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The Sun’ Energy Production Mechanism & the Earth — Sun Connection

The Sun’ Energy Production Mechanism & the Earth — Sun Connection. Astronomy 104 ; Lecture 1 April 5, 2004 Guest Lecture by Professor Christopher M. Anderson. Speed of light (3 x 10 8 m/sec) Squared. Change in Mass (kg). Energy (joules). The Sun ‘s Energy Source ? (1).

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The Sun’ Energy Production Mechanism & the Earth — Sun Connection

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  1. The Sun’ Energy Production Mechanism& the Earth — Sun Connection Astronomy 104 ; Lecture 1 April 5, 2004 Guest Lecture by Professor Christopher M. Anderson

  2. Speed of light (3 x 108 m/sec) Squared Change in Mass (kg) Energy (joules) The Sun ‘s Energy Source ? (1) • Energy Equilibrium - “Energy lost = Energy produced” • So, what are energy sources for Sun’s luminosity? • Chemical, C + O2 CO2 Adequate for perhaps 10,000 years • Gravity, E = GM / DR Adequate for perhaps 200,000 years 3. Nuclear E = Dm C2 Adequate for 10 x 109 (billion) years or more

  3. Overcoming Electrostatic Repulsion Why “Thermonuclear”? Positive charges Repel One another Very Strongly So it REQUIRES BOTH High Density (so it happens often) But Especially Very High Speed i.e. VERY HIGH TEMPERATURE

  4. Do Steps 1 & 2 A second time Thermonuclear Hydrogen Fusion 4 H  He But if getting two + Charged particles together is difficult Getting 4 at once together is REALLY tough So what’s needed is a “setp-wise” process The Proton – Proton Chain 2 Protons i.e. Hydrogen Nuclei Positron Deuterium Helium 3 Neutrino Helium 4

  5. White Light Sun “ I am at last convinced that the spots are objects close to the surface of the solar globe … also that they are carried around the Sun by its rotation” ---- Galileo 1613, Historia e Dimostrazioni intorno alle Macchie Solari Quotation recovered from Baliunas et al. 1995, ApJ 438, 269.

  6. SOHO white Light January 2003

  7. Sun Spots & Granulation Normal Photosphere Temperature =5700 K DT ~ 1500 K Sun Spot “Umbra” Temperature = 4200 K • Granulation • Size ~ 1000 km • DT ~ 150 K • Life time ~ 10 min • Tops of Convection Cells

  8. Sun Spot Number vs. Time

  9. The Maunder Diagram “ Maunder Minima” N N N N S S S S Sun Spot Number v Time Particularly Severe Winters George E. Hale Spot Magnetic Fields 1908 Hale & Nicholson Systematics of Bipolar Magnetic Regions 1925

  10. SOHO FeXII 195A Movie

  11. CoronalLoops

  12. Solar Corona, 1991 Eclipse Outflow (Solar Wind) V ~ 500 km s-1 Nelectron = Nproton ~ 1 cm-3 (at 1a.u ) T ~ 106 K

  13. Solar Activity, Some Facts & Figures (1) • Flares • Release of up to 1023 Joules in 10 – 100 minutes • Radio & X-ray Bursts, seen immediately • Correspond to gas at T ~ 107 K • High particle (1H & e-) Flux @ Earth, 1 – 5 days later • Frequency • at Solar Max, 1500 yr-1 • at Solar Min, only 40 yr-1 • Origin ? : “Magnetic Reconnection Events” • Coronal Mass Ejection

  14. SOHO LASCO X-ray Movie

  15. SOHO LASCO Movie

  16. Solar Activity, Some Facts & Figures (2) • Flares • Release of up to 1023 Joules in 10 – 100 minutes • Radio & X-ray Bursts, seen immediately • Correspond to gas at T ~ 107 K • High particle (1H & e-) Flux @ Earth, 1 – 5 days later • Frequency • at Solar Max, 1500 yr-1 • at Solar Min, only 40 yr-1 • Origin ? : “Magnetic Reconnection Events” • Coronal Mass Ejection • Mass expelled ~ 3 x 1013 kg • ~ 2 km cube of rock (but of course it’s mostly Hydrogen) • Energy, also ~ 1023 Joules • Speed of ejection ~ 500 – 1500 km s-1 • Much of it in the plane of the Ecliptic

  17. Aurora Borealis

  18. Aurora seen fromSpace

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