Vikash: Swamy ji, in many religious books it is mentioned that at the end of kaliyug, all dharmas religions (Islam, Christianity, Hinduism, etc) will be destroyed and only one new dharma will be established and called satyug. How? Kindly do reply.
Swami Ram Swarup: Satyug is not a dharma. Satyug, Treta, Dwapur, Kalyug are time-periods. In this connection, I paste my article in this regard-

About Yugas

Manusmriti gives the proof in its chapter one that present time of the earth is 7th Manvantar. Uptil now 6 manvantar have passed. Those are Swayambhuva, Swarochish, Auttami, Tamas, Raivat and Chaakshush, now it is 7th manvantar, called Vaivasvat.

71 chaturyugi = 1 manvantar.

There are four yug – Satyug, Treta, Dwapur and Kaliyug.

Satyug = 17 lakhs 28 thousands years

Treta = 12 lakhs 96 thousands years

Dwapur = 8 lakhs 64 thousands years

Kaliyug = 4 lakhs 32 thousands years

The total of four Yugas comes to be 43 lakhs and 20 thousands years which is equal to one Chaturyugi. 71 Chaturyugi i.e., 30 crore 67 lakhs and 20 thousands years equal to one Manvantar and 6 Manvantar have yet passed whose calculation comes to one Arab 84 crore 30 lakhs and 20 thousands years. This is 7th Manvantar and 28 Chaturyugi and the present Kaliyug has passed its time of 5002 years. So, uptil now the age of the earth and Vedas is one Arab 96 crore 8 lakhs 53 thousands one hundred and eleven years. Bhagwad Geeta shlok 8/17 also says about this fact.

14 Manvantar= 1 Kalp.

Yes, in final destruction, every matter which is created by human-beings and which has been created by God from Prakriti, in the shape of universe, will be destroyed. Again, you see the Vedic knowledge will only be originated by God in the heart of four Rishis in new creation, as before.

Aarti: Swamiji pranam, my question is while performing daily hawan, should we do brahmacharya palan also, as I am very spiritual n want to do more hawan n sadhna?
Swami Ram Swarup: My blessings to you, my daughter. Yes, Brahamcharya is the main divine quality, by maintaining which a person sure gets success in spiritualism as well as in worldly pious path (science, education, married life etc.).

Therefore, I would advise you, my daughter to read my book named Brahamcharya – Dukh nivarak divya manni (in Hindi) worth Rs.100/-, excluding postal charges. The book can be sent to you on receipt of your postal address, if you desire. Book will give you immense knowledge.