Nature goes through larger and smaller cycles of time, which repeat themselves in a recurring order. One cycle that we humans can directly experience is, for example, the four seasons: Spring, Summer, Fall and Winter. Each season is characterized by a certain energy and mood. In addition to these small cycles of time that we can experience, there are much larger ones. These are described in the Vedic scriptures as the four "yugas" (ages). "Veda" means "knowledge." It describes the universal and timeless knowledge about the connections and laws of nature. About 5000 years ago, this knowledge was written down in the so-called Vedas by Rishi (seer) Vyasa in order to preserve it beyond the current cycle. The Rishis already knew at that time that the ages would change then as well as now and created ways to preserve the knowledge. 
 
The current cycle, now ending, is called Kaliyuga (Age of Darkness). It is the most materialistic and disharmonious of all the ages. It is also called the age of war, separation and strife. In this age, mankind does not live in harmony with nature and the laws of nature. Egoism as well as materialism have the upper hand. As a result, the disharmonious energies in nature continue to increase. 
 
Currently, people and the earth are in a great process of upheaval. From the point of view of nature, mankind and the earth are passing from a Kaliyuga, the energetically lowest vibrating and most disharmonious of all ages, to a Satyayuga, the energetically highest vibrating and most harmonious of all ages. In a Satyayuga (Age of Truthfulness), people live peacefully together and in harmony with themselves and their souls, nature and the laws of nature. 

Before we can fully enter the new age, humanity is required to purify itself and the earth from all inner and outer disharmonious energies.