Nice demonstration

Some spelling errors:

(Java Simulaions in Physics)
should be
(Java Simulations in Physics)  (you left out a "t")

"16 centry" should be "16th century"

"Danish bobleman Tycho Brahe" should be "Danish nobleman Tycho Brahe"

Also, someplace I saw "summerized" which means "made ready for summertime" but you want "summarized".  To "summerize" is to fix the air conditioner, for example.

Sorry - I know you start with a different language - just trying to help
Peter