1 / 49

Our Sun

Our Sun. The Stars: Part A. The Sun in Bulk. Sole Source of Heat/Light All life sustained by sun’s energy Light -> Photosynthesis -> Food Chain Glowing Ball of Gas Held together by Gravity Powered by Nuclear Fusion Average/Mediocre Star. The Sun in Bulk. Physical Properties

cana
Download Presentation

Our Sun

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Our Sun The Stars: Part A

  2. The Sun in Bulk • Sole Source of Heat/Light • All life sustained by sun’s energy • Light -> Photosynthesis -> Food Chain • Glowing Ball of Gas • Held together by Gravity • Powered by Nuclear Fusion • Average/Mediocre Star

  3. The Sun in Bulk • Physical Properties • Mass = 1.99 x 1030 kg (300,000 earth masses) • Radius = 696,000 km (over 100 earth radii) • Surface Temp 5780 K (10,000 oF)

  4. The Sun in Bulk • Differential Rotation • Fastest at the Equator • Slows down towards the poles. • The rotation is measured by tracking sunspots travel time.

  5. The Sun in Bulk • Surface • Entirely Gas (no solids) • Photosphere • Visible outer edge of the Gas • Gas ball shape seen with eyes/telescope • Location of Sunspots

  6. The Sun in Bulk • Solar Atmosphere • Above the Photosphere • Chromosphere • Transition Zone • Corona (visible during eclipse) • Solar Wind

  7. The Sun in Bulk

  8. The Sun in Bulk • Solar Interior • Below the Photosphere • Convective Zone • RadiativeZone • Core • Site of Nuclear Fusion • Entire Energy Output

  9. The Sun in Bulk • Luminosity • Energy Output- Solar Constant • 1400 W/m2 • 50-70% Reaches Earth’s surface. • Sun Exposure- Absorbing total output of ~5, 100W bulbs • Total Energy Output • 4.0 x 1026 W = 100 billion, 1 Megaton Nuclear Bombs detonated PER SECOND.

  10. The Sun in Bulk

  11. The Solar Interior • Equilibrium • Pressure • Gravity • Gravity stops the fusion pressure from blowing the star apart • Fusion pressure stops gravity from collapsing under its own weight.

  12. The Solar Interior • Standard Solar Model • No Direct Measurements of the Sun’s Interior • Combines • Observations • Theoretical Knowledge • Best Current Model for the Internal Processes

  13. The Solar Interior • Observations • Notable Missions • SOHO (Solar and Heliospheric Observatory) ESA/NASA • SDO (Solar Dynamics Observatory) NASA • Sun’s Surface Vibrates • Pressure Fluctuations

  14. The Solar Interior • Solar Density Decreases with Distance

  15. The Solar Interior • Solar Temperature Decreases with Distance • Then Increases in Solar Atmosphere

  16. The Solar Interior • Radiation Zone • High Temperature and Density • Energy Carried primarily by fusion radiation (Gamma Rays) • Continuous scattering (absorption/emission) • Average of 171,000 years for gamma rays to leave.

  17. The Solar Interior • Convection Zone • Lower Temperature • Most Hydrogen has bound electrons • Outbound Radiation is absorbed. (Opaque) • Energy Reaches surface through Convection Cycles • Hot Gases Rise to the Surface (emit radiation) • Cool Gases Sink towards the center.

  18. The Solar Interior • Fusion -> Radiation -> Convection -> Radiation

  19. The Solar Interior • Evidence for Convection • Granulation • Bright/Dark Spots • 1000 km across • 5-10 Min Lifespan • Bright- Upwelling Gas (Hot) • Dark- Downwelling Gas (Cool) • Video

  20. The Solar Atmosphere • Absorption Spectrum • Chemical Composition from Absorption Lines

  21. The Solar Atmosphere • Composition • Mass % • 71% Hydrogen • 27% Helium • 1% Oxygen • 0.5 % Carbon • Less than 0.1% Each • Nitrogen, Silicon, Magnesium, Neon, Iron, Sulfur

  22. The Solar Atmosphere • Chromosphere • Redish/Pink Hue • Active Region Light and Dark Areas (Similar to Granulation in the Photosphere) • Spicules- Jets of Gas/Matter

  23. The Solar Atmosphere • Transition Zone to Corona • Switches from Absorption Spectrum to Emission • (Against the Black of Space) • Increased Temperature • 3 Million K • X-Ray Radiation

  24. The Solar Atmosphere

  25. The Solar Atmosphere • Solar Wind • Charged Particles/Radiation Escaping the Sun • Coronal Holes- Open regions where particles escape in greater amounts • Charged Particles follow magnetic field lines

  26. The Solar Atmosphere • False Color X-Ray Image

  27. The Active Sun • Solar Activity • Overall Energy Output (relatively) Constant • Explosive/Unpredictable Surface Activity • Directly Affects Coronal Holes-> Solar Wind • Sunspots, Prominences, Solar Flares, CME’s

  28. The Active Sun • Sun Spots • Dark Regions in the Photosphere • None or Hundreds at any time (Cyclic) • Always exist in pairs • Due to Erupting Magnetic Fields • One South Pole (emerging) • One North Pole (diving)

  29. The Active Sun • Rotation • Leading Pole is the same throughout hemisphere • Opposite in the other Hemisphere

  30. The Active Sun • Differential Rotation is the Likely Cause • Magnetic Field Distorts until segments erupt through the photosphere.

  31. The Active Sun • Sunspot Cycles • Approx 11 year cycle (8-14 years) • Solar Maximum- Hundreds of Sunspots • Strongest Magnetic Field • Spots form at Higher Latitudes • Solar Mininum- Few if any • Weakest Magnetic Field • Spots form Near the Equator

  32. The Active Sun

  33. The Active Sun • Maunder Minimum seems to correspond with a “Mini Ice Age” that chilled Europe during the Late 17th Century

  34. The Active Sun • Half of the 22 Year Solar Cycle • Magnetic Field • Max -> Zero -> Max (Opposite Polarity) -> Zero -> Max • North Pole/South Pole Switch polarity • Last Solar Maximum around 2000 • Next Solar Maximum around 2013 Video

  35. The Active Sun • Active Regions • Gas surrounding sunspots can erupt • Caused by Magnetic Instability around sunspots • Solar Prominences (Filaments)

  36. The Active Sun • Solar Flares • Occurs on the Surface • More Explosive than Prominences • Particles Blasted into Space • Internal Temp 100 Million K (6x hotter than Core)

  37. The Active Sun

  38. The Active Sun • Coronal Mass Ejections (CME’s) • Ionized Gas Bubble • Separates from Corona • 1/week at solar min vs. 2-3/day at solar max • Oriented with Earth • Increased Aurora Activity • Communications/Power Interruptions • Damaged satellite microchips

  39. The Active Sun

  40. The Heart of the Sun • Nuclear Fusion • Only Known Reaction that can achieve the Sun’s energy output. Nucleus 1 + Nucleus 2 = Nucleus 3 + Energy • Law of Conservation of Mass AND Energy • Total Mass Decreases (Mass Defect) • Converted to Energy (E = mc2)

  41. The Heart of the Sun • Proton-Proton Chain • Hydrogen Fuses -> Forms Helium + Energy • At Low Pressure/Temperature • Protons Deflect • +/+ Repulsion

  42. The Heart of the Sun • At High Pressure/Temperature • Protons Close enough to “Fuse” • Forms Hydrogen-2, • Deuteron, Isotope • “Heavy Hydrogen” • Release • Neutrino • Energy • Positron

  43. The Heart of the Sun • The Whole Chain • 6 Protons -> Helium-4 + 2 Protons + Energy

  44. The Heart of the Sun • The Whole Chain • 2 Protons fuse to Form Deuteron (x2) • Deuteron + Proton Fuse to Form Helium-3 (x2) • 2 Helium-3 Fuse to form Helium-4 + 2 Extra Protons • Energy Released at every Fusion stage.

  45. The Heart of the Sun • Energy Output • 600 Million Tons of Hydrogen Fused Every Second • Tiny Fraction of Total Mass • Can Sustain for another ~5 Billion Years

More Related