One verse

Srimad Bhagavatam 2.2.26

2.2.26

अथो अनन्तस्य मुखानलेन दन्दह्यमानं स निरीक्ष्य विश्वम् । निर्याति सिद्धेश्वरयुष्टधिष्ण्यं यद् द्वैपरार्ध्यं तदु पारमेष्ठ्यम् ॥ २६ ॥

atho anantasya mukhanalena dandahyamanam sa niriksya visvam niryati siddhesvara-yusta-dhisnyam yad dvai-parardhyam tad u paramesthyam

atho
thereupon
anantasya
of Ananta, the resting incarnation of Godhead
mukha-analena
by the fire emanating from His mouth
dandahyamanam
burning to ashes
sah
he
niriksya
by seeing this
visvam
the universe
niryati
goes out
siddhesvara-yusta-dhisnyam
airplanes used by the great purified souls
yat
the place
dvai-parardhyam
15,480,000,000,000 solar years
tat
that
u
the exalted
paramesthyam
Satyaloka, where Brahma resides

At the time of the final devastation of the complete universe (the end of the duration of Brahma’s life), a flame of fire emanates from the mouth of Ananta (from the bottom of the universe). The yogi sees all the planes of the universe burning to ashes, and thus he leaves for Satyaloka by airplanes used by the great purified souls. The duration of life in Satyaloka is calculated to be 15,480,000,000,000 years.