Amongst the four era's, the Satya yuga is the first and the most significant one. This era began on Sunday, Vaishakh Shukla Tritiya day which is also known as Akshaya Tritiya. This extends up to 17,28,000 years. God incarnated in four forms i.e. Matsya, Kurma, Varaha and Narsimha in this era. Knowledge, meditation and penance would hold special importance in this era. The average height of people was more than what it is today. Every king would attain the pre-determined attainments and would experience bliss. All the four pillars of religion i.e. truth, penance, yagya (religious sacrifice) and charity were present in totality. The only text which was considered credible and was followed was Manu's Dharma Shastra. Satya yuga shall be established by Kalki again after the Kali yuga. The average life expectancy of a human being in Satya yuga was approximately 4000 years.
At the end of this era when the Sun, Moon, Jupiter together enter Pushya Nakshatra that is the Cancer Zodiac then the Satya yuga shall begin. During this time the stars/constellations shall become auspicious and radiant. As a result it shall accrue in the well being of all creatures and the health will ameliorate. It is during this auspicious time that Vishnu's Incarnation Kalki shall take birth in a Brahmin family. This incarnation shall be mighty, intelligent and valiant. He shall engage in good of all benefactors. At the spun of the moment, no sooner he thinks he shall be armed with all the weapons, armours and an army, he shall be coronated king who shall know no enemy. He shall be benevolent and a radiant Brahmin and shall be the one who shall emancipate the ones in misery.
He shall be the one and only one to destroy the Kaliyuga and initiate the holy and divine Satya yuga. Bhagwan Kalki in the Satya yuga shall destroy all the dacoits and robbers. He shall perform the Ashwamedha Yagya and shall donate this entire world to the Brahmins. His success and deeds will be divine and sublime. He shall establish the auspicious ideals and principles propounded by Lord Brahma after which he shall go to the forest to practice penance.
After this all the generations to come shall follow the ideals established by Bhagwan Kalki and shall engage in religious activities. Accordingly on the advent of the Satya yuga all people shall engage assiduously in good, sublime deeds.
One shall witness the emergence of beautiful gardens, Dharmashalas (Resting Inns) and majestic temples. One shall see the execution of many a huge yagyas. Brahmins, sages, ascetics according to their nature shall be absorbed in penance. Ashrams shall be devoid of the wicked and the deceits. This era shall usher better agriculture and one shall be able to grow all foodgrains in all seasons. People shall generously donate and will follow all the rules and regulations mentioned. The kings shall protect their subjects and earth very sincerely.
The Vaishya (traders) of this era shall engage in trade and business very justly and honestly. Brahmins shall be engaged continually in religious sacrifices, study, teaching, charity etc. The Kshatriya (warriors) shall be inclined towards exhibition of valiance and might. The Shudras shall sincerely serve the Brahmins, Kshatriyas and Vaishyas. This form of religion shall remain intact and absolute in the Satya yuga.
One shall witness the total establishment of Sanatan Dharma (eternal religion). During the Satya yuga, the child was not ruined when the father or mother expired. All the gods, demons, Gandharvas, Yaksha would give up their hatred and differences. The Rik, Sama and Yajurveda were not separate and demarcated. This era was devoid of agricultural activities or rather any other type of activity. Just by mere contemplation one would beget desired results. The only religion that was relevant was- the renunciation of vested interests. People in this era would never fall ill. No one would try to point out faults or demerits in anyone's personality. The personality was not plagued by demerits alike ego, sorrow, violent thought (aggression), jealousy, hatred, backbiting, fear, anger and lethargy.
At that time, the colour of the Supreme cosmic soul that was situated in the heart of one and all and the saviour of all the sages was white.
All the people that are Brahmins, Kshatriyas, Vaishyas and Shudras were embellished with all the good qualities. At that time, the only saviour of all the people was God. People would practice austerities and penance to attain God. All would be inclined towards the supreme knowledge and all actions performed would be in the intention of attaining celestial bliss.
In this way all these divine people would be bestowed with sublime faith and piousness. Albeit, people were segregated on the basis of Varnashram method, they would all reponse their faith in the Vedas and the Sanatan Dharma.Because these people were devoid of selfishness, they would effortlessly attain sublimity or union with God, which is a salient feature of Satya yuga.Very valiant, mighty, intelligent and people gifted with all good qualities would take birth in this era. They would surprisingly give birth to thousands of children. Great sages embellished with divinity would take birth in this era.
TRETA YUGA
One sees the advent of religious sacrifices i.e. Yagyas in the Treta yuga. One pillar of the four pillars of religion meets its end. The colour of Bhagwan Achyut becomes red. People in this era will be truthful and would perform all the religious ceremonies according to the sacrifices. It is the Treta yuga where one can see the overtures of Yagyas, religion and allied activities. People would beget desired fruits by performing actions, donations mentioned in the Vedas and by taking resolutions.
All people in this era were assiduous and active. The main religion of Brahmins was truth that is truthful speech, good conduct and love towards all creatures. The common religion of all the Brahmins was Yagya, self-study and donation. The primary aim of Shudras was service towards Brahmins, Kshatriyas and Vaishyas. The duties of Kshatriyas and Vaishyas were the protection of people and agriculture, trade and poultry respectively. All people would sincerely adhere to their respective duties and as a result they would be blessed with celestial bliss.
The average life expectancy of a human in the Treta yuga was approximately 3000 years. All the Kshatriyas born in this era were valiant, zealous, big thinkers, pious, truthful, beautiful, suitable to be blessed, revered and the protectors of all people. The Vedas, religious sacrifices and Varnashram were adhered to very strictly in the Satyayuga and the Treta yuga.