In Hinduism also origin of the universe is told but there is some difference than the "Big Bang" theory. As per Hinduism, God or Brahman (ब्रह्मन् bráhman) is the one supreme, universal Spirit that is the origin of this universe. In that aspect God or Brahman is also referred to as the Absolute or Godhead which is the Divine Ground of all Creation.
As per Hinduism God created this universe out of "Zero" or nothing. Sometimes God himself in the un-manifest aspect is called "Zero" & Vedas tell us that "In the beginning was "Zero" or nothing & out of un-manifest aspect of God, came everything." Before the universe came into being, God in His un-manifest aspect was there & then He willed to create this universe. That "Zero" substance to which our Vedas call "God" is the source of Consciousness as well as Un-Conscious matter. He is also the source of Mind & Intellect. From this un-manifest aspect of God, on His will, He created this universe.
It is due to the WILL of GOD that whole creation takes place out of "un-manifest aspect" of God. God in His un-manifest aspect just willed & hence the energies required to form this universe sprang out of "Brahman (ब्रह्मन् bráhman)". "Big Bang" was started with the Will of God & also guided by His Super Intelligence. By just God's willing, Material Energies came into being which in turn created this vast infinite Space & later on out of Space came out the Air, Fire, Water & Earth. Unless until we consider & have faith in God with all His powers & His super Intelligence, we cannot appreciate the reality & truth about "Big Bang".
Below in simple words is defined Brahman (ब्रह्मन् bráhman):
God is called Bráhman,
Whole world dwells in Bráhman,
Whole world comes from Bráhman,
Whole world goes back in Bráhman,
Whole world breathes in Bráhman,
Let's worship that Bráhman, the God.
As per Vedas, Brahman is of the nature of truth, knowledge and infinity. Brahman is the source and ground of all things.
Below are some verses from Bhagwat Gita which describe the Brahman (ब्रह्मन् bráhman):
"prakritim svam avastabhya
visrijami punah punah
bhuta-gramam imam krtsnam
avasam prakriter vasat" (Bhagwat Gita: Chapter Nine verse 8)
"Sri Krishna said: The whole cosmic order is under Me. Under My will it is automatically manifested again and again, and under My will it is annihilated at the end."
"maya tatam idam sarvam
na chaham tesv avasthitah" (Bhagwat Gita: Chapter Nine verse 4)
"Sri Krishna said: By Me, in My unmanifested form, this entire universe is pervaded. All beings are in Me, but I am not in them."
vayuh sarvatra-go mahan
tatha sarvani bhutani
mat-sthanity upadharaya" (Bhagwat Gita: Chapter Nine verse 6)
"Sri Krishna said: Understand that as the mighty wind, blowing everywhere, rests always in the sky, all created beings rest in Me."
"yac chapi sarva-bhutanam
bijam tad aham arjuna
na tad asti vina yat syan
maya bhutam characharam" (Bhagwat Gita: Chapter Ten verse 39)
"Sri Krishna said: Furthermore, O Arjuna, I am the generating seed of all existences. There is no being—moving or nonmoving—that can exist without Me."
So let's have faith in the God who is also called Brahman (ब्रह्मन् bráhman), who in essence is of the nature of truth, knowledge and infinity & who is the source and ground of all things. Unless we know that God who created this universe out of His will & guided by His Super Intelligence, we in truth cannot understand the truth about "Big Bang".
Jai Shri Krishna