The Dark Town That Built a Giant Mirror to Deflect The
Sun
- By Linda Geddes
- From Mosaic
14 March
2017
The
inhabitants of Rjukan in southern Norway have a complex relationship with the
Sun. “More than other places I’ve lived, they like to talk about the Sun: when
it’s coming back, if it’s a long time since they’ve seen the Sun,” says artist
Martin Andersen. “They’re a little obsessed with it.” Possibly, he speculates,
it’s because for approximately half the year, you can see the sunlight shining high up on
the north wall of the valley: “It is very close, but you can’t touch it,” he
says. As autumn wears on, the light moves higher up the wall each day, like a
calendar marking off the dates to the winter solstice. And then as January,
February and March progress, the sunlight slowly starts to inch its way back
down again.
Rjukan was
built between 1905 and 1916, after an entrepreneur called Sam Eyde bought the
local waterfall (known as the smoking waterfall) and constructed a
hydroelectric power plant there. Factories producing artificial fertiliser
followed. But the managers of these factories worried that their staff weren’t
getting enough Sun – and eventually they constructed a cable car in order to give them
access to it.
When Martin
moved to Rjukan in August 2002, he was simply looking for a temporary place to
settle with his young family that was close to his parents’ house and where he
could earn some money. He was drawn to the three-dimensionality of the place: a
town of 3,000, in the cleft between two towering mountains – the first
seriously high ground you reach as you travel west of Oslo.
Rjukan sits
at the base of a valley in in southern Norway (Credit: Olav Gjerstad/Flickr/CC
BY 2.0)
I felt it
very physically; I didn’t want to be in the shade – Martin Andersen
But the
departing Sun left Martin feeling gloomy and lethargic. It still rose and set
each day, and provided some daylight – unlike in the far north of Norway, where
it is dark for months at a time – but the Sun never climbed high enough for the
people of Rjukan to actually see it or feel its warming rays directly on their
skin.
As summer
turned to autumn, Martin found himself pushing his two-year-old daughter’s
buggy further and further down the valley each day, chasing the vanishing
sunlight. “I felt it very physically; I didn’t want to be in the shade,” says
Martin, who runs a vintage shop in Rjukan town centre. If only someone could
find a way of reflecting some sunlight down into the town, he thought. Most
people living at temperate latitudes will be familiar with Martin’s sense of
dismay at autumn’s dwindling light. Few would have been driven to build giant
mirrors above their town to fix it.
Dark place
What is it
about the flat, gloomy greyness of winter that seems to penetrate our skin and
dampen our spirits, at least at higher latitudes? The idea that our physical
and mental health varies with the seasons and sunlight goes back a long way.
The Yellow Emperor’s Classic of Medicine, a treatise on health and disease
that’s estimated to have been written in around 300 BCE, describes how the
seasons affect all living things. It suggests that during winter – a time of
conservation and storage – one should “retire early and get up with the
sunrise... Desires and mental activity should be kept quiet and subdued, as if
keeping a happy secret.” And in his Treatise on Insanity, published in 1806,
the French physician Philippe Pinel noted a mental deterioration in some of his
psychiatric patients “when the cold weather of December and January set in”.
Why should darker months trigger this tiredness and low mood in
so many people?
Today, this
mild form of malaise is often called the winter blues. And for a minority of
people who suffer from seasonal affective disorder (SAD), winter is quite
literally depressing. First described in the 1980s, the syndrome is
characterised by recurrent depressions that occur annually at the same time
each year.
Even healthy
people who have no seasonal problems seem to experience this low-amplitude
change over the year, with worse mood and energy during autumn and winter and
an improvement in spring and summer.
The light
shines on the town square but not the rest of Rjukan (Credit: Getty Images)
Why should
darker months trigger this tiredness and low mood in so many people? There are
several theories, none of them definitive, but most relate to the circadian
clock. One idea is that some people’s eyes are less sensitive to light, so once
light levels fall below a certain threshold, they struggle to synchronise their
circadian clock with the outside world. Another is that some people produce
more of a hormone called melatonin during winter than in summer.
However, the
leading theory is the ‘phase-shift hypothesis’: the idea that shortened days
cause the timing of our circadian rhythms to fall out of sync with the actual
time of day, because of a delay in therelease of melatonin. Levels of this
hormone usually rise at night in response to darkness, helping us to feel
sleepy, and are suppressed by the bright light of morning. “If someone’s
biological clock is running slow and that melatonin rhythm hasn’t fallen, then
their clock is telling them to keep on sleeping even though their alarm may be
going off and life is demanding that they wake up,” says Kelly Rohan, a
professor of psychology at the University of Vermont. Precisely why this should trigger feelings of depression is still unclear. One
idea is that this tiredness could then have unhealthy knock-on effects. If
you’re having negative thoughts about how tired you are, this could trigger a
sad mood, loss of interest in food, and other symptoms that could cascade on
top of that.
However,
recent insights into how birds and small mammals respond to changes in day
length have prompted an alternative explanation. According to Daniel Kripke, an
emeritus professor of psychiatry at the University of California, San Diego,
when melatonin strikes a region of the brain called the hypothalamus, this
alters the synthesis of another hormone – active thyroid hormone – that
regulates all sorts of behaviours and bodily processes.
For
approximately half the year, you can see the sunlight shining high up on
the north wall of the valley above Rjukan (Credit: Bilfinger SE/Flickr/CC BY
2.0)
When dawn
comes later in the winter, the end of melatonin secretion drifts later, says
Kripke. From animal studies, it appears that high melatonin levels just after
the time an animal wakes up strongly suppress the making of active thyroid
hormone – and lowering thyroid levels in the brain can cause changes in mood,
appetite and energy. For instance, thyroid hormone is known to influence
serotonin, a neurotransmitter that regulates mood. Several studies have shown
that levels of brain serotonin in humans are at their lowest in the winter and
highest in the summer.
It’s
possible that many of these mechanisms are at work, even if the precise
relationships haven’t been fully teased apart yet. But regardless of what
causes winter depression, bright light – particularly when delivered in the
early morning – seems to reverse the symptoms.
Mirror,
mirror
It was a
bookkeeper called Oscar Kittilsen who first came up with the idea of erecting
large rotatable mirrors on the northern side of the valley above Rjukan, where
they would be able to “first collect the sunlight and then spread
it like a headlamp beam over the town and its merry inhabitants”.
A month
later, on 28 November 1913, a newspaper story described Sam Eyde pushing the
same idea, although it was another hundred years before it was realised.
Instead, in 1928, Norsk Hydro erected a cable car as a gift to the townspeople,
so that they could get high enough to soak up some sunlight in winter. Instead
of bringing the Sun to the people, the people would be brought to the sunshine.
The mirrors
are mounted in such a way that they turn to keep track of the Sun (Credit:
Getty Images)
Martin
Andersen didn’t know all of this. But after receiving a small grant from the
local council to develop the idea, he learned about this history and started to
develop some concrete plans. These involved a heliostat: a mirror mounted in
such a way that it turns to keep track of the Sun while continually reflecting
its light down towards a set target – in this case, Rjukan town square.
The three
mirrors stand proud upon the mountainside
The three
mirrors, each measuring 17 sq m, stand proud upon the mountainside above the
town. In January, the Sun is only high enough to bring light to the square for
two hours per day, from midday until 2pm, but the beam produced by the mirrors
is golden and welcoming. Stepping into the sunlight after hours in permanent
shade, I become aware of just how much it shapes our perception of the world.
Suddenly, things seem more three-dimensional; I feel transformed into one of
those ‘merry inhabitants’ that Kittilsen imagined. When I leave the sunlight,
Rjukan feels a flatter, greyer place.
Not everyone
in Rjukan has welcomed the Sun mirrors with open arms. Many of the locals I
spoke to dismissed them as a tourist gimmick – though all admitted they were
good for business. On the day I visited, the town was blessed with clear blue
skies and a golden shaft of light descending from the mirrors, yet few people
lingered in the town square. In fact, of the people I spoke to, it was recent
immigrants to Rjukan who seemed most appreciative of the mirrors.
People cheer
during an inauguration of the Sun mirrors (Credit: Krister Soerboe/AFP/Getty
Images)
Andersen
admits to having got used to the lack of sunlight over time. “I don’t find it
so bad anymore,” he says. It’s as though the people who’ve been brought up in
this uniquely shady place, or who have chosen to stay, have grown immune to the
normal thirst for sunlight.
This is
certainly the case in another Norwegian settlement: Tromso. One of the world’s
most northerly cities, it is some 400km north of the Arctic Circle. Winter in
Tromso is dark – the Sun doesn’t even rise above the horizon between 21
November and 21 January. Yet strangely, despite its high latitude, studies have
found no difference between rates of mental distress in winter and summer.
One
suggestion is that this apparent resistance to winter depression is genetic.
Iceland similarly seems to buck the trend for SAD: it has a reported prevalence
of 3.8%, which is lower than that of many countries farther south. And among
Canadians of Icelandic descent living in the Canadian province Manitoba, the
prevalence of SAD is approximately half that of non-Icelandic Canadians living
in the same place.
Some people
have an apparent resistance to winter depression – why?
However, an
alternative explanation for this apparent resilience in the face of darkness is
culture. “To put it brutally and brief: it seems like there are two sorts of
people who come up here,” says Joar Vitterso, a happiness researcher at the
University of Tromso. “One group tries to get another kind of work back down
south as soon as possible; the other group remains.”
Ane-Marie
Hektoen grew up in Lillehammer in southern Norway, but moved to Tromso 33 years
ago with her husband, who grew up in the north. “At first I found the darkness
very depressing; I was unprepared for it, and after a few years I needed to get
a light box in order to overcome some of the difficulties,” she says. “But over
time, I have changed my attitude to the dark period. People living here see it
as a cosy time. In the south the winter is something that you have to plough
through, but up here people appreciate the very different kind of light you get
at this time of year.”
Looking down
on Rjukan, the path of the reflected sunlight (Credit: Krister
Soerboe/AFP/Getty Images)
Stepping
into Hektoen’s house is like being transported into a fairy-tale version of
winter. There are few overhead lights, and those that do exist drip with crystals,
which bounce the light around. The breakfast table is set with candles, and the
interior is furnished in pastel pinks, blues and white, echoing the soft
colours of the snow and the winter sky outside. It is the epitome of kos
or koselig – the Norwegian version of hygge, the Danish feeling
of warmth and cosiness.
The period
between 21 November and 21 January in Tromso is known as the polar night, or
dark period, but for at least several hours a day it isn’t strictly speaking
dark, but more of a soft twilight. Even when true darkness does descend, people
stay active. One afternoon I hire a pair of cross-country skis and set off down
one of the street-lit tracks that criss-cross the edge of the city. Despite the
darkness, I encounter people taking dogs for walks on skis, a man running with
a head torch, and countless children having fun on sledges. I stop at a park
and marvel at a children’s playground lit up by floodlights. “Do children climb
here in winter?” I ask a young woman, who is struggling to pull on a pair of
ice skates. “Of course,” she answers. “It’s why we have floodlights. If we
didn’t, we’d never get anything done.”
Residents
gather to enjoy the light (Credit: Getty Images)
It sounds
dismissively simple, but a more positive attitude really might help to ward off
the winter blues
During
2014-15, a psychologist from Stanford University called Kari Leibowitz spent 10
months in Tromso trying to figure out how people cope during the cold, dark
winters. Together with Vitterso, she devised a ‘winter mindset questionnaire’
to assess people’s attitudes to winter in Tromso, the Svalbard archipelago and
the Oslo area. The farther north they went, the more positive people’s mindsets
towards winter were, she tells me. “In the south, people didn’t like winter
nearly as much. But across the board, liking winter was associated with greater
life satisfaction and being willing to undertake challenges that lead to
greater personal growth.”
It sounds
dismissively simple, but adopting a more positive attitude really might help to
ward off the winter blues. Kelly Rohan recently published a clinical trial comparing cognitive
behavioural therapy (CBT) to light therapy in the treatment of SAD, and found
them comparable during the first year of treatment. CBT involves learning to
identify patterns and errors in one’s way of thinking and challenging them. In
the case of SAD, that could be rephrasing thoughts such as ‘I hate
winter’ to ‘I prefer summer to winter’, or ‘I can’t do anything in winter’ to
‘It’s harder for me to do things in winter, but if I plan and put in effort I
can’.
It also
involves finding activities that a person is willing to do in winter, to pull
them out of hibernation mode. “I don’t argue that there isn’t a strong
physiological component to seasonal depression, which is tied to the light-dark
cycle,” says Rohan. “But I do argue that the person has some control over how
they respond to and cope with that. You can change your thinking and behaviour
to feel a bit better at this time of year.”
This is an
edited version of an article first published by Wellcome on Mosaic and is republished here
under a Creative Commons licence. Visit Mosaic to read the longer version, which also
describes how artificial light can regulate mood.
Sumber : http://www.bbc.com/future/story/20170314-the-town-that-built-a-mirror-to-catch-the-sun
