Check Royal Astronmical Society of Hardvard univeristy's publication on this
...Muslim scientits were calculating earth's accelration a thousand years before europe copied that idea and dramtized the whole affair by citing Gallilio as a great prophet..for saying things which are known to Muslims several hundred years....
adsabs.harvard.edu/abs/1972MNRAS.159..453N
The Earth's acceleration as deduced from al-Biruni's solar data
