1. Shadows on the Sun The story of sunspots Dr. Lyndsay Fletcher, University of Glasgow

2. Image: Bill Leslie, Forres

3. The first recorded observation Photocredit: Michael Myers 364 BC – Chinese astronomer Gan-De records a darkening on the face of the Sun. Sunspots recorded regularly by ~ 30 BC. Observing through thin cloud or smoke? Photocredit: Ed Sanders

4. A Perfect Body? 300-250 BC - The Aristotelian view of the Universe The Earth is at the centre of a set of revolving spheres, each carrying a perfect and immutable celestial body The Sun is one such perfect body and should therefore be free of flaws But Theophrastus (374-287 B.C.) claims to observe flaws on the Sun

5. The first known drawing of sunspots? by John of Worcester, 8th December 1128 The first sunspot drawing

6. The Copernican Revolution 1543 - the Sun at the centre of the ‘Universe’ Sunspot observations have a bearing on the 16 th C. cosmology, demonstrating that heavenly bodies are not perfect and unchanging.

7. The first telescopic observations Galileo is usually credited with first turning a telescope to look at the Sun. This might not be correct! Galileo Scheiner FabriciusHarriot The four contenders are:

8. Galileo claimed to have been observing sunspots since the Autumn of 1610. However, his first public demonstration was in 1611.

9. The first known record of a telescopic sunspot observation This was drawn by the English mathematician Thomas Harriot…...on 8th December 1610

10. ‘..the greatest mathematician that Oxford has produced.’ Thomas Harriot 1560 -1621

11. 1613, Italy 2001, Hawai’i

13. Heinrich Schwabe The 11-year cycle

14. Image: NASA/ISAS/LMSAL Yohkoh 1992 1996 2001

15. Movie: NASA Sun-Earth Connections

16. Close-up of an active region (TRACE satellite)

17. Iron filings around a bar magnet line up according to magnetic force field. Coronal plasma is also tied to magnetic force field

18. Solar magnetic field White = ‘north’ Black = ‘south’

19. umbra penumbra A Simple Sunspot

20. Images: Swedish Solar Telescope

21. Why are sunspots dark? Because they are cooler than their surroundings, and so produce less radiation:

22. Why are sunspots cool? Because they are so strongly magnetised Magnetic field ‘resists’ convection, so heat from the rest of the photosphere can’t be fed into the sunspot

25. Image: NASA/ISAS/LMSAL Yohkoh 1992 1996 2001

27. A topical question – the effect of solar activity on climate Clear historical association of periods of low sunspot number and the Earth’s climate. Is this still important?

28. http://solarb.msfc.nasa.gov/index.html http://sdo.gsfc.nasa.gov/ http://trace.lmsal.com/ http://sohowww.nascom.nasa.gov/ More images and movies at: