In Verse 16, it was said: وَأَلْقَىٰ فِي الْأَرْ‌ضِ رَ‌وَاسِيَ أَن تَمِيدَ بِكُمْ (And He placed mountains on the earth, lest it should shake with you). The word: رَ‌وَاسِيَ (rawasiya) is the plural of رَاسیۃ (rasiyah) which denotes a huge mountain. The word: تَمِیدَ (tamida) is a derivation from the verbal noun: مِيدَ (mayd) which means to shake or swing or sway from side to side (due to loss of balance).

The sense of the verse is that Allah Ta’ ala has not made the sphere of the Earth from components which are not solid and balanced, therefore, it is heavier on one side and lighter on some other. Its necessary outcome was that the Earth was to be taken as stationary, as commonly held by early thinkers; or, taken to be orbitally moving, as determined by some early and most modern scientists. Under both these views, this phenomenon would have caused terrestrial turbulence which is identified as shaking, swinging or swaying from side to side. To stop this turbulence and to provide a balance for the terrestrial composition, Allah Ta` ala placed on the Earth the weight of mountains so that it would not shake. As for its orbital movement like all planets which is the commonly held view from Pythagoras to modern scientists made more explicit through contemporary experiments, it is something which the Holy Qur’ an neither affirms nor rejects. In fact, this possible turbulence which has been stopped through the use of mountains should be more conducive to this orbital movement which is credited to the Earth like other planets. Allah knows best.