1. Crepuscular Rays Dust, water droplets, and haze all scatter light from the sun after passing through breaks in the clouds Rays are parallel Perspective makes rays appear to diverge

2. Crepuscular Rays Scattering

3. Anticrepuscular Rays Convergent at the anti-solar point (the point opposite the sun) Extension of crepuscular rays WestEast Anti-solar point

4. Anticrepuscular Rays © C. Godfrey Scattering

5. Green Flash

7. 22º Halo © S. Hudson

8. Halos and sundog 46 º Halo 22 º Halo Sundog Parhelic Circle © S. Hudson

9. 22º Halo and sundog 22 º Halo Sundog Parhelic Circle Sundog Sun © S. Hudson

10. Sundog (parhelion) © C. Godfrey

11. 22 º Halo Sundog (parhelion) Parhelic Circle Sun © E. Godfrey

12. Complex Display at South Pole © Marko Riikonen

13. Sun Pillar Reflection

14. Upper Tangent Arc © C. Godfrey Positioned at top of 22  halo Refraction

15. Circumzenithal Arc You are looking almost straight up with the sun at the bottom of the image 22º Halo Circumzenithal Arc 46º Halo © C. Godfrey Formed by refraction through hexagonal plate crystals Sun is below 32° elevation

16. Upper Tangent Arc with Circumzenithal Arc © S. Hudson

17. © C. Godfrey

18. Alexander’s Dark Band Secondary Bow Primary Bow

19. Supernumerary Rainbows

21. Coronas (diffraction) Light waves pass around tiny cloud droplets Light waves cancel or reinforce each other Colors appear when particles have uniform size Blue is on the inside, red is on the outside This is similar to what happens when light bounces off a CD onto the ceiling!

22. Corona Around the Moon

23. Iridescence (diffraction) Different size droplets distort a corona Pastel colors appear in high, thin clouds © Shannon Story

24. Glory Reflection, then refraction

25. Glory

26. Brocken bow (glory)

27. Heiligenschein Reflection

28. Heiligenschein

29. Noctiluscent Clouds Form in upper mesosphere above 75 km (46 miles) altitude Composed of tiny ice crystals, possibly from disintegrated meteoroids or from chemical breakdown of methane gas

30. Nacreous (Mother-of-Pearl) Clouds Form in stratosphere above 30 km altitude in polar regions Made of supercooled water or ice crystals at temperatures <  80°C

31. Aurora Borealis (Northern Lights)

32. Aurora From Space

33. Aurora Borealis (Northern Lights) Solar particles disturb Earth’s magnetic field Magnetic field rearranges itself and converts some of its energy into kinetic energy – fast moving particles Some particles are from Earth and others are from the Sun Particles flow inward along magnetic field lines and collide with air molecules to produce light Oxygen  green and red (high altitudes) Nitrogen  red, blue, violet

34. Aurora Borealis (Northern Lights)

35. Aurora Northern Hemisphere: Aurora Borealis/Northern Lights Southern Hemisphere: Aurora Australis/Southern Lights 21 October 1999 Newfield, NY © S. Hudson

36. Aurora When particles from the Sun are energetic enough, the auroral oval can reach Oklahoma! November 2004 Mulhall, OK © C. Godfrey

37. Aurora on Saturn

38. Aurora on Jupiter