Manvantara (from Skt. Manvantara) – is «period of Manu".
Mahamanvantara (from Skt. Mahâ-manvantara) - «great period of Manu."
What is the difference between Pralaya and Mahapralaya and between Manvantara and Mahamanvantara?
As you can see, the words "Mahapralaya" and "Mahamanvantara" contain the root "maha", which translates from Sanskrit as "a great, big".
During Mahapralaya Spirit and Souls are absent, because Pralaya - is Peace, Relief from the Manifestation.
Manifestation – it’s Manvantaras, and Unmanifestation - is Pralaya.
It says here as about Pralayas, and about Mahapralayas, about as Manvantaras and Mahamanvantaras.
What's the difference?
Pralaya – it is Breath of Brahma. Brahma – is the Spirit. And Manvantara – it is Breath of Brahma.
Inhale and exhale Brahma – it is constantly flowing process of creation and destruction of the Spirit (of the impulse of creation).
This process occurs in every elementary particle at every moment of time until there is this Universe. While Mahamanvantara lasts. And stop only with the onset of Mahapralaya.
This is the difference between simple Pralaya and Mahapralaya.
During Mahapralaya disappears all the Manifested Universe. Pralaya – it’s the term which refers only to the disappearance of the Spirit in a particular particle.
Exactly the same difference is between Manvantaras and Mahamanvantara.
Mahamanvantara - is the emergence of the entire Manifested Universe. While Manvantara - it's Exhalation, the birth of Brahma, the emergence of the Spirit, of the impulse in the particles.
In esoteric writings, for example, in the books of A. Bailey, E. Blavatsky, and N. Roerich you can find such expressions as "Day of Brahma" and "Night of Brahma." What is it?
It is natural to assume, by analogy with the human way of life, that the Day of Brahma – it’s a period of activity, and the Night – is a Rest time.
But what do we call by the Day and Night of Brahma – by Manvantara and Pralaya or Mahamanvantara and Mahapralaya?
The answer – apparently, you can call by the Day of Brahma as the Manvantara and Mahamanvantara, and by the Night of Brahma – and Pralaya, and Mahapralaya.
The same can obviously be said of the exhalation and inhalation of Brahma. Exhalation – this is the Day of Brahma, and inhalation –it’s the Night. With the help of inspiration and expiration can be characterized the common period of the Manifestation and Unmanifestation of God – it's about Mahapralaya and Mahamanvantara. And private, specific act committing within a single soul (elementary particle) – it’s Pralaya and Manvantara.
At the same time, the Night of Brahma, his inhalation – it’s a period or a moment of residence of the Space in a state of Non-Being. Accordingly, the Day of Brahma, Exhale – it’s a period or a moment of Being, of the Manifestation of the Universe.
During Mahapralaya the Manifested Universe is missing. There is no Ether (Spirit), or elementary particles (souls), there is only pure Space (Matter).
There is no one chemical element. Celestial bodies also there are not, and so there is not the usual process of the development of life on planets. The space is empty.
But this emptiness does not mean that it stops those underlying processes of consciousness, of mind, of which presence we guess, but know absolutely nothing.
The concept of "Being" refers only to the manifestations of God-Space, to two of its Hypostases – to the Spirit and Soul – and their combinations. The Space itself (the Matter) exists always and does not disappear.
In the state of Mahamanvantara in the Space appears all of what it dreamed and thought in its sleep "at night," in a state of Pralaya.
It is likely that only this Mahamanvantara marked by the presence of Ether and elementary particles.
It is possible that in the next Mahamanvantara familiar to us now the face of this Manifested Universe will change beyond recognition, and all the Laws of Nature will be quite different.
The end of Mahamanvantara and the beginning of Mahapralaya is marked by the process of "dilution", the disappearance of all that was displayed during the Mahamanvantara. For example, this Mahamanvantara, during which we now exist, will complete of disappearance of the Ether and elementary particles. And with them will disappear and all that exists.
The transition of the Universe from Manifested state to Unmanifested, from Manvantara to Pralaya is called in the Stanzas of the Books Dzyan the "Great Day “Be with Us”, and in the Bible – “Last Judgment "(or "Day of Judgment").
"It is the Ring called "Pass not" for those who descend and ascend; who during the Kalpaare progressing towards the Great Day "Be With Us"..." (Stanza 5.6).
"The Swift and the Radiant One produces the seven Laya Centres, against which none will prevail to the Great Day "Be With Us"" (Stanza 6.2).
"In the day when God shall judge the secrets of men by Jesus Christ according to my gospel. ..." (The New Testament, "The Epistle to the Romans St. Paul the Apostle").
Otherwise Day "Be with Us", Judgment Day can be called "end of the world", as the Light - is synonymous with the Spirit, and stop the manifestation of the Absolute is to be linked to the disappearance of the Spirit - that is, Light. This is - the End of the World.
How many times the Mahamanvantara has already been and Pralayas replacing them, no one knows. At least no one is in this world.
If you use computer terminology, it can be compared the Mahapralaya with Restart, after which will be presented a new version of the Universe.
Remember when we described the structure of elementary particles? There we talked about the Zone of Destruction – an area on the periphery of any particle, where is the destruction of the Ether (Spirit). So, Pralaya (from Skt. - Destruction) - this is the destruction, dissolution, disappearance of Ether, Spirit.