The moon is considered one of the planets of the heavenly kingdom. One can be promoted to this planet by executing different sacrifices recommended in the Vedic literature, such as pious activities in worshiping the demigods and forefathers with rigidity and vows. But one cannot remain there for a very long time. Life on the moon is said to last ten thousand years according to the calculation of the demigods. The demigods time is calculated in such a way that one day (twelve hours) is equal to six months on this planet. It is not possible to reach the moon by any material vehicle like a sputnik, but persons who are attracted by material enjoyment can go to the moon by pious activities. In spite of being promoted to the moon, however, one has to come back to this earth again when the merits of his works in sacrifice are finished. This is also confirmed in Bhagavad-gita (9.21): te tam bhuktva svarga-lokam visalam ksine punye martya-lokam visanti.