Naturalist sunspots

Sunspots & the Weather

One afternoon in June it got so bright outside we thought the
apocalypse might have begun.
We ran into the yard to look. Something was shining behind the clouds,
which were breaking up into rags and shreds. Patches of blue, a color only
faintly recollected but startlingly pleasant to the eye, were opening up.
There's a time for everything.
Then it dawned on us. The huge bright object over the firs was the sun,
which in June's relentless rain stopped seeming like a real object in nature
and more like an idea.
It has been rumored lately that the cause of the cloudy, misty, cranky
weather this month is a lack of sunspots. So before the sun could fade
again into the mist, I ran back inside and got the telescope to see if I could
verify the reports.
In the eyepiece - through a filter blocking out more than 99 percent of the
sunlight to stop my eye from being destroyed - appeared a round orange
disk. Clouds being a dominant force this summer, gray shreds floated
across it from time to time. But it was visible for long enough stretches to
verify that there were no sunspots. The sun's surface, at least in my little 4
½ inch wide telescope, was smooth.
Sunspots are small, dark, roughly circular patches, sometimes butted
together on the sun's photosphere, or visible surface. When your eyes get
adjusted for the finer details, the spots look like wide-mouthed volcanoes
with dark centers and lighter surrounding areas.
They occur in larger and smaller numbers over 11-year cycles, sort of
seasons of the sun. The last couple of years have been the period of
sunspot minimum in the 23rd cycle observed since the 1700s. The first
records of sunspot observation come from China in 28 B.C., and the first
(astonished) Europeans to see them were Galileo, Johann Fabricius of
Holland and Christopher Scheiner of Germany when they turned
telescopes sunward in the 1600s.
Since then it has been figured out that sunspots are cool areas produced
by disturbances in the sun's magnetic field. They're associated with solar
flares which blow off energy that can reach Earth, ignite auroras and
disrupt radio communications.
From 1645 to 1715 almost no sunspots were seen. This quiet period
corresponded roughly to the Little Ice Age, when Earth's average
temperature dropped about 1 degree.
It has been suggested that there could be a correlation between the lack
of sunspot activity and the cooler temperatures. When the sun is active
enough to produce sunspots, its heliosphere expands and acts like a shield
filtering out cosmic rays (pouring in from points far off - see Amateur
Naturalist, April 20, 2009) that otherwise strike the Earth pretty regularly.
The high-energy particles in cosmic rays can change the chemistry of the
Earth's atmosphere and influence cloud formation. If the changing
chemistry produces clouds higher up in the atmosphere, there's a
greenhouse effect that can warm things up down here. If clouds form
lower in the atmosphere, there's a cooling effect.
The idea is that during the Little Ice Age, the quiet sun might not have
been shielding the Earth from cosmic rays so well, and the rays were
fostering low clouds which were causing lower temperatures.
The sun in its active cycles also produces more ultraviolet and extreme
ultraviolet radiation, which also affect the chemistry of the Earth's upper
atmosphere, including clouds. So with less UV radiation- meaning fewer
sunspots - the climate also might be affected.
So what's got the scientists squinting this summer is that the 23rd
sunspot cycle should have bottomed out late last year and the start of the
24th cycle's active period (to peak around 2012-13) should have begun by
now, but hasn't. There are as yet almost no new sunspots. So it's possible
the protracted lack of sunspots is related to the cool, cloudy, rainy,
sunless weather.
However: There's not enough information to say for sure this is what's
happening. It may be that sunspots bear no relation to the local weather at
all. Maybe they influence the overall climate, or maybe not. The science is
cloudy.
Someday about 5 billion years from now the sun - so the theory goes - is
going to affect the weather here on an apocalyptic scale: It will expand
into a red giant and incinerate the Earth, Moon, Venus, Mercury and who
knows what else. For now, though, all things under the sun depend on it,
including our mental health. The weather forecast, as I write, is for more
clouds and gloom. So eat, drink and be merry. There's still nothing new on
the sun.

© Dana Wilde 2009
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