The Sun - PowerPoint PPT Presentation

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The Sun
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The Sun

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  1. The Sun Astronomy Unit

  2. Sun • Earth’s primary source of ENERGY • Exist in its stable state 10 billion years, the Sun is 4.5 billion years old “middle-aged” • Current estimate internal temp 15 million Kelvin • Average star • Diameter – 109 Earth diameters, or 1.35 million kilometers(km) • Volume – 1.25 million times as great as Earth’s • Mass – 332,000 times the mass of Earth • Density – ¼ that of solid Earth

  3. Sun • Four layers of the Sun • Solar interior • Photosphere • Chromosphere • Corona

  4. Photosphere • Radiates most of the sunlight we see and can be thought of as the visible “surface” • Layer of gas less than 500 kilometers(KM) thick • Granules are the yellowish-orange patches on the photosphere, last 10- 20 min, convection • Responsible for the transfer of energy in the uppermost part of the Sun’s interior

  5. Chromosphere • Located just above the photosphere • Thin layer of hot gases a few thousand km thick • Observable for a few moments during a total solar eclipse, appears as a red rim around the Sun

  6. Corona • Envelope of ionized gases normally extends a million km from the Sun • The outer fringe of the corona the ionized gases have high speeds to escape the gravitational pull of the Sun, the escaping protons and electrons make up the solar wind

  7. Solar Interior • Sun produces energy by nuclear fusion • Energy is released because some matter is converted to energy • Four hydrogen nuclei combine to form one helium nucleus • Einstein’s equation: E =mc2, E = energy, m = mass c= speed of light • Sun consumes 600 million tons of hydrogen each second, about 4 million tons are converted to energy

  8. Sunspots • Sunspots – are the dark regions on the surface of the photosphere • Sunspots appear dark because of their temperature, which is about 1500 K less than that of it’s surroundings • Number of sunspots observed varies in an 11-year cycle

  9. Sunspots

  10. Prominences • Prominences are ionized gases trapped by magnetic fields that extend from regions of intense solar activity

  11. Solar Flares • Brief outbursts that normally last about an hour and appear as a sudden brightening of the region above a sunspot cluster, release large amt of energy :ultraviolet, radio,and x-ray • Can affect long-distance radio communication • Most spectacular effect are the auroras

  12. Auroras