do not change: the outer circumference is above, and the centre is below. The surface of the earth, which Allah has laid out for His creatures and made firm with mountains, is where people, animals, trees, plants, mountains and flowing rivers are found.
As for the other side of the earth, the sea surrounds it, and there are no human beings or anything associated with them there. Even supposing someone were there, they would be on the earth’s surface. Those on one side would not be beneath those on the other, nor vice versa. Likewise, the celestial spheres encompass the centre, yet neither side of a sphere is beneath the other, nor is the north pole beneath the south pole, nor vice versa.
Although the north pole is the one visible to us above the earth, its elevation depends on people’s distance from the equator. For example, for someone thirty degrees from the equator, the pole’s elevation is thirty degrees. This is what is called the latitude of a place. Just as the various parts around the earth’s surface and those of the spherical heavens are neither above nor beneath one another, so too the animals, plants and heavy objects on the earth cannot be said to be beneath those on its other side. This is merely something a person imagines; it is ‘beneath’ only in a relative sense. If an ant were walking beneath a ceiling, the ceiling would be above it, even though its feet faced the ceiling.
Likewise, someone suspended upside down is beneath the sky, even though their feet point towards it. In the same way, when a person is on one side of the earth or a celestial sphere, they imagine that the other side is beneath them. No two people who hold that the celestial spheres are spherical disagree on this matter.
The sphericity of the celestial spheres is not only the position of astronomers and mathematicians; it is also the position of Muslim scholars, as mentioned by Abū al-Hasan ibn al-Munādī, Abū Muhammad ibn Hazm and Abū al-Faraj ibn al-Jawzī