BG 15.12 yad aditya-gatam tejo... cited

Expressions researched:
"jagad bhasayate 'khilam" |"tat tejo viddhi mamakam" |"yac candramasi yac cagnau" |"yad aditya-gatam tejo"

BG Chapters 13 - 18

BG 15.12, Translation and Purport:

The splendor of the sun, which dissipates the darkness of this whole world, comes from Me. And the splendor of the moon and the splendor of fire are also from Me.

The unintelligent cannot understand how things are taking place. But one can begin to be established in knowledge by understanding what the Lord explains here. Everyone sees the sun, moon, fire and electricity. One should simply try to understand that the splendor of the sun, the splendor of the moon, and the splendor of electricity or fire are coming from the Supreme Personality of Godhead. In such a conception of life, the beginning of Kṛṣṇa consciousness, lies a great deal of advancement for the conditioned soul in this material world. The living entities are essentially the parts and parcels of the Supreme Lord, and He is giving herewith the hint how they can come back to Godhead, back to home.

From this verse we can understand that the sun is illuminating the whole solar system. There are different universes and solar systems, and there are different suns, moons and planets also, but in each universe there is only one sun. As stated in Bhagavad-gītā (10.21), the moon is one of the stars (nakṣatrāṇām ahaṁ śaśī). Sunlight is due to the spiritual effulgence in the spiritual sky of the Supreme Lord. With the rise of the sun, the activities of human beings are set up. They set fire to prepare their foodstuff, they set fire to start the factories, etc. So many things are done with the help of fire. Therefore sunrise, fire and moonlight are so pleasing to the living entities. Without their help no living entity can live. So if one can understand that the light and splendor of the sun, moon and fire are emanating from the Supreme Personality of Godhead, Kṛṣṇa, then one's Kṛṣṇa consciousness will begin. By the moonshine, all the vegetables are nourished. The moonshine is so pleasing that people can easily understand that they are living by the mercy of the Supreme Personality of Godhead, Kṛṣṇa. Without His mercy there cannot be sun, without His mercy there cannot be moon, and without His mercy there cannot be fire, and without the help of sun, moon and fire, no one can live. These are some thoughts to provoke Kṛṣṇa consciousness in the conditioned soul.

SB Canto 5

SB 5.16.4, Purport:

The material world is only one fourth of the Supreme Personality of Godhead's creation, but it is unlimited and impossible for anyone to know or describe, even with the qualification of a life as long as that of Brahmā, who lives for millions and millions of years. Modern scientists and astronomers try to explain the cosmic situation and the vastness of space, and some of them believe that all the glittering stars are different suns. From Bhagavad-gītā, however, we understand that all these stars (nakṣatras) are like the moon, in that they reflect the sunshine (BG 15.12). They are not independent luminaries. Bhūloka is explained to be that portion of outer space through which the heat and light of the sun extend. Therefore it is natural to conclude that this universe extends in space as far as we can see and encompasses the glittering stars. Śrīla Śukadeva Gosvāmī admitted that to give full details of this expansive material universe would be impossible, but nevertheless he wanted to give the King as much knowledge as he had received through the paramparā system. We should conclude that if one cannot comprehend the material expansions of the Supreme Personality of Godhead, one certainly cannot estimate the expansiveness of the spiritual world.