There are various theories of creation, ranging from absurd to the sublime.
There is a classical theory in Hinduism that keeps coming back to me. It may have no scientific validity. Nonetheless, it appeals to my imagination. It springs from the following mantra:

This innocuous looking verse occurs towards the end of the Shukla Yajur Veda Samhita in the form of shanti mantra for the Ishavasya Upanishad.
“Pri” the root of Purna means, “to fill” .This verse has acquired a number of interpretations, including a one with a play of pun on the word purna. Many other layers of interpretations have sprung up by ascribing the meaning of “full”, “whole”, “complete” etc. In addition, mathematical interpretations are derived by assigning numerical values such as ∞ or zero and one, to the term purna. A number of debates center on these interpretations. Even the mathematical interpretation has its critics, who say infinity cannot be added/deducted to/from infinity. If we are talking of two infinities, then they just cannot be infinity because each, obviously, limits the other. Similarly, assigning other numerical values does not also appear to make sense.
Others say the verse talks about the sum total of the energy in the universe. (I was referring to this, at the outset).According to them, the verse states the Universe is infinite. The sum total of energy in the Universe is infinite (a constant). That energy can never be enhanced or diminished. The universe is in a continuous state of flux. All things are in a state of constant flux where energy and information are forever flowing. The matter and energy keep changing forms. Matter and energy are not distinct. Matter is in essence trapped energy. The energy can convert to matter; the Matter in turn can convert into energy. In other words, matter and energy are inter changeable. The energy in the universe can neither be created nor destroyed; it keeps changing its form, from one state to another.
This implies neither was there a creation nor will there be a total destruction. The Universe was not created and it will not be destroyed. It is forever. It always did exist. It has no boundaries either. It is limitless. To signify this endless time and space continuum, the Universe is termed in the texts as Anaadi (without a beginning) and Anantha (without an end). Timeless not in the sense of endless duration, but in the sense of completeness, requiring neither a before nor an after.
It is this continuous state of flux where the matter and energy keep changing their state that we recognize as creation or destruction, as birth or death. . From the absolute point of view, there is neither birth nor death. It is a process in the ever-changing state of matter / energy.
This concept of indestructibility of the Universe with its infinite combinations, its continuous state of flux; keep coming up in various manners. The expressions like, “It” (tat) remains or Brahman (tat) (Universe) rolls with in itself; all things come from tat and resolve into tat etc. capture the essence of the concept.
Manduka Upanishad says, “That supreme Brahman is infinite and this conditioned Brahman is infinite. The infinite proceeds from infinite. Then through knowledge, realizing the infinitude of the infinite, it remains as infinite alone”. Sankara in his Brahma Sutra commentary said Brahman is immanent in the Universe.
The body is one continuous stream of matter. The body is viewed as a vessel. It is energy encased in matter. That matter, again, is trapped energy, as mentioned earlier. That trapped inner energy is not different from the total energy surrounding it and is the same as that (tat). Vedanta calls it embodied self (jiva or vijnanaatma).The Adhyasa or Avidya (ignorance) consists in treating jiva as independent and having an existence of its own.
This concept of indestructibility of energy and matter and their interchangeability, strangely, seems to feed the belief in rebirth. On death, the physical body (matter) decomposes and returns to the elements and takes another form. The inner energy (call it life, jiva, soul, spirit, vital force or whatever) is not destroyed. In fact, the “death” occurs when/ after the energy is separate from the shell, (body).That energy is not, therefore, present in the corpse when it is destroyed. That energy may have returned to the total or may have changed into another form of energy or into matter of some form.
The texts say, “Just as the bubble becomes one with the ocean when it bursts, just as the pot-space becomes one with the universal space when the pot is broken, so also the Jiva or the empirical self becomes one with Brahman.”
Thus, energy thrives on energy. Life thrives on life .jeevo_jeevasya_jeevanam.