Pisan scientist (7)
I believe the answer is:
galileo
(Other definitions for galileo that I've seen before include "Astronomer - ogle Ali (anag)" , "Great Italian astronomer and physicist of 17th century, suppressed by Church" , "Sixteenth and seventeenth century Italian astronomer tried for heresy" , "Italian astronomer who had trouble with church" , "He said Eppur si muove (But it does move)" .)