Conversations with the Earth Tom Burbine [e-mail]

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Conversations with the EarthTom
Burbinetburbine_at_framingham.edu
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Figure 15.4
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Density
Temperature
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Parts of SunCore

• Core 15 million Kelvin where fusion occurs

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Figure 15.4
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Radiation zone

• Radiation zone region where energy is
  transported primarily by radiative diffusion
• Radiative diffusion is the slow, outward
  migration of photons

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Figure 15.13
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Photons emitted from Fusion reactions

• Photons are originally gamma rays
• Tend to lose energy as they bounce around
• Photons emitted by surface tend to be visible
  photons
• Takes about a million years for the energy
  produced by fusion to reach the surface

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Figure 15.4
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Convection Zone

• Temperature is about 2 million Kelvin
• Photons tend to be absorbed by the solar plasma
• Plasma is a gas of ions and electrons
• Hotter plasma tends to rise
• Cooler plasma tends to sink

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Figure 15.14
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Granulation bubbling pattern due to
convection bright hot gas, dark cool gas
Figure 15.14
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Figure 15.10
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Figure 15.4
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Photosphere

• Photosphere is the solar surface
• Where photons escape into space

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Sunspots

• Sunspots are on the photosphere
• Have temperatures of 4,000 K
• Photosphere is 5,800 K

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Sunspots

• Sunspots are regions of intense magnetic activity
• Charged particles tend to follow magnetic field
  lines
• A magnetic field exerts a magnetic force on
  moving electric charges

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Sunspot Cycle
Figure 15.21
The cycle has a period of approximately 11 years,
but the interval between maxima can be as short
as 7 years and as long as 15 years.
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Maunder Minimum

• Between 1645 and 1715, the sunspot activity
  virtually stopped
• Identified by E. W. Maunder from historical
  sunspot records

http//science.nasa.gov/headlines/y2003/17jan_solc
on.htm
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• Since sunspots are darker than the surrounding
  photosphere it might be expected that more
  sunspots would lead to less solar radiation.
• However, the surrounding margins of sunspots are
  hotter than the average, and so are brighter
• More sunspots increase the sun's brightness.

http//upload.wikimedia.org/wikipedia/commons/0/0d
/Solar-cycle-data.png
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Figure 15.4
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Atmosphere of the Sun

• Chromosphere above the photosphere and below
  the corona
• Temperature is about 10,000 Kelvin
• Most of the Suns ultraviolet light is emitted
  from this region

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See Corona during eclipse
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Atmosphere of the Sun

• Corona tenuous uppermost layer of the Suns
  atmosphere
• Temperature is about 1 million Kelvin
• Most of the Suns X-rays are emitted from this
  region

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Corona

• Extends millions of kilometers into space
• Sun's corona is constantly being lost as solar
  wind.

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Solar Wind

• Stream of charged particles continually blown
  outward from the Sun

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STEREO

• STEREO (Solar TErrestrial RElations Observatory)
  is a solar observation mission which was launched
  in October 2006.
• Two identical spacecraft were launched into
  orbits that cause them to (respectively) pull
  further ahead of and fall gradually behind the
  Earth.
• The spacecraft will do stereoscopic imaging of
  the Sun and processes such as Coronal Mass
  Ejections.

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• Coronal Mass Ejections are large clouds of
  magnetized gas ejected into space by the sun

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http//en.wikipedia.org/wiki/STEREO
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• http//www.nasa.gov/mission_pages/stereo/main/inde
  x.html

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• http//www.hulu.com/watch/63320/cosmos-the-lives-o
  f-the-starss-p1-so-i0

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Any Questions?