In the Quran, Sura 79 verse 30 uses the Arabic word دَحَاهَا to describe the earth. Typically this word is translated as “egg-shaped” or “spread”.
[79:30] He made the earth egg-shaped.
وَالْأَرْضَ بَعْدَ ذَٰلِكَ دَحَاهَا
Below is a word by word breakdown of the verse:
The word دَحَاهَا comes from the following root with the corresponding meanings.
Today in western culture if we think of an egg we typically think of a chicken egg, but the chicken was not introduced to the Arabian Peninsula during the time of the revelation of the Quran 1400 years ago. Instead, the common bird and egg that at that time would have been the Arabian ostrich. Unfortunately, this bird went extinct in the 20th century.
The connection with the word daḥāhā and the Arabian ostrich becomes more apparent by understanding the specific way the ostrich would lay its eggs was by spreading out the sand before laying on top of it. This is why the root word has the meanings to spread and that of an egg.
Despite the animal being extinct God has blessed us with an egg that has been discovered preserved. Below is an image of an Arabian ostrich egg that was gifted from the poet C.M. Doughty to archeologist T.E. Lawrence.
If we look at the shape of the Earth from space, we see that it flattened at the poles and bulges at the Equator, forming the shape described as an oblate spheroid. The radius of the earth from the center to the North Pole is 6356.752km, while the radius of the center of the earth to the equator is 6378.137km. This makes the distance from the center to the Equator ~0.33% longer than the distance from the center to the North Pole.
When we compare the shape of the Earth to that of the Arabian ostrich egg we see that out of all eggs this shape is the closest egg to an oblate spheroid. But there is more to this description.
If we were able to do a cross-section of the Earth we could divide the Earth into four parts.
Earth’s inner core is the innermost geologic layer of the Earth. It is primarily a solid ball with a radius of about 1,220 kilometers (760 miles), which is about 20% of the Earth’s radius. We have no samples of the Earth’s core available for direct measurement, but from the analysis of seismic waves and the magnetic field, the inner core is believed to be composed of an iron-nickel alloy with some other elements. The temperature at the inner core’s surface is estimated to be approximately 5700 K (5430 °C or 9806 °F), which is about the temperature at the surface of the Sun.
Earth’s outer core is a fluid layer of about 2,400 km (1,500 mi or 40% of Earth’s radius) thick and composed of mostly liquid iron and nickel. Its outer boundary lies 2,890 km (1,800 mi) beneath Earth’s surface. The transition between the inner core and outer core is located approximately 5,150 km (3,200 mi) beneath the Earth’s surface.
Earth’s mantle: The mantle is the mostly-solid bulk of Earth’s interior. The mantle lies between Earth’s dense, super-heated core and its thin outer layer, the crust. The mantle is about 2,900 kilometers (1,802 miles 40% of Earth’s radius) thick, and makes up a whopping 84% of Earth’s total volume.
The Earth’s crust is a thin shell on the outside of the Earth, accounting for less than 1% of Earth’s volume. The Earth’s crust ranges from 5–70 kilometers (3.1–43.5 mi) in depth.
While we do not have a cross-section of an Arabian Ostrich egg to compare this against, if we compare this structure to a chicken egg. Upon doing so we see more similarities between the Earth and an egg. Where just like the Earth we have a core yolk, the albumin (egg white), and the thin shell exterior similar to the crust of the Earth.
But the word دَحَاهَا, as mentioned, has another meaning as well as egg-shaped, it also means to spread. So how does this relate to the makeup of the Earth?
In the following verse God describes the mountains in the following way:
[27:88] When you look at the mountains, you think that they are standing still. But they are moving, like the clouds. Such is the manufacture of GOD, who perfected everything. He is fully Cognizant of everything you do.
One of the incredible facets of planet Earth is plate tectonics. The Earth has seven major plates that form the Earth’s crust. Each of these plates floats onto of the Earth’s mantle. Each year each plate moves about an inch. When these plates collide into one another the plate that is stronger moves below and the plate that is weaker moves on top. Then over millions of years this accumulation in moving causes the formation of mountains.
[88:17] Why do they not reflect on the camels and how they are created? [88:18] And the sky and how it is raised. [88:19] And the mountains and how they are constructed. [88:20] And the earth and how it is built.
If we wanted to describe a model of the Earth’s plates, a common model is to imagine an egg that is cracked yet not broken, where each of the remaining pieces would be floating on top of the contents of the egg with the ability to collide into one another. Because Earth’s crust is less dense than the mantle below, the crust “floats” on the mantle as it “spreads”.
So when the Quran describes the Earth as دَحَاهَا, not only is it describing the physical shape of the Earth, but also it is providing a depiction of the cross-section of the Earth, as well as describing that it is being spread in the form of continental drift.
Additionally, the Quran describes the mountains as pegs or stakes in the following verse, as they hold the plates of the Earth in place when they collide into one another.
[78:6] Did we not make the earth habitable? [78:7] And the mountains pegs (stabilizers)?
While in other verses, God describes the mountains as stabilizers, when it uses the term rawāsiya / رَوَاسِيَ . This word comes from the root ر س و which means to stabilize or to set an anchor.
[16:15] And He placed stabilizers (mountains) on earth, lest it tumbles with you, as well as rivers and roads, that you may be guided.
[21:31] And we placed on earth stabilizers, lest it tumbles with them, and we placed straight roads therein, that they may be guided.
[31:10] He created the heavens without pillars that you can see. He established on earth stabilizers (mountains) lest it tumbles with you, and He spread on it all kinds of creatures. We send down from the sky water to grow all kinds of beautiful plants.