‘And all the host of heaven will be dissolved,
And the heavens will be rolled together as a scroll,
And all their host will fade away,
As the leaf fades from the vine,
And as a fading leaf from the fig tree.'
This kind of vivid language in respect of heavenly bodies comes regularly on Isaiah's lips to describe both judgment and glory (see especially the parallel in Isaiah 13:10 when speaking of Babylon; and compare Isaiah 24:23; Isaiah 30:26; Isaiah 60:19-20). The ‘host of heaven' could mean sun, moon and stars, but it could also mean the gods they represented, the worship of whom was constantly condemned. Here they are seen as but leaves on a tree, to be dispensed with just as easily. However the point here is that as far as those under judgment are concerned there will be no help for them from the gods and that their last moments will make it seem as though the heavens themselves are dying and ceasing in their function, in a similar way to the leaves on trees when the harvest is past.
Note the extremeness of the language. It is drawn on in Revelation 6:13-14. If it really happened earth would not survive it. But it is not intended to be taken literally. It is stressing how great the catastrophe will be for Edom. They will never see the stars again.