1400 years ago people believed that objects fall intact. Nobody believed that a falling object can turn into ash. Today we know this is false.
Meteors burn up when they hit the Earth's atmosphere. Why doesn't the space shuttle?A meteor moving through the vacuum of space typically travels at speeds reaching tens of thousands of miles per hour. When the meteor hits the atmosphere, the air in front of it compresses incredibly quickly. When a gas is compressed, its temperature rises. This causes the meteor to heat up so much that it glows. The air burns the meteor until there is nothing left.
When those meteorites enter our atmosphere the heat generated on entry burns them into ashes. This was only known recently, however this was portrayed in the Quran 1400 years before it was discovered.
They would think that they are clouds because their ash looks like clouds.
How could an illiterate man who lived 1400 years ago have known that meteorites turn into cloud-like ash?
The Quran (Koran, the book of Islam) contains scientific knowledge that could not have been known 1400 years ago. It ranges from basic arithmetics to the most advanced topics in astrophysics. You are invited to go through those miracles and judge for yourself.