[Utah-astronomy] M31 merger

What's left out of the discussion is that the sun will be in its red giant phase before everything settles down into an elliptical galaxy, right? It seems to me that the last simulations I read about ended up with the earth spinning in (because of drag with the sun's outer atomosphere). Although just hi-temp sterilization would pretty much have the same effect as far as our descendents are concerned. They'd just need a good way to get a lot of water onto Mars, maybe, huh? John