Allaah, the Most High said:
He makes the Night overlap the Day, and the Day overlap the Night
[Surah Zumar (39): 5]
It is interesting to note that the Arabic word “Yukawwir” (meaning, “to wind”, or “to cause to go round successively”) and the Qur’anic description of the Day as overlapping the Night and of the Night as ovelapping the Day are in accord with the scientific fact verified in the 20th century by spacemen - that the Earth has a global shape.
http://www.gupistan.com/gallery/1/globalearth_1.gif
Ad-Dahak, one of the early Muslims, said, “Meaning, He wraps the Day around the Night and wraps the Night around the Day.” [Tafsir al-Qurtubi]
What also gave evidence to the fact that the earth is rounded (before man actually saw it with his eyes) is the difference in times across the earth. For example, when it is dawn in one place, at the very same time, it is evening or night or noon or sunset in other places. Hence, a complete day, in all of its stages is in existence at any one time. This indicates the roundness of the Earth.
http://www.gupistan.com/gallery/1/globalearth_2.gif
The above diagram shows that when the earth is round, as the Qur’an confirms, then it is possible for it to be day in one region and night in another region
[These materials translated & prepared by Abu Iyaad
from ‘Jaghraafiyyah Tad’u Ilal-Imaan’ of Marwan Hasan Mahmood,
with additional notes and comments.]
SUBHAN’ALLAH!
Rabbee zidnee `ilmaa My Lord! Increase me in knowledge.[20:114]
The Prophet (sallallaahu 'alayhe wa sallam) said:
“Whoever sets out on a path to seek knowledge, Allaah will make easy his path to Paradise.”
[Saheeh Muslim]