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? Orionis Orionis Orionis Orionis Orion Nebula The Horsehead Millimetre Map of Orionsci.edu/~inr/t hisweek1/200 9/thisweek27 8.html 2o2o 8o8o Harry Kroto 2004 2o2o 8o8o The Size of the Orion GMC Dimensions 2 o x 2 o x 8 o n(H 2 ) ~ 10 3 cm -3 2o2o 1o1o 8o8o Harry Kroto 2004 Orion 1500ly away 2o2o 1o1o 8o8o 1500 x sin 1 o Harry Kroto 2004 2o2o 1o1o 8o8o 1500 x sin 1 o = 1500 x Harry Kroto 2004 2o2o 1o1o 8o8o 1500 x sin 1 o = 1500 x = 26.2 ly Harry Kroto 2004 2o2o 1o1o 8o8o 1500 x sin 1 o = 1500 x = o ~ 25 ly Harry Kroto 2004 2o2o 1o1o 8o8o 200 ly 50 ly 1500 x sin 1 o = 1500 x = o ~ 25 ly Harry Kroto 2004 3.15 x10 7 sec in a year ~ 30x10 6 s 1ly ~ 3 x10 7 x 3 x ~ cm 3.15 x10 7 sec in a year ~ 30x10 6 s 1ly ~ 3 x10 7 x 3 x ~ cm 100ly ~ 10 2 x 3 x 10 7 x 3 x ~ cm 3.15 x10 7 sec in a year ~ 30x10 6 s 1ly ~ 3 x10 7 x 3 x ~ cm 100ly ~ 10 2 x 3 x 10 7 x 3 x ~ cm 1 exameter = meters 3.15 x10 7 sec in a year ~ 30x10 6 s 1ly ~ 3 x10 7 x 3 x ~ cm 100ly ~ 10 2 x 3 x 10 7 x 3 x ~ cm 1 exameter = meters and the cloud has a mass ~ 10 6 M o ie a million solar masses Harry Kroto 2004 Betelgeuse Bellatrix Mintaka Alnilam Alnitak Saiph Rigel Orion Nebula Flame and Horsehead The Orion Constellation Hot gas cloud the famous Orion Nebula At the centre is the Trapezium Cluster of very hot new stars Harry Kroto 2004 Infra red stars in Orion Harry Kroto 2004 Left hand star in Orions Belt Orionis Harry Kroto 2004 The Horsehead Nebula B33 Orion... at:Just how big is this Giant Molecular Cloud? Two Giant Molecular Clouds in Orion superimposed on the optical image at:co.jp/.../star/m olecule/orion.h tmco.jp/.../star/m olecule/orion.h tm Harry Kroto 2004 Betelgeuse Bellatrix Mintaka Anilam Alnitak Saiph Rigel Orion Nebul a Flame and Horsehead Millimetre Map of Orionsci.edu/~inr/t hisweek1/200 9/thisweek27 8.html Millimetre Map of Orionsci.edu/~inr/t hisweek1/200 9/thisweek27 8.html a/ 1500 x sin 1 o = 1500 x = 26.2 ~ 25 ly NB 3.15 x10 7 secs in a year ~ 3x10 7 s 1ly ~ 3x10 7 x 3x ~ cm [50 x 50 x 200] x [10 18 ] 3 x [2 x 10 3 ] [2x10 33 ] [6x10 23 ] 5x10 5 x x 2 x x = 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 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