When the rays of the two brahmastras combined, a great circle of fire, like the disc of the sun, covered all outer space and the whole firmament of planets

Expressions researched:
"When the rays of the two brahmastras combined, a great circle of fire, like the disc of the sun, covered all outer space and the whole firmament of planets"

Srimad-Bhagavatam

SB Canto 1

When the rays of the two brahmāstras combined, a great circle of fire, like the disc of the sun, covered all outer space and the whole firmament of planets.

SB 1.7.30, Translation and Purport

When the rays of the two brahmāstras combined, a great circle of fire, like the disc of the sun, covered all outer space and the whole firmament of planets.

The heat created by the flash of a brahmāstra resembles the fire exhibited in the sun globe at the time of cosmic annihilation. The radiation of atomic energy is very insignificant in comparison to the heat produced by a brahmāstra. The atomic bomb explosion can at utmost blow up one globe, but the heat produced by the brahmāstra can destroy the whole cosmic situation. The comparison is therefore made to the heat at the time of annihilation.