Sri Lord Vishnu's Navel Lotus?

What is in the lotus stem that sprouts from Sri Lord Vishnu's navel? Where are we, and all the Universes? Are we somewhere in, or on Sri Lord Vishnu's person? What is the meaning of the cobra Sri Lord Vishnu sleeps upon? Thanks

Sri Lord Vishnu's Navel Lotus?
Srimad Bhagavatam Canto 1. Chapter 3 Text 2 by His Divine Grace A.C. Bhacktivedanta Swami Prabhupada


A part of the purusa lies down within the water of the universe, from the navel lake of His body sprouts a lotus stem, and from the lotus flower atop this stem, Brahmä, the master of all engineers in the universe, becomes manifest.


PURPORT


The first purusa is the Karanodayakasayi Visnu(Maha Visnu). From His skin holes innumerable universes have spring up. In each and every universe, the purusa enters as the Garbhodakasayi Visnu. He is lying within the half of the universe which is full with the water of His body. And from the navel of Garbhodakasayi Visnu has sprung the stem of the lotus flower, the birthplace of Brahmä, who is the father of all living beings and the master of all the demigod engineers engaged in the perfect design and working of the universal order. Within the stem of the lotus there are fourteen divisions of planetary systems, and the earthly planets are situated in the middle. Upwards there are other, better planetary systems, and the topmost system is called Brahmaloka or Satyaloka. Downwards from the earthly planetary system there are seven lower planetary systems inhabited by the asuras and similar other materialistic living beings.


From Garbhodakasayi Visnu there is expansion of the Ksirodakasayi Visnu, who is the collective Paramätmä(Supersoul in the heart and in every atom) of all living beings. He is called Hari, and from Him all incarnations within the universe are expanded.


One who knows these plenary features of the Personality of Godhead knows Godhead properly, and thus the knower becomes freed from the material conditions of birth, death, old age and disease, as it is confirmed in Bhagavad-gitä, In this sloka the subject matter of Mahä-Visnu is summarized. The Mahä-Visnu lies down in some part of the spiritual sky by His own free will. Thus He lies on the ocean of käraëa, from where He glances over His material nature, and the mahat-tattva is at once created. Thus electrified by the power of the Lord, the material nature at once creates innumerable universes, just as in due course a tree decorates itself with innumerable grown fruits. The seed of the tree is sown by the cultivator, and the tree or creeper in due course becomes manifested with so many fruits. Nothing can take place without a cause. The Kärana Ocean is therefore called the Causal Ocean. Kärana means "causal." We should not foolishly accept the atheistic theory of creation. The description of the atheists is given in the Bhagavad-gitä. The atheist does not believe in the creator, but he cannot give a good theory to explain the creation. Material nature has no power to create without the power of the purusa, just as a prakrti, or woman, cannot produce a child without the connection of a puruña, or man. The puruña impregnates, and the prakrti delivers. We should not expect milk from the fleshy bags on the neck of a goat, although they look like breastly nipples. Similarly, we should not expect any creative power from the material ingredients; we must believe in the power of the puruña, who impregnates prakrti, or nature. Because the Lord wished to lie down in meditation, the material energy created innumerable universes at once, in each of them the Lord lay down, and thus all the planets and the different paraphernalia were created at once by the will of the Lord. The Lord has unlimited potencies, and thus He can act as He likes by perfect planning, although personally He has nothing to do. No one is greater than or equal to Him. That is the verdict of the Vedas.


After the universes come out of Mahä-Visnu, an expansion of His called Garbhodakasayi Visnu enters into the hollow interior of each one and fills it half full of water. Garbhodakasayi Visnu then lies down on this water, floating on a bed made by an expansion of His called Ananta Sesa (Balaram who is the first expansion of Lord Krishna),who appears like a many-headed serpent. From the navel of Garbhodakasayi Visnu a lotus grows; the bud opens, and in the center sits Lord Brahmä, the first created being. He is the engineer of the universe.