सहस्रयुगपर्यन्तमहर्यद् ब्रह्मणो विदुः | रात्रिं युगसहस्रान्तां तेऽहोरात्रविदो जनाः
sahasrayugaparyantamaharyad brahmaṇo viduḥ . rātriṃ yugasahasrāntāṃ te.ahorātravido janāḥ
ആയിരം യുഗങ്ങൾ ചേർന്ന ബ്രഹ്മാവിന്റെ പകലിനെയും, ആയിരം യുഗങ്ങൾ ചേർന്ന രാത്രിയെയും അറിയുന്നവർ അഹോരാത്രങ്ങളെ അറിയുന്നവരാണ്.
Those poeple who are knowers of what day and night are, know the day of Brahma which ends in a thousand yugas [The four yugas (in the human worlds), viz Satya, Treta, Dwapara, and Kali are made up of 4,320,000 years. This period multiplied by a thousand constitutes one day of Brahma. His night also extends over an eal period. See M.S. and V.S.A.], and His night which ends in a thousand yugas.
പ്രപഞ്ചത്തിന്റെ സൃഷ്ടിയെയും പ്രകടനത്തെയും ബ്രഹ്മാവിന്റെ പകലായും, പ്രപഞ്ചത്തിന്റെ ലയത്തെയും അഥവാ പ്രളയത്തെയും രാത്രിയായും കണക്കാക്കുന്നു. ലോകങ്ങൾ കാലത്താൽ പരിമിതമാണ്, അതിനാൽ അവ വീണ്ടും വരുന്നു. ബ്രഹ്മലോകം പോലും ആയിരം യുഗങ്ങൾ നിലനിൽക്കുന്നുണ്ടെങ്കിലും അത് നശ്വരമാണ്. നാല് മഹാ യുഗങ്ങൾ ആയിരം തവണ ആവർത്തിക്കുമ്പോൾ ബ്രഹ്മാവിന്റെ ഒരു പകലാകുന്നു, അത്രയും തന്നെ യുഗങ്ങൾ ചേരുമ്പോൾ ഒരു രാത്രിയും. ബ്രഹ്മാവിന്റെ ഈ രാവും പകലും അറിയുന്നവർക്ക് യഥാർത്ഥത്തിൽ രാവും പകലും എന്താണെന്ന് അറിയാം. ഈ പ്രപഞ്ചത്തിലെ നിത്യമായ രാവും പകലും (സൃഷ്ടിയും ലയവും) എന്ന താളം നിലനിർത്തപ്പെടുന്നു. ഈ ചക്രത്തിൽ വരുന്ന യാതൊന്നും എന്നെന്നേക്കുമായി നിലനിൽക്കുന്നില്ല. അതുകൊണ്ടാണ് ഉപനിഷത്തുകളിലെ ഋഷിമാർ ഈ രാവും പകലും അതീതമായ, അക്ഷയമായ, പരമമായ ആത്മാവിൽ, പുരുഷനിൽ, ജീവിതത്തിന്റെ പരമമായ ലക്ഷ്യത്തിൽ വസിച്ചത്.
Day means evolution or projection or manifestation of the universe. Night means involution of the universe or Pralaya. The worlds are limited or conditioned in time. Therefore they return again. The world of Brahma (Brahmaloka or Sattyaloka) is also transient? although it lasts for a thousand ages. When the four great Yugas have gone round a thousan times? it make a daytime of Brahma and when an eal number of Yugas pass again it makes a night. Those who can see and live through the day and night of Brahma can really know what is a day and what is a night.The Suryasiddhanta speaks of the same division of time.According to it YearsKaliyuga (with its Sandhya andSandhyamsa) consists of 432?000Dvapara Yuga (do) 864?000Tretayuga (do) 1?296?000Kritayuga (do) 1?728?000Thus a Mahayuga consisting ofthese four Yugas comprises 4?320?00071 such Mahayugas with an additionalSandhya? at the close of 1?728?000years make one Manvantara of 308?448?00014 such Manvantaras with anotherSandhya? at the close of 1?728?000years constitute one Kalpa of 4?320?000?000Two Kalpas make a day and nightof Brahma of 8?640?000?000360 such days and nights make oneyear of Brahma consisting of 3?110?400?000?000100 such years constituteHis lifetime of 311?040?000?000?000The world is absorbed in the Avyakta or the Unmanifested or Mulaprakriti during the cosmic Pralaya (involution of the world). Just as the tree remains in a latent state in the seed? so also this whole universe remains in a latent state in a seedform in the Mulaprakriti during Pralaya. This is the night of Brahma. This is the cosmic night. Again the world is projected at the beginning of the Mahakalpa (evolution). There comes the cosmic dawn or cosmic day. This eternal rhythm of cosmic day and night (evolution and involution) is kept up in the macrocosm.Nothing that comes under this everrevolving wheel of cosmic day and night lasts for ever. That is the reason why the seers of the Upanishads? the sages of yore? lived in the transcendental Supreme being? the imperishable Self? the indestructible Purusha? the supreme goal of life? the highest end of man? which is beyond the cosmic day and night. Just as the seeds that are fried can hardly germinate? so also those who have attained to the imperishable Brahman? the Absolute? the Eternal? cannot return to this world of sorrow? pain and misery. They know neither day nor night. They are one with Existence Absolute.The manifested and the unmanifested dwell in Brahman. Brahman is beyond the manifested and the unmanifested. When the world and the body are destroyed Brahman is not destroyed. The waves come out and subside? but the ocean remains unaffected. So also the worlds come and subside? but Brahman the source of everything? the source of Mulaprakriti? ever remains unaffected. Just as ornaments come out of gold and then go back to gold when they are melted? so also all the worlds come out of Brahman and go back to Brahman. Gold is in no way affected by the various forms such as earning? bracelets? anklets? etc.? that have been made of it. Even so Brahman is not in the least affected by the projection and destruction (dissolution) of the worlds and the bodies of beings. It remains always as It is.