1. Sound Waves From the Northern Lights Photo courtesy of Bjorn Jorgensen, 18 January 2005, near Tromsø, Norway http://www.spaceweather.com/aurora/images2005/17jan05/Jorgensen1.jpg Jada Maxwell

2. “Synergy means behavior of whole systems unpredicted by the behavior of their parts taken separately.” - Buckminster Fuller

3.  What creates the aurora?  Sound waves from the aurora  Wave transformation on the Sun  Beginning to answer my question Can magnetic waves in the aurorae transform into sound waves?

4. What creates the aurora?

5. Chain of Events The aurora is created by a chain of events, beginning with energy from the sun. Image courtesy of Tom Michalik http://faculty.rmwc.edu/tmichalik/solarwind.htm

6. The Magnetosphere Image courtesy of Minnesota Technolog http://technolog.it.umn.edu/technolog/novdec97/cover.htm

7. Coronal Mass Ejection (CME) Illustration by Steele Hill, courtesy of NASA http://sohowww.nascom.nasa.gov/localinfo/steele.html

8. South-North Magnetic Orientation of CME

9. North-South Magnetic Orientation of CME

10. Magnetic Reconnection on Dayside of Earth

11. Magnetic Field Lines are Drawn Back to Magnetotail

12. Magnetotail is Compressed

13. Magnetic Reconnection in Magnetotail

14. Particles Spiral Down Field Lines Image: Fundamentals of Physics, 2005

15. Particles 2  Collide with atomic and molecular oxygen and nitrogen  Emit energy as light Particles Spiral Down Field Lines

16. This Creates the Aurorae Image courtesy of Shawn Malone http://www.lakesuperiorphoto.com  Northern Lights = Aurora Borealis  Southern Lights = Aurora Australis

17. Nearly Mirror Images Aurora BorealisAurora Australis Images courtesy of NOAA http://sec.noaa.gov/pmap/

18. Can we hear the aurorae?  Anecdotal evidence of auroral sounds hissing, popping, crackling, swooshing corresponds with motions of light

19. 6 minutes  Sound would take at least 6 minutes to travel from the aurora to the ground  No recordings of audible aurorae

20.  Psychological  Freezing Breath  “Brush discharge” Explanations of Audible Sounds

21.  Humans can hear between 20 and 20,000 Hertz (Hz)  Infrasound is below 20 Hz  Currently being investigated  Gas expansion Evidence of Infrasound from Aurorae

22. The Sun Creates Sound Waves

23. Sound Waves on the Sun Created by Convection

24. Sound Waves Propagate through Sun’s Atmosphere Sun

25. Energy of Sound Waves is Transformed into Magnetic Waves Sun

26.  Alfvén waves (s-mode)  Magnetosonic waves (p-mode) Types of Magnetic Waves Images courtesy of Georgia State University http://hyperphysics.phy-astr.gsu.edu/hbase/sound/tralon.html BBC animations

27. Can magnetic waves in the aurorae transform into sound waves? My Question

28. Magnetic Waves Earth

29. Transform into Sound Waves Earth

30. Finding Beta Beta = β = Gas (atmospheric) Pressure Magnetic Field Pressure β = 1 ?

31. Resonance  All material has a frequency that it vibrates at  Matching the frequency allows the material to absorb energy  Singing wine glass

32. Resonance in the Aurora When β = 1,  Energy from magnetic waves can be transferred to the atmosphere  Found the right frequency

33. When Beta = 1 β = 1 ?  At 120 km  Near bottom of aurorae

34. More Questions to Investigate  How does β vary?  Compare gas expansion theory to wave transformation  How much might Alfvén and magnetosonic waves each contribute to this effect?  Which is more likely to transform?

35. Thanks to:  Dr. E.J. Zita for her guidance and helpful discussions  Beth Stinson for instruction in PowerPoint

36. Image Sources: ▪ NOAA (National Oceanic & Atmospheric Administration) http://sec.noaa.gov/pmap/ ▪ NASA http://sohowww.nascom.nasa.gov/localinfo/steele.html ▪ SpaceWeather.com http://www.spaceweather.com/aurora/images2005.htm ▪ Shawn Malone http://www.lakesuperiorphoto.com ▪ Tom Michalik http://faculty.rmwc.edu/tmichalik/solarwind.htm ▪ Minnesota Technolog http://technolog.it.umn.edu/technolog/novdec97/cover.htm ▪ Fundamentals of Physics, Halliday/Resnick/Walker, John Wiley & Sons, 2005, p 746