Purport

This is one of those shlokas is one of the most important Shloka on the subject of science and explains at the same time many complex facts. The very first concept it presents is the relativity of time and second, the time period of existence of the universe. This Shloka when combined with earlier Shloka and few Shlokas from chapter 9, explains the propagation and cycle of creation and dissolution of the universe.

As we all know, the great scientist Einstein given one of the most complex and revolutionary theory, that is that the theory of relativity. It has many aspects, but the core is that time is not an absolute measure but a separate dimension. To demonstrate he produces one explanation which is known as twin paradox.

This Shloka explains the same. It says the measure of time at earth is not the same as the measure of time at other planets. In fact the difference is huge. One day at the place of Bramha is called as Kalpa, which is equal to the 1000 times the triad of Yugas, ie Satyua+Treta yuga + Dvapara Yuga + Kali-yuga.
Shri Ramanujacharya has derived the measure of yugas and Kalpa as follows

Catur Yuga — Tetrad of Ages
Kali Yuga — 432,000 human years
Dvāpara Yuga — 864,000
Treta Yuga — 1,296,000
Krta Yuga — 1,728,000
1 tetrad of Yugas = 1 Mahā Yuga = 4,320,000 human years.
71 Mahā Yugas = 1 Manvantara = 308,448,000 human years
14 Manvantaras = 1 Kalpa = 4,320,000,000 human years
2 Kalpas = one day and night of Brahma = 8,640,000,000 human years
360 Brahma days = 1 Brahma year = 3,110,400,000,000 human years
100 such years = 1 lifetime of Brahma = 311,040,000,000,000 human years
The universe goes through the creation at the start of Bramha’s day, which is Kalpa and dissolution at the start of Bramha’s night. One Brahma's year is equal to 360 days, which means the universe is created and dissolved 360 times in one Bramha’s year. The total life of Bramha is 100 Bramha’s year. That means the universe is created for 100*360 = 36000 times in whole Bramha’s lifetime.

After that Bramha dies and then the whole cycle is again started by Bhagvan Shri Krishna. New Bramha is created and the universe cycle goes on.

This appears simple on paper, but can assume how vast this calculation is?

Though some other experts like Swami Yogananda have given some different calculations for Yugas.