Until the 1960's, scientists held to the Steady State theory that the universe has no beginning or end in time and that the earth has always existed in one form or another. They scoffed at the Bible for saying that the earth had a beginning.
The first use of the term 'big bang' was by physicist Fred Hoyle on a BBC broadcast in 1949 when he used it to contrast the Steady State theory to an emerging the hypothesis that all matter of the universe was created in one big bang at a particular time in the remote past, a concept he argued against and said was 'irrational and outside science.'
But, as a result of better telescopes and the results of experimental observations of the universe's constant expansion by Edwin Hubble and others, by the 1980's the 'big bang' was the preferred term used by astronomers and astrophysicists.
Today, the big bang theory is the predominant explanation of how the universe began and is now generally regarded as settled science. The theory says that the universe started with a 'singularity' (Christians say 'God'), then exploded, expanding and cooling over the next 13.8 billion years into the cosmos we know today – and it's still expanding!
In the first second after the universe began, the surrounding temperature reached about 10 billion degrees Fahrenheit according to NASA, heat so intense that light could not penetrate it.
The Bible says that in the beginning the earth was formless and empty – just gasses, everything vaporized.
There was darkness over the face of the deep – light could not penetrate the extreme heat, and the earth was a deep mass of swirling vapor.
The spirit of God was hovering over the waters (as steam began condensing) – God was giving special attention to planet earth because he planned to do something special here.
If the big bang is the beginning of nature, then some intelligence outside of nature, and above nature, had to trigger the big bang, to start everything out of nothing, and to establish those predetermined laws of nuclear energy, physics and chemistry that enabled it happen with orderly precision.
Apparently billions of years passed between Genesis 1:2 and Genesis 1:3, as the earth cooled, became liquid, and eventually developed a solid crust.
Then God started shaping the earth and putting life on it. In the first stage of transformation, light starts glowing through the cloud cover, the basic energy for all life. The stages are summarized in Genesis 1:3 through Genesis 2:3 [see 1.2].
The compiler/writer of Genesis (generally thought to be Moses) could not have had this scientific insight more than three thousand years ago without some special revelation from God.
Genesis 1 and the scientific community are now in essential agreement about the beginning of our physical world, the world of atoms.
Genesis 2 is another matter [see 1.5], outside the realm of science, because it's about creation of the non-physical parts, the parts that distinguish humans from animals ... our greatly enhanced soul (mind, will and emotion) ... our moral character ... and our connection to God.