Great Work. There is a lot of very useful and interesting information there.
I would consider using one template and layout for the entire site. Although neat, having a different template for each page make the website feel disconnected. The homepage template is my favorite; consider using that one for the entire site and just adding images and graphics or changing just certain parts of it to enhance each page.
The contact page:
http://www.theyoungearth.com/ayoungearth/id29.html does not work.
Again, you have done a great job with the content, I would just suggest unifying the layout. Continue with the great work God Bless you.