Text 46]
Bhāgavatam is the Answer
605
Puruṣa as Kāraṇodakaśāyī Viṣṇu with all the potencies of  mahat-tattva  and the sixteen principles of creative matter and instruments. The creative instruments are eleven, and the ingredients are five, and all of them are products of  mahat  or materialistic ego, and these creations by the Lord in His feature of Kāraṇodakaśāyī Viṣṇu are called  mahākalpa . Creation of Brahmā and dispersion of the material ingredients are called  vikalpa , and creation by Brahmā in each day of his life is called  kalpa . Therefore each day of Brahmā is called a  kalpa , and there are thirty  kalpas  in terms of Brahmā's days, which is also confirmed in the  Bhagavad-gītā  as follows:
sahasra-yuga-paryantam ahar yad brahmaṇo viduḥ rātriṁ yuga-sahasrāntāṁ te 'horātravido janāḥ  (Bg. 8.17)
In the upper planetary system the duration of one complete day and night is equal to one complete year of this earth. This is accepted even by the modern scientist and testified by the astronauts. Similarly, in the region of still higher planetary systems, the duration of day and night is still greater than in the heavenly planets. The four  yugas  are calculated in terms of the heavenly calendars and accordingly are twelve thousand years in terms of the heavenly planets. This is called  divya-yuga , and one thousand  divya-yugas  make one day of Brahmā. Creation during the day of Brahmā is called  kalpa , and creation of Brahmā is called  vikalpa , and when  vikalpas  are made possible by the breathing of Maha-Viṣṇu they are called  mahā-kalpa . There are regular and systematic cycles of these  mahākalpas ,  vikalpas  and  kalpas , and in answer to Mahārāja Parīkṣit's question about them, Śukadeva Gosvāmī answered in the Prabhāsa-khaṇḍa of the  Skanda Purāṇa , and they are as follows:
prathamaḥ śvetakalpas tu dvitīyo nīlalohitaḥ vāmadevas tṛtīyas tu tato gāthāntaroparaḥ rauravaḥ pañcamaḥ proktaḥ ṣaṣṭhaḥ prāṇa iti smṛtaḥ saptamo 'tha bṛhatkalpaḥ kandarpo 'ṣṭamaḥ ucyate savyotha navamaḥ prokta īśāno daśamaḥ smṛtaḥ dhyāna ekādaśaḥ proktas tathā sārasvato 'paraḥ trayodaśa udānas tu garuḍo 'tha caturdaśaḥ kaurmaḥ pañcadaśo jñeyaḥ paurṇamāsī prajāpateḥ ṣoḍaśo nārasiṁhas tu samādhis tu tato 'paraḥ āgneyo viṣṇujaḥ sauraḥ somakalpas tato 'paraḥ dvāviṁśo bhāvanaḥ proktaḥ supumān iti cāparaḥ vaikuṇṭhaś cārciṣas tadvat vallīkalpas tato 'paraḥ