Bg Introduction
In the effulgent rays of the spiritual sky there are innumerable planets floating. The brahmajyoti emanates from the supreme abode, Krsnaloka, and the anandamaya-cinmaya planets, which are not material, float in those rays. The Lord says, na tad bhasayate suryo na sasanko na pavakah. yad gatva na nivartante tad dhama paramam mama. One who can approach that spiritual sky is not required to descend again to the material sky. In the material sky, even if we approach the highest planet (Brahmaloka), what to speak of the moon, we will find the same conditions of life, namely birth, death, disease and old age. No planet in the material universe is free from these four principles of material existence. Therefore the Lord says in Bhagavad-gita, abrahma-bhuvanal lokah punar avartino 'rjuna. The living entities are traveling from one planet to another, not by a mechanical arrangement but by a spiritual process. This is also mentioned: yanti deva-vrata devan pitrn yanti pitr-vratah. No mechanical arrangement is necessary if we want interplanetary travel. The Gita instructs: yanti deva-vrata devan. The moon, the sun and higher planets are called Svargaloka. There are three different statuses of planets: higher, middle and lower planetary systems. The earth belongs to the middle planetary system. Bhagavad-gita informs us how to travel to the higher planetary systems (Devaloka) with a very simple formula: yanti deva-vrata devan. One need only worship the particular demigod of that particular planet and in that way go to the moon, the sun or any of the higher planetary systems.
Yet Bhagavad-gita does not advise us to go to any of the planets in this material world because even if we go to Brahmaloka, the highest planet, through some sort of mechanical contrivance by maybe traveling for forty thousand years (and who would live that long?), we will still find the material inconveniences of birth, death, disease and old age. But one who wants to approach the supreme planet, Krsnaloka, or any of the other planets within the spiritual sky, will not meet with these material inconveniences. Amongst all of the planets in the spiritual sky there is one supreme planet called Goloka Vrndavana, which is the original planet in the abode of the original Personality of Godhead Sri Krsna. All of this information is given in Bhagavad-gita, and we are given through its instruction information how to leave the material world and begin a truly blissful life in the spiritual sky.
Bg 2.51 P Contents of the Gita Summarized
Owing to ignorance, one does not know that this material world is a miserable place where there are dangers at every step. Out of ignorance only, less intelligent persons try to adjust to the situation by fruitive activities, thinking that the resultant actions will make them happy. They do not know that no kind of material body anywhere within the universe can give life without miseries. The miseries of life, namely birth, death, old age and diseases, are present everywhere within the material world. But one who understands his real constitutional position as the eternal servitor of the Lord, and thus knows the position of the Personality of Godhead, engages himself in the transcendental loving service of the Lord. Consequently he becomes qualified to enter into the Vaikuntha planets, where there is neither material, miserable life nor the influence of time and death. To know one's constitutional position means to know also the sublime position of the Lord. One who wrongly thinks that the living entity's position and the Lord's position are on the same level is to be understood to be in darkness and therefore unable to engage himself in the devotional service of the Lord. He becomes a lord himself and thus paves the way for the repetition of birth and death. But one who, understanding that his position is to serve, transfers himself to the service of the Lord, at once becomes eligible for Vaikunthaloka. Service for the cause of the Lord is called karma-yoga or buddhi-yoga, or in plain words, devotional service to the Lord.