فَإِذَا انشَقَّتِ السَّمَاءُ فَكَانَتْ وَرْدَةً كَالدِّهَانِ (37)
(55:37) (What will happen) when the heaven will be split asunder and will become crimson like leather? *34
*34) This refers to the Day of Resurrection. Bursting of the heavens implies loosening of the discipline of the heavens, scattering of the celestial bodies, upsetting of the system of the heavens. And the meaning of `reddening like red leather" is that during that great upheaval anyone who looks up towards the sky, will feel as though the entire heavens were on fire.