I'd be interested to hear people's comments. One thing especially. The current estimates are of the order of 20bn yrs and 5bn yrs respectively (the actual values are not important ... it's the 'order' of the ratio that interests me). So, our sun has been around for a quarter of the age of the universe. Just one insignificant star, in a insignificant galaxy, etc. etc. A related question would be to do with how many 'generations' of stars could there possibly have been since big bang? It can't be many. Are there really enough to have produced the distribution of elements as measured today? Another one would be about the expected lifespan of the universe itself. I assume that it's huge orders of magnitude larger than the lifespan of any 'typical' star, so surely that means that we must be living in the earliest stages of the life of the universe. Is any of this remarkable in any way?