Transcript 6-SolarEffectsOnEarth

Sun-Earth Connections
Effects of solar phenomena on Earth
The sun: our beautiful, peaceful,
life-giving star.
What do we get from the sun?
Light
 Heat
 Photosynthesis >>> LIFE!
 UV for tanning, sunburn & skin cancer
 Ozone layer provides some UV filtering
 A steady flux of charged particles
 Most deflected by Earth’s magnetic field
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Diversion: find the dot. What is it?
Not a sunspot, but the shuttle!
The spotty sun
Inside the sun, and other stars like the sun
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Three main interior
zones:
1.
2.
3.
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Core, where fusion
happens
Radiative Layer
Convective Layer
Surface
 Atmosphere
80,000 K
K
1,000,000
1,500,000 K
2,000,000 K
A roiling mass of plasma…
SUPERCOMPUTER SUNSPOT
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Researchers at the National Center for
Atmospheric Research (NCAR) in
Boulder, Colorado, have created an
unprecedented 3D supercomputer
model of a sunspot. The result is not
only scientificially informative, but also a
thing of beauty:
What goes on below the surface
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subsurface cross section of two sunspots.
Lighter/brighter colors = stronger magnetic
field
First glimpse below the visible surface to
understand underlying physical processes
http://www.ucar.edu/news/releases/2009/sun
spotvisuals.shtml
QuickTime™ and a
YUV420 codec decompressor
are needed to see this picture.
The sun affects the Earth environment
November 6, 1997: 12:36 UT
Coronal mass ejection (CME)
Interacting magnetic fields
(not to scale!)
Major white light flare
No big deal. Right?
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Wrong.
Major solar storm can disrupt or destroy
power grids on a large scale
1989 Quebec event offers a hint of what
could happen
Sun is the quietest now as it has been for the
last 100 years
Present technology developed during this
quiet period
Doubtful if it could survive a Carrington event
Richard Carrington’s 1859
sunspot & flare drawing
Carrinton event - 1859
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Giant spots, flare, CME
Most severe space
weather event in history
Eight days long
Stunning aurorae at
equatorial latitudes
Global telegraph network
disrupted, operators
suffered electric shocks
Magnetometers driven off
scale
From solar wind to solar storm
High-energy charged particles leave the
sun as the solar wind all the time
 CMEs release billion-tonne blobs of it
 If it strikes*, it changes configuration of
Earth’s magnetic field
 Induces huge DC currents in power grid
transmission lines
 swamps transformers, which melt
 This was the 1989 Quebec event
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A Carrington event today
Modern high-voltage, interconnected
grid is very vulnerable
 Grids are efficient antennas, channeling
huge DC to transformers, killing them
 All developed countries depend on grid
for power, water & sewage,
transportation, emergency services,
navigation, communications, etc.
 Increasingly we rely on vulnerable
satellite technology too
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NASA & NAS worst-case study
predicts:
15 minutes warning
 300 key transformers gone in 90
seconds
 Catastrophic loss of critical
infrastructure
 Health care systems collapse in 3 days
 Coal-fired power gone in 30 days
 Millions of lives lost
 4-10 years to recover
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The good news:
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With enough warning utilities and space
programs can take precautions to avoid worst
damage
ACE satellite monitors the sun, BUT:
ACE is aging and needs replacing
Hard to inspire action in preparation for
something that hasn’t happened in living
memory
“Unlikely” does not equal “won’t happen”
Next solar max in 2012 predicted to be big
The sun: not boring at all, eh?
NASA STEREO Mission