The science of modern cosmology, observational and theoretical, clearly indicates that, at one point in time, the whole universe was nothing but a cloud of 'smoke' (i.e. an opaque highly dense and hot gaseous composition). This is one of the undisputed principles of standard modern cosmology. Scientists now can observe new stars forming out of the remnants of that 'smoke'. The illuminating stars we see at night were, just as was the whole universe, in that 'smoke' material. God said in the Quran:
Then He turned to the heavens when it was smoke...
[Noble Quran 41:11]
Because the earth and the heavens above (the sun, moon, stars, planets, galaxies, etc.) have been formed from this same 'smoke' we conclude that the earth and the heavens were one connected entity. Then out of this homogeneous 'smoke', they formed and separated from each other. God said in the Quran:
Have not those who disbelieved known that the heavens and the earth were one connected entity, then We separated them?..
[Noble Quran 21:30]
Professor Alfred Kroner is one of the world's well-known geologists. He is a Professor of the Department of Geosciences, University of Mainz, Mainz, Germany. He said, "Thinking where Muhammad came from .. I think it is almost impossible that he could have known about things like the common origin of the universe, because scientists have only found out within the last few years with very complicated and advance technological methods that this is the case." (From 'This is the Truth' [video]). Also he said, "Somebody who did not know something about nuclear physics fourteen hundred years ago could not, I think, be in a position to find out from his own mind, for instance, that the earth and the heavens had the same origin."
Look closer to the heaven surrounding the earth. We call it the 'sky'. Notice the clouds? What are they?
The Quran on Clouds