The splitting is mentioned in other verses as well:

 {وَيَوْمَ تَشَقَّقُ السَّمَاءُ بِالْغَمَامِ}

(And [mention] the Day when the heaven will split open with [emerging] clouds) (Al-Furqaan: 25)

We believe in these cosmic phenomena and that they will happen certainly but How?

We do not have to know, but rather we have to know that the sky will be in a different new shape and will end with a condition that we have never seen. Not only the sky but rather all the universe would be out of its stability and system which we are familiar with.