I've been reading 'The Big Splat, or How Our Moon came to Be' by Dana Mackenzie. This describes how at a meeting in 1984, the consensus was quickly reached that the moon formed when a Mars-size planetoid collided with the Earth soon after its origin. What I found a bit surprising is that if this new idea suddenly became accepted, then why doesn't it seem to have entered the public consciousness very quickly? I have to admit that before reading the book I hadn't really taken in this idea, although I'd probably read about it in passing a few times. Contrast this with ideas such as a meteor impact causing the extinction of the dinosaurs, or of the acceleration of the expansion of the universe. These ideas seemed to spread quickly, being discussed in many popular science books and TV problems. So have I just missed the spread of this idea until now? Have other people come across this idea, heard it discussed etc., and if so, when did it seem to enter the popular mindset? If not then why not? Is the origin of the moon less interesting than the ideas above? I would have thought it would be something everyone could relate to, especially the generation brought up with the moon landings (the data from which lead to this idea).