drstvastra-tejas tu tayos
tril lokan pradahan mahat
dahyamanah prajah sarvah
Translation by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
All the population of the three worlds was scorched by the combined heat of the weapons. Everyone was reminded of the samvartaka fire which takes place at the time of annihilation.
Purport by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
The three worlds are the upper, lower and intermediate planets of the universe. Although the brahmastra was released on this earth, the heat produced by the combination of both weapons covered all the universe, and all the populations on all the different planets began to feel the heat excessively and compared it to that of the samvartaka fire. No planet, therefore, is without living beings, as less intelligent materialistic men think.