
never let exactly the right amount (22%) through.
Your invention has been a brilliant success and has led to the arrest of
nearly thirty forgers (including two senior public servants from your
office.). But that isn't why you are here at this strange conference today.
During your spare time, you have been pointing the glass eye of your
photometer at the eternally cloudy sky. Religious orthodoxy states that
once the Great God has switched on the light in the sky, it is always the
same brightness, throughout the day, and throughout the seasons.
Your photometer tells a different story. The sky starts off pretty dim at
dawn, but rapidly increases in brightness. It is at its brightest precisely
in the middle of the day, before gradually fading towards dusk. The
brightness two hours before mid-day is always exactly the same as the
brightness two hours after mid-day. Furthermore, its mid-day brightness is
brighter in summer than in winter: it is at its brightest in the middle of
the longest day and its dimmest in the middle of the shortest day.
This is radical, provocative stuff. Does the Great God have a dimmer
switch? Why doesn't the Great God simply switch the light of the sky on and
off: why this complicated pattern of dimming and brightening? The pattern
seems curiously regular: why does the brightness correlate so strongly with
the time of day and with the length of the day?
You've heard that some other scientists at this conference today have
discovered other curious things about day and night: other curious patterns
and regularities. Perhaps together you can figure out what is going on!



The Inquisition


You belong to the Moggish inquisition. You don't go around burning people
(unless you have to) - that is all a gross libel by your enemies. Your job
is to make sure that all these mad scientists at this conference don't get
too divorced from common sense. If they are saying something radical, try
and show them the error in their ways. Point out the other possible
interpretations of their data. Be respectful: these are important and
intelligent people. But make sure that they keep their feet firmly on the
ground. Defend orthodoxy.

All sensible people believe that the world if flat. You have only to look
out over the vast plains around Mog to see why. If the world was round,
people living on the sides and bottom would fall off. This means that Mog
must be on top. But if it is on top, you will always be going downhill when
you head away from Mog: all rivers should flow away from Mog, which they
certainly do not.

Every day, the clouds that always cover the sky begin to glow. The glow all
day, providing the life-giving light that makes life possible. Then, at
dusk, they stop glowing. Everybody knows that. At this conference, people
will come up with all sorts of complicated explanations for this. But
surely it is very simple. If you are in a dark room, and suddenly there is
light, it means that someone has switched the light on. Simple. So if the
world gets light, all of a sudden, that must mean that the Great God
switched the light on. It's only common sense.

Try and stop these mad scientists from coming up with unnecessarily
complicated theories. See if you can explain their data by slightly
modifying the orthodox idea, rather than coming up with some radical
bizarre new theory. Keep them intellectually honest by pointing out the
flaws in their arguments!

You will win this exercise if you can stop people coming up with any
convincing alternatives to the common-sense flat-world theory.



Conference Organisers


You are some of the organisers of this conference. You have brought
together some of the greatest and most unorthodox minds in Mog. You hope
that this conference will explain all the weird facts that have recently
been discovered. You are not experts in the data yourselves. You leave that
to your guests. But your job is to get these experts talking to each other,
to combine their information and to come up with a theory that explains all
the data.
This theory had better be pretty compelling, or you will be laughed at, and
probably burned at the stake by the inquisition. So you had better help
these experts come up with a good theory. Listen in to their discussions.
Discuss what you have learned. Try and bring together groups of experts who
might learn from each other. If you think that someone is going off on the
wrong track, tell them so. Come up with new ideas and try them out on your
guests.
You have invited the following guests to your conference:
. A group of explorers, who found that the length of the day seems
different if you travel far away from Mog
. A group of clock makers, who found that, averaged over the year, the
length of day and night is precisely equal.
. Some telegraph engineers, who discovered that their telegraph seems to
send signals forwards and backwards through time.
. Some people (you are not quite sure what they do) who build powerful
lamps. They find that light seems to curl upwards over long distances.
. Some government scientists, who have discovered that the brightness of
the sky varies from hour to hour and week to week in a curious way
. The makers of the world's most accurate scales, who find that objects
weigh different amounts in different places.
Some of the inquisition will doubtless have sneaked in too. There isn't
much you can do about those negative people except ignoring them.