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Unit 3 Study Guide: The Sun

1. Solar Interior

   1. How does the Sun vibrate like a complex set of bells?

      1. What is helioseismology?

      2. What is SOHO and what is its purpose?

   2. The process of energy transport from core to surface

   3. What is the evidence for solar convection?

      1. What is granulation?
         
         

2. Solar Atmosphere

   1. What are the most abundant elements of the Sun?

   2. How is the chromosphere unique compared to the photosphere?

   3. What are spicules?

   4. What is unique to the transition zone and corona as compared to the photosphere and chromosphere?

   5. The high coronal temperature directly affects what part of the Sun?
      
      

3. The Active Sun

   1. Identification of sunspots, flares, prominences – what are they and how are they significant in the powering of the Sun?

   2. What are solar cycles and solar maximums?

   3. What relationship exists between the corona and the strength of the solar wind with a certain process of the Sun?

   4. How is the corona heated?
      
      

4. The Heart of the Sun

   1. What is nuclear fusion?

      1. What is the law of conservation of mass and energy?

      2. What is the proton-proton chain and equation?

   2. What is a neutrino?

      1. The observation of solar neutrinos

      2. What is the solar neutrino problem?

         What is the Proton Proton Chain reaction

         order the steps of the proton proton chain reaction

      3. what light is emmited during the proton proton chain reaction

         What can you say about the density of the sun where is it the densest

         What region of the sun do protons get stuck at

         what is solar wind

         why are coronal mass ejections and solar flames dangerous to humans

         why are solar neutrinos so hard to detect

         how can we most easily tack the 11 year solar cycle

         

         What are neutrinos

         What is the main nucular fusion process in which the sun produces energy

         what element is three fourths of the suns mass

         What is SOHO

         What are sunspots?

         which part of the proton proton chain reaction takes the longest to complete

         What are solar Granuales caused by

         what process generates energy in the sun

         why do the poles of the sun move faster then other parts of it

         Where does fusion occur

         What layer of the sun is considered the surface of the sun

         what are the visible features of the sun

      4. Main regions of Sun: core, radiation zone, convection zone, photosphere, chromosphere, transition region, corona

      5. Energy comes from nuclear fusion; produces neutrinos along with gamma rays and energy

      6. Study of solar oscillations leads to information about interior

      7. Absorption lines in spectrum tell composition and temperature

      8. Sunspots associated with intense magnetism

      9. Number of sunspots varies in an 11-year cycle

      10. Large solar ejection events: prominences, flares, and coronal ejections

      11. 

          The first step of this process is the rate limiting step

          • It takes average solar proton 9 billion years to successfully fuse into a Deuterium nucleus 

          Each Deuterium nucleus fuses quickly

          • On average it lasts about a second

          Each Helium-3 lasts for a while

          • About 400 years Here’s the thing though. You do the calculations of how hot the sun needs to be for this rate of fusion and you get: 

            • 10,000,000,000 K
              But the sun is only: 

            • 15,000,000

          

          The Sun is our star—the main source of energy that powers weather, climate, and life on Earth. Humans simply would not exist without the Sun. Although we take it for granted each and every day, the Sun is extremely important to us in the cosmic scheme of things. This spectacular image shows a particularly large solar prominence on the limb of the Sun, arising from a powerful active region in 2005. The image was acquired by the Solar and Heliospheric Observatory—a 2-ton robot “parked” in space between the Sun and Earth. Its job is to stare at the Sun unblinkingly 24 hours a day, eavesdropping on this gas ball’s surface, atmosphere, and interior. (ESA/NASA)

          
          Density: 1400 kg/m³   (1.4 times that of water -  similar to the Jovian planets⁾

      12. Rotation: We use sunspots to determine. Faster at the equator (25 days), slower at the poles (31 days at 6°degree latitude)

      13. Core Temp: 27 million°F

      14. Surface Temp: 10,000°F (5,800K - above melting point of any known material)

      15. Apparent surface of Sun is photosphere –not a solid surface

      
      Sun does not rotate as a rigid sphere. The equator of the Sun rotates faster than the poles of the Sun. This is called the differential rotation. Sunspots and many other solar activities are due to this differential rotation.

      
      

      1. The Sun contains more than 99.85% of the total mass of the solar system

      2. If you put all the planets in the solar system, they would not fill up the volume of the Sun

      3. 110 Earths or 10 Jupiters fit across the diameter of the Sun

      4. On a 1-to-10 billion scale:

         • Sun is the size of a large grapefruit (14 centimeters).

         • Earth is the size of a tip of a ballpoint pen, 15 meters away.

      5. SOHO: Solar and Heliospheric Observatory

         Orbits at Earth’s L1 point, outside the magnetosphere

         Multiple instruments measure magnetic field, corona, vibrations, and ultraviolet emissions

         

         Interior structure of the Sun:  The core is where nuclear fusion takes place

         The Photosphere is the visible “surface” of the Sun. Below it lies the Convection zone, the Radiation zone, and the Core.  

         Above the photosphere is the Chromosphere, the Transition zone (temperature rises dramatically), and the Corona (ghostly shape).Corona not easily seen except with telescope filters or during a solar eclipse because the  Photosphere brightness obscures its light The core is about ⅕ to ¼ the diameter of the Sun

         • About 10 times Jupiter’s diameter

      6. Density about 150 times that of water

         •  7.5 times gold

      7. Temperatures around 27 million degrees F/15 million C

      8. About 70% hydrogen at the edge of the core

      9. 33% near the center of the core

      10. Radiation Zone (above core, below Convection)

          • Solar energy is transported due to radiation

          • Photons take a very long time to escape

          Convection Zone (above Radiation Zone)

          • Below photosphere where the material is in constant convective motion

          • Hotter fluids moving up due to lesser density, relatively “cooler” fluids moving downward due to greater density

          • Physical transport of energy in the Sun’s convection zone. We can visualize the upper interior as a boiling, seething sea of gas. Each convective loop is about 1000 km across. The convective cell sizes become progressively smaller closer to the surface. 

            The deeper you go, the hotter and denser things get

          • Solar Oscillations

            • The Sun has been found to vibrate in a very complex way. 

            • By observing the motion of the solar surface, scientists can determine the wavelength and the frequencies of the individual waves and deduce information about the solar interior

            • The alternating patches represent gas moving down (red) and up (blue). 

            • Depending on their initial directions, the waves contributing to the observed oscillations may travel deep inside the Sun, providing vital information about the solar interior 
              The atmosphere of the Sun is composed of several layers
              
              

              • Photosphere: The lowest visible layer

              • Chromosphere: barely visible. Kinda spiky

              • Transition zone: Border region for several things

              • Corona: The extending atmosphere of the Sun

              • Deepest layer we can see

              • Can be thought of as the “Surface” of the Sun

              • Where granules, sun spots, and other surface features are

              • About 500-1000 km thick

              • Convection from inside the sun causes the photosphere to be subdivided into 1000-2000 km cells.

              • Energy rises to the surface as gas wells up in the cores of the granules, and cool gas sinks around their edges. 

              • Grainy appearance to sun when look in a telescope caused by granules, areas of hotter gases rising—last 10 minutes and new ones arise causing a convection

              • 90% of sun’s surface is hydrogen

              • 10% helium

              • Sits atop the photosphere

              • Pinkish red and color but rarely seen 

              • Made of less dense gas

              • Has spikes called “spicules”

              • Kind of like the outer barrier of the Main “surface” of the Sun

                • Below, gravity tends to dominate the shape, making defined layers. Above, the shape becomes less well-defined

                • Below, most of the helium is not fully ionized. Above, it becomes fully ionized

                • Below, material is opaque to most colors

                • Below, fluid dynamics dominate. Above, magnetism dominates

                • Outermost portion of the atmosphere

                • Visible only when photosphere is covered

                • Ionized gases escape from the corona and make solar wind

                • The solar wind is a stream of energized, charged particles, primarily electrons and protons, flowing outward from the Sun.

                • The number and intensity change but there’s a pretty constant stream of particles at all time

                • They make comet tails!

                • The solar wind is what blows the tails of comets back away from the bodies of comets as they go through the solar system.

                • Solar wind is only responsible for the ion tail

                • Sunspots are temporary phenomena on the photosphere of the Sun that appear visibly as dark spots compared to surrounding regions.

                • They are caused by intense magnetic activity that draws off the convection of heat to the surface, thus cooling the surface.

                • Sunspots are usually in pairs because of the magnetic activity causing North and South poles at either of the spots.