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Sunspots >research worksheet answers
Researcher Qualifications Answer
- 1. Why are sunspots cooler than
the surrounding solar surface areas?
- The high magnetic pressure inside
sunspots forces the hot plasma out, so that pressure is balanced. So the matter
in the sunspot interior is less dense and somewhat cooler.
- 2. Describe the umbra and penumbra
of a sunspot and tell what makes each part a different color.
- Sunspots have a central shadow or
"umbra" area that is somewhat cooler and relatively dark because of
magnetic exclusion of the plasma. This is surrounded by a lighter
"penumbra," which is a little warmer.
- 3. How long does it take a photon
to migrate from the Sun's core to its surface, and why?
- This process can take a million years or
more, because a photon is scattered many, many times by the protons in the
hydrogen plasma inside the Sun.
- 4. Where is 99.8% of the solar
system's mass, and what two elements is it made of (mostly)?
- Nearly all the solar system's mass in
the sun, and it consists almost entirely of hydrogen and helium (98%).
- 5. Draw a diagram of the Sun's
interior, labeling five major zones. What is happening in each?
Core: nuclear fusion turns hydrogen into
zone: energy travels outward as photons
through a dense plasma, making it very hot.
Convection zone: energy is transferred
toward the surface as thermal energy in
Photosphere: visible light is emitted at
about 5800 K.
Corona: very hot gas emits x-rays (possibly
because of interactions with the sun's
- 6. What happens in the convection
zone and why?
- Energy is transferred toward the
surface as thermal energy in circulating plasma. Beneath, at the boundary with
the radiation zone, energy from fusion in the core heats the plasma, which
starts moving upward toward the cooler photosphere. At the photosphere, energy
escapes as the sun's visible spectrum, cooling the plasma, which then sinks
back toward the radiation zone.
- 7. What is the sunspot cycle?
How long is it? What happens?
- A regular variation in the average
number of sunspots. Sunspots decrease and then increase again over about 11
years, then the sun's magnetic dipole field reverses, and the cycle repeats,
for a total cycle time of about 22 years. As sunspots appear more and more
frequently near the peak of solar activity, they also tend to appear nearer the
- 8. What role do sunspots play in
solar flares and coronal mass ejections (CME's)?
- Sunspots are the places where dense
loops of magnetic field emerge from and re-enter the surface. These intense
fields are created by whirling eddies and "cyclones" of charged
plasma material. These loops may break or collapse, causing large volumes of
energetic particles to be discharged as the sun's magnetic field re-stabilizes
itself. These solar explosions are flares and CME's.
- 9. How can geomagnetic storms
affect satellites and communications on Earth?
- By damaging satellite electronics as
they pass through current sheets formed in the ionosphere
By disrupting radio, television, and telephone transmissions.
By creating fluctuating magnetic
fields that can overload power utility grids and cause transformer blow-outs.
- 10. Might sunspot activity affect
the Earth's weather patterns? What are your reasons for the answer you
- Yes, it might. A very active sunspot
cycle might affect the production of ozone or other chemical processes in the
outer atmosphere. Some correlation has been noted between solar activity and
Earth temperatures, but the earth and its atmosphere are very complex and the
sun's and human's effects on them are not yet understood.
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