I will accept global warming when someone can show me what the average temperature of the earth is supposed to be. I don't want an average over the past 30 years. I want the average over the last 4.5 billion years.[/QUOTE] Crapola ! Distortion ! You know this is not possible - Doesn't the bible say that the earth is only 6500 years old ;-) ;-) Same Argument but thrown back.... No the Big Band occurred some 16 Billion years back, if you average numbers that people suggest around ! The Climate sceptic says yes temperatures on Earth (the planet Terra-3 by correct astro notation) were higher ! BUT !!!! The Earth was covered by vegetation then ! …. Back to subject - the index is useful for Ducting … but as to propagation - more to be researched !!!