Surah al-Ma`arij (The Ways of Ascent) 70 : 9

Explantory Notes 

he Qur'an mentions in several places that great celestial events will take place on that promised day, and as a result change will affect different celestial bodies in their positions and characteristics, as well as their inter-relations. One of these events changes the sky making it like molten lead, or molten metals generally as signified by the Arabic word used here, al-muhl. These statements should be reflected upon by physicists and astronomers. They suggest that most probably celestial bodies are composed of metals that have melted and taken gas form, which is a stage far beyond that of melting by excessive heat. It is possible that they will lose their heat on the Day of Judgement and cool down to a fluid stage, changing their present status. Elsewhere in the Qur'an we have the following statement as a mark of the Day of Judgement: "When the stars fall and disperse." (81: 2)

At any rate, this is only one possible explanation, which may or may not be worth further study by scientific researchers. As for us, we read the text and look at the awesome image painted, with the sky becoming like molten metal and the mountains like tufts of wool. We also contemplate what is beyond this image of frightening events that leave their marks on people in an unusual way which the Qur'an accurately describes.