Board Thread:Warhammer 40k General Discussion/@comment-25618639-20150220210346/@comment-6078851-20150402140528

dude, this is the 40k wiki, where most of us are a little bit anal about the lore and the sciences of it (and some of us are very anal). and while almost every single thread regarding 40k lore is 'nerd chat', the science behind it matters - its hard to suspend disbelief if the sciences don't hold up :)  also this thread is for 40k in general, not a single specific topic, and though the end times can be discussed here that's not what was being talked about - the last, current, subject was tyranids and the shadow in the warp.

regarding the creation of elements: you're quite right about nucleosynthesis, although supernova class stars (the ones that widely disperse elements) are not particularly common, plus each star has vastly less matter to disperse than the stars of old, meaning that once tyranids eat everything the chances of life beginning anew are vastly reduced, though not impossible. but if life did begin anew from another cycle of supernova -> solar and planetary accretion -> geology -> organo-chemicals -> life, then this cycle will be a minimum of billions of years and tyranids will be long gone. but tyranids, if they still exist, won't actually be that far away in terms of universal distance - given that they have to travel between galaxies at sub-light speed then in billions of years they could still be within shouting distance (universally speaking) of the milky way. and if life begins anew in galaxies that tyranids once left barren then, one day, they will be back for dessert :P