How do we respond to those who say that the Day of Judgment is merely a planetary explosion and the end of its lifespan?

If the speaker intends by the planet's explosion that all things end there, this is incorrect, and his belief is an act of disbelief (kufr) for denying the Last Day. However, if he means what Dr. Zaghloul El-Naggar mentioned in his interpretation of the verse: "The Day when We will fold the heaven like the folding of a [written] scroll for [its] records" (Quran 21:104), that Allah will fold the universe to become a second primordial mass that will explode by Allah's command to create another earth and heavens, and then the afterlife begins, then he has predecessors among contemporary scholars.