HI Raven Mother
I know you said the Internet hasn't helped much but have you looked at NASA?
http://www.nasa.gov/home/index.html Here's another site I found that looks interesting
http://www.windows.ucar.edu/ I haven't explored them yet for your particular question but they may be helpful.
I love books. I believe you can never own enough books. But, the Internet is the world at our fingertips and the information can be much more timely.
Astronomy is making leaps and bounds from the Hubble telescope, International Space Station and the US has a new "robot" on Mars-- Phoenix. Phoenix might have discovered ice on Mars. Scientists are all excited about that.
I would be happy to do some more research on the Internet with you. Your question about earth has made me curious about the answer too : - >
It's cool--you're in England--I'm in the U.S. and we can communicate interactively!