How did Galileo come to the conlcusion that the moon has mountains on its surface?

Please don't give me the answer! Just a website that contains the answer would be great, thanks.

3 answers

http://galileo.rice.edu/lib/student_work/astronomy95/moon.html

http://solarsystem.nasa.gov/scitech/display.cfm?ST_ID=2259
oh my goodness, thank you so much!
You're very welcome. :-)