Galileo Galilei is the greek astronomer who you claim discovered the earth is round but he most certainly was not before muhamad. Galileo Galilei was born on 15 February 1564 and died in 8 January 1642. His birth date is approximately 444 years ago, for your information the quran was revealed approximately 1500 years ago proving a difference of about 1000 years.
I can let the others slide, but when you state that Galileo was Greek, it just proves your complete ignorance on the subject and the ignorance of whoever it was who told you that.
Galileo was Italian.
The Greeks had proven, by geometric calculations based on the shadow the earth casts on the moon, that the earth was round about a thousand years (give or take a century ) before the birth of Christ.