Our senses are so imperfect that we cannot even see all the planets that exist in the material sky. Vedic literature gives us information of many worlds that exist here. But one should hanker after the spiritual sky and the supreme kingdom. When one reaches the supreme kingdom, he doesn't have to return to the material world.
Now, a question may be raised: how do we approach the abode of the Supreme Lord? In Chapter Eight, verses 5-8, the means for approaching the Lord's supreme abode are given: At the time of death, if one thinks of Krsna and remembers the form of Krsna, and then quits the present body, he surely approaches the spiritual kingdom. Just as the transcendental nature of the Lord is  sac-cid-ananda-vigraha , so the Lord has His form, but this form is eternal. This present body of ours is not  sac-cid-ananda . This body is asat, or perishable, full of ignorance, and not happy.
The Lord says that when one quits this material body remembering the form of Sri Krsna, he at once achieves his  sac-cid-ananda-vigraha —the spiritual existence. This also applies to rebirth in this world. A man dies when his next birth has been decided by higher authorities. The acts of this life are a preparation ground for the next life. We are preparing for the next life by the activities of this life. So, if we make preparations to go to the abode of the Lord, we get a spiritual body, or spiritual nature, like the Lord has.
Now, there are different kinds of transcendentalists, as we have already explained. There is the  Brahman-Vadin , the  Paramatman-Vadin , and the devotee. In the spiritual sky, or  brahma-jyoti , there are innumerable spiritual planets. The number of these planets is far greater than all the universes of the material world. The spiritual world represents three-fourths of the Creation. One-fourth of the Creation consists of innumerable universes like this one. Each universe has millions and millions of planets, but all of these universes together comprise only one-fourth of the whole Creation.
Now, one who wishes to go to the spiritual abode, and wishes to enjoy the association of the Supreme Lord, enters into a planet of the spiritual sky. There are many names for these planets. Any transcendentalist who, at the time of death, thinks of the  brahma-jyoti , or Supersoul or Sri Krsna, enters the spiritual sky, but only the devotees may go to the Lord. The Lord further says that there is no doubt of this. One should not disbelieve. When the Lord speaks, we should not reject any part of what He says. Arjuna, whom we should emulate, says, "I believe everything that You have said." The Lord tells us that at the time of death, whoever thinks of Him will enter into the spiritual sky. There should be no doubt of this.