In early times, people believed that the earth is flat. For centuries, men were
afraid to venture out too far, lest they should fall off the edge. Sir Francis
Drake was the first person who proved that the earth is spherical when he
sailed around it in 1597. Consider the following Qur’aanic verse regarding
the alternation of day and night: “Seest thou not that Allah merges Night
into Day And He merges Day into Night?” [Al-Qur’aan 31:29]
Merging here means that the night slowly and gradually changes to day and
vice versa. This phenomenon can only take place if the earth is spherical. If
the earth was flat, there would have been a sudden change from night to day
and from day to night.
The following verse also alludes to the spherical shape of the earth: “He created the heavens And the earth In true (proportions): He makes the
Night Overlap the Day, and the Day Overlap the Night.” [Al-Qur’aan 39:5]
The Arabic word used here is Kawwara meaning ‘to overlap’ or ‘to coil’– the
way a turban is wound around the head. The overlapping or coiling of the day
and night can only take place if the earth is spherical.
The earth is not exactly round like a ball, but geo-spherical i.e. it is flattened
at the poles. The following verse contains a description of the earth’s shape:

“And the earth, moreover, Hath He made egg shaped.”
[Al-Qur’aan 79:30]

The Arabic word for egg here is dahaha, which means an ostrich-egg. The
shape of an ostrich-egg resembles the geo-spherical shape of the earth. Thus
the Qur’aan correctly describes the shape of the earth, though the prevalent
notion when the Qur’aan was revealed was that the earth is flat.