This world is lit by His potency

”In the spiritual world there is no need of sunlight, moonlight or stars, nor does any type of electricity exist. If none of these are required in the spiritual world then how can fire exist there? The Supreme Lord is self illuminated and from His transcendental potency the above­ mentioned items obtain their powers and this world is also lit by His potency.”

na tatra suryo bhati na candra tarakam ·
nema vidyuto bhanti kuto’nyam agnih
tameva bhantam anubhati sarvam
tasya bhasa sarvam idam vibhati

PURPORT BY SRI KRSNA BALARAM SWAMIJI

The Supreme Lord is transcendentally effulgent and His name is Lord Krsna. A minute particle of His effulgence is transferred to the sun therefore whatever quantity of heat and light the sun has is directly from the Lord. The moon and the stars are reflected lights of the sun. The spiritual world is self-lit that is why the lights of the sun, moon and starts are not needed there. If the sun is not needed then how can fire be needed there? It means that fire also does not exist in the spiritual world. The same thing is told by Lord Krsna in the Bhagavad Gita (15.6) that the light of the sun, moon and electricity is not needed in His spiritual world. And in (15.12) of the Bhagavad Gita Lord Krsna more clearly specifies about how the sun and the moon receive lighting power from Him. Such is the Lord and anyone who reaches in His spiritual world does not return again to this world to rotate in the cycle of birth and death.

[Svetasvatara Upanisad, 6.14, KBS0095]