Questions and Answers
What is a star?
What is the Sun's radius?
700,000 km
What is the Sun's mass?
2 x 10^30 kg
How is solar rotation measured?
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How long does it take the Sun to rotate?
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The Sun spins at the same speed at the equator and the poles.
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How is the Sun's temperature measured?
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What is the Sun's temperature?
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What is the photosphere?
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What is the thickness of the photosphere?
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What is the Sun's core?
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What is the chromosphere?
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What is the corona?
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What is solar wind?
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What is the radiation zone?
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What is the convection zone?
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Where do ions form in the Sun?
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What is the most important property of the Sun?
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What is luminosity?
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What is the Sun's core temperature?
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What is the standard solar model?
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The Sun's bulk properties vary significantly from day to day.
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What is hydrostatic equilibrium?
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Why doesn't the Sun's surface vibrate?
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What is helioseismology?
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Where is the Sun's density high?
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Where is 90% of the Sun's mass contained?
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How does energy produced in the Sun's core travel outward?
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Do photons reach the surface of the Sun?
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What is sunlight?
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How does escaped energy reach the Sun's surface?
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Hot solar gas moves _____ while cooler gas above it _____
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What is meant by the hierarchy of convection cells?
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What does the deepest tier of convection cells contain?
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Convection proceeds in the solar atmosphere.
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What is granulation?
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Study Notes
The Sun: Key Facts
- A star is a glowing ball of gas maintained by gravity and powered by nuclear fusion.
- The Sun has a radius of 700,000 km and a mass of 2 x 10^30 kg.
Solar Rotation and Structure
- Solar rotation is timed by the movement of sunspots across the solar disk, taking approximately a month to complete one rotation.
- The Sun experiences differential rotation, spinning faster at the equator than at the poles.
Temperature and Atmosphere
- The Sun's temperature measures 5800 K, determined by analyzing the solar spectrum.
- The photosphere is the Sun's visible surface, approximately 500 km thick, lying above the interior layers and below the chromosphere.
- The chromosphere constitutes the Sun's lower atmosphere, while the corona is the tenuous outer atmosphere, extending into the solar wind.
Solar Energy and Internal Structure
- The Sun’s core, with a temperature of 10 million K, is where nuclear reactions occur, generating all of its energy.
- The radiation zone features high temperatures that ensure complete ionization of gas, causing photons to travel easily through this region.
- The convection zone, extending about 20,000 km below the surface, is where solar material undergoes constant convective motion.
Characteristics and Dynamics
- Ions are formed in the convection zone where hot solar gas rises outward while cooler gas sinks.
- Luminosity represents the total energy radiated by the Sun per second across all wavelengths, seen as its crucial property of light.
- Hydrostatic equilibrium in the Sun occurs when gravity’s inward pull is balanced by pressure forces.
Helioseismology and Structure
- The Sun's surface stability results from internal pressure waves that reflect off the photosphere and traverse the solar interior.
- Helioseismology studies the internal conditions of the Sun by analyzing sound waves crossing through its interior.
Density and Mass Distribution
- The Sun's highest density is found in its core, with 90% of its mass contained within the inner half of its radius.
- Energy produced in the core travels outward as radiation, while convection processes occur to transport escaped energy to the surface.
Surface Characteristics
- Sunlight manifests as visible energy, produced by convection which does not extend into the solar atmosphere due to insufficient gas.
- Granulation describes the mottled appearance of the solar surface, resulting from the interaction of rising hot material and sinking cooler material within convection cells just beneath the photosphere.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Description
Test your knowledge of the Sun with these flashcards from Chapter 8. Each card presents important terms and definitions related to solar characteristics, including its mass, radius, and rotation. Perfect for students studying astronomy.
