"The War of the Worlds" was on TV today. I only watched for a few minutes since I have seen several versions of this movie. In the original story & some (all?) of the movies, the aliens die due to not being immune to some disease non-existent on their home world. While an interesting & clever SciFi concept, I wonder if it is valid biochemistry. I would expect alien biochemistry to be very similar to the Earthly biochemistry, but not an exact match. I think it is possible (actually likely) that aliens biochemistry would be based on the double helix as it is here on Earth. However, I think that it is possible for DNA to use more than one set of building blocks: Douglas R. Hofstadter described this in at least two of his books. Earthly disease bacteria/virus evolved to attack earthly creatures. I wonder if any would attack an ET. Very unlikely if the basic building blocks were different. Perhaps not likely even if the same building blocks were used, due to different evolutionary pressures. I do not have strong feeelings about the latter situation (same building blocks).