2001 SPACE SCIENCE VIDEOTAPES |
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Tape Title | Record ID |
Date Produced | TRT: |
Synopsis |
| CONFIRMING THE SUN'S CHILLY IMPACT ON EARTH | G01-081 | 12/06/01 |
00:08:43 | The Sun is responsible for heating our
planet and making it habitable. Now scientists believe they can
confirm a long-held theory that it also cooled Earth during what was
termed the 'Little Ice Age' from the late 17th to the early 18th
century that coincided with a period of little to no solar activity.
Scientists have produced a computer model that shows how the 'Maunder
Minimum', a period when solar activity, represented by sunspots and
explosions on its surface were at an extreme low, could have resulted
in a colder period in the Northern Hemisphere. It is believed that
the main influencing factor on our climate since the industrial
revolution has not been the Sun, but greenhouse gases.
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TAPE CONTENTS: |
| ITEM (1): Linking The Sun &
Earth - Unusually low solar activity between 1645-1715
likely triggered the 'Little Ice Age' in regions like Europe and
North America. A lag time of arguably 10-30 years allowed for the
climate system to be affected by an increased ozone layer that
altered the heating of the oceans. According to the model,
diminished jet stream winds caused by a dimmer sun created cold land
temperatures by reducing the transport of warm Pacific air to America
and warm Atlantic air to Europe. During this shift, winter
temperatures cooled as much as 2 to 4 degrees F - enough to freeze
rivers and alter agriculture, economy, disease, etc.
Pictured is the climate model used by researchers to watch
temperature anomalies. As such, 1780 was used as an arbitrary
baseline; the ice age period, then, is colder/bluer and 1780 is white
or neutral. Redder colors in more modern times reflect warmer
temperatures.
Courtesy: NASA
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| ITEM (2): The Cyclical
Sun - About five billion years old, the Sun shows signs of
variability, such as its eleven-year sunspot cycle. Within that
time, it goes from a minimum (seen here in 1996) to a maximum (2000)
period of activity that affects us everyday. When particularly
active, solar storms can spew tons of radiation to Earth in the form
of Coronal Mass Ejections (CMEs) that can affect power grids,
spacecraft, and communication systems. Scientists only really
studied the solar cycle from space since 1979. This allowed for close
observation of two cycles but not of a much longer cycle that would
encompass patterns of hundreds of years, such as the extreme 'Maunder
Minimum'.
Courtesy: NASA/ESA
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| ITEM (3): Why Care About
Sunspots? - In this case, the low solar activity (depicted by
fewer sunspots) during the Maunder Minimum meant decreased UV
radiation which impacted the protective ozone formation in the upper
atmosphere (stratosphere). The changes, then, in the upper
atmosphere, feed down to the surface climate and affect many systems,
including the Arctic Oscillation/North Atlantic Oscillation. These
are jet stream systems that would transport warmer air to America and
Europe. Sunspots are related to active regions from which explosions
like flares are generated. The exact link between sunspots and both
their 11-year cycle and relationship with active regions is not fully
understood.
Courtesy: NASA/ESA
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| ITEM (4): "Sports On a
Frozen River" Aert van der Neer - The few degrees'
difference was catastrophic and far-reaching. Greenland was largely
cut off by ice from 1410 to the 1720s and canals in Holland routinely
froze solid. Glaciers advanced in the Alps, and iced waterways
effectively sealed off Iceland in 1695. Rivers in Europe that were
typically ice-free, froze over as seen in various works of art.
'Frost Fairs' were held and people skated and golfed on the ice. In
North America, Native Americans formed leagues in response to food
shortages.
Courtesy: The Metropolitan Museum of Art
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| ITEM (5): Galileo's
Sunspots - Astronomers of the time kept a good record of
sunspot activity during the Maunder Minimum, encountering only about
50 sunspots in 30 years, as opposed to a typical 40-50,000. Here are
Galileo's sunspot drawings from 1611, prior to the Maunder Minimum.
Three other drastic minimums have been observed: the Oort Minimum
(1010-1050), the Wolf Minimum (1280-1340) and the Spoerer Minimum
(1420-1530).
Courtesy: Galileo Project, Rice University / Owen Gingrich
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| ITEM (6): What Are
Sunspots? - Sunspots appear dark because they are cooler
than the solar surface due to a strong magnetic field that traps the
Sun's core heat from travelling to the surface like a bottleneck.
The average sunspot is about 4500 degrees C, with the surroundings
about 6000 degrees C. Sunspots can last for weeks or more and can be
as large as 80,000 km (over 6 planet Earths). These are views from
Earth - the Dutch Open Telescope (DOT) resting atop a volcano on the
island of La Palma in the Canary Islands; the second is from the Big
Bear Solar Observatory located in the middle of Big Bear Lake,
California.
Courtesy: Dutch Open Telescope/Lockheed Martin & Big Bear
Solar Observatory / NJIT
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| ITEM (7): Climate Change
Today - The lack of activity on the Sun was strongly felt
during the Little Ice Age, yet scientists credit greenhouse gases and
global warming with having such an impact on us today. Most experts
point to 1850, start of the industrial age, to when the major
influence of climate started to shift from the Sun to ourselves. In
the first graph, a flat line reflects steady carbon measurements
prior to 1850. The other graphs show a stable increase of ambient
carbon dioxide oscillating as a general trend, but still rising and
falling with seasonal change. By truly understanding the Little Ice
Age, scientists hope to better understand the effects of change on
Earth's many systems and see how we might handle such change.
Courtesy: NASA / ORBIMAGE
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