Assalam oalaikum
In ancient times man was under the impression that earth is flat in structure. People used to be scared of traveling for a long distance because they feared that they would fall off from the edge of earth.
It was only in 1597 A.D when Sir Francis Drake happened to sail round the world that it was discovered that the earth is spherical and not flat in shape. More recently, the photographs taken from space provide clear evidence that the earth is spherical.
However, Allah (swt) who is the Master of the entire universe has already told us about this fact in a subtle way. Allah (swt) says in Al-Quran: ‘Seest thou not that Allah merges night into day and he merges day into night?’ (TMQ-31-29)
It requires only some effort to interpret the real meaning of the Quranic verses because as Allah (swt) has said, ‘And we have indeed made Quran easy to understand and remember; then is there anyone who will receive admonition?’ (TMQ- 54:17)
In the Quranic verse 31:29 the word ‘merge’ has been used to denote that the day changes into night gradually and the night changes into day gradually. The transformation does not take place all of a sudden. This shows that the earth is spherical because if the earth had been flat then the change from day to night would have been rather abrupt.
(Allah knows best)
remember me in your prayers
amel soname