"That supreme abode of Mine is not illumined by the sun or moon, nor by fire or electricity. Those who reach it never return to this material world."
This verse gives a description of that eternal sky. Of course we have a material conception of the sky, and we think of it in relationship to the sun, moon, stars and so on, but in this verse the Lord states that in the eternal sky there is no need for the sun nor for the moon nor electricity or fire of any kind because the spiritual sky is already illuminated by the brahmajyoti, the rays emanating from the Supreme Lord. We are trying with difficulty to reach other planets, but it is not difficult to understand the abode of the Supreme Lord. This abode is referred to as Goloka. In the Brahma-saṁhitā (5.37) it is beautifully described: goloka eva nivasaty akhilātma-bhūtaḥ. The Lord resides eternally in His abode Goloka, yet He can be approached from this world, and to this end the Lord comes to manifest His real form, sac-cid-ānanda-vigraha (Bs. 5.1). When He manifests this form, there is no need for our imagining what He looks like. To discourage such imaginative speculation, He descends and exhibits Himself as He is, as Śyāmasundara. Unfortunately, the less intelligent deride Him because He comes as one of us and plays with us as a human being. But because of this we should not consider the Lord one of us. It is by His omnipotency that He presents Himself in His real form before us and displays His pastimes, which are replicas of those pastimes found in His abode.