436
Śrīmad-Bhāgavatam
[Canto 2, Ch. 8]
yasmin —in which;  karma —actions;  samāvāyaḥ —accumulation;  yathā —as far as;  yena —by which;  upagrhyate —takes over;  guṇānām —of the different modes of material nature;  guṇinām —of the living beings;  ca —also;  eva —certainly;  pariṇāmam —resultant;  abhīpsatām —of the desires.
TRANSLATION
Then again, kindly describe how the proportionate accumulation of the resultant actions of the different modes of material nature act upon the desiring living being, promoting or degrading him among the different species of life, beginning from the demigods down to the most insignificant creatures.
PURPORT
The actions and reactions of all works in the material modes of nature, either in the minute form or in the gigantic form, are accumulated, and thus the result of such accumulated actions and reactions of  karma , or work, become manifested in the same proportion. How such actions and reactions take place, what are the different procedures, and in what proportion they act are all the subject matter of Mahārāja Parīkṣit’s inquiries from the great  brāhmaṇa , Śukadeva Gosvāmī.
Life in the higher planets, known as the abode of the denizens of heaven, is obtained not by the strength of spacecraft (as is now being contemplated by the inexperienced scientists), but by works done in the mode of goodness.
There is even restriction on the very planet where we are now living for entrance of foreigners to a country where the citizens are more prosperous. For example, the American government has many restrictions for entrance of foreigners from less prosperous countries. The reason is that the Americans do not wish to share their prosperity with any foreigner who has not qualified himself as a citizen of America. Similarly, the same mentality is prevailing in every other planet also where there are more and more intelligent living beings residing. The higher planetary living conditions are all in the mode of goodness, and anyone desiring to enter the higher planets like the moon, sun, Venus, etc., must qualify thoroughly by activity in complete goodness.
Mahārāja Parīkṣit’s inquiries are on the basis of proportionate actions of goodness which qualify one in this planet to be promoted to the highest regions of the universe.