Here's an over the top theory:
This is a Clark from an alternate universe where he and Lois are married. The explosion sent him into the alt-world where he and Lois aren't married.
Not so over the top. I had the same theory myself. Although, now I wonder if it could be HG Wells or Tempus playing with the future and past.
Anyway you do it, David, will work for me.
gerry
