Muslims often claim that modern science has confirmed the Quranic description of mountains as “pegs” that stabilize the Earth, presenting it as a miracle revealed 1,400 years ago.

Two key verses are cited:

• Quran 78:7: “And the mountains as pegs?”
• Quran 21:31: “And We placed on the earth firmly set mountains, lest it should shake with them.”

A related verse (16:15) uses the language of “casting” mountains into the earth. Another (41:10) states that Allah “placed” firmly set mountains on the earth “from above it.”

These descriptions, however, conflict with modern geology.

The Idea Predates Islam

The concept of mountains as stabilizers or pegs was already present in the ancient world. The Bible (Jonah 2:6) refers to the “roots of the mountains.” Similar ideas appear in Greek, Mesopotamian, and other Near Eastern traditions that viewed mountains as supports or pillars of the earth. The Quranic language reflects a common ancient understanding rather than advanced scientific insight.

Scientific Problems in the Quranic Description

1. Mountains are not “placed” or “cast” from above Modern geology shows that mountains form primarily through the collision of tectonic plates. When plates converge, crust is pushed upward, forming mountain ranges over millions of years. The process is gradual and internal to the Earth’s crust; mountains are not deposited or thrown onto the surface from above. The Arabic verbs used in the relevant verses (ja‘ala and alqā) convey the idea of placing or casting objects onto something, which does not match the actual mechanism of orogeny.

2. Mountains were not created on the second day of creation Quran 41:9–11 describes the creation of the earth in two days, the placement of mountains, and the determination of sustenance in four days, followed by the fashioning of the heavens. A hadith in Sahih Muslim (reported from Abu Hurayra) states that Allah created the mountains on Sunday, the second day of the creation sequence.

Geological reality is very different:

• The universe is approximately 13.8 billion years old.
• Earth formed about 4.5 billion years ago.
• The planet was initially molten; solid crust and tectonic plates developed much later.
• Mountain-building is an ongoing process that continues today. Old mountains erode and disappear; new ones rise.

The claim that mountains were finished on the second day of a six-day creation sequence is incompatible with this timeline.

3. Not all mountains have deep “roots” that function as pegs While some mountain ranges have deep crustal roots (isostasy), volcanic mountains form from accumulated lava and do not possess the deep stabilizing pegs imagined in the ancient model. Mountains are dynamic features, not permanent fixtures hammered into the earth.

Apologetic Responses and Replies

“The Quran is a book of guidance, not science.” Once a text makes specific claims about how natural features were formed or when they were created, those claims become subject to scientific evaluation. Guidance that includes incorrect descriptions of the physical world still contains errors.

“Science is unreliable and always changing.” While scientific theories are refined, well-established facts (the spherical shape of Earth, plate tectonics as the mechanism of mountain formation, the age of the Earth) are not reversed. The formation of mountains through plate tectonics is one such established fact.

“The translations are wrong.” Multiple word-for-word and scholarly Muslim translations of Quran 41:10 render the phrase as mountains being placed or made “from above it” or “over its surface.” The consistent rendering across independent sources indicates that the meaning is not an invention of critics.

Questions Raised by the Text

If the audience of seventh-century Arabia could not understand plate tectonics, why describe mountain formation at all in language that later proved inaccurate? Clearer formulations were available (for example, simply stating that mountains stabilize the earth without the imagery of placing or casting them from above). The chosen language matches the visual appearance of mountains and the cosmological ideas of the time rather than the actual geological process.

The Quran’s repeated claim that its verses are clear and easy to understand (54:17, 12:2, 27:1–2, 41:3) becomes difficult to reconcile with passages that require elaborate reinterpretation to avoid conflict with established science.

Some apologists argue that the “days” of creation are not ordinary days but unspecified long periods. Yet other verses quantify a divine day as a thousand years (22:47, 32:5). Even under that interpretation, six thousand years falls far short of the billions of years required by cosmology and geology. Early Muslim authorities, including Ibn Abbas and others recorded by Ibn Kathir, understood the creation days in terms of the thousand-year equivalence.

Conclusion

The description of mountains as pegs or stabilizers placed on the earth reflects a pre-scientific understanding common in the ancient Near East. It does not demonstrate knowledge of plate tectonics, isostasy, or the deep-time history of the Earth. When evaluated against modern geology, the relevant Quranic statements are inaccurate. The attempt to present them as scientific miracles rests on selective reading and post-hoc reinterpretation rather than on the plain sense of the text and its historical context.