In the realms of modern science, we know that:
1. Nuclear Fission is the process by which an atom is split open, releasing tremendous amounts of energy.
2. Fusion is the process of two atoms being smashed together, causing them to FUSE, a process that we can NOT imitate which the sun uses to produce its awesome, seemingly unending source of solar energy. If fusion is ever achieved by mankind, it would provide a limitless source of energy. It would literally provide a minature sun that would never burn out by which we could power every city on earth. Scientists continually research how to perform the process of Fusion.
In the spiritual application we know from the prophet Ezekiel, that in the last days, Ephraim and Yudah will be joined together as ONE stick. The Gentiles who love Jesus but have forsake Torah will return to Torah and the Jews who have foresaken Jesus but kept the Torah, will cleave to Jesus. Both will become one as Yisrael returns to the Torah and Messiah.
This spiritual nuclear fusion, this fusion of the two spiritual atoms -- the Gentile pagan church shedding her paganism and the Jewish pagans shedding their paganism, becoming one in the Jewish Messiah, one in observing Torah, will create a Bride that WILL BURN AS BRIGHT AS THE SUN AND WILL NEVER BURN OUT!!!