The whole universe was at first concentrated at one point or dot (Bindu). It is the Primordial Seed of creation. After a period of germination it undergoes an explosion (Sphota) resulting in the sound (Nada) of creation (OM). Sound is used in the scriptures for all kinds of vibrations. All creation (Kala) proceeds from this sound. Thus the doctrine of Nada, Bindu, and Kala is but an implied reference to the Big Bang theory of creation.
Big Bang Theory postulates that 12 to 14 billion years ago, the portion of the universe we can see today was only a few millimeters across. It has since expanded from this hot dense state into the vast and much cooler cosmos we currently inhabit
Multiple Universes in Scriptures :
.Srimad Bhagavatam [6.16.37] eulogizes the Supreme Lord Vishnu in following words:
There are Innumerable Universes besides this one, and although they are unlimitedly large, they move about like atoms in You. Therefore You are called 'Without-limits'.
http://www.sanskritimagazine.com/indian-religions/hinduism/vedic-scientific-explanation-big-bang-theory/
