From Sahaja Yoga Encyclopedia

The Bhavasagar is the entire universe within a human being. It is the ocean of illusion.

What is this Bhavasagara? This is the symbol or this is the reflection of the whole entire universe that is created. All this universe is created by Brahmadeva. He is the one who is the creator ... of this world, who created this beautiful universe. In that, especially He created the Mother Earth. He has placed the moon and the sun on both the sides of this Mother Earth. They represented to you the Mother Earth within us. It is the Kundalini, the Mooladhara. Now this universe is existing within us. That is the Bhavasagara. This Bhavasagara exists in many stages in its evolutionary form and today it is Kali Yuga in this Bhavasagara. I would say it is a dawn of Satya Yuga, at the end of Kali Yuga, in this Bhavasagara. It is placed in the centre of the Nabhi chakra and around it moves the centre of Swadisthana. The Nabhi chakra is governed by Shri Lakshmi as the power of Shri Vishnu and the Swadisthana moves around it, which delimits our own personality and which creates all these different stars within us or the planets within us. (1981-02-07)

The Bhavasagara is the ocean of illusion in which we live. And we are seekers.... If we are in the ocean, our ship should be seaworthy. Then any kind of illusion is not going to deter us if we are seaworthy. But seaworthy means we must know if there is a fog and how to move in right direction. (1983-03-09)