The Brahmanda egg shaped universes coming from Maha-Visnu.

Srimad Bhagavatam explains our material universe is deep inside a larger universal Body called a Brahmanda.

There are an unlimited amount of Brahmanda egg shaped universes coming from the Bodily pores and breathing of Maha-Visnu the creator of the material creation (mahat-tattva) 

The Brahmanda universal body is made up of 7 layers of material qualities both gross and subtle that surround and encase our small inner secondary material universe, that is 4 billion mile in diameter known as Bhu-Mandala.

However, I can see why some scholars claim there are 8 layers of material qualities, they also include the diameter of our small 4 billion mile inner material universe that houses its 14 planetary systems as one of layers making it 8 to them.

They then multiply the size of our 4 billion mile diameter universe by 10 to get the diameter of the first layer "earth" matter.

But the figure is actually 7 as follows-

1 -10×4=40 billion miles in diameter thick (earth)

2 - 10×40=400 billion for (water)

3 - 10×400= 4000 (4 trillion) (fire)

4 - 10×4 (trillion)=40 trillion (air)

5 - 10x40= 400 trillion (sky)

6 - 10x400=4000 trillion (4 quadrillion) (false ego)

7 - 10×4 quadrillion=40 quadrillion (total material energy)

So our Brahmanda universal  shell that our small 4 billion mile diameter secondary universe is deep within, is 44 quadrillion 444 trillion 444 billion miles in diameter, or double that figure if measured from one side of the inner edge of our secondary universe inside the Brahmanda.

If this description was drawn to proper scale, our inner Bhu-Mandala universe would appear almost invisible at the center to us because of the massive size of the Brahmanda universal shell we are in.

The first covering of our universe's shell (Brahmanda) that surrounds and encases our single universe, is the EARTH element.  (SB Canto 6 Ch 16 Text 37)

In most references in Bhagavatam, it is said "earth" is the first material layer covering our secondary material universe that is deep inside the greater outer Brahmanda universal shell.

There are billions of these Brahmanda greater egg shaped universal shells coming from the pores and breathing of Maha-Visnu, each with a smaller secondary universe made of planetary systems deep within it. 

All Brahmanda's originates from the Body of Maha-Vishnu as seen in photo.

Although Srimad-Bhagavatam Canto 3 Chapter 26 Text 52 says water is the first layer however. MOST references say the seven layers of the Brahmanda our single universe is deep within, begins with Earth.

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 by Srila Prabhupada.  

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

1 - The first covering is EARTH,

2 - the second is WATER,

3 - the third is FIRE,

4 - the fourth is AIR,

5 - the fifth is SKY,

6 - the sixth is the TOTAL MATERIAL ENERGY (MAHAT TATTVA),

7 - the seventh is the 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." (SB Canto 6 Ch 16 Text 37)

Srila Prabhupada - "The mahat-tattva, the total material energy, is called avyakta. Then, when it is agitated by the glance of the Supreme Lord, the three modes of material nature acts. And by interaction of these three modes of material nature, the whole cosmic manifestation comes into being." (Lecture on SB 1.2.33 - Vrndavana, Nov 12, 1972)

Srila Prabhupada - "So actually, there are twenty-six different elements which is conducting this material world. Etat kṣetraṁ samāsena sa-vikāram udāhṛtam. Kṣetra means this body. Either you take this body or this material world, they are interaction of these twenty-four elements.

Either you take the gigantic body of this universe or you take the body of this planet or you take this your body, my body, or a cat's body, dog's body, all these bodies, they are formed of these twenty-four elements, sa-vikāram, by action and reaction.

Just like chemically, if you mix one chemical with another chemical, a third element is produced, similarly, originally the reservation of all these elements is called mahat-tattva. It is called pradhāna, upadhāna.

So gradually they manifest, they divide by three guṇas. Three guṇas means in the mahat-tattva, in the total material reservoir, three guṇas, three modes of nature, first of all appear and they act with one another, and then gradually, one after another, the twenty-four elements become manifested. Etat kṣetraṁ samāsena sa-vikāram udāhṛtam." (Lecture on BG 13.6-7, Montreal, Oct 25, 1968)

Srila Prabhupada - "So mahat-tattva, the total material energy, and six, five elements, sixteen, sixteen, ṣoḍaśa-kalam.

What are those?

The five elements, namely, earth, water, fire, air, and sense objects and senses and the spirit soul. In this way, sixteen. And from sixteen, it expands to twenty-four. That is the explanation of our Vedic creation. Ṣoḍaśa-kalam." (Lecture on SB 1.3.1- Vrndavana, Nov 14, 1972)

Srila Prabhupada - "The total energy of material creation is called mahat-tattva or pradhāna. Then, when the mahat-tattva is agitated by the three guṇas, then they become divided into twenty-four elements." (Lecture on SB Canto 3 Ch 26 text 11-14 - Bombay, Dec 23, 1974)

Srila Prabhupada - "That mahat-tattva is above this universe, above the sky. Above the sky there are seven layers. Each layer is ten times more than the other layer. In this way, that is called mahat-tattva. Total material elements, they are stocked there. And then these varieties take place. And above that mahat-tattva, there is spiritual world." (Lecture on SB Canto 3 Ch 26 text 10, Bombay, Dec 22, 1974)

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." (BG 10.42)

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

Srimad-Bhagavatam Canto 2 Chapter 2 Text 28 Purport-

Srila Prabhupada - "The extent of the cosmic phenomenon or our individual universe is calculated to be diametrically four billion miles in size. Then the outer covering known as the ''Brahmanda shell'' begins.

The first covering of earth is calculated to extend forty billion miles which is 10 times the size of the inner universe and the subsequent coverings of the universe are respectively of 

earth,

water, 

fire, 

air, 

sky, 

total material energy, 

false ego,

one after another, each extending ten times further than the previous.

The fearless devotee of the Lord penetrates each one of them and ultimately reaches the absolute atmosphere where everything is of one and the same spiritual identity.

Then the devotee enters one of the Vaikuṇṭha planets, where he assumes exactly the same form as the Lord and engages in the loving transcendental service of the Lord.

That is the highest perfection of devotional life. Beyond this there is nothing to be desired or achieved by the perfect yogī." (SB Canto 2 Ch 2 Text 28 Purport)

Srimad Bhagavatam Canto 3 Chapter 29 Text 43-

Srila Prabhupada  - "The first layer is of earth, and it is ten times greater in size than the space within the universe;

The second layer is water, and that is ten times greater than the earthly layer;

The third covering is fire, which is ten times greater than the water covering. 

In this way each layer is ten times greater than the previous one." SB Canto 3 Ch 29 Text 43)

Srimad Bhagavatam says there are millions of individual Brahmanda universes coming from Maha Vishnu making up the entire material creation (1/4 of the Spiritual Sky) that also house their own inner universe.

All smaller universes inside their Brahmandas are of different sizes, some, like ours, are only 4 billion miles in diameter.

The "4 billion miles (500,000,000 yojanas)" diameter of our universe with its 14 planetary systems is one of the smallest.

Our small single universe with its 14 planetary Systems would therefore fit in the circumference of Bhu-Mandala. (4 billion miles (500,000,000 Yojanas) diameter)

Sadaputa dasa ACBSP (Richard L. Thompson) earned his Ph.D. in mathematics from Cornell University. He is the author of several books on Vedic Cosmology explain what Bhu-Mandala is-

''In the Srimad Bhagavatam, Bhu-Mandala, the “earth-mandala” (not to be confused with our small earth globe), is a disk 500 million yojanas in diameter (4 billion miles in diameter).

The yojana is a unit of distance about 8 miles long, and so the diameter of Bhu-Mandala is about 4 billion miles, which is the size of our inner secondary material universe inside the Brahmanda universe.

Bhu-Mandala is marked by circular features designated as islands (dvipas also means planets in outerspace as well as oceans.

Srila Prabhupada -"The "planets" are called "dvīpas". Outer space is like an ocean of air. Just as there are islands in the watery ocean, these planets in the ocean of space are called dvīpas, or islands in outer space" (CC, Madhya 20.218, Purport)

Sadaputa dasa - "Bhu-Mandala is far too big to be our small earth globe Sadaputa explains. Of course, Bhu Mandala is earth centered. Its innermost island, Jambudvipa, contains Bharata-varsha, which Srila Prabhupada has repeatedly identified as the planet earth." (End Sadaputa dasa quote)

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 earth, water, fire, air and sky, along with the total material energy and false ego—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 material universe to another, this is because our secondary material is deep inside the greater Brahmanda universal body.

The Brahmanda universal body surrounds and encases our inner material universe with 7 gross and subtle material layers which are the outer covering of our inner secondary material universe.

So, it is impossible to see the millions of other Brahmandas outside our inner universe (inside a massive Brahmanda) because of those 7 material layers that only rare mystic yogis and advanced devotees like Arjuna can see through and pass through.

So of course Krsna and Arjuna did not encounter such limitations that we experience with 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 (7 layers of the outer Brahmanda covering), and therefore although the universes are clustered together, we CANNOT see from one material 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." (SB Canto 5 Ch 21 Text 11, Purport)

In the purport in Srimad-Bhagavatam Canto 2 Chapter 2 Text 28-

Śrīla Śrīdhara Svāmī confirms that a part of the material nature, after being initiated by the Lord, is known as the mahat-tattva.

A fractional portion of the mahat-tattva is called the false ego. A portion of the ego is the vibration of sound, and a portion of sound is atmospheric air.

A portion of the airy atmosphere is turned into forms, and the forms constitute the power of electricity or heat.

Heat produces the smell of the aroma of the earth, and the gross earth is produced by such aroma. And all these combined together constitute the cosmic phenomenon.

The extent of the cosmic phenomenon or our individual universe is calculated to be diametrically four billion miles in size.

Then the outer covering, known as the Brahmanda shell begins.

The first covering of Earth is calculated to extend forty billion miles, (10 times the size of the inner universe) and the subsequent coverings of the universe are respectively of water, fire, air, sky, total material energy, false ego one after another, each extending ten times further than the previous.

The fearless devotee of the Lord penetrates each one of them and ultimately reaches the absolute atmosphere where everything is of one and the same spiritual identity.

Then the devotee enters one of the Vaikuṇṭha planets, where he assumes exactly the same form as the Lord and engages in the loving transcendental service of the Lord.

That is the highest perfection of devotional life. Beyond this there is nothing to be desired or achieved by the perfect yogī."

Srimad Bhagavatam Canto 6 Chapter 16 Text 37

kṣity-ādibhir eṣa kilāvṛtaḥ

saptabhir daśa-guṇottarair aṇḍa-kośaḥ

yatra pataty aṇu-kalpaḥ

sahāṇḍa-koṭi-koṭibhis tad anantaḥ

Synonyms:

kṣiti-ādibhiḥ — by the ingredients of the material world, headed by earth; eṣaḥ — this; kila — indeed; āvṛtaḥ — covered; saptabhiḥ — seven; daśa-guṇa-uttaraiḥ — each ten times more than the previous one; aṇḍa-kośaḥ — egg-shaped universe; yatra — in whom; patati — falls; aṇu-kalpaḥ — like a minute atom; saha — with; aṇḍa-koṭi-koṭibhiḥ — millions of such universes; tat — therefore; anantaḥ — (You are called) unlimited.

Translation:

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 by Srila Prabhupada 

The Brahma-saṁhitā (5.48) says:

yasyaika-niśvasita-kālam athāvalambya

jīvanti loma-vilajā jagad-aṇḍa-nāthāḥ

viṣṇur mahān sa iha yasya kalā-viśeṣo

govindam ādi-puruṣaṁ tam ahaṁ bhajāmi

The origin of the material creation is Mahā-Viṣṇu, who lies in the Causal Ocean. While He sleeps in that ocean, millions of universes are generated as He exhales, and they are all annihilated when He inhales.

This Mahā-Viṣṇu is a plenary portion of a portion of Viṣṇu, Govinda (yasya kalā-viśeṣaḥ). The word kalā refers to a plenary portion of a plenary portion.

From Kṛṣṇa, or Govinda, comes Balarāma; from Balarāma comes Saṅkarṣaṇa; from Saṅkarṣaṇa, Nārāyaṇa; from Nārāyaṇa, the second Saṅkarṣaṇa; from the second Saṅkarṣaṇa, Mahā-Viṣṇu; from Mahā-Viṣṇu, Garbhodakaśāyī Viṣṇu; and from Garbhodakaśāyī Viṣṇu, Kṣīrodakaśāyī Viṣṇu. Kṣīrodakaśāyī Viṣṇu controls every universe.

This gives an idea of the meaning of ananta, unlimited. What is to be said of the unlimited potency and existence of the Lord? This verse describes the coverings of the universe (saptabhir daśa-guṇottarair aṇḍa-kośaḥ).

The first covering is earth, the second is water, the third is fire, the fourth is air, the fifth is sky, the sixth is the total material energy, and the seventh is the 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 (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. (End of Purport)

Is the first layer of our outer Brahmanda shell Earth or water?

There is some passages in Bhagavatam that says the first layer is earth and other places it says the first layer is water.

Also in same places in Bhagavatam, only 6 layers are mentioned and not 7. Also the names of the layers sometimes change, for example, Maha tattva is said to be a layer and ether is also mentioned.

Srila Prabhupada says there are 7 layers that make up our outer Brahmanda shell that surrounds our single universe that is deep within it, 8 including our 4 billion miles diameter universe within the greater massive Brahmanda.

The circumference of our small single universe inside the Brahmanda shell is 12.6 billion miles. And within that area are the 14 planetary systems.

Srila Prabhupada - "The extent of the cosmic phenomenon or our individual universe is calculated to be diametrically four billion miles in size. Then the outer covering known as the Brahmanda shell begins.

The first covering of earth is calculated to extend forty billion miles, (10 times the size of the inner universe) and the subsequent coverings of the universe are respectively of water, fire, air, sky, total material energy, false ego one after another, each extending ten times further than the previous." (SB Canto 2 Ch 2 Text 28 Purport)

Srila Bhaktisiddhanta Sarasvati Thakura refers to the circumference of our Brahmanda universal shell that our single universe is inside in following text-

Caitanya Caritamrita Madhya 21.84

“Kṛṣṇa said to Brahma, ‘Your particular universe has a diameter of four billion miles; therefore it is the smallest of all the universes. Consequently you have only four heads."

Purport

Śrīla Bhaktisiddhānta Sarasvatī Ṭhākura, one of the greatest astrologers of his time, gives information from the Siddhānta-śiromaṇi that this material  universe measures 18,712,069,200,000,000 x 8 miles.

That's 18 quadrillion, 712 trillion, 69 billion, 200 million yojanas. 

So, multiply that figure by 8 to get miles which is 149 quadrillion 696 trillion 553 billion 600 million miles in circumference. 

This is the circumference of our Brahmanda universe that our smaller secondary material universe is deep within.

According to some scholars, this is only half the circumference of the Brahmanda universe.

It seems this is circumference of our Brahmanda universe that includes our small 4 billion mile diameter universe deep within it.*^*