1. www.shokabo. co.jp/.../star/m olecule/orion.h tm Two Giant Molecular Clouds in Orion superimposed on the optical image Just how big is this Giant Molecular Cloud?

2. δ Orionis ε Orionis ζ Orionis κ Orionis Orion Nebula The Horsehead

3. Millimetre Map of Orion http://www.st sci.edu/~inr/t hisweek1/200 9/thisweek27 8.html

4. 2o2o 8o8o Harry Kroto 2004

5. 2o2o 8o8o The Size of the Orion GMC Dimensions 2 o x 2 o x 8 o n(H 2 ) ~ 10 3 cm -3

6. 2o2o 1o1o 8o8o Harry Kroto 2004 Orion 1500ly away

7. 2o2o 1o1o 8o8o 1500 x sin 1 o Harry Kroto 2004

8. 2o2o 1o1o 8o8o 1500 x sin 1 o = 1500 x 0.0175 Harry Kroto 2004

9. 2o2o 1o1o 8o8o 1500 x sin 1 o = 1500 x 0.0175 = 26.2 ly Harry Kroto 2004

10. 2o2o 1o1o 8o8o 1500 x sin 1 o = 1500 x 0.0175 = 26.2 1 o ~ 25 ly Harry Kroto 2004

11. 2o2o 1o1o 8o8o 200 ly 50 ly 1500 x sin 1 o = 1500 x 0.0175 = 26.2 1 o ~ 25 ly Harry Kroto 2004

12. 3.15 x10 7 sec in a year ~ 30x10 6 s

13. 1ly ~ 3 x10 7 x 3 x 10 10 ~ 10 18 cm

14. 3.15 x10 7 sec in a year ~ 30x10 6 s 1ly ~ 3 x10 7 x 3 x 10 10 ~ 10 18 cm 100ly ~ 10 2 x 3 x 10 7 x 3 x 10 10 ~ 10 20 cm

15. 3.15 x10 7 sec in a year ~ 30x10 6 s 1ly ~ 3 x10 7 x 3 x 10 10 ~ 10 18 cm 100ly ~ 10 2 x 3 x 10 7 x 3 x 10 10 ~ 10 20 cm 1 exameter = 10 18 meters

16. 3.15 x10 7 sec in a year ~ 30x10 6 s 1ly ~ 3 x10 7 x 3 x 10 10 ~ 10 18 cm 100ly ~ 10 2 x 3 x 10 7 x 3 x 10 10 ~ 10 20 cm 1 exameter = 10 18 meters and the cloud has a mass ~ 10 6 M o ie a million solar masses

17. Harry Kroto 2004

20. http://pierredutoit.blogspot.com/2010_12_01_archive.html Betelgeuse Bellatrix Mintaka Alnilam Alnitak Saiph Rigel Orion Nebula Flame and Horsehead The Orion Constellation

21. Hot gas cloud –the famous Orion Nebula At the centre is the Trapezium Cluster of very hot new stars Harry Kroto 2004

22. Infra red “stars” in Orion Harry Kroto 2004

23. Left hand star in Orion’s Belt  Orionis Harry Kroto 2004

24. The Horsehead Nebula B33 Orion... www.fantom-xp.com

25. at: www.shokabo.co.jp/.../star/molecule/orion.htmwww.shokabo.co.jp/.../star/molecule/orion.htm Just how big is this Giant Molecular Cloud? Two Giant Molecular Clouds in Orion superimposed on the optical image

26. at: www.shokabo. co.jp/.../star/m olecule/orion.h tm www.shokabo. co.jp/.../star/m olecule/orion.h tm

27. http://pierredutoit.blogspot.com/2010_12_01_archive.html

28. Harry Kroto 2004

29. Betelgeuse Bellatrix Mintaka Anilam Alnitak Saiph Rigel Orion Nebul a Flame and Horsehead

30. Millimetre Map of Orion http://www.st sci.edu/~inr/t hisweek1/200 9/thisweek27 8.html

31. Millimetre Map of Orion http://www.st sci.edu/~inr/t hisweek1/200 9/thisweek27 8.html

32. www.nightskyinfo.com/archive/orion_nebul a/

35. 1500 x sin 1 o = 1500 x 0.0175 = 26.2 ~ 25 ly NB 3.15 x10 7 secs in a year ~ 3x10 7 s 1ly ~ 3x10 7 x 3x 10 10 ~ 10 18 cm [50 x 50 x 200] x [10 18 ] 3 x [2 x 10 3 ] [2x10 33 ] [6x10 23 ] 5x10 5 x 10 54 x 2 x 10 3 10 62 12 x 10 56 10 56 = 10 6 M o 2o2o 1o1o 8o8o 200 ly 50 ly Weighing an Interstellar Cloud Dimensions 2 o x2 o x8 o n(H 2 ) ~ 10 3 cm -3 Orion 1500ly away Harry Kroto 2004

36. 2o2o 1o1o 8o8o 1500 x sin 1 o Harry Kroto 2004 Weighing an Interstellar Cloud Dimensions 2 o x 2 o x 8 o n(H 2 ) ~ 10 3 cm -3 Orion 1500ly away