As this body, we have got this body on certain date, and it has got to be annihilated at a certain date, similarly, this gigantic cosmology, material manifestation, it has a date of creation, and it, it stays for some time... Everything material, there are six changes. First of all, birth; then staying for some time; then growing; then producing some by-products; and then dwindling; and then finish. Exactly like our body. Just like this body is born at a certain date, then it grows, it stays, it produces some by-product. From this body, many children come out-by-product. Then it becomes old, declining. And then one day, finished. This is called ṣaḍ-vikāra, six changes. Six changes.
So similarly, there are six changes of this material world also, because it is also material product. So as I and you enter in our body, similarly viṣṭabhya aham, Kṛṣṇa says He enters within this material world. Therefore the creation takes place, it grows, it gives off so many by-products, and then again there will be destruction. It is said at the time of destruction, first of all there will be no rain, no rain for hundreds of years. So everything will dry up and die, practically by continuous sunshine. And it is said the sunshine will be very, very powerful. Twelve times powerful. So everything will be ablaze, blazing into fire. Then there will be rain. As we have experience, after excessive heat, there is cloud and rain, so there will be rain, and everything will be absorbed into water, and the water will be evaporated. In this way, this material world, cosmic manifestation will be no more. Again there will be creation, mahat-tattva. Bhūtvā bhūtvā pralīyate (BG 8.19). That is stated in the... This material world comes into existence and stays for some time, again becomes annihilated.