Nomenclature of Yug cycle

The cycle of time is divided into 4 yugs (satya, treta, dwapara, kali) and their time periods are 4800, 3600, 2400, 1200 divine years respectively. 

The ratio or proportion of these time period are as follows :

  4800:3600:2400:1200

=4:3:2:1

Treta means thrice in Sanskrit and dwapara represents twice or double. The above ratio clearly depicts the value of each yug. So the naming system of our yugs were developed with the help of these ratios .

The most longest time was of satya yug which means the period of truth, purity, theistic while the kali yug is just opposite of satya yug. People start to develop evilness, greed, anger, falsehood inside them and live around the violence.