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Welcome!

Learn about the properties of the Sun, its influence on Earth through gravity, light, and solar wind, and its life cycle. Discover fascinating details about the Sun's size, rotation, magnetic field, atmosphere, energy production, sunspots, solar events, solar wind, auroras, and coronal mass ejections.

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Welcome!

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Presentation Transcript

  1. Welcome! Sun Photo from http://sohowww.nascom.nasa.gov/bestofsoho/bestofsoho.html Created by the Lunar and Planetary Institute For Educational Use Only LPI is not responsible for the ways in which this powerpoint may be used or altered.

  2. What are we going to cover • Properties of the Sun • Influence on Earth: • Gravity • Light • Solar wind • Life cycle of the Sun Photo from http://sohowww.nascom.nasa.gov/bestofsoho/bestofsoho.html

  3. The Sun • Is a star • Made of gases • Is our primary source of energy 70% hydrogen and 28% helium Light (radiation) Image at http://science.nasa.gov/headlines/y2007/images/chromosphere/LimbFlareJan12_strip2.jpg

  4. How Big is the Sun? About 110 times wider than Earth Or 1.3 million times bigger than Earth Photo from http://sohowww.nascom.nasa.gov/bestofsoho/bestofsoho.html

  5. How does our Sun compare to other Stars? Our Sun is a dwarf—medium mass • Active stars range in size from supergiants to dwarfs • Stars range from very bright (supergiants) to very dim (dwarfs) • Stars range from very hot blue on the outside (O class) to cool red on the outside (M class) Our Sun is a medium-bright dwarf Our Sun is in-between--yellow

  6. So is our Sun an average star? • No—most stars are smaller and cooler than our Sun BUT • Most of the bright stars we see are bigger and hotter

  7. Rotation At the equator, the Sun rotates once every 25.4 days Near its poles, the Sun rotates once every 36 days Known as “differential rotation” High cadence solar rotation, EIT 195Š(Dec. 10-24, 1999) Movie at http://sohowww.nascom.nasa.gov/bestofsoho/Movies/EITdec99/EITdec99sm.mpg

  8. Sun’s Magnetic Field • Winds up due to differential rotation • Eventually forms loops and becomes tangled Animation of how the Sun's magnetic field winds up and loops out. Movie at http://sohowww.nascom.nasa.gov/bestofsoho/Movies/dynamo/dynamosm.mpg

  9. Inside the Sun • Core • Radiative Zone • Convection zone Image at http://solarscience.msfc.nasa.gov/interior.shtml

  10. The Sun’s Atmosphere • Photosphere • Chromosphere • Corona Photosphere image: http://science.msfc.nasa.gov/ssl/pad/solar/surface.htm Chromosphere image: http://science.msfc.nasa.gov/ssl/pad/solar/chromos.htm Corona image: http://solarsystem.nasa.gov/multimedia/display.cfm?IM_ID=191

  11. Energy from the Sun • Nuclear chain reaction (hydrogen forming helium) • Releases radiation (gamma rays) • The gamma ray loses energy as it bounces around inside the Sun • It is finally released at the photosphere, primarily as visible light Image at http://solarscience.msfc.nasa.gov/interior.shtml

  12. Features in the Photosphere • Sunspots • Dark and small (but brighter than Full Moon and big as Earth) • Cool-- temperatures only 6,200 F (Sun’s surface is 10,000 F) • Associated with magnetic fields: one set of spots is positive, other is negative Image at http://sohowww.nascom.nasa.gov/gallery/top10/top10_results.html

  13. More on Sunspots • Our Sun has an activity cycle of 11 years • Sunspots appear at specific latitudes on Sun • Bands of latitude move towards equator during cycle Images at http://starchild.gsfc.nasa.gov/docs/StarChild/questions/question17.html andhttp://solarscience.msfc.nasa.gov/SunspotCycle.shtml

  14. Solar Events • Flares (Explosions of energy on the surface of the Sun) • Prominences • Coronal Mass Ejections (massive clouds of plasma ejected from the Sun) https://www.youtube.com/watch?v=TWjtYSRlOUI Movie: Six months with EIT 171 (Aug. 12, 2003 - Feb. 9, 2004) http://sohowww.nascom.nasa.gov/bestofsoho/Movies/171/EIT171sm.mpg

  15. 1.What solar layer do you find Sunspots? • Core • Radiative Zone • Convective Zone • Photosphere • Chromosphere

  16. 2. What solar layer does nuclear fusion occur? • Core • Radiative Zone • Convective Zone • Photosphere • Chromosphere

  17. 3.Which solar event(like an explosion) travels at the speed of light? • Flares • Prominences • Coronal Mass Ejections

  18. Solar Wind • Blows charged particles and magnetic fields away from the Sun • Charged particles captured by Earth’s magnetic field • Create Auroras or Northern and Southern Lights Image at http://solarscience.msfc.nasa.gov/the_key.shtml

  19. Auroras • Electrons from solar wind are captured by the Earth’s magnetic field • Interact with atoms in our atmosphere: oxygen and nitrogen make red and green; nitrogen can also make violet • Northern lights are Aurora Borealis, while southern are Aurora Australis Animation of solar wind impacting the magnetosphere and creating aurorahttp://sohowww.nascom.nasa.gov/bestofsoho/Movies/animation/Solarwind.mpg

  20. 4. Aurora Borealis can occur at which pole? • North • South C. Both

  21. Coronal Mass Ejection(CME) The eruption of a huge bubble of hot gas from the Sun This series of images of coronal mass ejections taken with LASCO C3 (May 1-31, 1997) at http://sohowww.nascom.nasa.gov/bestofsoho/Movies/C3May97/C3May97sm.mpg

  22. CME’s effects on Earth • Can damage satellites • Very dangerous to astronauts • Power problems Animation of a CME leaving the Sun, slamming into our magnetosphere. http://sohowww.nascom.nasa.gov/bestofsoho/Movies/recon/reconsm.mpg

  23. Radiation • Our Sun (and all active stars) emits radiation • Radio, infrared, visible, ultraviolet, x-ray and even some gamma rays • Most of the sunlight is yellow-green visible light or close to it The Sun at X-ray wavelengths Image and info at http://imagine.gsfc.nasa.gov/docs/teachers/gammaraybursts/imagine/page18.html and http://starchild.gsfc.nasa.gov/docs/StarChild/solar_system_level2/sun.html .

  24. 5. The sun produces most of it’s radiation in the visible spectrum. • True • False

  25. Young stars form in nebulaefrom Small Magellanic Cloud Image at http://hubblesite.org/newscenter/archive/releases/2007/04/image/a/results/50/

  26. Star-forming region in the Large Magellanic Cloud: http://hubblesite.org/newscenter/archive/releases/2008/31/image/a/results/50/

  27. Orion image at http://hubblesite.org/newscenter/archive/releases/2006/01/image/a/results/50/

  28. Our Sun is a Regular/ Small Star Image at http://www.gsfc.nasa.gov/topstory/20011210insidesun.html

  29. In a few Billion years… Red Giant Image at http://hubblesite.org/newscenter/archive/releases/1997/26/image/a/

  30. Our Sun’s Habitable Zone Billions of years ago, things may have been different • The Sun was cooler (by up to 30%!) • Earth’s atmosphere was different (thicker, carbon dioxide) • Conditions will be different in the future • By many accounts, increases in the Sun’s temperature will make Earth uninhabitable in 1 billion years or less • These changes will also affect other planets… Mars? Animation at http://www.nasa.gov/97994main_BHabitableZone.MPG

  31. By 5 billion years… White Dwarf Image at http://hubblesite.org/newscenter/archive/releases/nebula/planetary/1998/39/results/50/

  32. Image at http://hubblesite.org/newscenter/archive/releases/nebula/planetary/2000/28/image/a/format/web_print/results/50/

  33. Image at http://hubblesite.org/newscenter/archive/releases/nebula/planetary/2004/27/image/a/format/large_web/results/50/

  34. 5. The Sun will become a white dwarf when it dies……. • True • False

  35. Massive Stars are different Image from http://hubblesite.org/newscenter/archive/releases/nebula/emission/1997/33/results/50/

  36. Betelgeuse Image from http://hubblesite.org/newscenter/archive/releases/star/massive%20star/1996/04/image/a/results/50/

  37. Supernova—Massive Star Explodes Images at http://hubblesite.org/newscenter/archive/releases/star/supernova/2004/09/results/50/http://hubblesite.org/newscenter/archive/releases/nebula/supernova-remnant/2005/37/results/50/ http://chandra.harvard.edu/photo/2009/casa/

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