Heikki Ruskeepää, PhD, University of Turku, Finland
I began the use of Mathematica 2 in 1992. I can still remember my excitement when I began to realize the new possibilities that Mathematica opened for scientific calculation, mathematical research, and teaching mathematics.
I soon wrote a guide about Mathematica in Finnish. After some years, my wife Marjatta asked if I should write a book about Mathematica in English. Indeed, I then began to write a book that later got the name Mathematica Navigator; this name was suggested by my friend Pertti Näykki, the former reseller of Mathematica in Finland. Later, I wrote two new editions of this book.
In the early times of Mathematica, showing an animation was done by preparing some tens of separate figures and then by showing them in a rapid sequence. I was proud to be able to show a ball, like the Earth, and a smaller ball, like a satellite, moving around it. Now, the same can be done very simply, as the following example shows.