Billions of almost spherical universal bodies (Brahmanda's) emanate from the Body and breathing of Maha Vishnu.

Billions of almost spherical universal bodies emanate from the Body and breathing of Maha Vishnu.

These massive Universes are called Brahmandas.

Furthermore, each Brahmanda Universe surrounds and encases a smaller Universe deep inside it where Garbhodakashayi Vishnu and Lord Brahma reside.

This inner universe called Bhu-Mandala houses the 14 Planetary Systems.

Srimad Bhagavatam tells us there are billions of individual "Brahmanda Universes" however, the sizes of the each Brahmanda Universe and its small inner Universes inside it, varies in size.

For example, our inner Universe deep inside our Brahmanda called Bhu-Mandala, is one of the smallest and is "4 billion miles (500,000,000 Yojanas) in diameter"

According to Srimad Bhagavatam's 5th Canto, there are 14 Planetary Systems in our in our 4 billion mile diameter Bhu-Mandala Universe, but the amount may be different in others.

Within the stem of the lotus coming from the naval of Garbhodakashayi Vishnu, there are fourteen divisions of planetary systems created by Lord Brahma, and our earth spherical planet is situated in the middle of the stem.

Srila Prabhupada - ''We have to imagine that these universes (Brahmandas), which according to our limited knowledge are expanded unlimitedly, are so great that the gross and subtle ingredients—the five elements of the cosmic manifestation, namely

1 - Earth,
2 - Water,
3 - Fire,
4 - Air,
5 - Sky,
6 - Total material energy,
7 - False ego.

All are not only within the universe but cover the universe in seven layers, each layer ten times bigger than the previous one.

In this way, each and every universe is very securely packed, and there are numberless universes. All these universes float within the innumerable pores of the transcendental body of Mahā-Viṣṇu.

It is stated that just as the atoms and particles of dust are floating within the air along with the birds and their number cannot be calculated, so innumerable universes are floating within the pores of the transcendental body of the Lord. For this reason, the Vedas say that God is beyond the grasp of our knowledge. '' Krsna Book 87

We CANNOT see from one universe to another, this is because our individual universe is surrounded and encased by 7 thick material layers that is our outer egg shaped universe called a Brahmanda

And yes, it IS impossible to see the millions of other Brahmandas outside our inner universe (inside a massive Brahmanda) because of being surrounded by 7 thick material layers that only rare mystic yogis and advanced devotees like Arjuna can see and pass through.

So of course Krishna and Arjuna did not encounter such limitations we experience by the combination of these elements like earth, water, fire all gross elements as Bhagavad Gita explains.

Srila Prabhupada - ''The Lord is not visible to the eyes of ordinary men, those who are beyond the covering layers because of their transcendental devotional service can still see Him''. Krsna Book 87

We cannot see through our Brahmanda that surrounds and encases our small universe, Srila Prabhupada is clear on this

Srila Prabhupada - ''Lord Krishna and Arjuna crossed over the great region of darkness covering the material universes. Arjuna then saw the effulgence of light known as the brahmajyoti. The brahmajyoti is situated ''outside the covering of the material universes'', and because it cannot be seen with our present eyes, this brahmajyoti is sometimes called avyakta''. Krsna Book, 89

Srila Prabhupada - ''Each universe is covered by various layers of material elements (The 7 layers of the outer Brahmanda covering), and therefore although the universes are clustered together, we CANNOT see from one universe to another. In other words, whatever we see is within this one universe. In each universe there is one Lord Brahmā, and there are other demigods on other planets, but there is only one sun''.- Srimad Bhagavatam Canto 5 Chapter 21 Text 11, Purport

Srimad Bhagavatam Canto 6 Chapter 16 Text 37 -

''Every universe is covered by seven layers—earth, water, fire, air, sky, the total energy and false ego—each ten times greater than the previous one. There are innumerable universes besides this one, and although they are unlimitedly large, they move about like atoms in You. Therefore You are called unlimited [ananta]''.

PURPORT

This verse describes the coverings of the universe (saptabhir daśa-guṇottarair aṇḍa-kośaḥ).

The 7 layers covering and surrounding our inner Universe called a Brahmanda, is made up of

1 - Earth,
2 - Water,
3 - Fire,
4 - Air,
5 - Sky,
6 - Total material energy,
7 - False ego.

Beginning with the covering of earth, each covering is ten times greater than the previous one. Thus we can only imagine how great each universe is, and there are many millions of universes.

As confirmed by the Lord Himself in Bhagavad-gītā (BG 10.42):

athavā bahunaitena
kiṁ jñātena tavārjuna
viṣṭabhyāham idaṁ kṛtsnam
ekāṁśena sthito jagat

"But what need is there, Arjuna, for all this detailed knowledge? With a single fragment of Myself I pervade and support this entire universe."

The entire material world manifests only one fourth of the Supreme Lord's energy. Therefore He is called ananta''.

SB 1.3.2, Purport:

The first puruṣa is the Kāraṇodakaśāyī Viṣṇu. From His skin holes innumerable universes have sprung up. In each and every universe, the puruṣa enters as the Garbhodakaśāyī Viṣṇu.

He is lying within the half of the universe which is full with the water of His body. And from the navel of Garbhodakaśāyī Viṣṇu has sprung the stem of the lotus flower, the birthplace of Brahmā, 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.

SB Canto 2

The universe is divided into fourteen planetary systems. Seven planetary systems, called Bhūr, Bhuvar, Svar, Mahar, Janas, Tapas and Satya, are upward planetary systems, one above the other.