What is the interpretation of the verse: "The heavens are almost torn apart thereby," and does it mean that the heaven is solid? And why did Allah use "torn apart/split asunder" for the heaven and "cleave asunder" for the earth?

The meaning of Allah's saying: (And they say, "The Most Merciful has taken [for Himself] a son." You have certainly produced a grievous thing. The heavens almost rupture therefrom and the earth splits open and the mountains collapse in devastation) is a severe reproach and condemnation for those who claim that Allah has a son, such as the Christians, Jews, and polytheists. They have indeed uttered a greatly evil and reprehensible statement. The universe almost reacts to the atrocity of this statement; the heavens almost rupture, the earth splits open, and the mountains collapse. As for the diversification of the verbs "yatafattarna" (rupture) and "tanshaqqu" (splits open) in the verse, most scholars are of the opinion that they both carry the same meaning, which is splitting, and they were combined for linguistic variation, not for a difference in meaning. It was also said that "al-infitar" here means falling, and "al-inshiqaq" means sinking into the earth.